D2065 3 13 172 SERIES (1977 THRU 1986) Cessna_172_1977 1986_MM_D2065 Cessna 1977 1986 MM

User Manual: Cessna_172_1977-1986_MM_D2065-3-13

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Cessna
ATextron
Company
Service
Manual
1977
Thru
1986
MODEL
172
SERIES
Member
of
GAMA
FAA
APPROVAL HAS
BEEN
OBTAINED
ON
TECHNICAL
DATA
IN
THIS
PUBLICATION
THAT
AFFECTS
AIRPLANE
TYPE
DESIGN.
THIS
REPRINT
CONSISTS
OF
THE
BASIC
MANUAL,
DATED
20
MARCH
1985,
AND
INCORPORATES
REVISION
2,
DATED
1
MAY
1992.
AND
REVISION
3,
DATED
1
JULY
1995.
COPYRIGHT
1995
CESSNA
AIRCRAFT
COMPANY
20
MARCH
1985
WICHITA,
KANSAS.
USA
D2065-3-13
REVISION
3
1
JULY
1995
(RGI-200-10/00)
TEMPORARY
REVISION
NUMBER
5
DATED
7
January
2000
MANUAL
TITLE
MODEL
172
SERIES
1977
THRU
1986
SERVICE
MANUAL
MANUAL
NUMBER
-
PAPER
COPY D2065-3-13
AEROFICHE
D2065-3-13AF
TEMPORARY
REVISION NUMBER
PAPER
COPY
D2065-3TR5
AEROFICHE
N/A
MANUAL
DATE
20
MARCH
1985 REVISION
NUMBER
3
DATE
1
JULY
1995
This Temporary
Revision
consists
of the
following pages, which
affect
existing
pages
in
the
paper
copy manual
and
supersede
aerofiche information.
AEROFICHE
AEROFICHE
SECTION
PAGE
FICHE/FRAME
SECTION
PAGE
FICHE/FRAME
18
6A
Added
18
6B
Added
REASON
FOR
TEMPORARY
REVISION
To
provide
additional
information
for
the
stop
drilling
of
cracks
that
originate
at
the
trailing
edge
of
control
surfaces with
corrugated
skins.
FILING
INSTRUCTIONS
FOR
THIS
TEMPORARY
REVISION
For
Paper
Publications:
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cover
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behind
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publication's
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identify
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COPYRIGHT
©
2000
CESSNA AIRCRAFT
COMPANY
WICHITA,
KANSAS,
USA
TEMPORARY
REVISION
NUMBER
4
DATED
16
FEBUARY
1996
MANUAL
TITLE
MODEL
172
SERIES
1977
THRU
1986 SERVICE
MANUAL
MANUAL
NUMBER
-
PAPER
COPY D2065-3-13
AEROFICHE
D2065-3-13AF
TEMPORARY REVISION NUMBER -
PAPER
COPY
D2065-3TR4-13 AEROFICHE
N/A
MANUAL
DATE 20
MARCH
1985
REVISION
NUMBER
3
DATE
1
JULY
1995
This
Temporary
Revision
consists
of
the
following
pages,
which
affect
and
replace
existing pages
in
the
paper
cc-
manual and
supersede aerofiche
information.
CHAPTER/
CHAPTER/
SECTION/
AEROFICHE SECTION/
AEROFICHE
SUBJECT
PAGE FICHE/FRAME
SUBJECT
PAGE
FICHE/FRAME
11
11-11 2B19
11-15
2B23
REASON
FOR
TEMPORARY
REVISION
To
change
torque
values
for
engine mount-to-fuselage
bolts.
FILING
INSTRUCTIONS
FOR
THIS
TEMPORARY
REVISION
For
Paper
Publications:
File
this
cover
sheet
behind
the
publication's
title
page
to
identify
inclusion
of
the
temporary
revision
in
the
manual. Insert
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For
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draw
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Line
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notebook
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COPYRIGHT
1.996
CESSNA
AIRCRAFT
COMPANY
WICHITA,
KANSAS,
USA
MODEL
172
SERIES SERVICE
MANUAL
LIST
OF
EFFECTIVE
PAGES
INSERT
LATEST
REVISED
PAGES.
DESTROY
SUPERSEDED
PAGES.
NOTE
The
portion
of
the
text affected
by
the revision
is
indicated
by
a
vertical
line
in
the
outer margins of
the
page.
Changes to
illustrations
are
indicated
by
miniature
pointing
hands.
Original
0
20
March
1985
Revision
1
20
October
1985
Revision
2
1
May
1992
Revision
3
1
July
1995
TOTAL
NUMBER
OF
PAGES
IN
THIS
PUBLICATION
IS
652.
*The
asterisk
indicates
pages
changed,
added,
or
deleted
by
the
current
change
Page
Revision
Page
Revision
No.
No.
No.
No.
*Title
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thru
iv
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.....
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.....
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.....
.
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thru
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thru
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thru
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2
3-2
8
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thru
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......
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thru
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5-3
thru
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.................. 0
2-51
thru 2-54
. ................
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thru
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thru
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.................. 0
2-78
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...................
2
5-20A
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thru
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5
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thru
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............. 1
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thru
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.. .................. 1
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thru
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0
5-41
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3-12A
thru 3-12F
...............
0
*5-42
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3-13 thru
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............ 1
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thru 3-17
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A
Revision
3
MODEL
172
SERIES SERVICE
MANUAL
LIST
OF
EFFECTIVE
PAGES
Page
Revision
Page
Revision
No. No. No.
No.
6-2
thru
6-7
. ..................
0
*12-17
..................... 3
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......
2
12-18
thru
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6-9 thru
6-12
..........
........
0
12-23
..................... 3
7-1
...
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.. 1
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thru
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thru
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...................
0
12-34
Blank
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13-1
1
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thru 7-12
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.. 1.................. ..
8-5
. ...................... .
8-
.....................
0
14-1
....................... 3
*8-7
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14-2
thru
14-6
................ 0
8-8
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0
*15-1
...................... 3
9-1
........................ 1
15-2
thru
15-20
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9-2
thru
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0
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thru
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............ 0
10-1
......................... 1
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..................... 1
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thru
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................
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thru
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....... 3
11-2A
..1
15-23
thru
15-26
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11-2B
Blank
................... 1*
15-2
thru
51-2
....................
*11-15
3
15-29
thru
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.............. 0
11-36
................... ....
16-1
thru
................
1
11-37
thru
11-38
.............. 0-thru
16-6
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11-1
thru
11A-2......................
1-
.
.
....
0
11-13
thru
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0
1-
Blank
................. 0
*11-16
....................... 16-7
thru
16-40
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11-18
thru
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.............. 01-3 ................
11A-20
thru
11A-2
............... 1
16-B6A
tak
................ 0
11-3
thru
11A-
1 ..............
0
16-41
thru
16-50
.............. 0
11A-1
......................
3.
12-2
............. ..
0
*16-51
............... 3
*12-3
.
.3
16-52
thru
16-54
.. 0
11A-41
....................... 016
12-4A
0
.............................. 0
16-55
thru
16-60
................
11A-18
thru
11A-19
.............
0.
... . . ...
12-4B
Blank.0
16-60A
................ 0
11A-20
Blank
.................. 016-0
.....................
B
B a n k
0
12-.1
1
16-41
thru
16-50
.............. 0
12-21
........................
3
12-4
........................ 016-5
thru
16-54
.............. 0
12-4
........................ 016-55
thru
16-72
............
0
12-
.0...
16-
thru
16-1 .............. 0
12-
7 . . ...... . . . . .. ..........
0
16-72A
........ . . . . ...... . . . 0
*12-8
........................
3
16-72B
Blank
............ 0
12-9 thru
12-16
................
16-73
thru
16-75
. ..... ...... 0
Revision
3
B
MODEL
172
SERIES
SERVICE
MANUAL
LIST
OF
EFFECTIVE
PAGES
Page
Revision
Page
Revision
No.
No.
No.
No.
16-76
.......
........
.... 1
20-58A
thru 20-58B
............ 1
18-1
thru
18-2
................ 1
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thru
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thru
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.............. 0
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. ............. 0
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......................
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20-62B
Blank
................ 0
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thru
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...................... 1
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thru
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. ......... 0
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thru
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................
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thru
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................ 1
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Blank
. ........... 1
20-4
thru
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20-67
thru
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2
0
-5
8
...................... 1
Upon
receipt
of
a
revision
to
this
book,
personnel
responsible
for
maintaining
this
publication
in
current
status
should
ascertain
that
all
previous
revisions
havebeen
received
and
incorporated.
C
Revision
3
MODEL 172
SERIES
SERVICE
MANUAL
TABLE
OF
CONTENTS
SECTION
PAGE
NO.
AEROFICHE/MANUAL
1.
GENERAL
DESCRIPTION
.....................
.........
1A9/1-1
2.
GROUND
HANDLING,
SERVICING,
CLEANING,
LUBRICATION AND
INSPECTION
......................
1B11/2-1
3.
FUSELAGE
............................................
1F9/3-1
4.
WINGS
AND
EMPENNAGE
.............................
1H5/4-1
5.
LANDING GEAR
AND
BRAKES .........................
111/5-1
5.
AILERON
CONTROL
SYSTEM
..........................
1K5/6-1
7.
WING
FLAP
CONTROL SYSTEM
........................
1K21/7-1
8.
ELEVATOR
CONTROL SYSTEM
........................
1L13/8-1
9.
ELEVATOR
TRIM
TAB
CONTROL
SYSTEM
.............
2A3/9-1
10.
RUDDER CONTROL
SYSTEM
..........................
2A17/10-1
11.
ENGINE
(MODEL O-320-H2AD)
.........................
2B7/11-1
11A.
ENGINE
(MODEL O-320-D2J
AND
MODEL
O-360-A4N)
....................................
2D3/11A-1
12.
FUEL
SYSTEM .........................................
2E3/12-1
13.
PROPELLERS
AND
PROPELLER
GOVERNORS
..........
2F19/13-1
14.
SYSTEMS
..............................................
2G3/14-1
15.
INSTRUMENTS AND
INSTRUMENT
SYSTEMS
..........
2G13/15-1
16.
ELECTRICAL
SYSTEMS
......................
.........
217/16-1
17.
ELECTRICAL
SYSTEMS (DELETED)
18.
STRUCTURAL
REPAIR
.................................
3A3/18-1
19.
PAINTING
.............................................
3C3/19-1
20.
WIRING
DIAGRAMS
...................................
3C171/20-1
WARNING
When
performing
any
inspection
or
maintenance
that
requires
turning
on
the
master
switch,
installing
a
battery,
or
pulling
the
propeller
through
by
hand,
treat
the
propeller
as
if
the
ignition
switch
were
ON.
Do
not
stand,
nor
allow
anyone
else
to
stand,
within
the
arc
of
the
propeller,
since
a
loose
or
broken
wire,
or
a
component
malfunction,
could
cause
the
propeller
to
rotate.
Revision3
i
MODEL
172
SERIES
SERVICE
MANUAL
CROSS
REFERENCE
LISTING
OF POPULAR
NAME
VS.
MODEL
NUMBERS AND
SERIALS
All
aircraft,
regardless
of
manufacturer,
are
certified
under
model
number
designations.
However,
popular
names
are
often
used
for
marketing
purposes.
To
provide
a
consistent
method
of
referring
to
these aircraft,
the
model
number
will
be
used
in
this
publication
unless
the
popular
name
is
necessary
to
differentiate
between
versions
of
the
same
basic
model.
The
following
table provides
a
listing
of
popular
name,
model
number
and
serial
number.
MODEL SERIAL
POPULAR
NAME
YEAR
MODEL
BEGINNING ENDING
SKYHAWK,SKYHAWK
II
1977
172N
17261445,17267585
17069309
1978
172N
17261578,17269310
17271034
(except
17270050)
1979
172N
17271035
17272884
1980
172N
17270050,17272885
17274009
1981
172P
17274010 17275034
1982
172P
17275035
17275759
1983
172P
17275760
17276079
1984 172P
17276080 17276259
1985
172P
17276260
17276516
1986
172P
17276517
17276654
REIMS/CESSNA
F172
1977
F172N
F17201515 F17201639
SKYHAWK,
SKYHAWK
II
1978
F172N
F17201640 F17201749
1979
F172N
F17201750
F17201909
1980
F172N
F17201910
F17202039
1981
F172P
F17202040
F17202134
1982
F172P
F17202135
F17202194
1983
F172P
F17202195
F17202216
1984
F172P
F17202217 F17202233
1985
F172P
F17202234 F17202238
1986
F172P
F17202239
F17202254
CUTLASS,
CUTLASS
II
1983
172Q
17275869 17276054
1984
172Q
17276101 17276211
1985
172Q
NONE
ii
Revision
3
MODEL 172
SERIES
SERVICE
MANUAL
INTRODUCTION
This manual
contains
factory-recommended
procedures
and instructions
for
ground
handling,
servicing,
and
maintaining
Cessna
172
Series
airplanes.
Besides
serving
as
a reference
for the
experienced
mechanic,
this
manual
also
covers
step-by-step procedures
for
the
less experienced.
If
properly
used,
it
will
better enable
the
mechanic
to
maintain
Cessna
172
Series
airplanes
and
thereby
establish
a
reputation
for
reliable
service.
This
service
manual
is
designed
for
aerofiche
presentation.
To
facilitate
the
use
of
the
aerofiche,
refer
to
the
aerofiche
header
for
basic
information.
KEEPING
CESSNA PUBLICATIONS
CURRENT
The
information
in
this
publication
is
based
on
data
available
at
the
time
of
publication
and
is
updated, supple-
mented,
and
automatically
amended
by
all
information
issued in
Service
News
Letters,
Service
Bulletins,
Sup-
plier
Service
Notices,
Publication
Changes, Revisions, Reissues
and
Temporary
Revisions. All
such
amendments
become
part
of
and
are
specifically
incorporated
within
this
publication.
Users
are
urged
to
keep
abreast
of
the
latest
amendments
to
this
publication
through
information available
at
Cessna
Authorized
Service
Stations
or
through
the
Cessna
Product
Support
subscription
services. Cessna
Service
Stations
have
also
been
supplied
with
a
group
of
supplier
publications
which provide
disassembly,
overhaul,
and
parts
breakdowns
for
some
of
the
var-
ious supplier
equipment
items.
Suppliers
publications
are
updated,
supplemented,
and
specifically
amended
by
supplier
issued revisions
and
service
information
which
may
be
reissued
by
Cessna;
thereby
automatically
amending
this
publication
and
is
communicated
to
the
field
through Cessna's
Authorized
Service
Stations
and/or through
Cessna's
subscription
services.
WARNING:
ALL
INSPECTION
INTERVALS, REPLACEMENT TIME
LIMITS,
OVERHAUL TIME
LIMITS,
THE
METHOD
OF
INSPECTION,
LIFE
LIMITS,
CYCLE
LIMITS,
ETC.,
REC-
OMMENDED
BY
CESSNA
ARE
SOLELY
BASED
ON
THE
USE
OF
NEW,
REMANU-
FACTURED, OR
OVERHAULED
CESSNA
APPROVED
PARTS.
IF
PARTS
ARE
DE-
SIGNED,
MANUFACTURED,
REMANUFACTURED,
OVERHAULED,
PURCHASED,
AND/OR
APPROVED
BY
ENTITIES
OTHER
THAN
CESSNA,
THEN
THE
DATA
IN
CESSNA'S
MAINTENANCE/SERVICE
MANUALS
AND
PARTS
CATALOGS
ARE
NO
LONGER
APPLICABLE
AND
THE
PURCHASER
IS
WARNED NOT
TO
RELY
ON
SUCH
DATA
FOR
NON-CESSNA
PARTS.
ALL
INSPECTION
INTERVALS,
RE-
PLACEMENT
TIME LIMITS, OVERHAUL
TIME
LIMITS, THE
METHOD
OF
INSPEC-
TION,
LIFE
LIMITS,
CYCLE
LIMITS,
ETC.,
FOR
SUCH
NON-CESSNA
PARTS
MUST
BE OBTAINED FROM
THE
MANUFACTURER
AND/OR
SELLER
OF
SUCH
NON-
CESSNA
PARTS.
1.
REVISIONS/CHANGES.
These are
issued
to
the
dealers
by
Cessna
Aircraft
Company
for
this
publi-
cation
as required,
and
include
only
pages
that
require
updating.
2.
REISSUE.
Manual
is
reissued
to
dealers
as
required,
and
is
a
complete
manual incorporating
all
the
latest
information
and
outstanding
revisions/changes.
It
supersedes
and
replaces previous
issue(s).
REVISIONS/CHANGES
and
REISSUES
can
be
purchased
from
your
Cessna
Dealer
or
directly
from
the
Cessna
Parts
Distribution,
(CPD
2)
Dept.
701,
Cessna
Aircraft
Company,
5800
East
Pawnee,
Wichita,
Kansas
67201.
All
supplemental
service
information
concerning
this
manual
is
supplied
to
all
appropriate
Cessna
Dealers
so
that
they
have
the
latest
authoritative
recommendations
for
servicing
these Cessna aircraft.
Therefore,
it
is
rec-
ommended
that
Cessna owners
utilize
the
knowledge and experience
of
the factory-trained
Dealer
Service
Or-
ganization.
Revision
3
iii
MODEL
172
SERIES
SERVICE
MANUAL
CUSTOMER
CARE
SUPPLIES
AND
PUBLICATIONS
CATALOG
A
Customer
Care Supplies
and
Publications
Catalog
is
available
from
your
Cessna
Dealer
or
directly
from
the
Cessna
Parts
Distribution,
(CPD
2),
Dept.
701,
Cessna
Aircraft
Company,
5800
East
Pawnee,
Wichita,
Kansas
67201.
The
Supplies and
Publications catalog lists
all publications
and
Customer
Care
Supplies
available
from
Cessna
for
prior
year
models
as
well
as
new products.
SUPPLEMENTAL
TYPE CERTIFICATE
INSTALLATIONS
Inspection,
maintenance
and
parts requirements
for
supplemental
type certificate
(STC)
installations
are
not
in-
cluded
in
this manual.
When
an
STC
installation
is
incorporated
on
the
airplane,
those
portions
of
the
airplane
affected
by
the
installation
must
be
inspected
in
accordance
with the inspection
program
published
by
the owner
of
the
STC.
Since
STC
installations
may
change systems
interface,
operating
characteristics
and
component
loads
or
stresses
on
adjacent
structures,
Cessna
provided
inspection
criteria
may
not
be
valid
for
airplanes
with
STC
installations.
CUSTOMER
COMMENTS
ON
MANUAL
Cessna
Aircraft
Company
has
endeavored
to
furnish
you
with
an
accurate,
useful,
up-to-date
manual.
This
man-
ual
can
be
improved
with
your
help.
Please
use
the
return
card,
provided
with
your
manual,
to
report
any
errors,
discrepancies,
and
omissions
in
this
manual
as
well
as any comments
you
wish
to
make.
iv
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
1
GENERAL
DESCRIPTION
Page
No
Page
No
TABLE
OF
CONTENTS Aerofiche/Manual Aerofiche/Manual
GENERAL DESCRIPTION
.....
1A9/1-1
Safetying
Procedures
........
1A18/1-10
Model
172
Series
...............
1A9/1-1
Safety
Wire
Procedures
......
LA19/1-11
Description
.................
1A9/1-1
Use
of
Cotter
Pins
...........
1A23/1-15
Aircraft
Specifications
.......
1A9/1-1
Use of
Locking
Cips
..........
1B1/1-17
Stations
....................
1A9/1-1
Use
of
Lockwashers
..........
1B3/1-19
General
Airframe
Practices
.....
1A14/1-6
Use
of
Self-Locking
Nuts
.....
1B3/1-19
Torqueing
Procedures
...........
1A14/1-6
Control
Cable
Wire
Breakage
Calculating
Torque
..........
1A14/1-6
and
Corrosion
Limitations
..
1B411-20
Torque
Values
-
Bolts
........
1A14/1-6
Adhesives
Cements
and
Sealants-
Torque
Values
-
Fittings
.....
1A17/1-9
Shelf
Life
and
Storage
......
1B6/1-22
1-1.
GENERAL
DESCRIPTION.
1-2.
MODEL
172
SERIES.
1-3.
DESCRIPTION.
Cessna
Model
172
aircraft,
described
in
this
manual,
are
high-wing
mono-
planes
of
all-metal,
semimonocoque
construction.
These
aircraft
are
equipped
with
a
fixed
tricycle
landing gear with
tubular
spring-steel main
gear
struts.
The
steerable
nose
gear
is
equipped
with
an
air/hydraulic
fluid
shock
strut.
Four-place
seating
is
standard, and
a
double-width,
fold-up
auxiliary
rear
seat
may
be
installed
as
optional
equipment.
All
are
powered by four-cylinder, horizontally-opposed,
air-cooled
Lycoming
"Blue
Streak"
en-
gines. The engines
drive
an
all-metal,
fixed-pitch
propeller.
Model
172
Series
aircraft
fea-
ture
rear
side
windows,
a
"wrap-around"
rear
window
and
a
swept-back fin
and
rudder.
1-4.
AIRCRAFT
SPECIFICATIONS.
Leading
particulars
of
these
aircraft,
with
dimensions
based
an
gross
weight,
are
given
in
figure
1-1.
If
these
dimensions
are
used
for
constructing
a
hangar
or computing
clearances,
remember
that
such
factors
as
nose
gear
strut
inflation,
tire
pressure,
tire
sizes
and
load
distribution
may
result
in
some
dimensions
that
are
con-
siderably
different
from
those
listed.
1-5.
STATIONS.
Station diagrams
are
shown
in
figure
1-2
to
assist
in
locating
equipment
when
a
written
description
is
inadequate
or
impractical.
Revision
3
1-1
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
These
specifications
are
applicable to
Model
172
and
F172
Series
airplanes
and
Model
172Q
airplanes,
except
as
in-
dicated.
GROSS
WEIGHT
(Takeoff
and
Landing)
172
and
F172
Landplane
(1977
thru
1980)
....................
2300
Lbs.
172
and
F172
Landplane
(1981
&
On)
......................
2400
Lbs.
172
and
F172
Floatplane
................................
2200
Lbs.
172Q
Model
Only
......................................
2550
Lbs.
FUEL
CAPACITY
Standard
Wing
(Total)
...................................
43
Gal.
Standard
Wing (Usable)
.................................
40
Gal.
Long-Range
Wing
(Total)
...............................
.
54 Gal.
Long-Range
Wing
(Usable)
...............................
50 Gal.
Wet
Wing
(Total)
BEGINNING 1981
MODEL
YEAR
.............
68
Gal.
Wet
Wing
(Usable)
BEGINNING
1981
MODEL
YEAR
............
62 Gal.
OIL
CAPACITY
(Without
External
Filter)
THRU
1980
MODEL
YEAR
............
6
Quarts
(With
External
Filter)
THRU
1980
MODEL
YEAR
.............
7
Quarts
(Without
External
Filter)
BEGINNING 1981
MODEL
YEAR
.......
7
Quarts
(With
External
Filter)
BEGINNING
1981
MODEL
YEAR
..........
8
Quarts
ENGINE
MODEL
172
and
F172
Series
(Refer
to
Section
11
for
Engine
Data)
........
LYCOMING
0-320
Series
172Q
Model
Only
(Refer
to
Section
11A
for
Engine
Data)
.........
LYCOMING
0-360
Series
PROPELLER
(Fixed
Pitch)
(172
and
F172
Series)
................
75"
McCAULEY
PROPELLER
(Fixed
Pitch)
(Model
172Q
Only)
..................
76"
McCAULEY
MAIN
WHEEL
TIRES
(172
and
F172
Series)
....................
6.00
x
6,
4-Ply
Pressure
THRU
1980
MODEL
YEAR
........................
29
Psi
Pressure
BEGINNING
1981
MODEL
YEAR
...................
28
Psi
MAIN
WHEEL
TIRES
(Model
172Q
Only)
......................
6.00
x
6,6-Ply
Pressure
.............................................
38
Psi
NOSE
WHEEL
TIRE
(172
and
F172
Series)
TIRE
THRU
1980
MODEL YEAR
...........................
5.00
x
5,
4-Ply
Pressure
............................................
31
Psi
BEGINNING
1981
MODEL YEAR
..........................
5.00
x
5,
6-Ply
Pressure
...........................................
34
Psi
NOSE
WHEEL
TIRE
(Model
172Q
Only)
.......................
5.00
x
5,
6-Ply
Pressure
...........................................
45
Psi
NOSE
GEAR
STRUT
PRESSURE
(Strut
Extended)
................
45
Psi
WHEEL ALIGNMENT
(Tubular
Spring
Struts)
Cam
ber
.............................................. 2°
to
4°
Toe-in
...............................................
0"
to
.18"
(Tubular
Gear
is
non-adjustable)
AILERON
TRAVEL
Up
.. ..............................................
20
°±
1°
Down
...................................... ......
15
°
±1°
No
provisions
are
made
for
aligning
wheels
on
tubular
gear aircraft.
The
tolerances provided are
to
be
used
only
for
checking
existing
wheel
alignment.
Figure
1-1.
Aircraft
Specifications
(Sheet
1
of
2)
1-2
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
WING
FLAP
TRAVEL (172
and
F172
Series)
Landplane
THRU
1980
MODEL
YEAR
.......................
0°
to
40
°, +0 °- 2°
BEGINNING
1981
MODEL
YEAR
.......................... 0°
to
30
°, + 0°- 2°
WING
FLAP
TRAVEL
(Model
172Q
Only)
...................... 0 °
to
30
°,
+0°-
2°
RUDDER
TRAVEL
(Measured
Parallel
to Water
Line)
Right
...............................................
16
°
10'
1°
Left
.................................................
16
°
10'
±
1°
RUDDER
TRAVEL
(Measured
Perpendicular
to Hinge
Line)
Right
...............................................
17°
44'
±1
°
Left
................................................. 17°
44'
±
1°
ELEVATOR
TRAVEL
Up
......... . .................................
28
°+
1°
-0°
Down
...............................................
23°
+ 1 °- 0°
ELEVATOR
TRIM
TAB
TRAVEL
Up
THRU
1980
MODEL
YEAR
..............................
28
°+
1°-
0°
Down
THRU
1980
MODEL
YEAR
........................... 13 °+ 1°- 0°
Up
BEGINNING
1981 MODEL
YEAR
(Landplane)
..............
22
°+
1°-
0°
Down
BEGINNING
1981
MODEL
YEAR
(Landplane)
............ 19°+ 1°-
0°
Up
BEGINNING
1981 MODEL
YEAR
(Floatplane)
..............
28
° +
1°-
0°
Down
BEGNNING
1981
MODEL
YEAR
(Floatplane)
............ 13°+
1°-
0°
PRINCIPAL
DIMENSIONS
Wing
Span
(Conical-Camber
With
Strobe
Lights)
(172
and
F172
Series)
..................................
433.00"
Wing Span
(With Strobe
Lights)
(Model
172Q
Only)
.............
432.00"
Tail
Span
(172
and
F172
Series)
............................
135.14"
Length
THRU
1980
MODEL
YEAR
.........................
323.00"
Length
BEGINNING
1981
MODEL
YEAR
.....................
323.04"
Tail
Span
(Model
172Q
Only)
..............................
136.00".
Fin
Height
(Maximum
With
Nose
Gear
Depressed
and
Flashing
Beacon
Installed
on
Fin)
(172
and
F172
Series)
.........
104.00"
Fin
Height
(Maximum
With
Nose
Gear Depressed
and
Flashing
Beacon
Installed
on
Fin)
(Model
172Q
Only)
...........
107.00"
Track
Width
(172
and
F172 Series)
.........................
100.36"
Track
Width
(Model
172Q
Only)
...........................
100.50"
BATTERY
LOCATION
....................................
Firewall
*
Neutral
position
measured
with the
bottom
of
the
balance
area
flush
with
the
bottom
of
the
stabilizer.
Figure
1-1.
Aircraft
Specifications
(Sheet
2
of
2)
Revision
1
1-3
MODEL
172
SERIES
SERVICE
MANUAL
23.
62
NOTE
172.
00
190.
00
208. 00
56.70
Figure
1-2.
Reference Stations
(Sheet
1 of
2)
1-4
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Wet
wing
option
beginning
with
1981
model
year
22.
875
39.00
85.875
100.50
23.65
Figure
1-2.
Reference
Stations
(Sheet
2
of
2)
Revision
1
1-5
Revision
1
1-
5
MODEL
172
SERIES
SERVICE
MANUAL
1-6.
GENERAL
AIRFRAME PRACTICES.
the
following
paragraphs
deal
with
general torque
and
safetying
practices
used
to
ensure
security
of
installation
and
prevent
overstressing
of
com-
ponents.
Special
torque
values, when
required,
are
specified
with
the
specific
component
maintenance
and
installation
instructions.
1-7.
TORQUEING
PROCEDURES.
The
importance
of
correct application
cannot
be
overem-
phasized.
Undertorque
can
result
in
unnecessary
wear
of
nuts
and
bolts
as
well
as
parts
they
are
holding
together.
When
insufficient
pressures
are
applied,
uneven
loads
will
be
transmitted
throughout
assembly,
which
may
result
in
excessive
wear
or premature
failure
due
to
fatigue.
Overtorque
can
be
equally
damaging
because
of
failure
of
a
bolt
or
nut
from
overstressing
threaded
areas.
a.
Calculating
Torque.
There
are
a
few
simple,
but
very
important,
procedures
that
should
be
followed
to
assure
that
correct
torque-is
applied:
1.
Calibrate
torque
wrench
periodically
to
assure
accuracy;
and
recheck
frequently.
2.
When
using
a
torque
wrench
adapter
which
changes
distance
from
torque
wrench
drive
to
adapter
drive,
the
indicated
reading
must
be
adjusted
for
desired
torque reading.
(See
Figure
20-1.)
3.
Be
sure
that
bolt
and
nut
threads
are
clean
and
dry
unless
otherwise
specified.
4.
Determine
friction
drag
torque and
add
to
specified
dry
torque
value
to
ensure
proper
bolt
utilization.
(a)
Hand-turn
nut
onto
bolt
until
it
stops.
(b)
Using
a
torque wrench,
measure
running
torque
(torque
required
to
turn nut
on
bolt).
(c)
This
running
torque
must
be
added
to
specified
dry
torque
value to
ensure
proper
bolt
utilization.
EXAMPLE
Average
running
torque
for
a
nut
=
15
in.-lbs.
Dry
torque
required
=
125
±5
in.-lbs.
Final
torque wrench
reading
=
140
±5
in.-lbs.
(d)
Since
running
torque
will
become
less
due
to
nut/bolt
re-use
(in
accepted
ap-
plications),
this
procedure
must
be
repeated
each
time.
(e)
When
necessary
to
tighten
from
bolt
head,
increase
torque
value
by
an
amount
equal
to
shank
torque
(torque
required
to
turn
bolt
when installed).
Measure
with
a
torque
wrench.
EXAMPLE
Average
running
torque
for
a
nut
=
15
in.-lbs.
Average
running
shank
torque
for
installed
bolt
=
10
in.-lbs.
Dry
torque
required
=
125
±5
in.-lbs.
Final
torque
wrench
reading
=
150
±5
in.-lbs.
b.
Torque
Values
-
Bolts
and
Nuts.
(See
Table
1-1.)
1.
Tables
included
in
this
section
do
not
apply
to
the
following
exceptions:
(a)
Sheet
metal
screws
should
be
tightened firmly, but
with
no
specific
torque
value.
(b)
Screws
attached
to
nutplates
should
be
tightened
firmly,
but
with
no
specific
torque
value.
(c)
Bolts,
nuts,
and
screws
used
in
control
systems and
installations
where
re-
quired
torque
would
cause
binding or interfere
with
proper
operation
of
parts.
(d)
Screws
used
with
dimpled
washers
should
not
be
drawn
tight
enough
to elim-
inate
washer
crown.
(e)
Fasteners
that
have
a
specified
torque
in a
specific
installation.
1-6
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
When
using
a
torque
wrench
adapter
which
changes
the
distance
from
torque
wrench
drive
to
adapter
drive,
apply
following
formula
to obtain
corrected
torque
reading.
SHORT
OPEN
END
FORMULA
LEGEND
ADAPTER
T
=
Desired
Torque
T
x
L
=
Y
Y
=
Indicated Torque
L
=
Effective
Length
Lever
L
+ E E
=
Effective
Length
of
Extension
WRENCH
HANDGRIP
SETSCREW
DRIVE
CENTERLINE
ADAPTER
CENTERLINE
(PREDETERMINED)
ADAPTER
TORQUE
DRIVE
WRENCH
CENTERLINE
HOSE
CLAMP
ADAPTER
EXAMPLE
T
=
135
In.-Lbs
y
=
135
x 10
=
1350
=
117.39
Y
=
Unknown
L
=
10.0
In.-Lbs
10
+
1.5
11.5
L
=
10.0
In.-Lbs
E
=
1.5
In.
Y
=
117
In.-Lbs
OPEN-END
WRENCH
ADAPTER HANDGRIP
ADAPTER
DRIVE
CENTERLINE
CENTERLINE
(PREDETERMINED)
WRENCH
TORQUE
DRIVE
WRENCH
CENTERLINE
FLARE
NUT
WRENCH
ADAPTER
EXAMPLE
T
=
135
In.-Lbs
=
135
x
10
1350
158.82
SPANNER
WRENCH
Y =
Unknown
ADAPTER
L
=
10.0
In.-Lbs
10
-
1.5
8.5
E
=
-1.5
In.
Y
= 159
In.-Lbs
Figure
1-3.
Torque
Wrench
Adapter Adjustment
Revision
1
1-7
MODEL
172
SERIES
SERVICE
MANUAL
BOLT
TORQUE
VALUES
Tension
Shear
Tension
I
Shear
BOLTS
BOLTS
AN3
thru
AN20
MS20004
thru
MS20024
NAS464
AN42
thru
AN49
NOTE:
Bolts
in
tension
NAS144
thru
NAS148
AN73
thru
AN81
column
may
be
used
NAS172
AN173
thru
AN186
with
shear
nuts.
Bolts
NAS174
AN509NK9
in
shear
column
NAS333
thru
NAS340
AN525NK525
should not
be
used
un-
NAS585
thru
NAS590
MS20033
thru
MS20046
less
a
minimum of
two
NAS624
thru
NAS644
MS20073
threads extend
beyond
NAS1303
thru
NAS1320
MS20074
nut after
installation.
NAS517
MS24694
MS27039
NUTS
NUTS
AN310 AN320 AN310
AN320
AN315 AN364 AN315
AN364
AN363 MS20364
NA363
NAS1022
AN365
NAS1022
AN365
MS20364
MS20365
MS20365
MS20500
MS21045
MS21045
NAS679
NAS679
NAS1021
NAS1021
291
FINE
THREAD
SERIES
FINE
THREAD
SERIES
Nut-bolt
Nut-bolt
size
Torque
Limits
Torque
Limits
Torque
Limits
Torqu
Limits
size
in.-lbs.
in.-lbs.
in.-bs.
in.-lbs.
MIN.
MAX.
MIN.
MAX.
MIN.
I
MAX.
MIN.
I
MAX.
8-36
12 15
7 9
10-32
25
30
15
20
10
32
20
25
12
15
14-28
80
00
50
60
1
4-28
50
70
30 40
5
16-24
120
145 70
90
5
16-24
100 140
60
85
38-24
200
250
120
150
38-24
160
190
95
110
716-20
520
630
300
400
716-20
450
500
270 300
1
2-20
770
950
450
550
1
2-20 480
690
290
410
916-18
1100
1300
650
800
916-18
800
1000
480
600
58-18
1250
1550
750
950
58-18
1100 1300
660
780
34-16
2650
3200
1600
1900
34-16
2300
2500
1300
1500
78-14
3550
4350
2100
2600
7
8-14
2500
3000
1500
1800
1-14
4500
5500
2700
3300
1-14
3700 4500
2200 3300
1-1
8-12
6000
7300
3600
4400
1-1
8-12
5000
7000
3000 4200
1-1
4-12
11000
13400
6600
8000
1-1
4-12
9000
11000
5400 6600
COURSE
THREAD
SERIES
MS17825
MS17826
Nut-bolt
Nut-bolt
Torque
Limits
Torque
Limits
Torque
Limits
Torque
Limits
in.-lbs. in.-lbs.
in.-bs.
in.-lbs.
MIN.
MAMINM
.
I
MAX.
MIN.
I
MAX.
MIN.
MAX.
8-32
12 15
7 9
10-32
28
35
16
20
10-24
20
25
12 15
14-28
65
80
35
45
14-20
40
50 25 30
5
16-24
180
225
70
90
5
16-18
80
90
48
55
3,8-24 260
325
100
125
38-16
160
185
95
110
716-20
460
575
180
225
716-14
235
255
140
155
12-20
720
900
240
300
12-13
400
480
240
290
9.16-18
880
1100
320
400
9
16-12
500
700
300
420
5.8-18
1300
1600
480
600
58-11
700
900 420
540
3/4-16
2200
2800
880
1100
3.4-10
1150
1600
700
950
78-14
3700
4600
1500
1900
78-9
2200
3000
1300
1800
1-14
5400
6800
2400
3000
1-8
3700
5000
2200 3000
1-1
8-12
8000
10000
4000
5000
1-1
8-8
5500 6500 3300
4000
1-1
4-12
11000
14000
5600
7000
1-1
4-8
6500
8000 4000
5000
Table
1-1.
Torque
Values
-
Bolts
and
Nuts
1-8
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
2.
The
values
shown
in
Table
1-1
are
based
on
parts
being
clean
and dry
with
no
lu-
bricants
added.
3.
Castellated
nuts
requiring
cotter
pins
should
be
tightened
to
low
torque
value.
Torque can
be
increased
to
install
cotter pin,
but
should
never
exceed
maximum
torque
value.
NOTE
Self-locking
castellated
nuts,
MS17825
and
MS17826,
re-
quire
a
separate
torque
range.
These
values
are
shown
separately
in
torque
value
tables.
c.
Torque
Value
-
Threaded
Straight
Fittings.
NOTE
Tables
in
this
section
are
for
general
applications.
Refer
to
specific
installations
for
special
torque
values
and
pro-
cedures.
1.
Connectors
installed
in
bosses
with
no
required
orientation should
be
installed
using
torque
values given
in
Table
1-2.
2.
Connectors
installed
in
bosses
requiring
a
specific
orientation
do
not
use
a
torque
value,
but
use
the
following
steps:
(a)
Place
jam-nut
on
fitting
along with
retainer
and
packing.
(b)
Turn
nut
down
until
packing
is
firmly
against
lower
threaded
section
of
fit-
ting.
(c)
Install
fitting
into
boss
and
tighten
until
there
is
a
sudden
increase
in
torque.
(d)
Tighten
fitting
1-1/2
turns.
(e)
Orientation
is
accomplished
by
tightening
fitting,
but
not
exceeding
one
turn.
(f)
Tighten
jam-nut
to
torque
values
in
Table
1-2.
THREADED
CONNECTOR TORQUE
VALUE
-
HOSE
ASSEMBLIES
TUBE
JAM-NUT
CONNECTOR
Nipple
or
Nut
OUTSIDE
THREAD
w/
PACKING
HOSE
ALUMINUM
STEEL
INSIDE
DIAMETER
w/o
JAM-NUT
DIAMETER
Torque-Limits
Torque-Limits
(Inches)
Torque-Limits
Torque-Limits
in.-lbs.
in.-lbs
(in.-lbs.)
(in.-lbs.)
(in.-lbs.)
MAX.
MIN.
MAX.
MIN.
MAX. MIN.
MAX.
18
20
30
75
85
1/8
516-24
35
50 50 55
3.16
25 35
95
105
3'16
3/8-24
65 80 65
75
14
50 65
135
150
1/4
7/16-20
85
105
95
105
516
70 90
170
200
5'16
1/2-20
105 125 125
135
38
110
130
270
300
38
916-18
120
150 155 165
12
230 260 450
500
12
34-16
240
280
280
305
58
330 360 650
700
58
77-14
320 380 380 405
34
460 500
900
1000
34
116-12
500 600 550
600
1
500
700
1200
1400
1
1-516-12
720 880 800
900
1-14
800
900
1520
1680
1-14
1-5
8-12
960
1200
900 1000
1-1
2
800
900
1900
2100
1-12
1-7
8-12
1200
1440
900
1000
1-3
4
---
2
2-1
2-12
1400
1500
900
1000
2
1800
2000 2660
2940
Table
1-2.
Torque
Values
Table
1-3.
Torque
Values
Jam-Nuts
and
Threaded
Connector
Hose
Assemblies
Revision
1
1-9
MODEL
172
SERIES
SERVICE
MANUAL
THREADED
STRAIGHT
FITTING TORQUE
VALUE
(RIGID
TUBE)
FLARED
END
STRAIGHT
END
TUBE
ALUMINUM
ALUMINUM
STEEL
6061-0
ALUMINUM
STEEL
6061-T(X)
ALUMINUM
OUTSIDE
On
Oxygen
Lines
5052-0
ALUMINUM
w/
steel
sleeve
DIAMETER
Torque-Limits
Torque-Limits Torque-Limits Torque-Limits
Torque-Limits
Torque-Limits
in-lbs.
in-lbs.
in-lbs.
in-lbs.
in-lbs.
in-lbs.
MIN.
MAX.
MIN. MAX. MIN. MAX.
MIN.
MAX. MIN.
I
MAX.
TUBE
WALL
MIN. MAX.
1 8
20
30
45
55
316
90
100
30
40
90
100
0.028
45
55
14
40
65
135 150 40
65
135
150-
0.022 -80
105
0.028 80
105
0.035 80
105
0.049 90
115
516
60 80 100
125
180
200
60 80
180
200
0.028
80
105
0.035 80
105
0.042
125
175
38
75
125
270
300
75
125
270
300
0.028 125
175
0.035
125
175
0.049
125
175
12
150
250
450
500
150
250 450
500
0.028
135
180
0.035
200 300
0.049 400 500
0.058
400
500
0.065 400
500
58
200
350
700 800
200
350
700 800
All
500
600
34
300
500 1100
1150
300 500
1100
1150
All
600
700
1
500
700
1200
1400
500
700
1200
1400
All
1000 1300
1-1
4
600
900
1300
1450
600
900
1300 1450
All
1300
1500
1-1
2
600
900
1350
1500
600
900
1350 1500
All
1400
1700
2
600
900
1500
1700
Table
1-4.
Torque
Values
-
Straight
Threaded
Fittings
(Line)
3.
Bulkhead
fittings
are
installed
with
jam-nuts and
should
be
torqued
to
values
in
Table
1-2.
4.
Torque
values
for hose
end
fittings
(nipple
or
nut)
are
given
in
Table
1-3.
5.
Torque values
for
straight
threaded
fittings
used
with
rigid
lines are
given
in
Table
1-4.
1-8.
SAFETYING
PROCEDURES.
The
use
of
safety
wire,
cotter
pins,
lockwashers,
and
self-lock-
ing
nuts
is
to
prevent
relative
movement
of
critical
components
subject
to
vibration,
torque,
tension,
etc.,
which
could
cause
attaching
parts
to
be
broken,
loosened,
and/or
detached.
1-10
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
1-9.
SAFETY
WIRE PROCEDURES.
a.
Identification.
Lockwire
comes
in
three
types
which
are
identified
by size
and
color.
The
three
types
are
classified
by
use.
1.
Inconel
and
Monel
wire
is
used
for
general
lockwiring
and
is
identified
by
a
natu-
ral
wire
color.
(a)
Inconel
can withstand
temperatures
up
to
1500°F.
(b)
Monel
can
withstand
temperatures up
to
800°F.
2.
Copper
that
is
cadium-plated
and
dyed yellow
is
used
for
shear
and seal
wiring
applications.
(a)
Shear
applications
are
those
where
it is
necessary
to
break
or
shear
wire
to
permit
operation
or
actuation
of
emergency
devices.
(b)
Seal
applications
are
where
wire
is
used
with
a
lead
seal
to
prevent
tampering
or
use
of
a
device
without
indication.
3.
Aluminum
Alloy
(Alclad
5056)
is
dyed
blue
and
is
used
exclusively
for
safety-wir-
ing
magnesium
parts.
4. Size
of
wire
is
dependent
on
material and
purpose
of
installation.
(a)
0.020-inch
diameter copper
wire
should
be
used
for
shear
and
seal
applica-
tion.
(b)
0.020-inch
diameter
wire
may
be
used
to
lockwire
parts
with
tie
holes
smaller
than
0.045
inches;
or,
on
parts
with
tie
hole
diameters
between
0.045
and
0.062
when
spacing
between
ports
is
less
than
two
inches; or, when
bolts
and
screws
of
0.25-inch
diameter
or
less
are
closely
spaced.
(c)
0.032-inch minimum
diameter
wire
is
used
for
general
purpose lockwiring.
NOTE
When
using
single-wire
method
of
locking,
the
largest
wire
that
will
fit tie
holes
should
be
used.
b.
Lockwire
Installation.
There
are
two
basic
forms
of
lockwiring.
The
single-wire
method
has
limited
application;
the
double-twist
method
is
the
common
method
of
lockwiring.
1.
Use
new
wire
for
each
application;
do
not
try
to
re-use
old
wire.
2.
Single-wire
method
is
accomplished
by
passing
a
single
wire
through
tie
holes
and
back
with
ends
then
twisted
together.
(See
Figure
1-4.)
(a)
Single-wire method
is
used for
shear and
seal
wiring
applications.
(b)
Single-wire
method
can
be
used
in
closely
spaced,
closed
geometric
patterns.
Closely
spaced
is
defined
as
spacing
two
inches
or
less
between
centers
of
parts.
CAUTION
Screws
in
closely
spaced
geometric
patterns
which
secure
hydraulic
or
air
seals,
hold
hydraulic
pressure, or
are
used
in
critical
areas
should
use
double-twist
method
of
lockwiring.
3.
Lockwiring
by
the
double-twist method is
really
one
wire
twisted
on
itself
several
times
and
is
accomplished
by
the
following
steps
(see
Figure
1-4).
(a)
Insert
one
end
of
wire
through
tie
holes
of
bolt
head
and
firmly
loop
around
bolt
head.
NOTE
This
does
not
necessarily
apply
to
castellated
nuts
when
slot
is
close
to top
of
nut.
The
wire
will
be
more
secure
if
it is
made
to
pass along
side
of
stud.
Revision
1
1-11
MODEL
172
SERIES
SERVICE
MANUAL
FOR
LEFT-HAND
THREADS.
SINGLE
FASTENER
APPLICATION
CASTELLATED
NUTS
ON
DRILLED
STUDS
DOUBLE-TWIST
METHOD
DOUBLE-TWIST
METHOD
Figure
1-4.
Lockwire
Safetying
(Sheet
1
of
2)
1-12
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
DOUBLE-TWIST METHOD
STEP
1.
Insert
wire
through
bolt
A
and
bend
BOLT
A
around
bolt
(if
necessary,
bend
wire
across
bolt
head).
Twist
wires
clockwise
until
they
reach
bolt
B.
STEP
2.
Insert
one
end
of
wire
through
bolt
B.
Bend
other
end
around
bolt
(if
necessary,
bend
wire
across
head
of
bolt).
Twist
wires
counterclockwise
1/2
inch
or
six
twists.
Clip
ends.
Bend
pigtail
back
againt
part.
BOLT
B
CLOCKWISE
DOUBLE-TWIST
METHOD
COUNTERCLOCKWISE
CLOCKWISE
COUNTERCLOCKWISE
CLOCKWISE
MULTIPLE
FASTENER
APPLICATION
ELECTRICAL
CONNECTION
DOUBLE-TWIST
METHOD
Figure
1-4.
Lockwire
Safetying
(Sheet
2
of
2)
Revision
1
1-13
MODEL
172
SERIES
SERVICE
MANUAL
(b)
While
taut,
twist
strands
to
within
1/8
inch
of
next
part.
The
twisting
keeps
wire
taut
without
overstressing
and
prevents
wire
from
becoming
nicked,
kinked,
or
mutilated.
(c)
Lockwiring
multiple
groups
by double-twist
method
is
accomplished
in a
similar
manner
except
twists
between
parts
are alternated
between
clockwise
and
counterclockwise.
(d)
After
last
tie
hole,
wire
is
twisted
three
to
five
times
to
form
a
pigtail.
(e)
Cut
off
any excess
wire
and
bend
pigtail
towards
part.
4.
When
lockwiring
widely
spaced
multiple
groups
by double-twist method,
three
units
shall
be
the
maximum
number
in a
series.
NOTE
Widely
spaced
multiple
groups
shall
mean
those
in
which
fasteners
are
from
four
to
six
inches
apart.
Lockwiring
shall
not
be
used
to
secure
fasteners
or
fittings
which
are
spaced
more
than
six
inches
apart,
unless
tie
points
are
provided on
adjacent
parts
to
shorten
span
of
lockwire
to
less
than
six
inches.
5.
When
lockwiring
closely
spaced
multiple
groups,
the
number
of
units that
can
be
lockwired
by
a
24-inch
length
of
wire
shall
be
the
maximum
number
in a
series.
6.
Parts
should
be
lockwired
so
that
wire
is
placed
in
tension
(pulled
on)
if a
part
at-
tempts
to loosen.
c.
Required
Lockwire
Installation
Applications.
1.
Bolts
and other
fasteners
securing
critical
parts
that
affect
airplane
safety
and
operation.
(a)
In
blind-tapped
hole
applications
or
bolts
or
castellated
nuts
on
studs.
lockwiring
is
installed
in
same
manner
as
described
for
bolt heads.
(b)
Hollow
head bolts
are
safetied
in
manner
prescribed
for
regular
bolts.
(c)
Drain
plugs and
cocks may
be
safetied to
a
bolt,
nut,
or
other
part
having
a
free
tie
hole
in
accordance
with
instructions
described.
(d)
External
snap
rings
may
be
locked
if
necessary
using
general
locking
princi-
ples
as
described
and illustrated.
Internal
snap
rings
should
not
be
lockwired.
(e)
When
locking
is
required
on
electrical
connectors
which
use threaded
cou-
pling
rings,
or
on
plugs
which
employ
screws
or
rings
to
fasten
individual
parts
of
plug
together,
they
shall
be
lockwired
with
0.020-inch diameter
wire
in
accordance
with
locking principles
as
described
and
illustrated.
It is
prefer-
able
to
lockwire
all
electrical
connectors
individually.
Do
not
lockwire
one
connector
to
another
unless
it is
necessary to
do
so.
(f)
Drilled
head bolts
and
screws
need
not
be
lockwired
if
installed
into
self-lock-
ing
nuts
or
installed
with
lockwashers.
Castellated
nuts
with cotter
pins
or
lockwire
are
preferred
on bolts
or
studs
with
drilled
shanks,
but
self-locking
nuts
are
permissible
within limitations
described
in
Paragraph
1-13.
2.
For
new
design,
lockwire
shall
not
be
used
to
secure
nor
shall
lockwire
be
depen-
dent upon
fracture
as
basis
for
operation
of emergency
devices
such
as handles,
switches,
and
guard-covering
handles
that
operate
emergency
mechanisms
such
as
emergency
exits,
fire
extingushers,
emergency cabin
pressure
release,
emergency
landing
gear
release,
and
the
like.
However,
where
existing
structural
equipment or
safety
of
flight
emergency
devices
requires
shear
wire
to
secure
equipment
while
not
in
use,
but
which
are
dependent
upon
shearing
or
breaking
of
lockwire
for
successful
emergency operation
of
equipment,
particular
care
exercised
to
assure
that
wiring under
these
circumstances
shall
not prevent
emergency
operations
of
these
devices.
1-14
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
1-10.
USE OF COTTER
PINS.
a.
Cotter
Pin
Installation.
Castellated
nuts
and
pins
may
be
safetied
with cotter
pins
or
lockwire.
The
preferred
method
is
to
use
cotter
pins.
1.
Select
cotter
pin
material
in
accordance
with
temperature,
atmosphere, and
service
limitations
(see
Table
1-5).
2.
Cotter
pins
shall
be
new
upon
each
application.
3.
When
nuts
are
to
be
secured
to
fastener
with cotter
pins,
tighten
nut
to
low
side
(minimum)
of
applicable
specified
or
selected
torque
range,
unless
otherwise
specified, and
if
necessary,
continue
tightening
until
slot
aligns
with
hole.
In
no
case
shall
you
exceed
high
side
(maximum)
torque
range.
4.
If
more
than
50
percent
of
cotter
pin
diameter
is
above
nut
castellation,
a
washer
should
be
used
under
nut
or
a
shorter
fastener
should
be
used.
A
maximum
of
two
washers
may
be
permitted
under
a
nut.
5.
The
largest
diameter
cotter
pin which
hole
and
slots
will
accommodate
should
be
used,
but
in
no
application
to a
nut,
bolt,
or
screw
shall
pin
size
be
less
than
sizes
described
in
Table
1-6.
6.
Install
cotter
pin
with head
firmly
in
slot
of
nut
with
axis
of
eye
at
right
angles
to
bolt
shank.
Bend
prongs
so
that
head
and
upper
prong
are
firmly
seated
against
bolt
(see
figure
1-5).
7.
In
pin
applications, install cotter
pin
with
axis
of
eye
parallel
to
shank
of clevis
pin
or
rod
end.
Bend
prongs
around
shank
of
pin
or
rod
end
(see
Figure
1-5).
CAUTION
Cadium-plated
cotter
pins
should
not
be
used
in
applica-
tions
bringing
them
in
contact
with
fuel,
hydraulic
fluid,
or
synthetic
lubricants.
COTTER
PIN
-
MINIMUM
SIZE
THREAD
SIZE
MINIMUM
PIN
SIZE
COTTER
PINS
(MS24665)
0.028
MATERIAL TEMPERATURE
USE
8
0.044
Carbon
Steel
Up
to
450°F
Pins
that
contact
cadmium-
10
0.044
plated
surfaces.
14
0.044
516
0.044
General
Applications
3
8
0.072
12
0.072
7 16
0.072
Normal
Atmospheres
12
0.086
9
16
0.086
Corrosion-Resistant
Up
to
800°F
Pins
that
contact
cor-
58
0.086
rosion-resistant
steel.
3 4
0.086
7 8
0.086
Corrosive
atmospheres
1
0.086
1-18
0.116
1-1
4
0.116
1-38
0.116
1-12
0.116
Table
1-5.
Cotter
Pin
Table
1-6.
Cotter
Pin
Temperature
and
Use
Minimum
Size
Revision
1
1-15
MODEL
172
SERIES
SERVICE
MANUAL
TO
PROVIDE
CLEARANCE
PRONG
MAY
BE
CUT
HERE
PREFERRED
METHOD
ALTERNATE
METHOD
CASTELLATED
NUT
ON
BOLT
TANGENT
TO
PIN
MAXIMUM MINIMUM
COTTER
PIN COTTER
PIN
LENGTH
LENGTH
PIN
APPLICATION
Figure
1-5.
Installation
of
Cotter
Pins
1-16
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
1-11.
USE
OF
LOCKING
CLIPS.
a. afetying
Turnbuckles.
(ee
Figure
1-6.)
1.
Prior
to
safetying,
both
threaded
terminals
shall
be
screwed
an
equal
distance
into
turnbuckle
body
and shall
be
screwed
in
at
least
so
far
that
not more
than
three
threads
of
any
terminal
are
exposed
outside
body.
2.
After
turnbuckle
has
been
adjusted
to
its
locking
position,
with
slot
indicator
groove
on
terminals
and
slot
indicator
notch
on
body
aligned,
insert
end
of lock-
ing
clip
into terminal
and
body
(refer
to
Figure
1-6)
until
U-curved
end
of
locking
clip
is
over
hole
in
center
of
body.
(a)
Press locking
clip
into
hold
to
its
full
extent.
(b)
Curved
end
of
locking
clip
will
expand
and
latch
in
body
slot.
(c)
To
check
proper
seating
of
locking
clip,
attempt
to
remove
pressed
"U"
end
from
body
hole
with
fingers
only.
NOTE
Do
not
use
tool
as
locking
clip
could
be
distorted.
3.
Locking clips
are
for
one
time use
only
and
shall not
be
re-used.
4.
Both
locking
clips may
be
inserted
in
same hole
of
turnbuckle
body
or
in
opposite
holes
of
turnbuckle
body.
Revision
1
1-17
MODEL
172
SERIES
SERVICE
MANUAL
LOCKING
CLIP
BARREL
Detail
A
Figure
1-6.
Safetying Turnbuckle
Assemblies
Revision
1
1-12.
USE
OF
LOCKWASHERS.
a.
Lockwashers
can
be
used
only
under
the
following
conditions.
1.
When
self-locking
feature
cannot
be
provided
in
externally
or
internally
threaded
part.
2.
When
a
cotter
pin
cannot
be
used
to
prevent
rotation
of
internal
threads
with
re-
spect
to
external
threads.
3.
When
lookwire
cannot
be
used
to
prevent
loosening
of
threaded
parts.
4.
When
fastening
is
not
used
for
fabrication
of
primary
structure.
5.
When
loosening
of
threaded
parts
would
not
endanger
safety
of
airplane
or
people.
6.
When
corrosion encouraged
by
gouging
aluminum
or
magnesium
alloys
by
edges
of
teeth
on
tooth-locked
washers
would
not
cause
malfunctioning
of
parts
being
fastened
together.
1-13.
USE
OF
SELF-LOCKING
NUTS.
a.
Restrictions.
1.
Self-locking
nuts
cannot
be
used
under
certain
conditions.
(a)
Used.
reworked, or
reprocessed
nuts
should
not
be
installed
for
any
applica-
tion.
(b)
Do
not
use
if
at
joints
in
control
systems
for
singular
attach
points.
(c)
Do
not
use
on
externally
threaded
parts
that serve
as
an
axle
of
rotation
for
another
part
where
tensional
(torque)
loads
can
cause
nut
to
loosen
and/or
be-
come
separated.
Examples
are
pulleys,
levers,
linkages,
and
cam
followers.
NOTE
Self-locking
nuts
can
be
used
when
threaded
parts
are
held
by
a
positive
locking
device
that
requires
shearing
or
rupture
before
torsional
loads
can
act
on
threaded
parts.
(d)
Do
not
use where
a
loose
nut,
bolt,
or
screw
could
fall
or
be
drawn
into
an
area
that
would
impede
or
damage
or
otherwise
distort
operation.
(e)
Do
not
use
to
attach
access
panels
and
doors
or
to
assemble components
that
are
routinely
disassembled
or
removed
for
access
and
servicing.
(f)
In
general,
do
not
use
self-locking
nuts
where
loss
of
bolt
affects
safety
of
flight.
2.
Bolts,
studs,
or
screws,
excluding
Hi-Locks,
must
extend
through
self-locking
nut
for
a
length
equivalent
of
two
threaded
pitches.
This
length
includes
chamfer.
3.
Self-locking
nuts
which
are
attached
to
structure
shall
be
attached
in a
positive
manner
to
eliminate
possibility
of
their
rotation
or
misalignment
when
tighten-
ing
is
to
be
accomplished
by
rotating
bolts
to
structure,
and permit
replacement
of
nuts.
Revision
2
1-19
MODEL
172
SERIES
SERVICE
MANUAL
1-14.
CONTROL
CABLE
WIRE
BREAKAGE
AND
CORROSION
LIMITATIONS.
a.
Inspection
of
Control Cables.
1.
Control
cable
assemblies
are
subject
to
a
variety
of
environmental
conditions
and
forms
of
deterioration
that
ultimately
may
be
easy
to
recognize
such
as
wire/strand
breakage, or
the
not
so
readily visible
types
ofdeterioration
including
corrosion
and/or
distortion.
Thefollowing
information
will
aid
in
detecting
these
cable conditions.
2.
Broken
Wire.
(a)
Examine cables
for
broken
wires
by
passing
a
cloth along
length
of
cable.
This
will
detect
broken
wires,
if
cloth
snags
on
cable.
Critical
areas
for
wire
breakage
are
those
sections
of
cable
which
pass
through fairleads,
across
rob
blocks,
and
around
pulleys.If
no
snags
are
found,
then
no
further
inspection
is
required.
If
snags
are
found
or
broken
wires
are
suspected,
then
a
more
detailed
inspection
is
necessary
which
requires
that
the
cables
be
bent
in
a
loop
to
confirm broken
wires (refer
to
figure
1-7).
Loosen
or
remove
cable
to
allow
it
to
be
bent
in
a
loop
as
shown.
While
rotating
cable,
inspect
bent
area
for
broken
wires.
(b)
Wire
breakage
criteria
for
cables in flap,
aileron, rudder,
and
elevator
systems
are
as
follows:
(1)
Individual
broken wires
are
acceptable in
primary
and
secondary
control
cables
at
random
locations
when
there
are
no
more
than
six
broken
wires
in
any
given
ten-inch
cable
length.
3.
Corrosion.
(a)
Carefully
examine
any
cable for
corrosion
that
has
a
broken
wire
in
a
section
not
in
contact
with
wear-producing
airframe
components
such
as
pulleys,
fairleads,
rub
blocks,
etc.
It
may
be
necessary
to
remove
and
bend
cable
to
properly
inspect
it
for
internal
strand
corrosion
as
this
condition
is
usually
not
evident
on
outer surface
of
cable.
Replace
cable
if
internal
corrosion
is found.
If
a
cable
has
been
wiped
clean
of
its
corrosion-preventive
lubricant
and
metal-brightened,
the
cable
shall
be
examined
closely
for
corrosion.
For
description
of
control
cable
corrosion,
refer
to
Chapter
18,
Corrosion
and
Corrosion
Control.
1-20
Revision
2
MODEL 172
SERIES
SERVICE
MANUAL
BROKEN
WIRE
UNDETECTED
BY
WIPING
CLOTH
ALONG
CABLE
BROKEN
WIRE
DETECTED
VISUALLY
WHEN
CABLE
WAS
REMOVED
AND
BENT
NORMAL
TECHNIQUE
FOR
BENDING
CABLE
AND
CHECKING
FOR
BROKEN
WIRES
00
NOT
BEND
INTO
LOOP
SMALLER
THAN
50
CABLE
DIAMETERS
55611119
Figure
1-7.
Cable
Broken
Wire
Inspection
Revision
2
1-21
MODEL
172 SERIES
SERVICE
MANUAL
1-15.
ADHESIVES,
CEMENTS
AND
SEALANTS
-
SHELF
LIFE
AND
STORAGE.
a.
General.
1.
This
section
provides
information
which
defines
the proper
storage
and usable
life
(shelf
life)
of
adhesives,
cements and
sealents
which
are
used
for
maintenance and/or
repair
of
the
airplane.
Also
included
in
this
section
is
the
criteria
used
for
testing
these
materials
after
the
normal
shelf
life
has expired,
to
determine
if
an
extension
to
the
shelf
life
is possible.
2.
Shelf
life
refers
to
a
specified period
of
time
usually
from
the
date of
manufacture
(normally
stamped
or
printed
on
the
product
container
)
to
the expiration date
(which
should
be
determined
using
limits
specified
in
Table
1-7
or
if
applicable,
the
manufacturer's
expiration
date
printed
or
stamped
on
the
product
container).
The
specified
shelf
life
is
dependent
on
proper
storage
in
accordance
with
the
limits
specified
in
this
section
and/or the
manufacturer's
instructions.
b.
Storage
Criteria.
1.
Storage
of
Adhesives
and
Cements.
All
adhesives and
cements
shall
be
stored
under
controlled
temperature
conditions.
.
If
open
shop
storage
becomes
necessary,
these
products
shall
in
no
case
be
stored
in
an
area
which
will
subject
them
to
temperatures
in
excess
of
95°F.
Containers
shall
be
tightly
closed
prior
to
being
placing
them
into
the
proper
storage
environment.
For
proper storage
environment,
refer
to
Table
1-7
and the-following
paragraphs.
(a)
Class
I -
These adhesives
are
epoxy
base
materials
and
have
one
year
storage
at
room
temperature.
0°F
storage
will extend
the storage
life.
Refer
to
the
product
container
instructions
for
storage
temperature
and
life.
(b)
Class
II,
III
and
IV
-
These
adhesives
are
rubber
and resin
base
and
are
good
for six
months
at
room
temperature
storage.
40°F
storage
will
extend
the
storage
life.
Refer
to
the
product
container
instructions
for
limits
of
each adhesive.
(c)
Class
V
-
These
are
silicone
rubber
adhesives.
If
stored
in
their
original containers
at
a
temperature
below
80°F,
have
a
shelf
life
of
one
year
or
as
indicated
on
the
storage
container.
(d)
Class
VI
-
These
are
solvent
bonding
solvents.
They
should
be
stored
in
their
original
containers
and
tightly
closed,
and stored
at
40°F
temperature.
(e)
ClassVII
-
Cyanoacrylate
base
materials
must
be
stored
in
the
original containers
at
40°F
or
as
specified
on
the
container
instructions.
(f)
Class
VIII
-
These
are
pressure sensitive
materials.
The
shelf
life
is
two
years
when
stored
at
75°F
and
50
percent
relative
humidity.
(g)
Class
IX
-
These
are
polyurethane
products.
Store
in
original
container,
between
70
and
100°F.
Urethanes
are moisture
sensitive
and
precautions should
be
taken
to
ensure
complete protection
from
moisture
contamination.
Container
must
be
tightly
closed
at
all
times.
(h)
Class
X
-
These
are
acrylic
base
materials.
They
require
storage
at
40°F
or
per
instructions
on
product
container.
c
Storage
of
Sealants.
1.
All
sealants
shall
be
stored
under
controlled
temperature
conditions.
If
open shop
storage
becomes
necessary,
these
products
shall
in
no
case
be
stored
in
an
area
which will
subject
them
to
temperatures
in
excess
of
95°F
or
below
40°F.
Containers
shall
be
tightly
closed
prior
to
placing
them
in
the proper
storage environment.
For proper
storage
environment,
refer
to
Table
1-7
and
the
following
paragraphs.
(a)
Premixed
and
frozen
sealants
shall
bestored
at
-40°F
or
colder
and shall
not be
used
more
than
six weeks
after
the
date
of
mixing
even
if
all
storage
is
at
-40°F
or colder.
If
storage
temperatures
rise above
40°F,
but
not
warmer
than
-30°F,
the
material
may
be
stored
for
a maximum
of
two
weeks
warmer
than
-40°F
plus
time
at
-40°F
or
colder
for
a
combined
total
not
to
exceed
five
weeks beyond
the
date
of
mixing. If
storage
temperatures
rise
above
-40°F
but are
not
warmer
than
-20°F,
the
materials
may
be
stored
for a
maximum
of one
week
above
-30°F
plus
time
at
-40°F
or
colder
for
a
combined
total
not
to exceed
four
weeks
beyond
the
date
of
mixing.
(b)
Unmixed
sealants
shall
be
stored
at
a
controlled
temperature
of
between
40
and
80°F
and
have
a
shelf
life of
approximately
six
months
when
stored
within
this
temperature
range.
Unmixed
sealants
stored
at
temperatures
exceeding
80°F
shall
be
used
within
five
weeks.
2.
All
materials
should
be
used
on
a
"first
in-first
out"
basis.
The
adhesives,
cements
and
sealants
should
be
rotated
so
this
requirement
can
be
accomplished.
All
material containers
should
be
clearly
marked
with
a
"use
by"
date,
consisting
of
the
year
and
month.
All
materials
not
used
by
this
date
must
be
tested prior
to
use.
Refer
to
Testing
criteria
and Table
1-7.
d.
Testing
Criteria.
1.
Any
material
(adhesive,
cement or
sealant)not
used
within its
shelf
life
will
be
tested
and the
results
reviewed
to
determine
if
the
material
is
usable.
If there
is
doubt
about
the
material
being
usable,
it must
be
properly
disposed
of.
Material
that
has
exceeded
its
original
shelf
life
may
be
retested
to
determine
if
the
material
meets
its
requirements.
Materials
meeting
their
requirements
will
have
their
shelf
life
extended
as
specified
in
Table
1-7.
Materials
with
shelf
life
extensions must
be
retested
after
a
specified
period of
time.
Refer
to
Table
1-7.
1-22
Revision
2
MODEL 172
SERIES
SERVICE
MANUAL
2.
Testing
of Overaged
Adhesives
and
Cements.
NOTE
Overaged
adhesives
and cements
are
those
that
have
exceeded
their
original shelf
life
and
must
be
tested
prior
to
use
and/or
given
extended
shelf
life.
(a)
Class
I
Epoxy
Adhesive
-
Examine
bothcomponents
to
ensure
that
they
are still
workable.
Check
for
gelling
and/or
contamination.
Stir
components
and
mix
a small
amount
of
adhesive.
Verify
that
adhesive
sets
up
and
hardens.
(b)
Class
II,
III
and
IV
Rubber
and
Resin
Base
Adhesives
-
Open
containers
and
check
for
gelling
and/or
contamination.
Check
for
spreading
and
drying.
(c)
Class
V
Silicone Rubber
Adhesives
-
Examine adhesive
for
hardness.
If
adhesive
is
still
soft
and
can
be
spread,
it
is
acceptable.
Verify
that
adhesive
will
harden.
(d)
Class
VI
Solvent
Bonding
Solvents
-
Check
for
signs
of
apparent
contamination.
Solvents
should
be
clean
and
clear with
no
signs
of
cloudiness.
(e)
Class
VII
Cyanoacrylic Base Adhesives
-
Verify
that
product
is
still
liquid
with
no
visible signs
of
contamination.
(f)
Class
VII
Pressure
Sensitive
Materials
-
Open
containers
and
inspect
for
hardening,
gelling
and
contamination.
Stir
components
and
mix
a
small
amount
of
adhesive.
Verify
that
adhesive
sets
up
properly.
(g)
Class
X
Acrylic
Adhesives
-
Inspect base
material
to
ensure
that
it
is
still
liquid.
Mix
a
small
amount
of
the
components and
verify
that
it
sets
up
properly.
3.
In
general,
if
these
materials
exhibit
normal
physical
properties,
with
no
signs
of
hardening,
gelling
or
contamination
and
set
up
and/or
harden
properly
as
applicable,
the
shelf
life
may
be
extended
as
specified
in
Table
1-7.
e.
Testing
of
Overaged
Sealants.
NOTE
Overaged
sealants
are
those
that
have
exceeded
their
original
shelf
life
and
must
be
tested
prior
to
use
and/or
given
extended
shelf
life.
1.
For identification
of
sealants
Classification,
refer
to
Fuel,
Weather,
Pressure
and
High-
Temperature
Sealing
-
Maintenance
Practices.
2.
Overaged
sealants
to
be
tested
for
possible
shelf
life
extension
shall
be
properly
mixed
using
the
correct
materials,
procedures
and equipment.
3.
Overaged premixed
frozen
sealants,
along
with unmixed
sealants
should
be
visually
inspected.
Sealants
whic
show
conclusive evidence
of
separation,
discoloration
and/or gelling
prior
to
the
addition
of
a
thinner
or
curing
agent
shall
be
discarded. When
in
doubt
of
the
sealant
quality,
the overaged
sealant
should
be
compared
with
the
same
type
of
sealant,
under
six
months
old,
which
is
known
to
be
satisfactory.
4.
The
mixed
sealants
may
be
tested
by
placing
a
small
amount
of
sealant
(smaple
buttons)
on
a
sheet
of
paper.
After
the
sample
buttons
have
cured,
they
should
be
cut in
half
and
examined.
The
sealant
should
show
no
signs of
spots
or
streaks
of
unmixed
base
compound
or
curing
agent.
However,
sample
buttons
containing
spots,
streaks,
discoloration
and/or
variations
in
uniformity
of
color
are
acceptable
if
these
spots,
streaks,
etc.,
are
tack
free
upon
inspection.
All
mixed
sealant
should
be as
void
free
as
possible.
5.
Contaminated
sealant,
premixed
sealant
that
have
been
thawed
and
refrozen
shall
be
discarded.
6.
Type
I,
Class
A
sealants
should
be
checked
for
appearance,
application
time,
tack-free time,
cure
time
and adhesion.
7.
Type
I,
Class
B
sealants
should
be
checked
for
appearance, applicatiion
time,
cure
time,
tack-
free
time
and
adhesion.
In
addition,
Class
B-2
and
B-4
sealants
should
be
checked
for
initial
flow.
8.
Type
I,
Class
C
sealants
should
be
checked
for
appearance,
application
time,
cure
time
and
adhesion.
In
addition, Class
C
sealants
should
be
tested
to
determine
that
they
ARE
NOT
at
a
tackfree
condition
at
the
end
of
their
rated
work
life
(squeeze
out
life).
9.
Type
II
sealants
should
be
checked
for
appearance,
application
time,
tack-free
time
and
cure
time.
10.
Type
III
sealants
should
be
easily
thinned
with
MEK,
when
difficulty
is
encountered
in
thinning
the
sealant,
it
should
be
discarded.
Revision
2
1-23
MODEL
172
SERIES
SERVICE
MANUAL
11.
Type
IV
sealants
should
be
checked
for
appearance,
application
time,
tack-free
time
and
cure
time.
12.
Type
V
and
VI
sealants
should
be
checked
for
appearance,
tack-free
time
and
cure
time.
13.
Type
VII
sealants
should
be
checked
for
appearance,
application
time,
tack-free
time
and
cure
time.
14.
Type
VIII
sealants
should
be
checked
for
appearance, application time,
tack-free
time,
cure
time
and
adhesion.
Adhesion
to
aluminum
should
be
(peel)
less
than
two-pounds,
per
inch
of
width.
1-24
Revision
2
MODEL 172
SERIES
SERVICE
MANUAL
STORAGE
CONDITION
EXTEND
PRODUCT
(TEMPERATURE
SHELF
LIFE
IN
DEGREES
IN MONTHS IN
MONTHS MONTHS
FAHENHEIT)
ADHESIVES
AND
CEMENTS
EA9309.3NA
40
TO
80°F
12
Months
6
Months
6
Months
EA9339
40 TO
80°F
12
Months
6
Months
6
Months
EA9314
40
TO
80°F
12
Months
6
Months
6
Months
EA9330
40
TO
80°F
12
Months
6
Months
6
Months
EA907
40
TO
80°F
12
Months
6
Months
6
Months
Devcon
F
40
TO
80°F
12
Months
6
Months
6
Months
EA934NA
40 TO
80°F
12
Months
6
Months
6
Months
380/6
40
TO
80°F
12
Months
6
Months
6
Months
A1186B
40
TO
80°F
12
Months
6
Months
6
Months
EC2216
40
TO
80°F
12
Months
6
Months
6
Months
#10
Fastset
40
TO
80°F
12
Months
6
Months
6
Months
608
Quickset
40 TO
80°F
12
Months
6
Months
6
Months
EC880
40
TO
80°F
8
Months
3
Months
3
Months
EC847
40
TO
80°F
8
Months
3
Months
3
Months
EC1300L
40
TO
80°F
*6
Months
*3
Months
*3
Months
5452
40
TO
80°F
12
Months
6
Months
6
Months
56431
40 TO
80°F
12
Months
6
Months
6
Months
1636
40
TO
80°F
12
Months
6
Months
6
Months
RTV
-
157
40TO
80°F
12
Months
6
Months
6
Months
RTV
- 158
40
TO
80°F
12
Months
6
Months
6
Months
RTV
-
159
40 TO
80°F
12
Months
6
Months
6
Months
RTV732
40
TO
80°F
12
Months
6
Months
6
Months
RTV102
40
TO
80°F
12
Months
6
Months
6
Months
RTV103
40
TO
80°F
12
Months
6
Months
6
Months
RTV106
40
TO
80°F
12
Months
6
Months
6
Months
RTV108
40 TO
80°F
12
Months
6
Months
6
Months
RTV109
40
TO
80°F
12
Months
6
Months
6
Months
RTV94034 40
TO
80°F
12
Months
6
Months
6
Months
Loctite
222
40
TO
80°F
12
Months
6
Months
6
Months
Loctite
242
40 TO
80°F
12
Months
6
Months
6
Months
Loctite
271
40
TO
80
°
F
12
Months
6
Months
6
Months
Loctite
277 40 TO
80°F
12
Months
6
Months
6
Months
Loctite
290
40 TO
80°F
12
Months
6
Months
6
Months
Loctite
416
40 TO
80°F
12
Months
6
Months
6
Months
Loctite
495 40 TO
80°F
12
Months
6
Months
6
Months
Loctite
515
40 TO
80°F
12
Months
6
Months
6
Months
Loctite
569
40 TO
80°F
12
Months
6
Months
6
Months
Loctite
592
40
TO
80°F
12
Months
6
Months
6
Months
Loctite
595
40 TO
80°F
12
Months
6
Months
6
Months
*
Do
not
use
after
three months
of
storage
in
the
81
°
F to
90°F
range
Do
not
use
after
five
days
of
storage
above
90°F.
Table
1-7.
(Sheet
1
of
2)
Revision
2
1-25
MODEL
172
SERIES
SERVICE
MANUAL
STORAGE
CONDITION
EXTEND
CONDITION
SHELF LIFE EXTEND RETEST
IN
PRODUCT
(TEMPERATURE
IN
MONTHS
SHELF
LIFE
MONTHS
IN
DEGREES
IN
MONTHS
FAHENHEIT)
ADHESIVES
AND
CEMENTS
(CONTINUED)
Loctite
601
40
TO
80°F
12
Months
6
Months
6
Months
Loctite
620 40 TO
80°F
12
Months
6
Months
6
Months
Loctite
680
40
TO
80°F
12
Months
6
Months
6
Months
Loctite
1282
40
TO
80°F
12
Months
6
Months
6
Months
Loctite
1283
40TO
80°F
12-Months
6Months
6
Months
DA-5521
40
TO
80°F
12
Months
6
Months
6
Months
PS-
18
40
TO
80°F
12
Months
6
Months
6
Months
PS-30 40
TO
80°F
12
Months
6
Months
6
Months
XA-3678 40
TO
80°F
12
Months
6
Months
6
Months
XF-3585
40 TO
80°F
12
Months
6
Months
6
Months
LR-100-226
40TO
80°F
12
Months
6
Months
6
Months
EC776
40
TO
80°F
*
8
Months
*
3
Months
*3
Months
SB
and
P2
40 TO
80°F
12
Months
6
Months
6
Months
SEALANTS
Pro-Seal
890 40
TO
80°F
6
Months
2
Months
2
Months
GC-408
40
TO
80°F
6
Months
2
Months
2
Months
PR1422
40TO
80°F
6
Months
2
Months
2
Months
PR1440
40
TO
80°F
6
Months
2
Months
2
Months
GC435 40
TO
80°F
6
Months
2
Months
2
Months
Pro-Seal
567
40
TO
80°F
6
Months
2
Months
2
Months
PR810 40
TO
80°F
6
Months
2
Months
2
Months
Pro-Seal
700
40 TO
80°F
6
Months
2
Months
2
Months
GC
1900
40
TO
80°F
6
Months
2
Months
2
Months
PR366
40
TO
80°F
6
Months
2
Months
2
Months
Pro-Seal
735
40 TO
80°F
6
Months
2
Months
2
Months
Pro-Seal
895 40
TO
80°F
6
Months
2
Months
2
Months
Pro-Seal
706B
40
TO
80°F
6
Months
2
Months
2
Months
PR1321
40
TO
80°F
6
Months
2
Months
2
Months
GC200
40
TO
80°F
6
Months
2
Months
2
Months
RTV-730
40
TO
80°F
6
Months
2
Months
2
Months
Pro-Seal
815 40
TO
80°F
6
Months
2
Months
2
Months
GC402 40
TO
80°F
6
Months
2
Months
2
Months
PR-1005L
40
TO
80°F
*8
Months
*3
Months
*3
Months
GC-3001
40
TO
80°F
*8
Months
*3
Months
*3
Months
444R
40
TO
80°F
*8
Months *3Months
*3
Months
*
Do
not
use
after three
months
of
storage
in
the
81°F to
90°F
range
Do
not use
after
five
days
of
storage
above
90°F.
Table
1-7.
(Sheet
2
of
2)
1-26
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
2
GROUND
HANDLING,
SERVICING,
CLEANING,
LUBRICATION
AND
INSPECTION
WARNING
When
performing
any
inspection
or
maintenance
that
re-
quires
turning
on
the
master
switch,
installing
a battery,
or pulling
the
propeller
through
by
hand, treat
the
prop-
eller
as
if
the
ignition
switch
were
ON.
Do
not
stand,
nor
allow
anyone
else
to
stand,
within the
arc
of
the
propel-
ler,
since
a
loose
or
broken
wire,
or
a
component
mal-
function,
could
cause
the
propeller
to
rotate.
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
GROUND
HANDLING
.........
1B14/2-4
Engine
Induction
Air
Filter
Towing
..................
1B14/2-4
(172
&
F172
Series
Only)
....
1C1
2-15
Hoisting
.................
1B14/2-4
Engine
Induction
Air
Filter
Jacking
...............
1B14/2-4
(172Q
Only)
.............
1C2
2-16
Leveling
.................
1B14/2-4
Vacuum
System
Filter
.......
1C2
2-16
Weighing
................
B14/2-4
Battery
..................
C2
2-16
Parking
.................
1B14/2-4
Tires
.................
1C3
2-17
Tie-Down
...............
1B14/2-4
Nose
Gear
Shock
Strut
.......
1C3
2-17
Flyable
Storage
............
1B15/2-5
Nose
Gear
Shimmy
Damper
..
1C3
2-17
Returning
Aircraft
to
Service
..
1B16.2-6
Hydraulic
Brake
System
. . .
1C4
2-18
Temporary
Storage
.........
1B16/2-6
CLEANING
......... ....
.C4
2-18
Inspection
During
Storage
..
1B18/2-8
Cleaning
and
Care
Returning
Aircraft to
of
Windshield
and
Windows
.
1C4
2-18
Service
................
1B18/2-8
Plastic
Trim
....
1C6
2-20
Indefinite
Storage
..........
1B18/2-8
Painted
Surfaces
...... . .
1C6
2-20
Inspection
During
Storage
....
1B20/2-10
Aluminum
Surfaces
.........
1C7
2-21
Returning
Aircraft
to
Service
..
1B20/2-10
Engine
Engine
Compartment
..
1C7
2-21
SERVICING
................
1B21/2-11
Upholstery
and
Interior
......
1C9
2-23
Fuel
....................
1B21/2-11
Propeller
......... .... .
1C10
2-24
Use
of
Fuel
Additives
for
Wheels
......... .......
1C10 2-24
Cold
Weather
Operation
.....
1B21/2-11 LUBRICATION
............
C10
2-24
Fuel
Drains
...............
1B22/2-12
Wheel
Bearings
............
1C10
2-24
Carburetor
Drain
Plug
Nose
Gear
Torque
Links
.....
1C10 2-24
Inspection
...............
1B22/2-13
Wing Flap
Acuator
.........
1C11
2-24
Engine
Oil
...............
B23/2-13
Fuel
Selector
Valve
.........
1C11
2-25
Engine
Oil
Additive
.........
1C1/2-15
Rod
End
Bearings
..........
1C11
2-25
INSPECTION
...............
1C21
2-35
Revision
1
2-1
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Use
tow
bar
carefully
to
avoid
scarring
finish
on
speed
fairing.
Figure
2-1.
Tow
Bar
REFER
TO
SHEET
2
FOR
JACKING
-
INFOR
MATION
NOTE
Corresponding
points
on
both
upper door
sills
may
be
used
to
level
the
aircraft
laterally.
Reference points
for longitudinal
leveling
of
aircraft
are
two
screws
on
left
side
of
tailcone
at
zero
waterline.
These
are
indicated
in
illustration
by
A
(Also
refer
to
paragraph
2-5)
Figure
2-2.
Jacking
and
Leveling
(Sheet
1
of
2)
2-2
MODEL
172
SERIES SERVICE
MANUAL
JACKING
INFORMATION
ITEM
NUMBER
TYPE
AND
NUMBER
REMARKS
1
Block
1x4x4
padded with
1/4"
rubber
2
#2-170
Basic
jack
(includes
#2-71
Min.
closed
height:
34"
Slide
tube:
Liftstroke
22-1/2")
Max.
extension
height:
56-1/2"
#2-70
Slide
tube:
Liftstroke
Min.
closed
height:
57-1/2"
22-1/2"
Max.
extension
height:
80"
#2-64
Extension
cap
Adds
4"
#2-109
Leg
extension
Adds
12"
3
Built-in
jack
pad
Part
of
step
bracket
(SEE CAUTION)
4
Cessna
#SE2-168
Tail
tie-down
stand
1.
Wing
jacks
are
placed under
front
spar
of
wing
just
outboard
of
wing
strut,
and
must
extend far
enough
to
raise
wheels
off
ground,
and
must
be
adequate
strength.
2.
Attach
a
Cessna
#SE2-168
stand
to
the
tie-down
ring.
Beure
tail
stand
weighs
enough
to keep
tail
down
and
under
all
conditions
that
it
is
stong
engough
to
sup-
port
any
weight
that
might
be
placed
on
it
(place
shot
bags
or sand
bags
on
tail
stand).
In
addition,
the
base of
adjustable
tail
stand
is
to
be
filled
with
concrete
for
additional
weight
as
a
safety
factor.
3.
Operate jacks
evenly
until
desired
height
is
reached.
CAUTION
When
using
built-in
jack
pad,
flexibility
of
the
gear
strut
will cause
the
main
wheel
to
slide
inboard
as
the
wheel
is
raised,
tilting
the
jack.
The
jack
must
be
lowered
for
a
second
operation
jacking
both
wheels
simultaneously
at
built-in
jack
pads
is
not
recommended.
jack pad
may
be
used
to
raise
only
one
main
wheel.
Do
not
USE
brake
casting
as
a
jack
point.
4.
Items
2
and
4
are
available
from
the
Cessna
Supply Division.
Figure
2-2.
Jacking
and
Leveling (Sheet
2
of
2)
2-3
MODEL
172
SERIES
SERVICE
MANUAL
2-
.
GROUND
HANDLING.
2-2.
TOWING.
Moving the
aircraft
by
hand
is
accomplished
by
using
the
wing
struts
and
landing
gear
struts
as
push points.
A
tow
bar
attached
to
the
nose
gear
should
be
used
for
steering
and
maneuvering
the
aircraft
on
the
ground.
When
no tow
bar
is
available,
press
down
at
the
horizontal
stabilizer
front
spar
adjacent
to
the fuselage
to
raise
the
nose
wheel
off
the
ground.
With
the
nose wheel
clear
of
the
ground,
the
aircraft
can
be
turned
by
pivoting
it
about
the
main
wheels.
Beginning
with
serials
17275035
and
F1722135
tow
bar
stowage
provisions
are
provided.
In
the
baggage
area
a
strap
located
at
FS
110.75
and
a
bracket
located
at
FS
140.10
are used
to
secure
and
store
the
tow
bar
assembly
when
not
in
use.
CAUTION
When
towing
the
aircraft,
never
turn
the
nose wheel
more
than
30
degrees
either
side
of
center
or
the
nose
gear
will
be
damaged.
Do
not
push
on
control
surfaces
or
outboard
empennage
surfaces.
When
pushing
on
the
tailcone.
always
apply
pressure
at
a
bulkhead
to
avoid buckling
the
skin.
2-3.
HOISTING.
The
aircraft
may
be
lifted with
a
hoist
of
two-ton
capacity
by
using
hoisting
rings,
which
are
optional
equipment,
or
by
means
of
suitable
slings.
The
front
sling
should
be
hooked
to
each
upper
engine
mount
at
the
firewall,
and
the
aft
sling
should
be
positioned
around
the
fuselage
at
the
first
bulkhead forward
of
the
leading
edge
of
the
stabilizer.
If
the
optional
hoisting
rings
are
used,
a
minimum
cable
length
of
60
inches
for
each
cable
is
required
to
prevent bending
of
the
eyebolt-type
hoisting rings.
If
desired,
a
spreader
jigmay
be
fabricated
to
apply
vertical
force
to
the
eyebolts.
2-4.
JACKING.
See
figure
2-2
for
jacking
procedures.
2-5.
LEVELING.
Corresponding
points
on
both
upper
door
sills
may
be
used
to
level
the
aircraft
laterally.
The
reference
points
for
longitudinally
leveling
the
aircraft
are
the
two
screws
located
on
the
left
side
of
the
tailcone.
See
figure
2-2
for
screw
locations.
2-5A.
WEIGHING
AIRCRAFT.
Refer
to
Pilot's
Operating
Handbook.
2-6.
PARKING.
Parking
precautions
depend
principally
on
local conditions.
As
a
general
precaution,
set
parking
brake
or
chock
the
wheels
and
install
the
controls
lock.
In
severe
weather
and
high
wind
conditions,
tie
down
the
aircraft
as
outlined
in
paragraph
2-7
if
a
hangar
is
not
available.
2-7.
TIE-DOWN.
When
mooring
the
aircraft
in
the
open,
head
into
the
wind
if
possible.
Secure
control
surfaces with
the
internal
control
lock
and
set brakes.
CAUTION
Do
not set
parking
brakes
when
they
are
overheated
or
during
cold
weather
when
accumulated
moisture
may
freeze
them.
2-4
MODEL
172
SERIES SERVICE
MANUAL
After
completing
the
preceding,
proceed
to
moor
the
aircraft
as
follows:
a.
Tie
ropes,
cables,
or
chains
to
the wing
tie-down
fittings
located
at
the
upper
end
of
each
wing
strut.
Secure
the
opposite
ends
of
ropes,
cables,
or
chains
to
ground
anchors.
b.
Secure
rope
(no
chains
or
cables)
to
forward
mooring
ring
and
secure
opposite
end
to
ground
anchor.
c.
Secure
the
middle
of
a
rope
to
the
tail
tie-down
ring.
Pull
each
end
of
rope
away
at
a
45
degree
angle
and
secure
to
ground
anchors
at
each
side
of
tail.
d.
Secure
control
lock
on
pilot
control
column.
If
control
lock
is
not
available,
tie
pilot
control
wheel
back
with
front
seat
belt.
e.
These
aircraft
are
equipped
with
a
spring-loaded
steering
system
which
affords
protection
against
normal
wind
gusts.
However,
if
extremely
high
wind
gusts
are
anticipated,
additional
external
locks may
be
installed.
2-8.
FLYABLE
STORAGE.
Flyable storage
is
defined
as
a
maximum
of
30
days
nonoperational
storage
and/or
the
first
25
hours
of
intermittent
engine
operation.
NOTE
O-320-H2AD
ENGINES
Thru aircraft
serial
17274009,
these
engines
are
deliv-
ered
from
the
factory with
SAE
20W-50
Ashless
Disper-
sant
Oil
conforming
to
MIL-L-22851.
This
oil
must
be
used
in
these engines
for
all
operations.
(See
figure
2-4,
sheet
2
of
6.)
MODEL
172Q
ONLY
-
0-360-A4N
ENGINES
172
AND
F172
SERIES
-320-D2J
ENGINES
Beginning
with
aircraft
serial
17274010,
these
engines
are
delivered
from
the
factory
with
MIL-L-6082
Aviation
Grade Mineral
Oil.
This
oil
is
to
be
used
to
replenish the
oil
supply
during
the
first
25
hours
of
operation,
at
the
first
25-hour
oil
change,
and
until
a
total
of
50
hours
have
accumulated
or
oil
consumption
has
stabiized.
Then
use
MIL-L22851
Ashless
Dispersant
Oil
conforming
to
AVCO
Lycoming
Service
Instruction
No. 1014
and
all
re-
visions
and
supplements thereto.
(See
figure
2-4,
sheet
3
of
6).
During
the
30
day
nonoperational
storage or
the
first
25
hours
of
intermittent
engine
operation,
every
seventh
day
the
propeller
shall
be
rotated
through
five
revolutions,
without
running
the
engine.
If
the
aircraft
is
stored
outside,
tie-down
in
accordance with
paragraph
2-7.
In
addition,
the
pitot
tube,
static
air
vents,
air
vents,
openings
in
the engine
cowling,
and
other
similar
openings
shall
have
protective
covers
installed
to
prevent
entry
of
foreign
material.
After
30
days,
aircraft
should
be
flown
for
30
minutes
or
ground
run-up
until
oil
has
reached
operating
temperature
(lower
green
arc
range).
CAUTION
Excessive
ground operation
shall
be
avoided.
Revision
1
2-5
MODEL
172
SERIES
SERVICE
MANUAL
2-9.
RETURNING
AIRCRAFT
TO
SERVICE.
After
flyable
storage,
returning the
aircraft
to
service
is
accomplished
by
performing
a
thorough
preflight
inspection.
At
the
end
of
the
first
25
hours
of
engine
operation,
drain
engine
oil
and
clean
oil
screens
(or
change
external
oil
filter).
Service engine
with correct
grade and
quantity
of
engine oil.
See
figure
2-4
and
paragraph
2-21
for
correct grade
of
engine
oil.
2-10.
TEMPORARY
STORAGE.
Temporary
storage
is
defined
as
aircraft
in a
nonoperational
status
for
a
maximum
of
90
days.
The
aircraft
is
constructed
of
corrosion
resistant
alclad
aluminum,
which
will
last
indefinitely
under
normal
conditions
if
kept clean,
however,
these
alloys
are
subject
to
oxidation.
The
first
indication
of
corrosion
on
unpainted
surfaces
is in
the
form
of
white
deposits
or
spots.
On
painted
surfaces,
the
paint
is
discolored
or
blistered.
Storage
in a
dry
hangar
is
essential
to
good
preservation
and
should
be
procured,
if
possible.
Varying conditions
will
alter
the
measures
of
preservation,
but
under
normal
conditions
in
a
dry
hangar,
and for
storage periods
not
to
exceed
90
days,
the
following
methods
of
treatment
are
suggested:
a.
Fill
fuel
tanks
or
bays
with the
correct
grade
of
gasoline.
WARNING
DURING
ALL
FUELING
PROCEDURES,
FIRE
FIGHTING
EQUIPMENT
MUST
BE AVAILABLE.
TWO GROUND
WIRES FROM
DIFFERENT
POINTS
ON
THE
AIRPLANE
TO
SEPARATE APPROVED
GROUND
STAKES
SHALL
BE USED
TO
PREVENT
ACCIDENTAL DISCONNECTION
OF ONE
GROUND WIRE.
ENSURE
THAT
FUELING
NOZZLE
IS
GROUNDED
TO
THE
AIRPLANE.
NOTE
Tie-down
rings
should
be
used
as
grounding
points
for
all
grounding
wires
during
refueling
procedures.
b.
Clean
and
wax
aircraft thoroughly.
c.
Clean
any
oil
or
grease
from
tires
and
coat
tires
with
a
tire
preservative.
Cover
tires
to
protect
against
grease
and
oil.
d.
Either
block
up
fuselage
to
relieve
pressure
on
tires
or
rotate
wheels
every
30
days
to
change
supporting
points
and
prevent
flat
spotting
the tires.
e.
Lubricate
all
airframe
items
and
seal
or
cover
all
openings
which could allow
mois-
ture
and/or
dust
to
enter.
NOTE
The
aircraft
battery
serial
number
is
recorded
in
the
aircraft
equipment
list.
To
assure
accurate
warranty
records,
the
battery
should
be
reinstalled
in
the
same
aircraft
from
which
it
was
removed.
If
the
battery
is
returned
to
service
in a
different
aircraft,
appropriate
record
changes
must
be
made
and
notification
sent
to
the
Cessna
Claims Department.
f.
Remove
battery
and
store
in a
cool,
dry
place;
service
battery
periodically
and
charge
as
required.
2-6 Revision
1
MODEL
172
SERIES SERVICE
MANUAL
NOTE
An
engine
treated
in
accordance
with
the
following
may
be
considered
being
protected
against
normal
atmos-
pheric
corrosion
for
a
period
not
to
exceed
90
days.
g.
Disconnect
spark
plug
leads
and
remove
upper
and
lower
spark
plugs
from
each
cylinder.
NOTE
The
preservative
oil
must
be
Lubricating
Oil-Contact
and
Volatile,
Corrosion
Inhibited,
MIL-C-6529.
Type
I
heated
to
200°F-220°F
spray
nozzle
temperature.
h.
Using
a
portable
pressure
sprayer,
atomize
spray
preservative
oil
through
the
upper
spark
plug
hole
of
each
cylinder with the
piston
in a
down
position.
Rotate
crankshaft
as
each
pair
of
cylinders
is
sprayed.
i.
After
completing
step
"h,"
rotate crankshaft
so
that
no
piston
is
at
a
top
position.
If
the
aircraft
is
to
be
stored
outside,
stop
two-bladed
propeller
so
that
blades are as
near
horizontal
as possible
to
provide
maximum clearance
for
passing
aircraft.
j.
Again,
spray
each
cylinder
without
moving
the
crankshaft
to
thoroughly
cover all
interior
surfaces
of
the
cylinder
above
the
piston.
k.
Install
spark
plugs
and
connect
spark
plug
leads.
l.
Apply
preservative
oil
to
the
engine
interior
by
spraying
approximately
two
ounces
of
the
preservative
oil
through
the
oil
filler
tube.
m.
Seal
all
engine
openings
exposed
to
the
atmosphere,
using
suitable plugs
or
non-
hygroscopic tape. Attach
a
red
streamer
at each
point
that
a
plug
or
tape
is
installed.
n.
If
the
aircraft
is
to
be
stored
outside,
perform
the
procedures
in
paragraph
2-7.
In
addition, the
pitot
tube,
static
source vents.
air
vents,
openings
in
the
engine
cowling.
and
other
similar
openings should have
protective
covers
installed
to
prevent
entry
of
foreign
material.
o.
Attach
a
warning
placard
to
the
propeller
to
the
effect
that
the
propeller
shall
not
be
moved
while the
engine
is in
storage.
2-7
MODEL
172
SERIES SERVICE
MANUAL
2-11.
INSPECTION
DURING
STORAGE.
a.
Inspect
airframe
for
corrosion
at
least
once
a
month
and
remove
dust
collections
as
frequently
as
possible.
Clean and wax
aircraft
as
required.
b.
Inspect
the
interior
of
at
least
one
cylinder through
the
spark
plug
hole
for
corrosion
at
least
once
a
month.
NOTE
Do
not
move
crankshaft
when
inspecting
interior
of
cylinder
for
corrosion.
c.
If
at
the
end
of
the
90
day
period.
the
aircraft
is
to
be
continued
in
nonopertional
storage,
repeat
the
procedural
steps
"g"
thru
"o"
of
paragraph
2-10.
2-12.
RETURNING
AIRCRAFT
TO
SERVICE.
After
temporary
storage.
use
the
following
procedures
to
return
the
aircraft
to
service.
a.
Remove
aircraft
from
blocks
and
check
tires
for
proper
inflation
Check
for
proper
nose
gear
strut
inflation.
(See
figure
1-1.)
b.
Check
battery
and
install.
c.
Check
that
oil
sump
has
proper
grade
and
quantity
of
engine
oil.
d.
Service
induction
air
filter
and remove
warning
placard
from
propeller.
e.
Remove
materials
used
to
cover
openings.
f.
Remove
spark
plugs
from
engine.
g.
While
spark
plugs
are
removed,
rotate
propeller several
revolutions
to
clear
excess
rust
preventive
oil
from
cylinders.
h.
Clean.
gap and
install
spark
plugs.
Torque
plugs
to
the
value
specified
in
Section
11
or
11A
and
connect
spark
plug
leads.
i.
Check fuel
strainer.
Remove
and
clean
filter screen
if
necessary.
Check
fuel
tanks
or
bays
and
fuel
lines
for
moisture
and
sediment,
drain
enough
fuel
to
eliminate
moisture
and
sediment.
j.
Perform
a
thorough pre-flight
inspection,
then
start
and
warm-up
engine.
2-13.
INDEFINITE STORAGE.
Indefinite
storage
is
defined
as
aircraft
in a
nonoperational
status
for
an
indefinite
period
of
time.
Engines treated
in
accordance
with
the following
may
be
considered
protected
against
normal
atmosphere corrosion,
provided
the
procedures
outlined
in
paragraph
2-14
are
performed
at
the
intervals
specified.
a.
Operate
engine
until
oil
temperature
reaches
normal operating
range.
Drain
engine
oil
sump
and
reinstall
drain
plug
and
safety.
b.
Fill
oil
sump
to
normal
operating
capacity with
corrosion
preventive
mixture
which
has
been
thoroughly
mixed.
NOTE
Corrosion-preventive
mixture
consists
of
one
part
com-
pound MIL-C-529.
Type
I.
mixed
with
three
parts
by
volume
of
MIL-L-6082
mineral
aircraft
engine
oil.
c.
Immediately
after
filling
the
oil
sump
with
corrosion-preventive
mixture.
fly
the
aircraft
for
a
period
of
time
not
to
exceed
a
maximum
of
30
minutes.
2-8
MODEL
172
SERIES SERVICE
MANUAL
d.
With
engine
operating at
1200
to
1500
rpm
and
induction
air
filter
removed,
spray
corrosion-preventive
mixture
into
induction airbox, at the
rate
of
one-hall
gallon
per
minute,
until
heavy
smoke comes from
exhaust stack,
then
increase
the
spray
until
the
engine
is
stopped.
CAUTION
Injecting
corrosion-preventive
mixture
too
fast
can
cause
a
hydrostatic
lock.
e.
Do
not
rotate propeller
after
completing
step
"d".
f.
Remove all spark
plugs
and
spray
corrosion-preventive
mixture.
which
has
been
preheated
to
200°F
to
220°F,
into
all
spark
plug
holes
to
thoroughly
cover
interior
surfaces
of
cylinders.
g.
Install
lower
spark
plugs
or
install
solid
plugs,
and
install
dehydrator plugs
in
upper
spark
plug
holes.
Be
sure
that
dehydrator
plugs
are
blue
in
color when
installed.
h.
Cover
spark
plug
lead
terminals
with
shipping
plugs
(AN4060-1)
or
other
suitable
covers.
i.
With
throttle
in
full
open
position,
place
a
bag
of
desiccant
in
the
carburetor
intake
and
seal
opening
with
moisture
resistant
paper
and
tape.
j.
Place
a
bag
of
desiccant
in
the
exhaust
tailpipe(s)
and
seal
openings
with
moisture
resistant
tape.
k.
Seal
cold
air
inlet
to
the
heater
muff
with
moisture
resistant
tape.
L
Seal
engine breather
by
inserting
a
protex
plug
in
the
breather
hose
and
clamping
in
place.
m.
Seal
all
other
engine
openings
exposed
to
atmosphere
using
suitable
plugs or
non-
hygroscopic
tape.
NOTE
Attach
a
red
streamer
to
each
place
plugs
or
tape
is
installed.
Either
attach
red
streamers
outside
of
the
sealed
area
with tape
or
to the
inside
of
the
sealed
area
with
safety
wire
to
prevent
wicking
of
moisture
into
the
sealed
area.
n.
Drain
corrosion-preventive
mixture
from
engine
sump
and
reinstall
drain
plug.
NOTE
The
corrosion-preventive,
mixture
is
harmful
to
paint
and
should
be
wiped
from
painted surfaces
immediately.
o.
Attach
a
warning
placard
on
the
throttle
control
knob,
to
the
effect
that
the
engine
contains
no
lubricating
oil.
Placard
the
propeller
to
the
effect
that
it
should
not
be
moved
while
the
engine
is in
storage.
p.
Prepare
airframe
for
storage
as
outlined
in
paragraph
2-10
thru step
"f".
2-9
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
As
an
alternate method
of
indefinite
storage.
the
aircraft
may
be
serviced
in
accordance
with
paragraph
2-10
providing
the
aircraft
is
run
up
at maximum
intervals
of
90
days
and
then
reserviced
per
paragraph
2-10.
2-14.
INSPECTION
DURING
STORAGE.
Aircraft
in
indefinite
storage
shall
be
inspected
as
follows:
a.
Inspect cylinder
protex
plugs
each
7
days.
b.
Change
protex
plugs
if
their
color
indicates
an
unsafe
condition.
c.
If
the
dehydrator
plugs have
changed
color
in
one
half
of
the
cylinders.
all
desiccant
material
in
the
engine
shall
be
replaced
with
new
material.
d.
Every
6
months
respray
the cylinder
interiors
with
corrosion-preventive
mixture.
NOTE
Before
spraying,
inspect
the
interior
of
one
cylinder
for
corrosion
through
the
spark
plug
hole
and
remove
at
least
one
rocker
box
cover
and inspect
the
valve
mecha-
nism.
2-15.
RETURNING AIRCRAFT
TO
SERVICE. After
indefinite
storage.
use
the following proce-
dure
to
return
the
aircraft
to
service.
a.
Remove
aircraft
from
blocks
and
check
tires
for
correct
inflation.
Check
for
correct
nose
gear
strut
inflation.
b.
Check
battery
and
install.
c.
Remove
all
materials
used
to
seal
and cover
openings.
d.
Remove
warning
placards
posted
at
throttle
and
propeller.
e.
Remove
and clean
engine
oil
screen,
then
reinstall
and safety.
On
aircraft
that
are
equipped
with
an
oil
filter,
install
new
filter.
f.
Remove
oil sump
drain
plug
(or
open
quick-drain
valve)
and
drain
sump.
Install
and
safety
drain
plug
(or
close
quick-drain
valve)
and
service
engine
with
correct
quantity
and grade
of
engine oil
in
accordance
with
figure
2-4.
NOTE
The
corrosion-preventive
mixture
will
mix
with
the
engine
lubricating
oil.
so
flushing
the
oil
system
is
not
necessary.
Draining
the
oil
sump
will
remove
enough
of
the
corrosion-preventive
mixture.
g.
Service
and
install
the
induction
air
filter.
h.
Remove
dehydrator
plugs
and
spark
plugs
or
plugs
installed
in
spark
plug
holes
and
rotate
propeller
by
hand
several
revolutions
to
clear
corrosion-preventive
mixture
from
cylinders.
i.
Clean,
gap,
and
install
spark
plugs.
Torque
plugs
to
the
value
listed
in
Section
11
or
11A.
j.
Check
fuel
strainer.
Remove
and
clean filter
screen.
Check
fuel
tanks
or
bays
and
fuel
lines
for
moisture
and
sediment,
and
drain
enough
fuel
to
eliminate.
k.
Perform
a
thorough
preflight
inspection,
then
start
and
warm-up
engine.
l.
Thoroughly
clean
aircraft
and
flight
test
aircraft.
2-10
MODEL
172
SERIES SERVICE
MANUAL
2-16.
SERVICING.
2-17.
Servicing
requirements
are
shown
in
figure
2-4.
The
following
paragraphs
supplement
this
figure
by
adding
details
not
included
in
the
figure.
2-18.
FUEL.
Fuel
tanks
or
bays
should
be
filled
immediately
after
flight
to
lessen
moisture
con-
densation.
Tank
or
bay
capacities
are
listed
in
Section
1.
The
recommended
fuel
grade
to
be
used
is
given
in
figure
2-4.
WARNING
DURING
ALL
FUELING PROCEDURES,
FIRE
FIGHTING
EQUIPMENT
MUST
BE
AVAILABLE.
TWO
GROUND
WIRES
FROM
DIFFERENT
POINTS
ON
THE
AIRPLANE
TO
SEPARATE
APPROVED
GROUND
STAKES
SHALL
BE
USED
TO
PREVENT
ACCIDENTAL
DISCONNECTION
OF
ONE
GROUND
WIRE.
ENSURE
THAT
FUELING
NOZZLE
IS
GROUNDED
TO
THE
AIRPLANE.
NOTE
Tie-down
rings
should
be
used
as
grounding
points
for
all
grounding
wires
during
refueling
procedures.
2-18A.
USE
OF
FUEL
ADDITIVES
FOR
COLD
WEATHER
OPERATION.
Strict
adherence
to
recommended
preflight draining
instructions
will
eliminate any
free
water
accumulations
from
the
tank
sumps.
While
small
amounts
of
water
may
still
remain
in
solution
in
the
gasoline,
it
will
normally
be
consumed
and
go
unnoticed
in
the
operation
of
the
engine.
One
exception
to
this
can
be
encountered
when
operating
under
the
combined
effect
of: (1)
use
of
certain
fuels, with
(2)
high
humidity
conditions
on
the
ground
(3)
followed
by
flight
at
high
altitude
and
low
temperature.
Under
these
unusual
conditions
small amounts
of
water
in
solution
can
precipitate
from
the
fuel
stream
and
freeze
in
sufficient
quantities
to
induce
partial
icing
of
the
engine
fuel
system.
While
these conditions
are
quite
rare
and
will
not
normally
pose
a
problem
to
owners
and
operators,
they
do
exist
in
certain
areas
of
the
world
and
consequently
must
be
dealt
with.
when
encountered.
Therefore,
to
alleviate
the
possibility
of
fuel
icing occuring under
these
unusual
conditions
it is
permissible
to
add
isopropyl
alcohol
or ethylene
glycol
monomethyl
ether
(EGME)
compound
to
the fuel
supply.
See
Figure
2-2A
for
fuel
additive
mixing
ratio.
The
introduction
of
alcohol
or
EGME
compound into
the
fuel
provides
two
distinct
effects:
(1)
it
absorbs
the
dissolved
water
from
the
gasoline
and
(2)
alcohol
has
a
freezing
temperature
depressant
effect.
Alcohol,
if
used,
is
to
be
blended
with the
fuel
in
a
concentration
of
1%
by
volume.
Concentrations
greater than
1%
are
not
recommended since
they
can be
detrimental
to
fuel
tank
materials.
Revision
1
2-11
MODEL
172
SERIES
SERVICE
MANUAL
The
manner
in
which
the
alcohol
is
added
to
the
fuel
is
significant
because
alcohol
is
most
effective
when
it
is
completely
dissolved
in
the
fuel.
To
insure
proper
mixing
the
following
is
recommended:
1.
For
best
results
the
alcohol should
be
added
during
the
fueling
operation
by
pouring
the
alcohol
directly
on
the
fuel
stream
issuing
from
the fueling
nozzle.
2.
An
alternate
method
that
may
be
used
is
to
premix
the
complete
alcohol
dosage
with
some
fuel
in a
separate
clean
container
(approximately
2-3
gallon
capacity)
and
then
transfer this
mixture
to
the
tank
or
bay
prior
to
the
fuel
operation.
Any
high
quality
isopropyl
alcohol
may
be
used,
such
as:
Anti-icing
fluid
(MIL-F-5566)
or
Isopropyl
alcohol (Federal Specification
TT-I-735a).
Ethylene
glycol
monomethyl
ether
(EGME)
compound
in
compliance
with
MIL-I-27686
or
Phillips
PFA-55MB,
if
used,
must
be
carefully
mixed
with
the
fuel
in
concentrations
not
to
exceed
0.15%
by
volume.
CAUTION
Mixing
of
the
EGME
compound
with
the
fuel
is
extremely
important
because
concentration
in
excess
of
that
recom-
mended
(0.15
percent
by
volume
maximum)
will
result
in
detrimental
affects
to
the
fuel
tanks,
such
as
deterioration
of
protective
primer
and
sealants
and
damage
to
O-rings
and
seals
in
the
fuel
system
and
engine
components.
Use
only
blending
equipment
that
is
recommended
by
the
manufacturer
to
obtain
proper
proportioning.
Do
not
allow
the
concentrated
EGME
compound to
come
in
contact with
the
airplane
finish
or fuel
cell
as damage
can
result.
Prolonged
storage
of
the
airplane
will
result
in
a
water
build-up
in
the
fuel
which
"leeches
out"
the
additive.
An
indication
of
this
is
when
an
excessive
amount
of
water accumulates
in
the
fuel
tank
sumps.
The
concentration
can
be
checked
using
a
differential
refractometer.
It
is
imperative
that
the
technical
manual
for
the
differential
refractometer
be
followed
explicitly
when
checking
the
additive
concentration.
2-19.
FUEL
DRAINS.
On
aircraft
serials
17267585
thru
17275034
and
F17201515
thru
F17202134,
the
fuel
drains
are
located
in
the
fuel
tanks
or
bays,
fuel
strainer,
and
carburetor.
Drain plugs
are
installed
in
the
fuel
selector valve
and
carburetor;
drain
valves
are
located
in
the
fuel
tanks
or bays
and
fuel
strainer.
Beginning
with
17275035
and
F17202135,
a
drain
valve
is
located
in
the
bottom
of
the
fuel
selector valve
for
sampling
and
draining
of
fuel.
To
activate
the
drain
valves
for
fuel
sampling,
place
cup
up
to
valve
and
depress
valve
with
rod
protruding
from
cup.
Refer
to
Section
12
for
illustration
of
fuel
tank
and
bay
drain
valve.
The
strainer
valve
is
an
integral
part
of
the
fuel
strainer
assembly.
The
strainer
drain
is
equipped
with
a
control
which
is
located
adjacent
to
the
oil
dipstick.
Access
to
the
control
is
through
the
oil dipstick
access
door. Open
drains
and
remove
drain
plugs
at
intervals
specified
in
figure
2-4.
Also,
during
daily
inspection
of
the
fuel
strainer,
fuel
selector,
and
tanks
or
bays,
if
water
is
found
in
the
system,
all
fuel
drain
plugs
should
be
opened
and
all
water
drained
from
the
system.
2-12
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
18
4.5
140
-
16
-
4.0
120-
GALLONS
OF
GASOLINE
Figure
2-2A.
Fuel Additive
Mixing
Ratio
Chart.
2-20.
CARBURETOR
DRAIN
PLUG
INSPECTION.
In
order
to
prevent
the
possibility
of
thread
sealant
contamination
in
the
carburetor
float
chamber,
cleaning
and
inspection
of
the
carburetor
should
be
accomplished
at
each
100-hour
inspection
and
anytime
water
in
the
fuel
is
suspected.
a.
With
the
fuel
selector
valve
OFF,
remove
carburetor
drain plug
and
clean
off
any
sealant
present
on
the
end
of
the
plug or
in
the
threads
on the
plug.
b.
Inspect
drain
plug
hole
in
the
carburetor
and
remove
any
sealant
remaining
in
the
hole.
c.
Turn fuel
selector valve
to
BOTH
to
flush
float
chamber
and
drain
plug
chamber
while
probing
drain
plug
hole
to
ascertain
that
all
residue
of
sealant
material
is
dislodged
and
washed
out
of
the chamber.
Flushing
operation
should
last
15
to
30
seconds.
d.
A
second
flushing
should
then
be
accomplished
and the
drained
fuel
retained
for
inspection
to
ensure
that
no
sealant
particles
are
present.
e.
Install drain
plug
as
follows:
1.
Install
drain
plug
in
carburetor
1-1/2
to
2
turns.
2.
Apply
sealant
to
drain
plug
threads
(use
NS-40
[RAS-4]
or
equivalent).
3.
Tighten
and
safety drain
plug.
f.
Turn fuel
selector
valve
to
BOTH
and
inspect
for
evidence
of
fuel
leakage.
2-21.
ENGINE
OIL.
Check
engine
lubricating
oil
with
the
dipstick
five
to
ten
minutes
after
the
en-
gine
has
been
stopped.
The
aircraft
should
be
in
as
near
a
level
position
as
possible
when
checking
the
engine
oil,
so
that
a
true
reading
is
obtained.
Engine
oil
should
be
drained
while
the
engine
is
still
hot, and
the
nose
of
the
aircraft
should
be
raised
slightly
for
more
Revision
1
2-13
MODEL
172
SERIES SERVICE
MANUAL
positive
draining
of
any sludge
which
may
have
collected
in
the
engine
oil
sump.
Engine
oil
should
be
changed
as
specified
in
servicing
intervals
figure
2-4.
Reduce
these
intervals
for
prolonged
operations
in
dusty
areas,
in
cold
climates
where
sludging
conditions
exist,
or
where
short
flights
and
long
idle
periods
are encountered, which
cause
sludging
conditions.
Always
change
oil
and
oil
filter
whenever
oil
on
the
dipstick
appears
dirty.
Aviation
grade
oil
conforming
to
AVCO
Lycoming
Service
Instruction
No.
1392
for the
0-320-H2AD
engine,
and
AVCO
Lycoming
Service
Instruction
No.
1014
for
the
O-320-D2J
engine
(Model 172
and
F172
Series)
and
0-360-A4N
engine
(Model
171Q
only)
and
any
revisions
or
supplements
thereto,
shall
be
used.
NOTE
O-320-H2AD
ENGINES
Service
with
20W-50
Ashless
Dispersant
Oil
conforming
to
MIL-L-22851. (See
figure
2-4,
sheet
2
of
6.)
O-320-D2J
AND
0-360-A4N
ENGINES
Service
with
SAE
20W-50
(MIL-L-6082)
Aviation
Grade
Mineral
Oil
when
new
or
newly
overhauled,
during
the
first
25
hours
of
operation,
at
the
first
25
hour
oil
change,
and
until
50
hours
have
accumulated
or
oil
con-
sumption
has
stabilized.
(See
figure
2-4,
sheet
3
of
6.)
WARNING
The
U.S.
Environmental
Protection
Agency
advises
that
mechanics
and
other
workers
who
handle
engine
oil
are
advised to
minimize
skin
contact
with
used
oil
and
promptly
remove
used
oil
from
the skin.
In a
laboratory
study,
mice
developed
skin
cancer after
skin
was
exposed
to
used
engine
oil twice
a
week
without
being
washed
off,
for most
of
their
life
span.
Substances
found
to cause
cancer
in
laboratory
animals
may
also
cause
cancer
in
humans.
Valve
shown open.
To
close,
twist
screwdriver
until
valve
unlocks
and
snaps
down
to
closed
position.
Figure
2-3.
Quick-Drain
Valve
2-14
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
An
oil
quick-drain
valve
may
be
installed.
This
valve provides
a
quicker and
cleaner method
of
draining
the engine
oil.
This
valve
is
installed
in
the
oil
drain
port
of
the
oil
sump
and
allows
oil
to
be
drained
by
attaching
a
hose
over
the
fitting
end
and
pushing
up,
causing
the
oil
to
drain through
the
hose
into
a
container.
To
drain the
engine
oil,
proceed
as follows:
a.
Operate
engine
until
oil
temperature
is
at
normal
operating
temperature.
b.
(With
Quick-Drain
Valve.)
Attach
a
hose
to the
quick-drain
valve
in
the oil
sump.
Push
up
on
quick-drain
valve
until
it
locks
open,
and
allow
oil
to
drain through
the
hose
into
the
container,
and
remove
oil
filter
(if
installed).
c.
(Without
Quick-Drain
Valve.) Remove
oil
drain
plug
from
engine
sump
and
allow
oil
to
drain
into
a
container,
and remove oil
filter
(if
installed).
d.
After
engine
oil
has
drained,
close
quick-drain
valve as
shown
in
figure
2-3
and
remove
hose.
Install
and safety
drain
plug
and
oil
filter.
Torque
oil
filter
to
18-20
lb-ft.
e.
Service
engine
with
correct
quantity
and
grade
of
engine
oil
in
accordance
with
figure
2-4.
2-21A.
ENGINE
OIL
ADDITIVE.
Refer
to
AVCO
Lycoming
Service Bulletin
No.
446.
2-22.
ENGINE
INDUCTION AIR
FILTER
(MODEL
172
AND
F172
SERIES
ONLY).
The
induction
air
filter
keeps
dust
and
dirt
from
entering
the
induction
system.
The
value
of
maintaining
the
air
filter
in a
good
clean
condition
can
never
be
overstressed.
More
engine
wear
is
caused
through
the
use
of
a
dirty
or
damaged
air
filter
than
is
generally
believed.
The
fre-
quency
with
which
the
filter
should
be
removed,
inspected,
and
cleaned
will
be
determined
primarily
by
aircraft operating
conditions.
A
good
general
rule,
however,
is
to
remove,
in-
spect
and
clean
the
filter
at
least
every
100
hours
of
engine
operating
time
and
more fre-
quently
if
warranted
by
operating
conditions.
Some
operators
prefer
to
hold
spare
induction
air
filters
at
their
home
base
of
operation
so
that
a
clean
filter
is
always
readily
available
for
use.
Under
extremely
dusty
conditions,
daily
servicing of the
filter
is
recommended.
To
ser-
vice
the
filter,
proceed
as
follows:
a.
Remove
filter
from
aircraft.
NOTE
Use
care
to
prevent
damage
to
filter
element
when
cleaning
filter with
compressed
air.
b.
Clean
filter
by
blowing
with compressed
air
(not
over
100
psi)
from
direction
opposite
of
normal
air
flow.
Arrows
on
filter
case
indicate
direction
of
normal
air
flow.
CAUTION
Do
not
use
solvent
or
cleaning fluids
to
wash
filter.
Use
only
water and
a
household
detergent solution
when
washing the filter.
c.
After
cleaning
as
outlined
in
step
"b",
the
filter
may
be
washed,
if
necessary,
in
a
solution
of
warm water
and
a
mild
household
detergent.
A
cold
water solution
may
be
used.
NOTE
The
filter assembly
may
be
cleaned
with
compressed
air
a
maximum
of
30
times
or
it
may
be
washed
a
maximum
of
20
times.
A
new
filter
should
be
installed
after
using
500
hours
of
engine
operating
time
or
one
year,
whichever
Revision
1 2-15
MODEL
172
SERIES SERVICE
MANUAL
should
occur
first.
However,
a
new
filter
should
be
installed
at
anytime
the
existing
filter
is
damaged.
A
damaged
filter
may
have
sharp
or
broken
edges
in
the
filtering
panels
which
would
allow
unfiltered
air
to enter
the
induction
system.
Any
filter
that
appears
doubtful,
shall
have
a
new
filter
installed
in
its
place.
d.
After
washing,
rinse
filter
with
clear
water
until rinse
water
draining
from
filter
is
clear.
Allow
water
to
drain
from
filter
and
dry
with
compressed
air
(not
over
100
psi).
NOTE
The
filtering panels
of
the
filter
may
become
distorted
when
wet,
but
they
will return
to
their original
shape
when
dry.
e.
Be
sure
air
box
is
clean,
inspect
filter.
If
filter
is
damaged,
install
a
new
filter.
f.
Install
filter
at
entrance
to
air
box
with
gasket
on
aft
face
of
filter
frame and
with
air
flow
arrows
on
filter
frame
pointed
in
the
correct
direction.
2-22A.
ENGINE
INDUCTION
AIR
FILTER
(MODEL
172Q
ONLY).
The
induction
air
filter
keeps
dust
and
dirt
from
entering
the induction system.
More
engine
wear
is
caused
through
the
use
of
a
dirty
or
damaged
air
filter
than
is
generally
believed.
The
polyurethane
foam
filter
element
should
be
changed
every
200
hours.
Under
extremely
dusty
conditions, the filter
should
be
replaced
on
condition.
CAUTION
This
filter
cannot
be
washed
or
cleaned
by
compressed
air;
it
is
a
remove
and
replace
item.
Prior
to
installation
of
a
new
filter,
squeeze
out
excess
wettant.
It
is
possible
that
the
runoff
of
excess
wettant
could damage
the
paint.
2-23.
VACUUM
SYSTEM CENTRAL
AIR FILTER.
The
vacuum
system
central
air
filter
keeps
dirt
and
dust
from
entering
the
vacuum
operated
instruments.
Inspect
vacuum
system central
air
filter
every
200
hours
of
operating
time
for
damage.
Change
central
air
filter
element
every
500
hours
of
operating
time
and
whenever
it
becomes
sufficiently
clogged
to
cause
suction
gage
readings
to
drop
below
4.5
inches
of
mercury.
Also, do
not
operate
the
vacuum
system
without
a
filter,
or
with
the
filter
removed,
or
a
vacuum line
disconnected
as
parti-
cles
of
dust
or
other
foreign
matter
may
enter
the
system
and
damage
the
vacuum
operated
instruments.
CAUTION
Smoking
will
cause
premature
filter clogging.
2-24.
BATTERY.
Battery
servicing
involves
adding
distilled
water
to
maintain
the
electrolyte
18"
below
the
horizontal
baffle
plate
at
the
bottom
of
the
filler
holes,
checking
the
battery
cable
connections,
and
neutralizing and
cleaning
spilled
electrolyte
or
corrosion.
Use
bicarbonate
of soda
(baking
soda)
and
water
to neutralize
electrolyte
or
corrosion.
Follow
with
a
thor-
ough
flushing
with
water.
Brighten
cables
and terminals
with
a
wire
brush, then
coat
with
petroleum
jelly
before
connecting.
The
battery
box
also
should
be
checked
and
cleaned
if
any
corrosion
is
noted.
Distilled
water,
not
acid
or
"rejuvenators",
should
be
used
to
maintain
electrolyte
level.
Check
the
battery
every
100
hours (or at
least
every
90
days),
more
often
in
hot
weather.
Refer
to
Section
16
for
detailed
battery
removal,
installation and
testing.
2-16 Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
2-25.
TIRES.
Maintain
tire
pressure
at
the
pressure
specified
in
figure
1-1.
When
checking
tire
pressure,
examine
tires
for wear,
cuts,
bruises,
and
slippage.
Remove
oil,
grease,
and mud
from
tires
with
soap
and
water.
NOTE
Recommended
tire
pressures
should
be
maintained.
Especially
in
cold
weather,
remember
that
any
drop
in
temperature
of
the
air
inside
a
tire
causes
a
correspond-
ing
drop
in
air
pressure.
2-26.
NOSE
GEAR
SHOCK STRUT.
The
nose
gear
shock
strut
requires
periodic
checking
to
ensure
that
the
strut
is
filled with
hydraulic
fluid and
is
inflated
to
the
correct
air
pressure.
To
service
the
nose
gear
shock
strut,
proceed
as
follows:
a.
Remove
valve
cap
and
release
all
air.
b.
Remove
valve housing
assembly.
c.
Compress
strut
completely
(stops
in
contact
with
outer
barrel
hub).
d.
Oil
Level.
1.
Fluid
used
should
comply
with
specification
MIL-H-5606
2.
Fill
strut
to
bottom
of
valve
installation
hole.
3.
Maintain oil
level
at
bottom
of
valve
installation
hole.
e.
Fully
extend
strut.
f.
Replace
valve
housing
assembly.
g. With
strut
fully
extended
and
nose
wheel
clear
of
ground, inflate
strut
to
45
psi.
NOTE
The
nose
landing
gear
shock
strut
will
normally
require
only
a
minimum
amount
of
service.
Maintain
the
strut
extension
air
pressure, as
shown
in
figure
1-1.
Lubricate
landing gear as
shown
in
figure
2-5.
Check
the
landing
gear
daily
for
general
cleanliness,
security
of
mounting,
and for
hydraulic
fluid
leakage.
Keep
machined
surfaces
wiped
free of
dirt
and
dust,
using
a
clean,
lint-free cloth
saturated
with
MIL-H-5606
hydraulic
fluid or
kerosene.
All
surfaces
should
be
wiped
free
of
excessive
hydraulic
fluid.
2-27.
NOSE
GEAR
SHIMMY
DAMPER.
The
nose
gear shimmy
damper
should
be
serviced at
least
every
100
hours.
The
shimmy
damper
must
be
filled
completely
with
fluid,
free
of
entrapped
air,
to
serve
its
purpose.
To
service
the
shimmy
damper,
proceed
as
follows:
a.
Remove
shimmy
damper
from
aircraft.
b.
While
holding the
damper
in a
vertical position
with
fitting
end
pointed
downward,
pull
fitting
end
of
the
damper
shaft
to
its
limit
of
travel.
c.
While
holding
damper
in
this
position,
fill
damper
through
open
end
of
cylinder
with
hydraulic
fluid.
d.
Push the
shaft
upward
slowly to
seal
off
the
filler
hole.
e.
Clean
dampener
with
solvent.
Be
sure
to
keep
the
shaft
protruding
through
the
filler
hole
until
damper
is
installed
on
the
aircraft.
f.
Install dampener
on
aircraft.
NOTE
Keep
the shimmy
damper,
especially
the
exposed
por-
tions
of
the
damper
piston
shaft,
clean
to
prevent
collec-
Revision
1
2-17
MODEL
172
SERIES
SERVICE
MANUAL
tion
of
dust
and
grit
which
could
cut
the seals
in
the
damper
barrel.
Keep
machined
surfaces
wiped
free
of
dirt
and
dust, using
a
clean
lint-free
cloth
saturated
with
MIL-H-5606
hydraulic
fluid
or
kerosene.
All
surfaces
should
be
wiped
free
of
excessive
hydraulic
fluid.
2-28.
HYDRAULIC
BRAKE
SYSTEMS.
Check
brake
master cylinders
and
refill
with
hydraulic
fluid
as
specified
in
the
inspection
charts.
Bleed
the
brake
system
of
entrapped
air
whenever
there
is a
spongy
response
to
the
brake
pedals.
Refer
to
Section
5
for
filling
and
bleeding
of
the
brakes.
2-29.
CLEANING.
2-30.
Keeping
the
aircraft
clean
is
important.
Besides
maintaining
the
trim
appearance
of
the
aircraft,
cleaning
lessens
the
possibility
of
corrosion
and
makes
inspection
and mainte-
nance
easier.
2-31.
CLEANING
AND
CARE
OF
THE
WINDSHIELD
AND WINDOW.
a.
General
Maintenance Procedures.
The following
procedures
provide
information
re-
garding
cleaning
and
servicing
windshields and
windows.
Improper
cleaning,
or
use
of
unapproved
cleaning
agents
can
cause
damage
to
windshield
and
windows.
b.
Materials
Required:
NAME
MANUFACTURER
USE
Mild
soap
or
detergent
Commercially
available
Cleaning
windshields
and
(hand
dishwashing
type)
windows.
Aliphatic
Naphtha
Type
II
Commercially
available
Removing
deposits
which
conforming
to
Federal
cannot
be
removed
with
Specification
TT-N-95
mild
soap
solution.
Polishing
wax:
S.C.
Johnson
and
Son,
Inc. Waxing acrylic wind-
(Refer
to
Note
1)
shields
and
windows.
Turtle
Wax
(paste)
Turtle
Wax,
Inc.
Chicago,
IL
60638
Great
Reflections
E.I.
duPont
deNemours
Paste
Wax
and
Co.
(Inc)
Wilmington,
DE
19898
Slip-stream
Wax
Classic
Chemical
(paste)
Grand
Prairie,
TX
75050
Acrylic
polish
conforming
Permatex
Company,
Inc.
Cleaning
and
polishing
to
Federal
Specification
Kansas
City,
KS
66115
acrylic
windshields and
P-P-560
such
as:
windows.
Permatex
plastic
cleaner
Number
403D
Soft
cloth,
such
as:
Commercially
available
Applying
and
removing
wax
Cotton
flannel
or
old
and
polish.
tee
shirt
material
2-18
Revision
1
MODEL 172
SERIES SERVICE
MANUAL
c.
Cleaning
Instructions.
CAUTION
Windshields
and
windows
(Acrylic Faced)
are
easily
dam-
aged
by
improper
handling
and cleaning techniques.
1.
Place
airplane
inside
hangar
or
in
shaded
area
and
allow
to
cool
from
heat
of
sun's
direct
rays.
2.
Using
clean
(preferably
running)
water,
flood
the
surface.
Use
bare
hands
with
no jewelry
to
feel
and
dislodge
any
dirt
or
abrasive
materials.
3.
Using
a
mild
soap
or
detergent
(such
as
a
dishwashing
liquid)
in
water,
wash
the
surface.
Again
use
only
the
bare
hand
to
provide
rubbing
force.
(A
clean cloth
may
be
used to
transfer
the
soap
solution
to
the surface,
but
extreme
care
must
be
exercised
to
prevent
scratching
the
surface.)
4.
On
acrylic
windshields
and
windows
only,
if
soils
which
cannot
be
removed
by
a
mild
detergent
remain,
Type
II
aliphatic
naphtha
applied
with
a
soft
clean
cloth
may
be
used
as
a
cleaning
solvent.
Be
sure
to
frequently
refold
cloth
to
avoid
re-
depositing soil
and/or
scratching
windshield
with
any
abrasive
particles.
5.
Rinse
surface
thoroughly
with
clean
fresh
water
and
dry
with
a
clean
cloth.
CAUTION
Do
not
use
any
of
the
following
on
or
for
cleaning
windshields
and
windows:
methanol,
denatured
alcohol,
gasoline, benzene,
xylene,
MEK,
acetone,
carbon
tet-
rachloride,
lacquer
thinners,
commercial
or
household
window
cleaning
sprays.
6.
Hard
polishing
wax
should
be
applied
to
acrylic
surfaces.
(The
wax
has
an
index
of
refraction
nearly
the
same
as
transparent
acrylic
and
will
tend
to
mask
any
shallow
scratches
on
the
windshield surface).
7.
Acrylic
surfaces
may
be
polished
using
a
polish
meeting
Federal
Specification
P-
P-560
applied
per
the
manufacturer's
instructions.
NOTE
When
applying
and
removing
wax
and
polish, use
a
clean
soft
cloth
such
as
well
worn
tee
shirt
material
or
cotton
flannel.
8.
DO
NOT USE
rain
repellent
on
acrylic
surfaces.
Revision
1
2-19
MODEL
172
SERIES
SERVICE
MANUAL
d.
Windshield
and
Window
Preventive Maintenance.
NOTE
Utilization
of
the
following
techniques
will
help
minimize
windshield
and
window
crazing.
1.
Keep
all
surfaces
of
windshields and
windows
clean.
2.
If
desired,
wax
acrylic
surfaces.
3.
Carefully
cover
all
surfaces
during
any
painting,
powerplant
cleaning
or
other
procedure
that
calls
for
use
of
any
type
of
solvents
or
chemicals.
The following
coatings
are
approved
for
use
in
protecting
surfaces
from
solvent
attack.
(a)
White
Spary
Lab,
MIL-C-6799,
Type
I,
Class
II.
(b)
WPL-3
Masking
Paper
-
St.
Regis,
Newton, MA.
(c)
5
X N
-
Poly-Spotstick
-
St.
Regis,
Newton, MA.
(d)
Protex
40
-
Mask
Off
Company,
Monrovia,
CA,
and
Southwest
Paper
Co.,
Wichita,
KS.
(e)
Protex
10VS
-
Mask
Off
Company,
Monrovia,
CA,
and
Southwest
Paper
Co.,
Wichita,
KS.
(f)
Scotch
344
Black Tape
-
3M
Company.
4.
Do
not
park
or
store
airplane
where
it
might
be subjected to
direct
contact
with
or
vapors
from:
methanol, denatured
alcohol,
gasoline,
benzene,
xylene,
MEK,
acetone,
carbon
tetrachloride,
lacquer
thinners,
commercial
or
household
window
cleaning
sprays,
paint
strippers,
or
other
types
of
solvents.
5.
Do
not
use
solar
screens
or shields
installed
on
inside
of
airplane
or
leave
sun
vis-
ors up
against
windshield.
The
reflected
heat
from
these
items
causes
elevated
temperatures
which
accelerate
crazing
and
may
cause
formation
of
bubbles
in
the
inner
ply of
multiple
ply
windshields.
6.
Do
not
use
a
power
drill
motor
or
other
powered
device
to
clean,
polish,
or
wax
surfaces.
2-32.
PLASTIC
TRIM.
The
instrument
panel,
plastic
trim,
and
control
knobs
need
only
be
wiped
with
a
damp
cloth.
Oil
and
grease
on
the
control
wheel
and
control
knobs can
be
removed
with
a
cloth
moistened
with Stoddard solvent.
Volatile
solvents,
such
as
mentioned
in
paragraph
2-31.
must
never
be
used
since
they
soften
and
craze
the
plastic.
2-33. PAINTED
SURFACES.
The
painted
exterior
surfaces
of
your
new Cessna
have
a
durable,
long
lasting
finish.
Approximately
10
days
are required
for the
paint
to
cure
completely;
in
most
cases,
the
curing
period
will
have
been
completed
prior
to
delivery
of
the
airplane.
In
the
event
that
polishing
or
buffing
is
required
within
the
curing
period,
it is
recommended
that
the
work
be
done
by
someone
experienced
in
handling
uncured
paint.
Any
Cessna
Deal-
er
can
accomplish
this
work.
2-20
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
Generally,
the
painted
surfaces
can
be
kept
bright
by
washing
with
water
and
mild
soap,
fol-
lowed
by
a
rinse
with
water
and
drying
with
cloths
or
chamois.
Harsh
or
abrasive
soaps
or
detergents
which
could
cause
corrosion
or
scratches should
never
be
used.
Remove
stubborn
oil
and
grease
with
a
cloth
moistened
with
Stoddard
solvent.
To
seal
any minor
surface
chips
or
scratches
and
protect
against
corrosion,
the
airplane
should
be
waxed
regularly
with
a good
automotive
wax
applied
in
accordance
with
the
man-
ufacturer's
instructions.
If
the
airplane
is operated
in a
seacoast
or
other
salt
water
environ-
ment,
it
must
be
washed
and
waxed
more
frequently
to
assure
adequate
protection.
Special
care
should
be
taken
to
seal
around
rivet
heads
and
skin
laps,
which
are
the areas most
sus-
ceptible
to
corrosion.
A
heavier
coating
of
wax
on
the
leading
edges
of
the
wings
and
tail
and
on
the
cowl
nose
cap
and
propeller
spinner
will
help
reduce
the
abrasion
encountered
in
these
areas.
Reapplication
of
wax
will
generally
be
necessary
after
cleaning with
soap
solu-
tions
or after
chemical
de-icing
operations.
2-34.
ALUMINUM
SURFACES.
The
aluminum
surfaces
require
a
minimum
of
care,
but should
never
be
neglected.
The
aircraft
may
be
washed
with
clean
water
to
remove
dirt
and may
be
washed
with
nonalkaline grease
solvents
to
remove
oil
and/or
grease.
Household type
deter-
gent
soap
powders
are
effective
cleaners,
but
should
be
used
cautiously
since
some
of
them
are
strongly
alkaline.
Many
good
aluminum
cleaners,
polishes
and
waxes
are
available
from
commercial
suppliers
of
aircraft
products.
2-35.
ENGINE
AND
ENGINE
COMPARTMENT.
An
engine
and
accessories
wash-down
should
be
accomplished
during
each
100-hour
inspection
to
remove
oil,
grease,
salt
corrosion
or
other
residue
that
might
conceal
component
defects
during
inspection.
Also,
periodic
cleaning
can
be
very
effective
preventive
maintenance.
Precautions
should
be
taken
when
working
with
cleaning
agents
such
as
wearing
of
rubber
gloves,
an
apron
or
coveralls
and
a
face
shield
or
goggles.
Use
the
least
toxic
of
available
cleaning
agents
that
will
satisfactorily
accomplish
the
work.
These
cleaning
agents
include:
(1)
Stoddard
Solvent (Specification
P-D-680
type
II),
(2)
A
water
alkaline
detergent
cleaner
(MIL-C-25769J)
mixed,
1
part
cleaner,
2
to
3
parts
water
and
8
to
12
parts
Stoddard
solvent
or
(3)
A
solvent
base
emulsion
cleaner
(MIL-C-4361B)
mixed
1
part
cleaner and
3
parts
Stod-
dard
sovlent.
CAUTION
Do
not
use
gasoline
or
other
highly
flammable
sub-
stances
for
wash
down.
Revision
1
2-21
MODEL
172
SERIES
SERVICE
MANUAL
Perform all
cleaning
operations
in
well
ventilated
work
areas
and
ensure
that
adequate
fire-
fighting
and
safety
equipment
is available.
Do
not
smoke
or
expose
a
flame,
with
100
feet
of
the
cleaning
area.
Compressed
air,
used
for
cleaning
agent,
application
or
drying,
should
be
regulated
to
the
lower
practical
pressure.
Use
of
a
stiff
bristle
brush
rather
than
a
steel
brush
is
recommended
if
cleaning
agents
do
not
remove
excess
grease
and
grime
during
spraying.
A
recommended
procedure
for
cleaning
an
engine
and
accessories
is
as
follows:
CAUTION
Do
not
attempt
to
wash
an
engine
which
is
still hot
or
running.
Allow
the engine
to
cool
down
before
cleaning.
a.
Remove
engine
cowling.
b.
Carefully
cover
the
coupling
area
between
the vacuum
pump
and the
engine
drive
shaft
so
that
no
cleaning
solvent
can
reach
the
coupling
or
seal.
c.
Cover
the
open
end
of
the
vacuum
discharge
tube.
d.
Cover
the
vacuum
relief
valve
filter,
if
installed
in
the
engine
compartment.
e.
Use
fresh
water
for
wash-down
when
the
engine
is
contaminated
with
salt
or
corro-
sive
chemicals.
A
cleaning
agent
such
as
described
previously
may
then
be
used
to
remove
oil
and
grime.
CAUTION
Care
should
be
exercised
to
not
direct
cleaning
agents
or
water
streams
at
openings
on
the
starter,
magnetos,
al-
ternator
or
vacuum
pump.
f.
Thoroughly rinse
with
clean
warm
water
to
remove
all
traces
of
cleaning
agents.
CAUTION
Cleaning
agents
should
never
be
left
on
engine
compo-
nents
for
an extended
period
of
time.
Failure
to remove
them
may
cause
damage
to
components
such
as
neoprene
seals
and
silicone
fire
sleeves,
and
could
cause
additional
corrosion.
2-22
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
g.
Completely
dry
engine
and
accessories
using
clean,
dry
compressed
air.
h.
Remove
the
cover over
the
coupling
area
i.
Remove
the
cover
from the
vacuum
discharge
tube.
j.
Remove
the
cover
from
the
vacuum
relief
valve
filter,
if
installed.
k.
If
desired,
engine
cowling
may
be
washed
with
the
same
cleaning
agents,
then
rinsed
thoroughly
and
wiped
dry.
After
cleaning
engine,
relubricate
all
control
arms
and
moving
parts
as
required.
WARNING
For
maximum
safety,
check
that
the
magneto
switches
are
off,
the
throttle
is
closed,
the
mixture
control
is in
the
idle
cut-off
position,
and
the
airplane
is
secured
be-
fore
rotating
the
propeller
by
hand.
Do
not
stand
within
the
arc
of
the
propeller
blades while
turning
the
propel-
ler.
m.
Before
starting
engine,
rotate the
propeller
by
hand
no
less
than
four
complete
revo-
lutions.
2-36.
UPHOLSTERY
AND
INTERIOR.
Keeping the
upholstery
and
interior
trim
clean prolongs
upholstery
fabric
and
interior
trim
life.
To
clean
the
interior,
proceed
as
follows:
a.
Empty
all
ash
trays
and
refuse
containers.
b.
Brush
or
vacuum
clean
the
upholstery
and
carpet
to
remove
dust
and
dirt.
c.
Wipe
leather
and
plastic trim
with
a
damp cloth.
d.
Soiled
upholstery
fabrics
and
carpet
may
be
cleaned
with
a
foam-type
detergent
used
according
to
manufacturer's instructions.
e.
Oil
spots
and
stains
may
be
cleaned
with
household spot
removers,
used
sparingly.
Before
using
any
solvent,
read
the
instructions
on
the
container
and
test
it
on
an
obscure
place
in
the
fabric to
be
cleaned.
Never
saturate
the
fabric
with
volatile
solvent;
it
may
damage
the
padding
and
backing
material.
f.
Scrape
sticky
material
from
fabric
with
a
dull
knife,
then
spot
clean
the
area.
Revision
1
2-23
MODEL
172
SERIES
SERVICE
MANUAL
2-37.
PROPELLER.
Wash
hub
and
blade
with
a
soft cloth
and Stoddard
cleaning
solvent
or
equivalent,
then
dry
thoroughly
with compressed
air.
The
propeller
should
be
wiped
occasionally
with
an
oily cloth,
then
wiped
with
a
dry
cloth.
In
salt
water
areas
this
will
assist
in
corrosion proofing
the
propeller.
2-38.
WHEELS.
The
wheels
should
be
washed
periodically
and
examined
for
corrosion,
chipped
paint,
and
cracks
or
dents
in
the
wheel
halves
or
in
the
flanges
or hubs.
If
defects
are
found,
remove
and
repair
in
accordance with Section
5.
Discard
cracked
wheel
halves,
flanges
or
hubs
and
install
new
parts.
2-39.
LUBRICATION.
2-40.
Lubrication
requirements
are
shown
in
figure
2-5.
Before
adding grease
to
grease
fittings,
wipe
dirt
from
fitting.
Lubricate
until
grease appears
around
parts
being
lubricated,
and
wipe
excess
grease
from
parts.
The
following
paragraphs
supplement
figure
2-5
by
adding
details.
2-41.
WHEEL
BEARINGS.
Clean
and
repack
the
wheel
bearings at
first
100-hour
inspection
and
at
each
500-hour
inspection
thereafter.
If
more
than
the
usual
number
of
takeoffs
and
landings
are
made,
extensive
taxiing
is
required,
or
the
aircraft
is
operated
in
dusty
areas
or
under
seacoast
conditions,
cleaning
and
lubrication
of
the
wheel
bearings
shall
be
accomplished
at
each
100-hour
inspection.
2-42.
NOSE
GEAR
TORQUE
LINKS.
Lubricate
nose
gear
torque
links
every
50
hours.
When
operating
in
dusty
conditions,
more
frequent
lubrication
is
required.
2-43.
WING
FLAP
ACTUATOR.
Clean
and
lubricate
wing
flap
actuator
jack
screw each
100
hours
as
follows:
a.
Expose
jack
screw
by
operating flaps
to full down
position.
b.
Clean
jack
screw
threads
with
solvent
rag
and
dry with
compressed
air.
NOTE
It is
not
necessary
to
remove
actuator
from
aircraft
to
clean
or
lubricate
threads.
c.
With
oil
can,
apply
light
coat
of
No.
10
weight,
non-detergent
oil
to
threads
of
jack
screw.
2-24
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
2-44.
FUEL
SELECTOR VALVE.
At
each
100
hour
inspection,
check
the
fuel
selector
valve
and
drive
shaft
for
the
following:
a.
Valve
control detent
plate
for
cleanliness and
excessive
wear.
Dirt accumulation
on
this
plate
can
cause
binding,
poor
detent
feel
and rapid
wear
of
the
plate.
b.
All
drive
shaft
attach
points
for
security,
binding,
excessive
wear
and
lubrication,
if
required.
c.
Operate
valve
handle
through
all
positions
and
check
for
proper
operation,
detent
feel
and
freedom
of
movement.
2-45.
ROD
END
BEARINGS.
Periodic
inspection
and
lubrication
is
required
to
prevent
corrosion
of
the
bearing
in
the
rod end.
At
each
100-hour
inspection,
disconnect
the
control
rods
at
the
aileron,
flap
and
nose
gear
steering
rods,
and
inspect
each
rod
end
for
corrosion.
If
no
corrosion
is
found,
wipe
the
surface
of
the
rod
end
balls
with
general
purpose
oil
and
rotate
ball
freely
to
distribute the
oil
over
its
entire
surface
and
connect
the
control
rods
to
their
re-
spective
units.
If
corrosion
is
detected
during
the
inspection,
install
new
rod
ends.
Revision
1
2-25
MODEL
172
SERIES
SERVICE
MANUAL
Refer
to
Sheets
2
& 3
for
Fuel
and
Oil
Specifications.
Figure
2-4.
Servicing
(Sheet 1
of
6)
2-26
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
SPECIFIED
AVIATION
GRADE
FUELS:
WARNING
ONLY AVIATION
GRADE
FUELS
ARE
APPROVED
FOR
USE.
ENGINE MODEL
APPROVED
FUEL
GRADES
NOTE
100LL
(blue)
1
LYCOMING
0-320-H2AD LYCOMING
O-320-100
(green)
(formerly
100/130)
1
NOTE
1.
Compliance
with
Avco
Lycoming
Service Instruction
No.
1070,
and
all
revisions
thereto,
must
be
accomplished.
SPECIFIED
AVIATION
GRADE
OIL:
AVERAGE
AMBIENT
TEMPERATURE
(°F)/OIL
GRADE
MAXIMUM
OIL
TEMPERATURE
0°
10°
20°
30
°
40°
50
°
60°
70
°
80°
90
°°
F
SAE
60 245
°
SAE 40
or
SAE
50
SAE
40
245°
SAE
30.
SAE
40
or
SAE
20W-40
SAE 30
or
210°
SAE
20W-30
SAE
15W-50
or
SAE
20W-50
245°
The
overlap
of
oil
grades
is
based
on a
mid-range
of
ambient
ground
temperature
vs
maximum oil
inlet
temperature.
Aviation
grade
ashless dispersant
oil
conforming
to
Avco
Lycoming
Service
Instruction
No.
1392,
and
all
revisions
and
supplements
thereto
MUST
BE
USED.
Oil
capacities
for
the
aircraft
are
given in
the
following
chart
For
extended
flight,
fill
to
FULL
mark
on
dipstick.
Do
not
operate
with
less
than
MINIMUM
FOR
FLIGHT
quantities
listed.
If
an
external
oil
filter
is installed,
one
additional
quart
of
oil
is
re-
quired
when
filter
is
changed.
CAPACITY
CAPACITY (TOTAL
NORMAL
MINIMUM
(TOTAL)
WITH
FILTER)
OPERATION
FOR
FLIGHT
6
67 5 4
Figure
2-4.
Servicing
(Sheet
2
of
6)
Revision
1
2-27
MODEL
172
SERIES
SERVICE
MANUAL
SPECIFIED
AVIATION
GRADE
FUELS:
WARNING
ONLY
AVIATION
GRADE FUELS
ARE
APPROVED
FOR
USE.
ENGINE MODEL
APPROVED
FUEL
GRADES
NOTE
LYCOMING
0-320-D2J
&
0-360-A4N
100LL
(blue)
100
(green)
(formerly
100/130)
1
NOTE
1.
Compliance
with
Avco
Lycoming
Service
Instruction
No.
1070,
and
all
revisions
thereto,
must
be
accomplished.
SPECIFIED
AVIATION
GRADE
OIL:
AVERAGE
AMBIENT
TEMPERATURE
(°F)/OIL
GRADE
MAXIMUM
OIL
TEMPERATURE
0°
10°
20
°
30°
40
°
50°
60°
70° 80°
90°
°
F
SAE
60
245°
SAE
40
or
SAE
50
245
°
SAE
30,
SAE
40
or
SAE
20W-40
245
°
SAE
30 or
SAE
20W-30
210°
SAE
15W-50
or
SAE
20W-50
245
°
Aviation
grade
oils
conforming
to
Avco Lycoming
Service Instruction
No.
1014,
and
all
revisions
and
supplements
thereto,
MUST
BE
USED,
except
as
noted
in
paragraph
2-21.
Oil
capacities
for
the
aircraft-
are
given
in
the
following
chart.
For
extended
flight,
fill
to
FULL
mark
on
dipstick.
Do
not
operate
with
less
than
MINIMUM
FOR
FLIGHT
quantities
listed.
If
an
external
oil
filter
is
installed,
one
additional
quart
of
oil
is
re-
quired
when
filter
is
changed.
CAPACITY
CAPACITY
(TOTAL
NORMAL
MINIMUM
(TOTAL)
WITH
FILTER)
OPERATION
FOR
FIGHT
7
8 6
5
Figure
2-4.
Servicing
(Sheet
3
of
6)
2-28
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
DAILY
3
FUEL
TANK
OR
BAY
FILLER
Service
after
each
flight.
Keep
full to
retard
condensation.
Refer
to
paragraph
2-18
for
details.
4
FUEL
TANK
OR
BAY
SUMP
DRAINS:
Drain
off
any
water
and
sediment
before
first
flight
of
the
day.
10
FUEL
STRAINER
Drain
off
any
water
and
sediment
before
first
flight
of
the
day.
Refer
to
paragraph
2-19
for
details.
6
PITOT
AND
STATIC PORTS
Check
for
obstructions
before
first
flight
of
the
day.
13
INDUCTION
AIR
FILTER
Inspect
and
service
under
dusty
conditions.
Refer to
paragraphs
2-22
and
2-22A
for
details.
16
OIL
DIPSTICK
Check
oil
on
preflight.
Add
oil
as
necessary.
Refer
to
paragraph
2-21
for
details.
Gouges
or
deep
marks
on
the
lower
end
of
the
dipstick
would
be
evidence
of
prior
in-
terference
with
the
crankshaft
and
is
cause
for
further
investigation
of
the
engine.
18
OIL
FILLER
CAP
Whenever
oil
is
checked
or
added,
check
that
filler
cap
is
tight
and
oil
filler
door
is
secure.
FIRST
25
HOURS
15
ENGINE
OIL SYSTEM
On
O-320-H2AD
engines,
drain
oil
sump and
clean
pressure
screen
or
replace
oil fil-
ter,
if
installed.
Refill
with
MIL-L-22851
Ashless
Dispersant
Oil.
(See
figure
2-4.)
On
O-320-D2J
engines,
drain
oil
sump,
replace
oil
filter
and
refill with
MIL-L-6082
Avia-
tion
Grade
Mineral
Oil.
FIRST
50
HOURS
15
ENGINE
OIL
SYSTEM
On
O-320-H2AD
engines,
drain
oil
sump
and
clean
pressure
screen
or
replace
oil
fil-
ter,
if
installed.
Refill
with
MIL-L-22851
Ashless
Dispersant
Oil.
(See
figure
2-4.)
On
O-320-D2J
Engines,
drain
oil
sump,
replace
oil
filter
and
service
with
MIL-L-22851
Ashless
Dispersant
Oil
in
accordance with
oil
chart
in
figure
2-4.
Figure
2-4.
Servicing
(Sheet
4
of
6)
Revision
1
2-29
MODEL
172
SERIES
SERVICE
MANUAL
50
HOURS
15
ENGINE
OIL
SYSTEM (WHEN
NOT
EQUIPPED
WITH
EXTERNAL
OIL
FILTER)
Drain
engine
oil
sump,
clean
oil
pressure
screen,
and
refill with
ashless
dispersant
oil.
NOTE
Refer
to
100
hour
servicing
interval
when
equipped
with
long
external
oil
filter.
100
HOURS
12
NOSE
GEAR
SHIMMY
DAMPER
Check
fluid
level
and
refill
as
required
with
hydraulic
fluid.
Refer
to
paragraph
2-27
for
details.
11
NOSE
GEAR
SHOCK
STRUT
Keep
strut
filled and
inflate
to
correct pressure.
Refer to
paragraph
2-26
for
details.
13
INDUCTION
AIR
FILTER
Clean
filter
per
paragraph
2-22
(172
&
F172 Series)
and
paragraph
2-22A
(Model
172Q
Only).
Replace
as
required.
14
BATTERY
Check
electrolyte
level
each
100
hours
or
each
90
days,
which
ever
comes
first.
7
TIRES
Maintain
correct
tire
inflation
as listed
in
figure
1-1.
Also
refer
to
paragraph
2-25
for
details.
5
FUEL
SELECTOR
VALVE
DRAIN
Drain
off
any
water
or
sediment.
Refer
to
paragraph
2-19.
10
FUEL
STRAINER
Disassemble
and
clean
strainer
bowl
and
screen.
15
ENGINE
OIL
SYSTEM
On
O-320-H2AD
engines,
drain
oil
sump
and
clean
pressure
screen
or
replace
oil
filter,
if
installed.
Refill
with
MIL-L-22851
Ashless
Dispersant
Oil.
(See
figure
2-4.)
On
0-320-
D2J
and 0-360-A4N
engines,
drain
oil
sump,
replace
oil
filter,
and
service
with
MIL-L-
22851
Ashless
Dispersant
oil
in
accordance
with
oil
chart
in
figure
2-4.
NOTE
Refer
to
50
hour
servicing
interval
when
not
equipped
with
long
external
oil
filter.
Change
engine
oil
at
least
every
6
months,
even
though
the recommended
hours
have
not
accumulated.
Figure
2-4.
Servicing
(Sheet
5
of
6)
2-30
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
1
VACUUM
RELIEF
VALVE
URETHANE
FILTER
Replace
filter.
2
VACUUM
SYSTEM
CENTRAL
AIR
FILTER
Inspect
for
damage.
See
paragraph
2-23
for
details.
BRAKE
MASTER CYLINDERS
Check
fluid
level
and
refill
as
required
with
hydraulic
fluid.
Refer
to
paragraph
2-28
for
details.
200
HOURS
8
GROUND
SERVICE RECEPTACLE
Connect to
24-volt
DC.
negative-ground
power
unit.
Refer
to
Section
11
for
details.
500
HOURS
2
VACUUM
SYSTEM
CENTRAL AIR
FILTER
Replace
every
500
hours.
Figure
2-4.
Servicing
(Sheet
6
of
6)
Revision
1
2-31
MODEL
172
SERIES
SERVICE
MANUAL
FREQUENCY
(HOURS)
METHOD
OF
APPLICATION
HAND
GREASE
OIL
SYRINGE
GUN
CAN
(FOR
POWDERED
GRAPHITE)
WHERE
NO
INTERVAL
IS
SPECIFIED,
LUBRICATE
AS
REQUIRED
AND
WHEN ASSEMBLED
OR
INSTALLED.
NOTE
The
military
specifications
listed
are
not
mandatory,
but
are
intended
as
guides
in
choosing
satisfactory materials.
Products
of
most
reputable
manufacturers
meet
or
exceed
these
specifications.
LUBRICANTS
PG
-
SS-G-659
............
POWDERED
GRAPHITE
GR-
MIL-G-81322A
..........
GENERAL
PURPOSE
GREASE
GH-
MIL-G-23827A
...........
AIRCRAFT
AND
INSTRUMENT
GREASE
GL-
MIL-G-21164C
...........
MOLYBDENUM
DISLULFIDE GREASE
OG
-
MIL-L-7870A
..........
GENERAL
PURPOSE
OIL
PL-
VV-P-236
.............
PETROLATUM
GP-.....
NO.
10-WEIGHT,
NON-DETERGENT
OIL
OL-
VV-L-800A
............
LIGHT
OIL
SYSTEM
ALSO
REFER
TO
OG
SHIMMY
DAMPENER
PIVOTS
ALSO
REFER
TO
BEARING
2-32
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
CONTROL
WHEEL SHAFT
BUSHINGS
AND
UNIVERSALS
BUSHINGB
AND
BATTERY
ELEVATOR
TRIM TAB
ACTUATOR
ALSO
REFER
TO
INSPECTION
CHART
IN
THIS
SECTION
AND
TO SECTION
9
OF
THIS MANUAL
NEEDLE
BEARNGS
CONTROL
"U"
ALL
PLANO
HINGES
*ENGINE
CONTROLS
USE NO
LUBRICANT
UNDER
EXTREME
DUSTY
CONDITIONS
AILERON BELLCRANK
NEEDLE
BEARINGS
ROD
END
BEARINGS
TYPICAL
SPRING
STOP
CABIN
DOOR
WINDOW
INSERT
GROOVES
Figure
2-5.
Lubrication.
(Sheet
2
of
3)
Revision
1
2-33
MODEL
172
SERIES
SERVICE
MANUAL
ALL
LINKAGE
OILITE
BEARINGS
POINT
PIVOTS
NEEDLE
(RUDDER
BAR
ENDS)
BEARINGS
.
RUDDER
BARS
AND
PEDALS
WING
SPAR
AND
STRUT-ATTACH
,
BOLTS
ELECTRIC
FLAP
DRIVE
MECHANISM
REFER
TO
SCREW JACK
PARAGRAPH
2-43
THREADS
NOTES
Sealed
bearings
require
no
lubrication.
Do
not
lubricate
roller
chains
or
cables
except
under
seacoast
conditions.
Wipe
with
a
clean,
dry
cloth.
Lubricate
unsealed
pulley
bearings,
rod
ends,
Oilite
bearings,
pivot
and
hinge
points, and
any
other
friction
point
obviously
needing
lubrication,
with
general purpose
oil
every
1000
hours
or
oftener
if
required.
Paraffin
wax
rubbed
on
seat
rails
will
ease
sliding the
seats
fore
and aft.
Lubricate
door
latching
mechanism
with
MIL-G-81322A
general
purpose
grease,
applied
sparingly
to
friction
points,
every
1000
hours
or
oftener,
if
binding
occurs.
No
lubrication is
recommended
on
the
rotary
clutch.
Figure 2-5.
Lubrication
(Sheet
3
of
3)
2-34
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
2-46.
GENERAL
INSPECTION
(MODEL
172
AIRPLANES).
NOTE
Cessna
Aircraft
Company
recommends PROGRESSIVE
CARE
for airplanes
flown
200
hours
or
more
per
year,
and
100-HOUR
INSPECTION
for airplanes
flown
less
than
200
hours
per
year.
A.
Inspection
Requirements.
(1)Two
basic
types
of
inspections
are
available
as
defined
below:
(a)
As
required
by
Federal
Aviation
Regulation Part
91.409(a),
all
civil
airplanes
of
U.S.
registry
must
undergo
an
annual
inspection each
12
calendar
months.
In
addition
airplanes operated
commercially
(for
hire)
must
also
have
an
annual
100
hour
inspection
each
100
hours
of
operation
as
required
by
Federal
Aviation
Regulation Part
91.409(b).
(b)
In
lieu
of
the
above
requirements,
an
airplane may
be
inspected
in
accordance
with
a
progressive
inspection
program
in
accordance
with
Federal
Aviation
Regulation
Part
91.409(d), which
allows
the
work
load
to
be
divided
into
smaller
operations
that
can
be
accomplished
in
a
shorter
time
period.
The
CESSNA
PROGRESSIVE
CARE
PROGRAM
has
been
developed
to
satisfy
the
requirements
of
Part
91
409
(d).
B.
Inspection
Program
Selection.
(1)
As
a
guide
for
selecting
the
inspection
program
that
best
suits
the
operation
of
the
airplane,
the
following
is
provided:
(a)
If
the
airplane is flown less than
200 hours
annually,
the
following
conditions
apply:
1. If
flown
for
hire.
a.
An
airplane
operating
in
this
category
must
be
inspected
each
100
hours
of
operation
(100-HOUR)
and
each
12
calendar
months
of
operation
(ANNUAL).
2.
If
not
flown
for
hire.
a.
An
airplane
operating
in
this
category
must
be
inspected
each
12
calendar
months
of
operation
(ANNUAL).
It
is
recommended that
between
annual
inspections,
all
items
be
inspected
at
the
intervals
specified
in
the
Inspection
Time
Limits Charts
and
Component
Time
Limits
Charts.
(b)
If
the
airplane
is
flown
more
than 200 hours
annually,
the
following
condition
applies:
1.
Whether
flown
for
hire
or not,
it is
recommended
that
airplanes
operating
in
this
category
be
placed on
the
CESSNA
PROGRESSIVE
CARE
PROGRAM.
However.
if
not
placed
on the
CESSNA
PROGRESSIVE
CARE
PROGRAM,
the
inspection
requirements
for
airplanes
in
this category
are
the
same
as
those
defined
under
Paragraph
B.
(1)(a)1.a. or 2.a.
CESSNA PROGRESSIVE
CARE
PROGRAM
may
be
utilized
as
a
total
concept
program
which
ensures
that
the
inspection
intervals in
the
inspection
charts
are
not
exceeded.
Manuals
and
forms
which
are
required
for
conducting the
CESSNA
PROGRESSIVE
CARE
PROGRAM
inspections
are
available
from the
Cessna
Supply
Division.
Revision
2 2
35
MODEL
172
SERIES
SERVICE
MANUAL
C.
Inspection
Charts.
NOTE
Cessna
has
prepared
these
Inspection
Charts
to
assist
the owner
or
operator
in
meeting
the
foregoing
responsibilities
and
to
meet
the intent
of
Federal
Aviation
Regulation
Part
91.409(d).
The
Inspection
Charts
are
not
intended to
be
all-
inclusive,
for
no
such
charts
can
replace
the
good
judgment
of
a
certified
airframe
and
powerplant
mechanic
in
performance
of
his
duties.
As
the one
primarily
responsible
for
this
airworthiness
of
the
airplane,
the owner
or
operator
should
select
only
qualified
personnel
to maintain the
airplane.
(1)
The
following
Inspection
Charts
(Inspection
Time
Limits, Component
Time
Limits,
Progressive
Care
Inspection,
and
Expanded Inspection)
show
the
recommended
intervals
at
which
items
are
to
be
inspected
based
on
normal
usage
under
average
environmental conditions.
Air-
planes operated
in
extremely
humid
tropics,
or
in
exceptionally
cold,
damp
climates,
etc.,
may
need
more
frequent
inspections
for
wear,
corrosion,
and
lubrication.
Under
these
adverse
con-
ditions,
perform
periodic
inspections
in
compliance
with
this chart
at
more
frequent
intervals
until the
operator
can
set
his
own
inspection
periods
based
on
field
experience.
The opera-
tor's
inspection
intervals
shall
not
deviate
from
the
inspection time
limits
shown
in
this
manual
except
as
provided
below:
(a)
Each
inspection
interval
can
be
exceeded
by
10
hours
or
can
be
performed
early
at
any
time prior
to
the
regular
interval
as
provided below:
1. In
the
event
of late
compliance
of
any operation
scheduled, the
next
operation
in
sequence
retains
a
due
point
from
the
time
the
late
operation was
originally
sched-
uled.
2.
In
the
event
of
early
compliance
of
any
operation
scheduled, that
occurs
10
hours
or
less
ahead
of
schedule,
the
next
phase
due
point
may
remain where
originally
set.
3.
In
the
event
of
early
compliance
of
any
operation
scheduled,
that
occurs
more
than
10
hours ahead
of
schedule, the
next
phase due
point
must
be
rescheduled
to
es-
tablish
a
new
due point
from
the
time
of early
accomplishment.
(2)
As
shown
in
the
charts,
there
are
items
to
be
checked
at 50
hours,
100
hours,
200
hours,
or
at
Special
of
Yearly
inspection.
Special
or
Yearly
inspection
items
require
servicing
or
inspec-
tion
at
intervals
other
than
50.
100,
or
200
hours.
If
two
inspection
time
requirements
are
list-
ed
for
one
inspection
item,
one
hourly
and
the
yearly, both
apply
and
whichever
requirement
occurs first
determines
the
time
limit.
(a)
When
conducting
a
50-hour
inspection. check
all
items
listed
under EACH
50
HOURS.
A
100-hour
inspection
includes
all
items listed
under
EACH
50
HOURS
and
EACH
100
HOURS.
The
200-hour
inspection
includes
all
items
listed
under
EACH
50
HOURS,
EACH 100
HOURS,
and
EACH
200
HOURS.
All
of
the
items
listed
would
be
inspected,
serviced, or
otherwise
performed
as
necessary
to
ensure compliance
with
the
inspection
requirements.
(b)
A
COMPLETE
AIRPLANE
INSPECTION
includes
all
50-,
100-,
and
200-hour
items
plus
those Special
and
Yearly
Inspection
Items
which
are
due
at the
specified
time.
(c)
Component
Time
Limits
Charts
should
be
checked
at
each
inspection
interval
to
ensure
proper
overhaul
and replacement requirements
are
accomplished
at
the
specified times.
2-36
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
D.
Inspection
Guidelines.
(1)
The
Inspection
Charts
are
to be
used
as
a
recommended
inspection
outline.
Detailed
informa-
tion
of
systems
and components
in
the
airplane
will
be found
in
various
chapters
of
this
Main-
tenance
Manual
and the
pertinent
vendor
publications.
It
is
recommended
that
reference
be
made
to
the applicable
portion of
this
manual for
service
instructions, installation
instructions,
and
to
the
vendor's
data
or
publications
specifications
for
torque
values,
clearances, settings,
tolerances,
and
other
requirements.
(2)
For
the
purpose
of
this
inspection,
the term
on
condition
is
defined
as
follows:
The
neces-
sary
inspections
and/or
checks
to determine
that
a
malfunction
or failure
will
not
occur
prior
to
the
next scheduled
inspection.
(3)
MOVABLE
PARTS:
Inspect for
lubrication, servicing, security
of attachment, binding,
exces-
sive
wear,
safetying,
proper
operation, proper
adjustment,
correct
travel,
cracked
fittings,
se-
curity
of
hinges, defective
bearings,
cleanliness, corrosion,
deformation,
sealing,
and
tension.
(4)
FLUID
LINES
AND
HOSES:
Inspect for
leaks,
cracks,
bulging,
collapsed,
twisted,
dents,
kinks, chafing,
proper
radius,
security, discoloration,
bleaching,
deterioration,
and
proper
rout-
ing;
rubber
hoses for
stiffness
and
metal
lines
for
corrosion.
(5)
METAL PARTS:
Inspect
for
security
of
attachment,
cracks,
metal
distortion,
broken
spotwelds,
condition
of
paint
(especially
chips
at
seams
and
around
fasteners
for
onset
of
corrosion)
and
any
other
apparent
damage.
(6)
WIRING:
Inspect
for
security,
chafing,
burning,
arcing,
defective
insulation,
loose or
broken
terminals,
heat
deterioration,
and
corroded
terminals.
(7)
STRUCTURAL
FASTENERS:
Inspect
for
correct torque
in
accordance
with
applicable
torque
values. Refer
to
Bolt
Torque
Data
during
installation
or
when
visual
inspection
indicates
the
need
for
a
torque
check.
NOTE
Torque values
listed
are
not
to
be
used
for
checking tightness
of
installed
parts
during
service.
(8)
FILTERS, SCREENS,
AND FLUIDS:
Inspect
for
cleanliness
and
the
need
for
replacement
at
specified
intervals.
(9)
System
check
(operation
or
function)
requiring
electrical
power
must
be
performed using
28.5
±0.25
volts
bus
voltage.
This
will
ensure
all
components
are
operating
at
their
designed
re-
quirements.
(a)
Airplane
file.
1.
Miscellaneous
data,
information,
and
licenses
are
a
part
of
the
airplane
file.
Check
that
the
following
documents
are
up-to-date
and
in
accordance
with
current
Federal
Aviation
Regulations. Most
of the
items
listed
are
required
by the
Federal
Aviation
Regulations.
Since
the
regulations
of
other
nations
may
require
other
documents
and
data,
owners
of
exported
airplanes
should
check
with
their
own
aviation
offi-
cials
to
determine
their individual requirements.
a.
To
be
displayed
in
the
airplane
at
all
times:
1)
Standard
Airworthiness
Certificate
(FAA
Form
8100-2).
2)
Aircraft
Registration Certificate
(FAA
Form
8050-3).
3)
Aircraft Radio
Station
License
(Federal
Communication Commission
Form
556
if
transmitter
is
installed).
4)
Radio
Telephone
Station
License
(Federal
Communication
Commission
Form
409
it
Flitetone
Radio
Telephone
is
installed).
b.
To
be
carried
in
the
airplane
at all
times:
1)
Weight
and
Balance
Data
Sheets
and
associated papers
(all
copies
of
the
Repair
and
Alteration
Form,
FAA
Form
337,
are
applicable).
2)
Equipment
List.
3)
Pilot's Operating Handbook
and
FAA-Approved
Airplane
Flight
Manual.
c.
To
be
made
available
upon request:
1)
Airframe,
Engine,
Propeller,
and
Avionics Maintenance
Records.
Revision
2 2
37
MODEL
172
SERIES
SERVICE
MANUAL
2-47.
PRE-INSPECTION
CHECKS.
(MODEL
172
AIRPLANES.)
A.
Pre-inspection Operational
Checks.
(1)
Before
beginning
the
step-by-step inspection,
start
and
run
up
the engine
and
upon
comple-
tion,
shut
down
the engine
in
accordance
with
instructions
in
the
Pilot's
Operating
Handbook
and
FAA-Approved
Airplane Flight
Manual.
During
the
run-up,
observe
the
following,
making
note
of
any
discrepancies
or
abnormalities:
(a)
Engine
temperatures
and
pressures.
(b)
Static RPM. (Also
refer
to
Section
11
and 11A
of
this
manual.)
(c)
Magneto
drop.
(Also
refer
to
Section
11
and
11A
of
this
manual.)
(d)
Engine
response
to changes
in
power.
(e)
Any
unusual
engine
noises.
(f)
Fuel
selector
and/or
shutoff
valve;
operate
engine
on
each
tank
(or
cell)
position
and
OFF
position
long enough
to ensure
shutoff
and/or
selector
valve
functions
properly.
(g)
Idling
speed
and
mixture; proper
idle
cut-off.
(h)
Alternator and
ammeter.
(i)
Suction
gage.
(j)
Fuel
flow
indicator.
(2)
After
the
inspection
has been
completed,
an
engine
run-up
should
again
be
performed
to
de-
termine
that
any
discrepancies
or
abnormalities have
been
corrected.
(3)
Some
of
the items
in
the
Inspection
Time
Limits
paragraph
are
optional,
therefore
not
applica-
ble
to
all
airplanes.
Mechanic's
Pre-nspection
Discrepancies or
Abnormalities to
be
Checked:
Mechanic's
Post-inspection
Corrective
Action
Taken:
2-38
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS HOURS
HOURS
HOURS
YEARS
A
Placards
(Refer
to
Pilot's
Operating
Handbook).
A
1
Placards and
Decals
-
Inspect
presence, legibility,
and
security.
Consult
Pilot's
Operating
Handbook
and
FAA-
Approved
Airplane
Flight
Manual
for
required placards.
B
Fuselage
(Section
3).
B
1
Fuselage
Surface
-
Inspect for
skin
damage,
loose rivets,
condition
of
paint,
and
check
pitot-static
ports
and drain
holes
for obstruction.
Inspect
covers
and
fairings
for
security.
B
2
Internal
Fuselage
Structure
-
Inspect
bulkheads,
doorposts,
stringers,
doublers,
and
skins
for
corrosion,
cracks,
buckles,
and
loose
rivets,
bolts
and nuts.
B
3
Control Wheel
Lock
-
Check
general condition
and
operation.
B
4
Fuselage
Mounted Equipment
-
Check
for
general
condition
and
security
of
attachment.
B 5
Antennas
and
Cables
-
Inspect
for security
of
attachment,
connection,
and
condition.
B
6
Emergency
Locator
Transmitter
-
Inspect for
security
of
attachment
and
check
operation
by
verifying transmitter
output. Check
cumulative
time
and
useful life
of
batteries
in
accordance
with FAR
Part
91.207.
Refer
to
Section
16
-
Emergency
Locator
Transmitter
-
Checkout
Interval.
B
7
Instrument
Panel
Shock
Mounts, Ground
Straps,
and
Covers
-
Inspect
for
deterioration, cracks,
and
security
of
attachment.
B
8
Pilot's
and
Copilot's
Inertia
Reels
-
Inspect
for
security
of
installation,
proper operation,
and
evidence
of
damage.
B
9
Seats.
Seat
Belts,
and
Shoulder
Harnesses
-
Check
general
condition
and
security. Check
operation
of
seat
stops
and
adjustment
mechanism. Inspect
belts
for
condition
and
security
of
fasteners.
B
10
Windows,
Windshield,
Doors,
and
Seals
-
Inspect
general
condition.
Check
latches,
hinges,
and
seals
for
condition,
operation,
and
security
of
attachment.
B
11
Upholstery,
Headliner,
Trim,
and
Carpeting
-
Check
EACH EACH
condition
and
clean
as
required.
400
1
B
12
Flight
Controls
-
Check
freedom
of movement
and
proper
operation
through
full
travel
with
and
without
flaps
extended. Check
electric
trim
controls
for
operation
(as
applicable).
B
13
Aileron,
Elevator,
and
Rudder
Stops
-
Check
for
damage
and
security.
B
14
Portable
Hand
Fire
Extinguisher
-
Inspect
for
proper
operating
pressure,
condition,
security
of
installation,
and
servicing
date.
B
15
Seat
Tracks
and
Stops
.
Inspect
seat
tracks
for
condition
and
security
of
installation. Check
seat
track
stops
for
damage
and
correct
location.
Ensure
inspection
of
seat
rails
for
cracks
EACH
50
HOURS.
Refer
to
Section
3.
Revision
3
2-39
MODEL
172
SERIES
SERVICE
MANUAL
SPECIAL
EACH EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS. (MODEL
172
50
100
200
AIRPLANES.)
HOURS
HOURS
HOURS
HOURS
YEARS
B
16
Control
Column
-
Inspect
pulleys,
cables,
sprockets,
bearings,
chains,
bungees,
and
turnbuckles
for
condition
and
security.
B
17
Fuel
Line
and
Selector
Valve
Drain(s)
-
Remove
plug
and
drain.
C
Wings
and
Empennage
(Section
4).
C 1
Wing
Surfaces
and
Tips
-
Inspect
for
skin damage,
loose
rivets,
and
condition
of
paint.
C
2
Wing
Struts
and Strut
Fairings
-
Check
for
dents,
cracks,
loose
screws
and
rivets,
and
condition
of
paint.
C
3
Wing
Spar and
Wing
Strut
Fittings
-
Check
for evidence
of
wear.
Check
attach
bolts
for
indications
of
looseness
and
retorque
as required.
C
4 Wing
Structure
-
Inspect
spars,
ribs,
skins,
and
stringers
for
cracks,
wrinkles,
loose
rivets,
corrosion,
or
other
damage.
C
5
Metal
Lines,
Hoses,
Clamps,
and
Fittings
- Check
for
leaks,
condition,
and
security.
Check
for
proper
routing
and
support.
C
6
Wing
Access
Plates
-
Check for damage
and
security
of
installation.
C
7
Vertical
and
Horizontal
Stabilizers,
Tips
and
Tailcone
-
Inspect
externally
for
skin
damage and
condition
of
paint.
C
8
Vertical
and
Horizontal
Stabilizers
and
Tailcone
Structure
-
Inspect
bulkheads,
spars,
ribs, and
skins
for
cracks,
wrinkles,
loose
rivets,
corrosion,
or
other
damage.
Inspect
vertical
and
horizontal
stabilizer
attach
bolts
for
looseness. Retorque
as
necessary.
Check
security
of
inspection
covers,
fairings,
and
tips.
D
Landing
Gear
and Brakes
(Section
5).
D 1
Brakes,
Master
Cylinders,
and
Parking
Brake
-
Check
master
cylinders
and
parking
brake
mechanism
for
condition
and
security.
Check
fluid
level
and
test
operation
of
toe
and
parking brake.
D
2
Main
Gear
Tubular
Struts
-
Inspect
for
cracks,
dents,
corrosion,
condition
of
paint
or
other
damage. Check
axles
for
condition
and
security.
D
3
Brake
Lines,
Wheel
Cylinders,
Hoses.
Clamps,
and
Fittings
EACH EACH
-
Check
for
leaks,
condition,
and
security
and
hoses
for 400
1
bulges
and
deterioration.
Check brake
lines
and
hoses
for
proper
routing
and
support.
D
4
Wheels,
Brake
Discs. and
Linings
-
Inspect for
wear,
cracks,
warps,
dents,
or
other damage.
Check
wheel
through-bolts
and
nuts
for
looseness.
D
5
Tires
-
Check
tread
wear
and
general
condition.
Check
for
proper
inflation.
D
6
Wheel
Fairings.
Strut
Fairings,
and
Cuffs
-
Check
for
A
cracks.
dents,
and
condition
of
paint.
D
7
Main
Landing
Gear
Attachment
Structure
-
Check
for
damage.
cracks,
loose
rivets, bolts
and
nuts
and
security
of
attachment.
2-40 Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS HOURS
HOURS HOURS
YEARS
D 8
Nose
Gear Steering
Mechanism
-
Check
for
wear,
security,
and
proper rigging.
D
9
Nose Gear
-
Inspect
torque
links, steering
rods,
and
boots
for condition
and
security
of
attachment.
Check strut
for
evidence
of
leakage
and proper extension.
Check
strut
barrel
for
corrosion, pitting,
and
cleanliness.
Check
shimmy
damper
and/or
bungees
for operation,
leakage,
and
attach
points
for
wear
and
security.
D
10
Nose
Gear
Fork
-
Inspect
for cracks,
general
condition,
and
security
of
attachment.
D
11
Wheel
Bearings
-
Clean,
inspect
and
lube.
B
D
12
Nose
Gear Attachment Structure
-
Inspect
for
cracks,
corrosion,
or
other
damage
and
security
of
attachment.
E
Aileron
Control
System (Section
6).
E 1
Ailerons
and
Hinges
-
Check
condition,
security
and
operation.
E
2
Aileron Structure, Control
Rods.
Hinges,
Balance
Weights,
Bellcranks,
Linkage,
Bolts, Pulleys,
and
Pulley
Brackets
-
Check
condition,
operation,
and
security of
attachment.
E
3
Ailerons
and
Cables
-
Check
operation
and
security
of
stops. Check
cables
for
tension,
routing,
fraying,
corrosion,
and
turnbuckle
safety.
Check travel
if
cable
tension
requires
adjustment
or
if
stops
are
damaged.
Check
fairleads
and
rub
strips
for
condition.
E
4
Autopilot
Rigging
-
Check
per Avionics
Installation
Manual.
C
E
5
Aileron Controls
- Check
freedom
of
movement
and proper
operation
through
full
travel
with
and
without
flaps
extended.
F
Wing
Flap
Control
System
(Section
7).
F 1
Flaps
-
Check
tracks,
rollers,
and
control
rods
for
security
of
attachment. Check
operation.
F
2
Flap
Actuator
Threads
-
Clean
and
lubricate. Refer
to
paragraph
2-43
for
detailed
instructions.
F
3
Flap
Structure,
Linkage, Bellcranks,
Pulleys,
and
Pulley
Brackets
-
Check
for
condition,
operation
and
security.
F
4
Wing
Flap
Control
-
Check
operation through full travel
and
observe
Flap
Position
indicator
for
proper
indication.
F
5
Flaps
and
Cables
-
Check cables
for
proper
tension.
routing,
fraying,
corrosion,
and
turnbuckle safety.
Check
travel
if
cable
tension
requires
adjustment.
F
6
Flap
Motor, Actuator,
and
Limit Switches
(electric
flaps)
-
Check
wiring
and
terminals
for condition
and
security.
Check actuator
for
condition
and
security.
G
Elevator Control
System
(Section
8).
G
1
Elevator
Control
-
Check
freedom
of
movement
and
proper
operation
through full travel
with
and
without
flaps
extended.
G
2
Elevator,
Hinges,
and
Cable
Attachment
-
Check
condition.
security,
and
operation.
Revision
3
2-41
MODEL
172
SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS
HOURS
HOURS
HOURS
YEARS
G
3
Elevator
Control System
-
Inspect
pulleys,
cables,
sprockets, bearings,
chains,
and
turnbuckles
for
condition,
security,
and
operation.
H
Elevator
Trim
Tab
Control
System
(Section
9).
H 1
Elevator Trim
Tab and
Hinges
-
Check
condition,
security,
and
operation.
H
2
Elevator
Trim
System
-
Check
cables,
push-pull
rods,
bellcranks,
pulleys,
turnbuckles,
fairleads, rub strips,
etc.
for
proper
routing,
condition,
and
security.
H
3
Trim
Controls
and
Indicators
-
Check freedom
of
movement
and proper operation
through
full
travel.
Check
pulleys,
cables, sprockets,
bearings,
chains,
bungees,
and
turnbuckles
for
condition
and
security.
Check
electric
trim
controls
for
operation
as
applicable.
H
4
Elevator Trim
Tab
Stop Blocks
-
Inspect
for
damage
and
security.
H
5
Elevator
Trim
Tab
Actuator
-
Clean,
lubricate,
and
check
D
free-play.
H
6
Elevator
Trim
Tab
Actuator
-
Free-Play
limits
inspection.
Refer to
Section 9
for cleaning,
inspection,
and
repair
procedures.
Rudder
Control
System
(Section
10).
I 1
Rudder
-
Inspect
the
rudder skins
for
cracks
and
loose
rivets,
rudder hinges
for
condition, cracks
and
security;
hinge
bolts,
hinge
bearings,
hinge
attach
fittings,
and
bonding
jumper
for
evidence
of
damage
and
wear,
failed
fasteners,
and
security.
Inspect
the rudder
hinge
bolts
for
proper
safetying
of
nuts
with
cotter
pins.
Inspect
balance
weight
for
looseness
and
the supporting
structure
for
damage.
2
Rudder
Pedals
and
Linkage
-
Check
for
general
condition,
proper
rigging,
and
operation.
Check
for
security
of
attachment.
3
Rudder,
Tips,
Hinges. and
Cable
Attachment
-
Check
condition,
security,
and
operation.
4
Rudder
-
Check
internal
surfaces for
corrosion, condition
of
fasteners,
and
balance
weight attachment.
J
Engines
(Sections
11
and
11
A).
J 1
Cowling
-
Inspect
for
cracks.
dents.
and
other
damage,
security
of
cowl fasteners,
and
cowl mounted
landing
lights
for
attachment.
J
2
Engine
- Inspect
for
evidence
of
oil
and
fuel
leaks.
Wash
engine
and
check
for
security
of
accessories.
J
3
Engine
Controls
and
Linkage
-
Check general
condition.
E
freedom of
movement through
full range.
Check
for
proper
travel.
security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks
for
proper operation.
J
4
Ignition
Switch
and
Electrical
Harness
-
Inspect
for
damage.
condition,
and
security.
2-42 Revision
3
MODEL 172
SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS
HOURS HOURS HOURS
YEARS
J
5
Firewall
Structure
-
Inspect
for
wrinkles,
damage,
cracks,
sheared
rivets,
etc.
Check
cowl
shock
mounts
for
condition
and
security.
J
6
Engine
Shock
Mounts,
Engine
Mount
Structure,
and
Ground
Straps
-
Check condition,
security,
and
alignment.
J
7
Induction System
-
Check
security of
clamps, tubes,
and
ducting.
Inspect
for
evidence
of
leakage.
J
8
Induction
Airbox,
Valves,
Doors,
and
Controls
-
Remove
air
filter
and
inspect
hinges, doors,
seals,
and
attaching
parts
for
wear
and
security.
Check
operation.
Clean
and
inspect.
J
9
Induction
Air
Filter
-
Remove
and
clean.
Inspect
for
F
damage,
and
service
per Paragraph
2-22
and
2-22A.
J
10
Alternate
Induction
Air
System
-
Check
for
obstructions,
operation,
and
security.
J
11
Alternator,
Mounting
Bracket
and
Electrical
Connections
-
Check condition
and
security.
Check
alternator
belts
for
condition
and
proper adjustment.
Check
belt
tension
per
Section
16,
Paragraph
16-38.
J
12
Alternator
-
Check
brushes,
leads,
commutator
or
slip
ring
G
for wear.
J
13
Starter,
Starter
Solenoid,
and
Electrical
Connections
- H
Check
for
condition
of
starter
brushes,
brush
leads,
and
commutator.
J
14
Oil
Cooler
-
Check
for obstructions,
leaks,
and
security
of
attachment.
J
15
Exhaust System
- Inspect
for
cracks
and
security.
Special
check
in
area
of
heat
exchanger.
Refer
to
Section
11,
Paragraph
11-73
for
inspection procedures.
J
16
Auxiliary
(Electric)
Fuel
Pump
(172Q)
-
Check
pump
and
fittings for
condition,
operation,
security.
Remove
and
clean
filter
(as
applicable).
J
17
Engine-Driven
Fuel
Pump
-
Check for
evidence
of
leakage,
security
of
attachment,
and
general
condition.
J
18
Magnetos
-
Check external
condition,
security,
and
electrical
leads
for condition.
Check
timing
to
engine
and
internal
timing
if
engine
timing
requires
adjustment.
J
19
Magnetos
-
Check
impulse
coupling
and
stop
pins
for
J
condition,
replace
as
required.
J
20
Magnetos
-
Inspection, lubrication,
and
overhaul
K
procedures.
J
21
Ignition
Harness
and
Insulators
-
Check
for
proper
routing,
deterioration.
and
condition
of
terminals.
J
22
Spark
Plugs
-
Remove.
clean,
analyze.
test.
gap,
and
rotate
top
plugs-to-bottom
and
bottom
plugs-to-top.
J
23
Cylinder
Compression
-
Perform
differential
compression
test.
J 24
Carburetor
-
Drain
and
flush
carburetor bowl,
clean
inlet
strainer,
and
drain
plug. Check general
condition
and
security.
J
25
Engine
Primer
-
Check for
leakage,
operation.
and
security.
Revision
3
2-43
MODEL
172
SERIES SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS
HOURS HOURS
HOURS
YEARS
J
26
Hoses.
Metal Lines,
and
Fittings
-
Inspect
for
signs
of
oil
and
fuel
leaks.
Check
for
abrasions,
chafing,
security,
proper
routing
and
support
and
for
evidence
of
deterioration.
J
27
Cold
and
Hot Air
Hoses
-
Check
condition, routing,
and
security.
J
28
Engine
Cylinders,
Rocker
Box
Covers,
and
Pushrod
Housings
-
Check
for
fin
damage,
cracks,
oil
leakage,
security
of
attachment,
and
general
condition.
J
29
Engine
Baffles
and
Seals
-
Check condition
and
security
of
attachment.
J
30
Crankcase,
Oil
Sump,
and
Accessory
Section
-
Inspect
for
cracks
and
evidence
of
oil
leakage.
Check
bolts
and
nuts
for
looseness
and
retorque
as
necessary.
Check
crankcase
breather
lines
for obstructions,
security,
and
general
condition.
J
31
Engine
Oil
With
Oil
Filter
-
Drain oil
sump
and
oil
cooler,
L
replace
filter
and
refill
with
recommended
grade
aviation
oil.
J
32
Engine
Oil
Without
Oil
Filter
-
Drain oil
sump
and
oil
L
cooler,
clean
and
inspect
screens,
and refill
with
recommended
grade
aviation oil.
K
Fuel
System
(Section
12).
K 1
Fuel
Tanks
or Integral
Fuel
Bays
-
Check
for
evidence
of
leakage
and
condition
of
fuel caps,
adapters,
and placards.
K
2
Fuel
Tanks
or
Integral
Fuel
Bays
-
Drain
fuel
and
check M
tank
interior
and
outlet
screens.
K
3
Fuel
System
-
Inspect
plumbing
and
components
for
mounting
and
security.
K
4
Fuel
Tank
or Bay Drains
-
Drain
water
and
sediment.
K
5
Fuel Tank Vent
Lines
and
Vent
Valves
-
Check
vents
for
obstruction
and proper
positioning.
K
6
Fuel
Selector
Valve
-
Check
controls
for
detent
in
each
position,
security
of
attachment,
and
for
proper
placarding.
K
7
Fuel
Strainer,
Drain
Valve,
and
Controls
-
Check
freedom
of
movement,
security,
and
proper
operation.
Disassemble.
flush,
and
clean
screen
and
bowl.
K
8
Fuel
Quantity
Indicators
-
Check
for
damage,
security
of
EACH
installation.
and
perform
accuracy test.
1
L
Propeller
and
Propeller
Governor
(Section
13).
L 1
Propeller
Mounting
-
Check
for security
of
installation.
L
2
Propeller
Blades
-
Inspect
for
cracks,
dents,
nicks,
scratches,
erosion,
corrosion,
or
other
damage.
L 3
Spinner
-
Check
general
condition
and
attachment.
L
4
Spinner
and
Spinner Bulkhead
-
Remove spinner,
wash,
and
inspect
for
cracks
and
fractures.
L
5
Propeller
Mounting
Bolts
-
Inspect
mounting
bolts
and
safety-wire
for
signs
of
looseness.
Retorque
mounting
bolts
as
required.
L 6
Propeller
Hub
-
Check
general
condition.
2-44
Revision 3
MODEL
172 SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS. (MODEL
172
50
100
200
AIRPLANES.)
HOURS
HOURS
HOURS
HOURS
YEARS
Utility
Systems
(Section
14).
M
1
Ventilation
System
-
Inspect clamps,
hoses,
and
valves
for
400
EACH
condition
and
security. 1
M
2
Heater
Components,
Inlets,
and
Outlets
-
Inspect
all
lines,
·
connections,
ducts,
clamps,
seals,
and
gaskets
for
condition.
restriction,
and
security.
M 3
Cabin
Heat
and
Ventilation Controls
-
Check
freedom
of
movement
through
full travel. Check
friction
locks
for
proper
operation.
M
4
Pitot
Tube
and
Stall
Warning
Vane
-
Check
for
condition
and
obstructions.
N
Instruments
and
Instrument
Systems
(Section
15).
N 1
Vacuum System
-
Inspect for
condition
and
security.
N
2
Vacuum
System
Hoses
- Inspect
for
hardness,
deterioration,
looseness,
or
collapsed
hoses.
N
3
Vacuum
Pump
-
Check
for
condition
and
security.
Check
vacuum
system
breather
line
for
obstructions,
condition,
and
security.
N
4
Vacuum System
Air
Filter
-
Inspect
for damage,
N
deterioration
and
contamination.
Clean or
replace,
if
required.
NOTE: Smoking
will
cause
premature filter
clogging.
N
5
Vacuum System
Relief Valve
-
Inspect
for
condition
and
O
security.
N
6
Instruments
-
Check
general
condition
and
markings
for
legibility.
N
7
Instrument
Lines,
Fittings,
Ducting,
and
Instrument
Panel
Wiring
-
Check
for
proper
routing,
support,
and
security
of
attachment.
N 8
Static
System
-
Inspect
for security
of
installation,
cleanliness,
and
evidence
of damage.
N 9
Navigation
Indicators, Controls,
and
Components
-
Inspect
for
condition
and
security.
N
10
Airspeed
Indicator, Vertical Speed
Indicator.
and
Magnetic
EACH
Compass
-
Calibrate.
2
N
11
Altimeter
and
Static
System
-
Inspect
in
accordance
with
EACH
FAR
Part
91.411.
2
N
12
Instrument
Panel
Mounted
Avionics
Units
(Including
Audio
Panel,
VHF
Nav Com(s),
ADF,
Transponder.
DME,
and
Compass
System)
-
Inspect
for
deterioration.
cracks.
and
security
of
instrument
panel
mounts. Inspect
for
security
of
electrical
connections,
condition,
and
security
of wire
routing.
N
13
Avionics
Operating Controls
-
Inspect
for
security
and
proper
operation
of
controls
and
switches
and
ensure
that
all
digital
segments
will
illuminate
properly.
N
14
Remote
Mounted
Avionics
-
Inspect
for
security
of
units
and
electrical
connectors.
condition
and
security
of
wire
routing.
Also.
check
for
evidence
of
damage
and
cleanliness.
Revision 3
2-45
MODEL
172
SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS HOURS
HOURS
HOURS YEARS
N
15
Microphones,
Headsets,
and
Jacks
-
Inspect
for
cleanliness, security,
and
evidence
of
damage.
N
16
Magnetic
Compass
-
Inspect
for
security
of
installation,
cleanliness,
and
evidence
of
damage.
O
Electrical
Systems
(Section
16).
O 1
General
Airplane
and
System
Wiring
-
Inspect for
proper
routing,
chafing,
broken
or
loose
terminals,
general
condition,
broken
or
inadequate clamps,
and
sharp bends
in
wiring.
O
2
Instrument,
Cabin,
Navigation, Beacon, Strobe,
and
Landing Lights
-
Check
operation, condition
of
lens,
and
security
of
attachment.
O
3
Circuit
Breakers
and
Fuses
- Check
operation
and
condition.
Check
for
required number
of
spare
fuses.
O
4
Battery
-
Check
general
condition
and
security.
Check
P
level
of
electrolyte.
O
5
Battery
Box
and Cables
-
Clean
and
remove
any
corrosion. Check
cables
for
routing,
support, and
security
of
connections.
O
6
Switch
and
Circuit
Breaker
Panel,
Terminal
Blocks,
and
Junction
Boxes
-
Inspect
wiring
and
terminals for
condition
and
security.
O
7
Alternator
Control
Unit
- Inspect
wiring,
mounting,
condition,
and
wire
routing.
O
8
Switches
-
Check
operation,
terminals,
wiring,
and
mounting
for
conditions,
security,
and
interference.
O
9
Instrument
Panel
and
Control
Pedestal
-
Inspect
wiring,
mounting,
and
terminals
for
condition
and
security.
Check
resistance
between
stationary
panel
and
instrument
panel
for
proper
ground.
O
10
External
Power
Receptacle
and
Power Cables
-
Inspect
for
condition
and
security.
P
Post
Inspection.
P 1
Replace
all
fairings,
doors,
and
access
hole
covers.
Ground
check
engine,
alternator
charging
rate,
oil
pressure, tachometer,
oil
temperature
and
pressure
gages.
and
general operation
of
components.
Q
Perform
the
Following
Operational
Checks:
Q
1
Brakes
-
Test
toe
brakes
and
parking
brake
for
proper
operation.
R
Service
Bulletins/Airworthiness
Directives.
R 1
Check
that
all
applicable
Cessna
Service
Bulletins
and
Supplier Service
Bulletins
are
complied
with.
R 2
Check
that
all
applicable
Airworthiness
Directives
and
Federal
Aviation
Regulations are
complied
with.
2-46 Revision 3
MODEL
172
SERIES
SERVICE
MANUAL
SPECIAL
EACH
EACH
EACH
INSPECTIONS
2-48
INSPECTION
TIME
LIMITS.
(MODEL
172
50
100
200
AIRPLANES.)
HOURS
HOURS
HOURS
HOURS YEARS
R
3
Ensure
all
Maintenance
Record
Entries required
by
Federal
Aviation
Regulations
are
completed before
returning
the airplane to
service.
Revision
3
2-47
MODEL
172 SERIES
SERVICE
MANUAL
Special
Inspections
Legends:
A.
If
the
airplane
is
flown
from
surfaces
with
mud,
snow.
or
ice,
the
main
gear
speed
fairings
should
be
checked
that
there
is
no
accumulation
which could
prevent
normal
wheel
rotation.
B.
First
100
hours
and
each
500
hours
thereafter.
More
often
if
operated
under
prevailing
wet or
dusty
con-
ditions.
C.
Each 600
hours
or
1
year,
whichever
comes
first.
D.
Lubrication
of
the
actuator
is
required each
1000
hours
or
3
years,
whichever
comes
first.
See figure
2-5
for
grease
specification.
E.
Lubricate each
50
hours
(except
in
extreme dusty
conditions).
These
controls
are
not
repairable
and
should
be
replaced every
1500
hours
or
whenever
maximum
linear
movement
exceeds
.050
inch.
F.
Model
172Q:
Replace
polyurethane
foam
filter
every
200
hours
or
on
condition.
Model
172
Series:
Filter
may
be
washed 20
times
maximum,
cleaned
by
compressed
air
30
times
maximum.
Replace filter
each
500
hours
or
1
year, whichever comes
first.
G.
Inspect
each
500 hours.
H.
Check
solenoid
and
electrical
connections
each
100
hours,
inspect
the
commutator and brushes
each
500
hours.
I. If
timing
to
engine
is
within
tolerance -
plus
zero
degrees, minus
two
degrees,
internal
timing will not
re-
quire
checking.
Model
172
with
0-320-H2AD engine
(1977
thru
1980):
Check
magnetos
at
first
25
hours,
first
50
hours,
first
100
hours, and each
100
hours
thereafter.
Model
172 with
0-320-D2J engine
(1981
and
ON),
Model 172Q
with
0-360-A4N
engine
(1983
and
ON):
Check
magnetos
at
first
100
hours,
and
ev-
ery
100
hours
thereafter
or
each
one year,
whichever
occurs
first.
J.
Compliance with Lycoming
Service
Bulletin
425B
or
latest
revision
is
required.
Model
172
with
0-320-
H2AD
engine (1977
thru
1980):
Each
500
hours.
K.
1.
Inspect
contact
points
for
condition
and
adjust
or
replace
as required.
2.
Inspect
carbon
brush,
high-tension
lead,
and
distributor
block
for
condition
and
clean
or
replace
as
re-
quired.
3.
Inspect
impulse coupling
and pawls
for condition and
replace
as
required.
Use
light
pressure
only,
do
not
force
pin
(or drill
bit)
when
checking
pawls.
4.
Inspect
bearings
and
lubricate,
replace
bearings,
if
required.
5.
Lubricate
contact
point
cam.
6.
Completely
overhaul,
or
replace existing
magneto
with
a
new
or
rebuilt
exchange
magneto,
at
every
engine
overhaul.
Refer
to
Overhaul
and
Maintenance
Manual,
Publication
No.
1037C1-13,
covering
Model
4200/6200
series
magnetos.
Manual
No.
1037C1-13
is
available
from
Cessna
Supply
Division.
Effectivity,
Model
172
with
0-320-0-2J
engine
(1981
and
ON)
and
Model
172Q
with 0-360-A4N
engine
(1983
and
ON);
Each
500
hours
and
every
engine
overhaul.
L.
Model
172
with
0-320-H2AD
engine
(1977 thru
1980):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace
oil
filter,
and
refill with
MIL-L-22851
ashless
dispersant
oil.
If
oil
must
be
added
during
first
25 hours,
use
MIL-L-6082
aviation
grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an oil
filter,
change
oil
and
clean
pressure screen
at
50
hours, and
each
50
hours
thereafter.
If
engine
is
equipped
with
an oil
filter,
change
oil
and
filter
at
50
hours.
and
each
100
hours thereafter. Model
172
with
0-320-
D2J
engine
(1981
and
ON)
and
Model
172Q with
0-360-A4N
engine
(1983
and
ON):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace
oil
filter,
and
refill
with MIL-L-6080
aviation
grade
straight
min-
eral
oil.
If
engine
is
not
equipped
with
an
oil
filter,
change
oil
and
clean
pressure
screen
at
50 hours and
each
50
hours
there
after.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at
50
hours
and
each
100
hours
there
after.
Beginning
with the
50-hour
oil
change
and
thereafter.
refill
oil
sump
with
MIL-L-
22851
ashless
dispersant
oil.
M.
Each
1000
hours.
N.
Replace
every
500
hours.
O.
Replace
filter
each
100
hours.
P.
Check electrolyte
level
and
clean
battery
box each
100
hours
or
90
days.
2-48
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
2-49.
COMPONENT
TIME
LIMITS.
(MODEL
172
AIRPLANES.)
1.
Component
Time
Limits.
a.
All
components
not
listed
herein
should
be
inspected
as
detailed elsewhere
in
this chapter
and
repaired.
overhauled or
replaced
as
required.
Items
shown
here
should
be
overhauled
or
replaced
during the
regular maintenance
periods.
REPLACE
*
OVERHAUL
*
2.
Schedule.
a.
POWERPLANTS (Sections
11
REFER
TO
LATEST
and
11A).
ISSUE
OF
(1)
Engines
(Avco
Lycoming MANUFACTURER'S
Engine
Overhaul
Manual)
MAINTENANCE
(See
NOTE
2)
MANUAL
OR
SERVICE
(2)
Magnetos
(Sections
11
BULLETIN
and
11A)
(See
NOTE
3)
(3)
Engine
Compartment
(NOTE
4)
Flexible Fluid
Carrying
Rubber
Hoses
(Cessna
Installed)
Except
Drain
Hoses
(4)
Engine
Compartment
ON
CONDITION
Drain
Hoses
(5)
Engine
Flexible
Hoses
(NOTE
5)
(Avco
Lycoming
Installed)
(See
Lycoming
Engine
Maintenance
Manual)
b.
FUEL
SYSTEM
(Section
12).
(1)
Auxiliary
Electric
Fuel
Pump
(See NOTE
6)
c.
PROPELLER
(Section
13).
REFER
TO
LATEST
(1)
Propeller
(See McCauley
ISSUE
OF
Maintenance
and
MANUFACTURER'S
Overhaul
Manual)
MAINTENANCE
(2)
Governor
(See
MANUAL
OR
SERVICE
Manufacturer's)
BULLETIN
McCauley)
d.
NAVIGATION
(Section
15).
(NOTE
1)
(1)
Locator
Beacon
Battery
Pack
See
Note
7.
Revision
3
2-49
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
1:
If
battery
has
been
in
use
for
more
than
one collective
hour
and
or
at
50
percent
of
the
useful
life
of
the
battery,
date
on
the
battery
indicates
50 percent
of
the
useful
life.
NOTE
2:
It
is
recommended
the
items
listed
below
be
inspected
at
engine
overhaul
to
establish
condition
for
their
replacement
or
overhaul.
Although
no
overhaul
or
replacement
interval
has
been
established
for
these
items,
the inspection
of
these items
at
engine
overhaul
could
eliminate
overhaul
or
re-
placement
of
the
items
at
a
later
time.
a.
Inspect hoses
within
the
engine
compartment
in
accordance
with
Engine
Compartment
Hoses
(Refer
to
Inspection Time
Limits).
It
is
recommended
the
replacement
interval
not
exceed
en-
gine
overhaul
interval.
b.
Engine
components,
such
as
turbocharger,
controller,
manifold
pressure
relief
valve
and
wastegate,
magnetos,
vacuum pumps,
etc.,
should
be
inspected
for
condition,
at
the
time
of
engine overhaul,
as
it
may
be
cost effective
to
overhaul
or
replace
marginal
components
at
that
time.
A
determination
is
to
be
made during engine
overhaul
such
that
if
the
components
have less
hours
in
service
than
the
engine,
or
have
not accumulated hours
sufficiently
close
to
the
engine
overhaul
time
to
warrant
overhaul
as
judged
by
inspection or
the
economic
as-
pect, these
components
may
not require
overhaul
or
replacement
concurrent
with
engine
overhaul.
It
is
recommended
that
the
overhaul
or
replacement
interval
for
these
components
not
exceed
the
engine
overhaul
interval.
c.
Inspect
the
engine
compartment for structural
damage
when engine
is
removed
for overhaul.
and
make
the necessary
repairs.
d.
Inspect
the
engine exhaust
as
it
may
be
cost
effective
to
replace
marginal
components
at
en-
gine
overhaul.
e.
Inspect
electrical harnesses
for
damage
which
would be
cost
effective
to
replace
at
engine
overhaul.
NOTE
3:
Overhaul
Magneto(s)
at
engine
overhaul
or when
engine
is
partially overhauled
for
severe
envi-
ronmental
affects,
engine
overspeed, engine
sudden
stoppage or
other
unusual
circumstances.
NOTE
4:
(This
life
limit
is
not
intended
to
allow
flexible
fluid
carrying
rubber
hoses
in
a
deteriorated
or
dam-
aged
condition
to remain
in
service.)
Replace engine
compartment
flexible
fluid
carrying hoses
(Cessna
installed
only)
manufactured
of rubber
material
every
five
years
or
at
engine
overhaul,
whichever occurs
first.
This
does
not
include
drain
hoses. Hoses which
are
beyond
these
limits
and
are
in
a
serviceable condition,
must
be
placed
on
order
immediately
and
then
be
replaced
within
120
days
after
receiving
the new hose
from
Cessna.
NOTE
5:
Refer
to
latest
Avco
Lycoming
Engine
Service
Bulletins.
NOTE
6:
Refer
to
latest
Dukes
Inc.
Service
Bulletins.
NOTE
7:
The
terms overhaul
and
replacement
as
used
within
this
section dictate
action
as
defined below:
a.
Overhaul
-
Item
may
be
overhauled
as
defined
in
Federal
Aviation Regulation 43.2
or
can
be
replaced
as
defined below:
b.
Replacement
-
Item
must
be
replaced
with
a
new
item
or
one that
has
been rebuilt
as
defined
in
Federal
Aviation
Regulation
43.2.
2-50
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
2-50.
SCHEDULED
MAINTENANCE
CHECKS.
(MODEL
172
AIRPLANES)
2-51.
PROGRESSIVE
CARE
PROGRAM.
(MODEL
172
AIRPLANES)
A.
Progressive
Inspection
Program.
(1)
Purpose
and
Use.
(a) As
detailed
in
Federal
Aviation
Regulation
Part
91.409.
paragraph
(d),
airplanes that
de-
sire
to
use
a
Progressive
Inspection
Program
must
be
inspected
in
accordance
with
an
authorized
progressive
inspection
program.
This
chapter presents
the
current
progres-
sive
inspection
program
for
the
Cessna
Model
172,
recommended
by
the
Cessna
Air-
craft
Company.
B.
Introduction.
(1)
Following
is
the
recommended
Progressive
Care
Program
for
Model
172
airplanes.
(2)
This
program
is
divided
into
four
separate
operations which
are
to
be
accomplished initially
after
50
hours
of
operation
and
each
50
hours
of
operation thereafter.
Additional
special
re-
quirements
indicated
as
Special
Inspection,
which
are
required
at
other intervals
are
specified
separately.
(3)
Recommended
progressive
care
inspection
may be
accomplished
by
one
of
the
following.
NOTE
Some
100
HOUR
items
are
covered
in
Operation
1
and
3.
also
some 200
HOUR
items
are
covered
in
Operation
1,
2, 3
and
4.
These
items
are
placed
here for
convience
and
expediency
of
the
total
inspection.
After
the
first
completion
of
all
four
Operations,
these
items
will
be
at
the
proper
intervals.
(a)
NEW
DELIVERED
AIRCRAFT
-
A
new
delivered
aircraft
must
have
less
than
50
hours
total
time
in
service
and
enough
calander time
remaining since
the issuance date
of
the
original
Airworthiness
Certificate
to allow the
owner/operator
to
complete
a
cycle
of
all
four
Operations
before
the
first
annual
inspection becomes
due.
Operation
1
will
be
due
at
50
hours time
in
service.
Operation
2
will
be
due
at
100
hours.
Operation
3
will
be
due
at
150
hours
and
Operation
4
will
be
due
at
200
hours.
There
are
additional
inspec-
tion
requirements
for
new
aircraft
at
the
FIRST
50
HOUR
inspection
point.
In
addition
to
preforming
Operation
1,
the
FIRST
50 HOUR ITEMS
listed
in
the inspection Time
Limits
Charts in
2-59
must
also be
performed.
After
these
FIRST
50
HOUR
items
have been
accomplished,
they
have
permanent
inspection
time
limits
which
are
covered
in
the Op-
erations
Schedules.
(b)
ALL
OTHER
AIRCRAFT
-
To
qualify
other
aircraft
which
have
more
than 50
hours
time
in
service
for
the
Progressive Inspection
Program,
conduct
a
COMPLETE
AIRPLANE
IN-
SPECTION. Operation
1
will become
due
50
hours
from
the
time
the
COMPLETE
AIR-
PLANE INSPECTION was
accomplished.
(4)
Performance
of the
inspections
as listed
herein
at
the
specified
points
will
assure
compliance
with
the
Inspection
Time Limits
detailed
in
2-59.
Special
inspections
shall
be
complied
with
at
prescribed
intervals
and/or
intervals
coinciding
with
operations
1
through
4
as
outlined
in
2-62.
(5)
An
operator
may
elect
to
perform
the
recommended
inspections
on
a
schedule
other
than
that
specified.
Any
inspection
schedule
requiring
the
various
inspection
items
detailed
in
this
chap-
ter
to
be
performed
at
a
frequency
equal
to
that
specified
herein
or
more
frequently
is
accept-
able.
Any
inspection
item
performed
at
a
time
period
in
excess
of
that
specified herein
must
be
approved
by
the
appropriate
regulating
agency.
(6)
As
defined
in
Federal
Aviation
Regulations
Part
91.409,(d)
the frequency
and
detail
of
the
Pro-
gressive
Inspection
Program
shall
provide
for
the
complete inspection
of
the
airplane
within
each
12-calendar months.
If
the
airplane
is
approaching
the
end
of
a
12-calendar
month
pe-
riod, but the
complete
cycle
of
4
operations
has
not
been
accomplished,
it will
be
necessary
to
complete
the remaining
operations, regardless
of
airplane
hours
before
the
end
of
the
12-
calendar
month
period.
If
the
Progressive Inspection
Program
is
to
be
discontinued,
an
annual
inspection
becomes
due
at
the
time
when
any item
reaches
a
maximum of
12
calendar
months
from
the
last
time
it
was
inspected
under
the
Progressive
Inspection
Program.
Refer
to
Federal Aviation Regulation
Part
91.409(d)
for
detailed information.
Revision
2
2-51
MODEL
172
SERIES
SERVICE
MANUAL
C.
Inspection
Time
Limitations.
(1)
Each
inspection
interval
may be
exceeded
by
10
hours
or
can
be
performed
early
at
any
time
prior
to
the
regular
interval
as
provided
below:
(a)
In
the
event
of late
compliance
of
any
operation
scheduled,
the
next
operation
in
se-
quence
retains
a
due point
from the
time
the late
operation
was
originally
scheduled.
(b)
In
the event
of
early
compliance
of
any
operation
scheduled,
that
occurs
10
hours
or
less
ahead
of
schedule, the
next phase
due
point
may
remain
where
originally
set.
(c)
In
the
event
of
early
compliance
of
any
operation
scheduled,
that
occurs
more
than
10
hours
ahead
of
schedule,
the
next
phase due
point
must
be
rescheduled
to
establish
a
new
due
point
from the time
of early
accomplishment.
D.
Procedures.
(1)
The
following
instructions
are
provided
to
aid
in
implementation
of
the
Model
172
Series
Pro-
gressive
Care
Program
Schedule.
(a)
Use
the
Progressive
Care
Program
Inspection
Chart,
provided herein,
for
each airplane.
The
chart
is
to
be
placed
in
the
airplane
flight
log
book
for
use
as
a
quick
reference
for
pilots
and
maintenance personnel
in
determining
when
inspections
are
due
and
that
they
are
performed
within
prescribed
flight
time
intervals.
(b)
Use
the
Progressive
Care
Program
Component
Overhaul
and
Replacement
Log,
pro-
vided herein,
for
each
airplane.
This
log
is
to
be
kept
with
the
airplane
maintenance
records
and
serves
as
a
periodic
reminder
to
maintenance
personnel when
various
com-
ponents
are
due
for
overhaul
or
replacement.
(c)
To
start
the
Progressive
Care
Program,
begin
conducting
the
inspections
defined
herein
and
refer
to Federal
Aviation
Regulations
Part
91.409(d)
for
procedures
to
notify
the Fed-
eral
Aviation
Administration
of
the
intent
to
begin
a
progressive
inspection
program.
(d)
Accomplish
each
inspection
and
maintenance
item
per
the
checklists
on
the
operation
sheets
of
the
Progressive
Care
and
Maintenance
Schedule.
Spaces
have been
pro-
vided for
the
mechanic's
and
inspector's
signatures
as
required,
as
well
as
any
remarks.
These
are
to
become
part
of the
maintenance
records
for
each
airplane.
Each
inspection
is
to
be
logged
in
the airplane
and/or
engine
log
books.
Refer
to
Federal
Aviation
Regula-
tion
Part 43
for
the
recommended
entry
statement.
2-52
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
PROGRESSIVE CARE
PROGRAM
(MODEL
172
AIRPLANES)
COMPONENT
OVERHAUL
AND REPLACEMENT
RECORD
REPLACEMENT NEXT
OVERHAUL
COMPONENT
DATE
REASON
FOR
REPLACEMENT
PART
NUMBER
AIRPLANE
SERIAL
NUMBER
HOURS
DATE
NUMBER
x
x
x
x
x
x
x
x
x
x
x
Revision
2
2.531
MODEL
172
SERIES SERVICE
MANUAL
PROGRESSIVE
CARE
PROGRAM
INSPECTION
CHART
AIRPLANE
MODEL:
172
REGISTRATION NUMBER:
TIME
TIME
INSPECTION
POINTS INSPECTION
INSPECTION
INSPECTION
INSPECTION
DUE
ACCOMPLISHED
DUE
ACCOMPLISHED
OPERATION
1
OPERATION
2
OPERATION
3
OPERATION
4
EXAMPLE:
The
airplane
in
this
example was placed
on
the
Progressive
Care
Program
after
flying
a
total of
110
hours.
At
that
point,
a
complete
initial
inspection
of
the
airplane was
performed. The
following
steps
in-
dicate
what
will have
taken
place
up
through
an
hourmeter
reading of
261
hours.
1.
After
the
initial
inspection
at
110
hours,
the
first
Inspection
Due
Column
was
filled out
to
show
the
total
flying
time
at
which
each
of
the four
(4)
operation
inspections
would
be
due.
2.
As
each
inspection
was
performed,
the
total
flying
time
was
recorded
in
the Inspection Ac-
complished
column.
The
next Inspection
Due
space
for
that
particular
operation
is
also
filled
in
at
this
time.
These
times
will always be
200
hours
from
the
last
due
point
providing
the
opera-
tion was
actually
accomplished
within
the ten
(10)
hours
limit.
3.
The
sample
airplane
now has
a
total
flying
time of
261
hours
and
the
inspection
chart
shows
that
a
Phase
4
will
be due
at
310
hours.
TIME
TIME
INSPECTION
POINTS
INSPECTION
INSPECTION INSPECTION INSPECTION
DUE
ACCOMPLISHED
DUE
ACCOMPLISHED
OPERATION
1
160
162
360
OPERATION
2
210
209
409
OPERATION
3
260
261
460
OPERATION
4
310
2-54 Revision
2
MODEL 172
SERIES
SERVICE
MANUAL
CESSNA PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
1
Registration
No.
Airplane
Model
and
SN Airplane
Time
INSPECTION
COMPLETED
BY
B
13
Aileron,
Elevator,
and
Rudder
Stops
-
Check
for
damage
and
security.
B
15
Seat
Tracks
and
Stops -
Inspect
seat
tracks
for
condition
and
security
of
installation.
Check
seat
track
stops
for
damage
and
correct
location.
Ensure
inspection
of
seat
rails
for
cracks
EACH
50
HOURS. Refer
to Section
3.
C 1
Wing
Surfaces
and
Tips
-
Inspect
for
skin
damage,
loose
rivets,
and
condition
of
paint.
C
2
Wing
Struts
and
Strut
Fairings
-
Check
for
dents,
cracks,
loose
screws
and
rivets,
and
condition
of
paint.
C
7
Vertical
and
Horizontal
Stabilizers,
Tips
and
Tailcone
-
Inspect
externally
for
skin
damage
and
condition
of
paint.
C
8
Vertical
and
Horizontal
Stabilizers
and
Tailcone
structure
-
Inspect
bulkheads,
spars,
ribs,
and
skins
for
cracks,
wrinkles,
loose
rivets,
corrosion,
or
other
damage.
Inspect
vertical
and
horizontal
stabilizer
attach
bolts
for
looseness.
Retorque
as
necessary.
Check
security
of
inspection
covers,
fairings,
and
tips.
E 1
Ailerons
and
Hinges
-
Check
condition,
security
and
operation.
E
2
Aileron
Structure,
Control
Rods,
Hinges,
Balance Weights,
Bellcranks,
Linkage, Bolts,
Pulleys,
and
Pulley
Brackets
-
Check
condition,
operation,
and
security
of
attachment.
E
5
Aileron
Controls
-
Check
freedom
of
movement
and
proper
operation
through
full
travel
with
and
without
flaps
extended.
F
1 Flaps -
Check
tracks, rollers,
and
control
rods
for
security
of
attachment.
Check
operation.
F
2
Flap
Actuator
Threads
-
Clean
and
lubricate.
Refer
to
paragraph
2-43
for
detailed
instructions.
G
1
Elevator
Control
-
Check
freedom
of
movement
and
proper
operation
through
full
travel
with
and
without
flaps
extended.
G
2
Elevator, Hinges,
and
Cable Attachment
-
Check
condition,
security,
and operation.
H
1
Elevator
Trim
Tab
and
Hinges
-
Check
condition,
security,
and
operation.
I 1
Rudder
-
Inspect the
rudder
skins
for
cracks
and
loose
rivets,
rudder
hinges
for
condition,
cracks and
security;
hinge
bolts,
hinge bearings,
hinge
attach
fittings,
and
bonding
jumper
for
evidence
of
damage
and
wear,
failed
fasteners,
and
security.
Inspect
the
rudder
hinge
bolts
for
proper
safetying
of
nuts with
cotter
pins.
Inspect
balance
weight
for
looseness
and
the
supporting
structure
for
damage.
I
3
Rudder,
Tips,
Hinges,
and
Cable
Attachment
-
Check
condition,
security,
and
operation.
J
1
Cowling
-
Inspect
for
cracks,
dents,
and
other
damage,
security
of
cowl
fasteners,
and
cowl
mounted landing
lights
for
attachment.
J
2
Engine
-
Inspect
for
evidence
of
oil
and
fuel
leaks.
Wash
engine
and
check
for
security
of
accessories.
Revision
3
2-55
MODEL
172
SERIES SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
1
Registration
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
J
3
Engine
Controls
and Linkage
-
Check
general
condition,
freedom
of
movement through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear.
Check
friction locks
for proper
operation.
J
4
Ignition
Switch
and
Electrical
Harness
- Inspect
for
damage,
condition,
and
security.
J
5
Firewall
Structure
-
Inspect
for
wrinkles,
damage,
cracks,
sheared
rivets,
etc.
Check
cowl
shock
mounts
for
condition
and
security.
J
6
Engine
Shock
Mounts, Engine
Mount
Structure, and
Ground
Straps
-
Check
condition, security,
and
alignment.
J
7 Induction
System
-
Check
security
of
clamps,
tubes,
and
ducting.
Inspect
for
evidence
of
leakage.
J
8
Induction
Airbox,
Valves,
Doors,
and
Controls
-
Remove
air
filter
and
inspect
hinges,
doors,
seals,
and
attaching parts
for
wear and
security.
Check
operation.
Clean
and
inspect
air
filter.
J
9
Induction
Air Filter
-
Remove
and clean.
Inspect
for
damage,
and
service
per
Paragraph
2-22
and
2-22A
J
10
Alternate
Induction
Air
System
-
Check
for
obstructions,
operation,
and
security.
J
11
Alternator,
Mounting
Bracket,
and Electrical
Connections
-
Check
condition
and
security. Check
alternator
belts
for
condition
and
proper
adjustment.
Check belt
tension
per
Section
16,
Paragraph
16-38.
J
13
Starter,
Starter
Solenoid,
and
Electrical
Connections
-
Check
for
condition
of
starter
brushes,
brush
leads,
and
commutator.
J
14
Oil
Cooler
-
Check
for
obstructions,
leaks,
and
security
of
attachment.
J
15
Exhaust
System
-
Inspect
for
cracks
and
security. Special
check
in
area
of
heat
exchanger.
Refer to Section
11,
Paragraph
11-73
for
inspection
procedures.
J
16
Auxiliary
(Electric)
Fuel
Pump
(172Q)-
Check
pump
and
fittings
for
condition,
operation,
security.
Remove and
clean
filter
(as
applicable).
J
17
Engine-Driven
Fuel
Pump
-
Check for
evidence
of
leakage,
security
of
attachment,
and
general
condition.
J 18
Magnetos
-
Check
external
condition,
security,
and
electrical
leads
for
condition.
Check
timing
to
engine
and
internal
timing
if
engine
timing
requires
adjustment.
J
21
Ignition
Harness
and
Insulators
-
Check
for proper routing,
deterioration,
and
condition
of
terminals.
J
22
Spark
Plugs
-
Remove,
clean,
analyze,
test, gap, and rotate
top plugs-to-bottom
and
bottom
plugs-to-top.
J
23
Cylinder
Compression
-
Perform
differential
compression
test.
J
24
Carburetor
-
Drain
and
flush
carburetor
bowl,
clean inlet
strainer,
and
drain
plug.
Check general
condition
and
security.
J
25
Engine
Primer
-
Check
for
leakage,
operation,
and
security.
2-56
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE CARE
MODEL
172
OPERATION
NO.
1
Registration
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
J
26
Hoses,
Metal
Lines,
and
Fittings
-
Inspect
for
signs
of
oil
and
fuel
leaks.
Check
for
abrasions,
chafing,
security,
proper
routing
and
support
and
for
evidence
of
deterioration.
J
27
Cold
and
Hot
Air
Hoses
-
Check condition,
routing,
and
security.
J
28
Engine
Cylinders,
Rocker
Box
Covers,
and Pushrod
Housings
-
Check
for
fin
damage,
cracks,
oil
leakage,
security
of
attachment, and
general
condition.
J
29
Engine
Baffles
and
Seals
-
Check
condition
and security
of
attachment.
J
30
Crankcase,
Oil
Sump,
and Accessory
Section
-
Inspect
for
cracks
and
evidence
of
oil
leakage.
Check
bolts
and
nuts
for
looseness
and
retorque
as
necessary.
Check
crankcase
breather
lines
for
obstructions, security,
and
general
condition.
J
31
Engine
Oil
With
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
replace
filter,
and
refill
with
recommended grade
aviation
oil.
J
32 Engine
Oil
Without
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
clean
and
inspect
screens,
and
refill
with
recommended
grade
aviation
oil.
K 1
Fuel Tanks
or
Integral Fuel
Bays
-
Check
for
evidence
of
leakage
and
condition
of
fuel
caps,
adapters,
and placards.
K
3
Fuel
System -
Inspect
plumbing
and components
for
mounting
and
security.
K
4
Fuel
Tank
or
Bay
Drains
-
Drain
water
and
sediment.
K
5
Fuel Tank
Vent
Lines
and
Vent
Valves
-
Check
vents
for
obstruction
and proper
positioning.
K
7
Fuel Strainer,
Drain
Valve,
and
Controls
-Check
freedom
of
movement,
security,
and
proper operation.
Disassemble,
flush,
and clean
screen
and
bowl.
L 1
Propeller
Mounting
-Check
for
security
of
installation.
L
2
Propeller
Blades
-
Inspect
for
cracks, dents,
nicks,
scratches,
erosion,
corrosion,
or
other
damage.
L
3 Spinner
-
Check
general
condition
and
attachment.
L
4
Spinner
and
Spinner
Bulkhead
- Remove
spinner,
wash,
and
inspect
for
cracks and
fractures.
L
5
Propeller
Mounting
Bolts
- Inspect
mounting
bolts
and
safety-wire
for
signs
of
looseness.
Retorque
mounting
bolts
as
required.
L
6
Propeller
Hub
-
Check
general
condition.
M
2
Heater
Components,
Inlets,
and
Outlets
-
Inspect
all
lines,
connections,
ducts,
clamps,
seals,
and
gaskets
for
condition, restriction,
and
security.
M
4
Pitot
Tube
and
Stall
Warning Vane
-
Check
for
condition
and
obstructions.
N
3
Vacuum
Pump
-
Check
for
condition and
security.
Check
vacuum
system
breather
line
for
obstructions,
condition,
and
security.
O
4
Battery
-
Check
general condition
and
security.
Check
level of
electrolyte.
Revision 3
2-57
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE CARE
MODEL
172
OPERATION
NO.
1
Registration
No.
Airplane
Model
and SN
Airplane
Time
INSPECTION COMPLETED
BY
O
5
Battery
Box and
Cables
-
Clean
and remove
any
corrosion.
Check
cables
for
routing,
support,
and
security
of
connections.
O
7
Alternator
Control
Unit
-
Inspect
wiring,
mounting,
condition,
and
wire routing.
O 10
External Power
Receptacle
and
Power Cables
-
Inspect
for
condition
and
security.
2-58
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
1
INSPECTION
SPECIAL
INSPECTION
AND
YEARLY
ITEMS
HOURS
YEARS
COMPLETED
BY
Please
review
each
of
these
items
for
required
compliance
B
11
Upholstery,
Headliner,
Trim,
and Carpeting
-
Check
condition
EACH
EACH
and
clean
as
required.
400
1
D
3
Brake
Lines,
Wheel
Cylinders,
Hoses,
Clamps,
and
Fittings
-
EACH
EACH
Check
for
leaks,
condition,
and
security
and
hoses
for
bulges
400
1
and
deterioration.
Check
brake
lines
and
hoses
for
proper
routing
and
support.
D
6
Wheel
Fairings, Strut
Fairings,
and Cuffs
-
Check
for
cracks,
A
dents,
and
condition
of
paint.
D
11
Wheel Bearings
-
Clean,
inspect
and
lube.
B
E
4
Autopilot Rigging
-
Check
per Avionics Installation
Manual.
C
H
5
Elevator
Trim
Tab
Actuator
-
Clean,
lubricate,
and
check
free-
D
play.
J
3
Engine Controls and
Linkage
-
Check
general
condition,
E
freedom
of
movement through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks for
proper
operation.
J
9
Induction
Air
Filter
-
Remove
and
clean.
Inspect
for
damage,
F
and
service
per
Paragraph
2-22
and
2-22A.
J
12
Alternator
-
Check
brushes,
leads,
commutator
or
slip
ring
for
G
wear.
J
13
Starter, Starter
Solenoid,
and
Electrical
Connections
-
Check
for
H
condition
of
starter
brushes, brush
leads,
and
commutator.
J
18
Magnetos
-
Check
external
condition,
security,
and
electrical
I
leads
for
condition.
Check
timing
to engine
and
internal
timing
if
engine
timing
requires
adjustment.
J
19
Magnetos
-
Check
impulse
coupling
and
stop
pins
for
condition,
J
replace
as
required.
J
20
Magnetos
-
Inspection,
lubrication
and
overhaul
procedures.
K
J
31
Engine
Oil
With
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
replace
L
filter,
and
refill
with
recommended
grade
aviation
oil.
J
32
Engine
Oil
Without
Oil
Fitter
-
Drain
oil
sump
and
oil
cooler,
L
clean
and
inspect screens,
and
refill
with
recommended
grade
aviation
oil.
K
2
Fuel
Tanks
or
Integral
Fuel
Bays
-
Drain
fuel
and
check
tank
M
interior
and
outlet
screens.
K
8
Fuel
Quantity
Indicators
-
Check
for
damage,
security
of
EACH
installation,
and
perform
accuracy
test.
1
M
1
Ventilation
System
-
Inspect
clamps,
hoses, and
valves
for
400
EACH
condition
and
security.
1
N
4
Vacuum
System
Air
Filter
-
Inspect
for
damage,
deterioration
N
and
contamination.
Clean
or
replace,
if required.
NOTE:
Smoking
will
cause
premature
filter
clogging.
N
5
Vacuum
System relief
Valve
-
Inspect for
condition
and security.
O
N 10
Airspeed Indicator,
Vertical
Speed
Indicator, and
Magnetic
EACH
Compass
-
Calibrate.
2
N
11
Altimeter
and
Static
System
-
Inspect
in
accordance
with
FAR
EACH
Part 91.411.
2
O
4
Battery
-
Check
general
condition
and
security.
Check
level
of
P
electrolyte.
Revision
3
2-59
MODEL
172 SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
1
Special
Inspections Legends:
A. If
the
airplane
is
flown from
surfaces with
mud,
snow,
or
ice,
the
main
gear
speed
fairings
should
be
checked
that there
is
no
accumulation
which
could
prevent
normal
wheel
rotation.
B.
First
100
hours
and
each 500
hours
thereafter.
More
often
if operated
under
prevailing
wet
or
dusty
conditions.
C.
Each
600
hours
or
1
year,
whichever
comes
first.
D.
Lubrication
of
the actuator
is required
each
1000
hours or
3
years,
whichever
comes first.
See
fig-
ure
2-5
for
grease
specification.
E.
Lubricate each
50
hours
(except
in
extreme
dusty
conditions).
These
controls
are
not
repairable
and
should
be
replaced
every
1500
hours or whenever
maximum linear
movement
exceeds
.050
inch.
F.
Model
172Q:
Replace
polyurethane
foam
filter
every
200
hours
or on
condition.
Model
172 Series:
Filter
may
be washed 20
times
maximum,
cleaned
by compressed
air 30
times
maximum.
Replace
filter
each
500
hours
or
1
year,
whichever
comes
first.
G.
Inspect
each
500
hours.
H.
Check
solenoid
and
electrical
connections
each
100
hours, inspect the
commutator
and brushes
each
500
hours.
I. If
timing to
engine
is
within tolerance
-
plus
zero degrees,
minus two
degrees,
internal
timing
will
not
require
checking.
Model 172
with 0-320-H2AD
engine
(1977
thru
1980):
Check
magnetos
at
first
25
hours, first
50
hours,
first
100
hours,
and
each
100
hours
thereafter.
Model
172
with
0-320-D2J
en-
gine
(1981
and
ON),
Model
172Q
with
0-360-A4N
engine
(1983
and ON):
Check
magnetos
at
first
100
hours,
and every
100
hours
thereafter
or
each
one year, whichever
occurs
first.
J.
Compliance
with
Bendix
Service
Bulletin 425B
is
required.
Model
172
with
0-320-H2AD
engine
(1977
thru
1980): Each
500 hours.
K
1.
Inspect
contact points
for
condition
and
adjust
or replace
as
required.
2.
Inspect
carbon
brush,
high-tension
lead,
and
distributor block
for
condition
and
clean
or
replace
as required.
3.
Inspect
impulse
coupling
and
pawls
for
condition
and replace
as required.
Use
light
pressure
only,
do
not
force
pin
(or
drill
bit)
when
checking
pawls.
4.
Inspect
bearings and
lubricate,
replace bearings,
if
required.
5.
Lubricate
contact
point
cam.
6.
Completely
overhaul,
or
replace existing
magneto
with
a
new
or
rebuilt
exchange
magneto,
at
every
engine
overhaul. Refer
to
Overhaul and
Maintenance
Manual,
Publication
No.
1037C1-13,
covering
Model
4200/6200
series
magnetos. Manual No. 1037C1-13
is
available
from
Cessna
Supply Division.
Effectivity,
Model
172
with
0-320-0-2J
engine
(1981
and
ON)
and
Model
172Q
with
0-360-A4N
engine
(1983 and
ON); Each
500
hours
and
every
engine
overhaul.
L.
Model
172
with
0-320-H2AD engine
(1977
thru
1980):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace
oil
filter,
and refill
with
MIL-L-22851
ashless
dispersant
oil.
If
oil
must
be
added
during
first
25
hours, use MIL-L-6082 aviation grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an oil
filter,
change
oil
and
clean
pressure
screen at
50
hours,
and
each 50
hours
thereafter.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at
50
hours,
and
each
100
hours
thereafter.
Model
172
with 0-320-D2J
engine
(1981
and ON)
and
Model
172Q
with
0-360-A4N
engine
(1983
and
ON):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace
oil
filter,
and
refill
with
MIL-L-6080
aviation grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an
oil
filter,
change
oil
and clean
pressure
screen
at
50
hours
and
each
50
hours
there
after.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at
50
hours
and
each
100
hours
there
after.
Beginning
with
the
50-hour
oil change
and
thereafter,
refill
oil
sump
with MIL-L-22851
ashless
dispersant
oil.
M.
Each
1000
hours.
N.
Replace
every
500
hours.
O.
Replace
filter
each
100
hours.
P.
Check
electrolyte
level
and
clean
battery
box
each
100
hours
or
90
days.
2-60
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
2
Registration
No.
Airplane Model
and
SN Airplane
Time
INSPECTION
COMPLETED BY
B
1
Fuselage Surface
-
Inspect for
skin
damage,
loose
rivets,
condition
of
paint,
and
check
pitot-static
ports and drain
holes
for
obstruction. Inspect
covers
and
fairings
for
security.
B
6
Emergency
Locator
Transmitter
-
Inspect
for
security
of
attachment
and
check
operation
by
verifying transmitter
output
Check
cumulative
time
and
useful
life of
batteries
in
accordance
with
FAR
Part 91.207.
Refer
to
Section
16
-
Emergency
Locator
Transmitter
-
Checkout Interval.
B
8
Pilot's
and
Copilot's
Inertia
Reels
-
Inspect
for
security
of
installation,
proper operation,
and
evidence
of
damage.
B 9
Seats, Seat Belts,
and
Shoulder
Harnesses
-
Check
general
condition
and
security.
Check
operation of
seat
stops
and
adjustment
mechanism.
Inspect belts
for
condition
and
security
of fasteners.
B
10
Windows,
Windshield,
Doors, and
Seals
-
Inspect
general
condition.
Check
latches,
hinges,
and
seals
for
condition,
operation,
and
security
of
attachment.
B
12
Flight
Controls
-
Check freedom
of
movement
and
proper
operation
through
full
travel
with and
without
flaps
extended.
Check
electric
trim
controls for
operation
(as
applicable).
B
14
Portable
Hand Fire
Extinguisher
-
Inspect
for
proper
operating
pressure,
condition,
security
of
installation,
and
servicing
date.
B
15
Seat
Tracks
and
Stops
-
Inspect
seat
tracks
for
condition
and
security
of installation.
Check seat
track
stops for
damage
and
correct
location.
Ensure
inspection of
seat
rails
for
cracks
EACH
50
HOURS. Refer
to
Section
3.
B
17
Fuel
Line
and
Selector
Valve
Drain(s)
-
Remove
plug
and
drain.
D 1
Brakes, Master
Cylinders,
and
Parking Brake
-
Check
master
cylinders
and
parking
brake mechanism
for
condition
and
security.
Check
fluid
level and
test
operation
of
toe
and parking
brake.
D
2
Main
Gear
Tubular
Struts
-
Inspect
for
cracks,
dents,
corrosion,
condition
of
paint
or
other
damage. Check
axles
for
condition
and
security.
D
4
Wheels,
Brake
Discs,
and
Linings
-
Inspect
for
wear,
cracks,
warps,
dents,
or other
damage.
Check
wheel
through-bolts
and
nuts
for
looseness.
D
5
Tires
-
Check
tread
wear
and
general
condition.
Check
for
proper
inflation.
D
6
Wheel
Fairings,
Strut
Fairings,
and Cuffs
-
Check
for
cracks,
dents,
and
condition
of paint.
D
7 Main
landing
Gear
Attachment
Structure
-
Check
for
damage,
cracks,
loose
rivets,
bolts
and
nuts
and
security
of
attachment.
D
8
Nose
Gear
Steering Mechanism
-
Check
for
wear,
security,
and
proper rigging.
Revision
3
2-61
MODEL 172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE CARE
MODEL
172
OPERATION
NO.
2
Registation
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
D
9
Nose Gear
-
Inspect
torque
links,
steering rods,
and
boots
for
condition
and
security
of
attachment.
Check
strut
for
evidence
of
leakage and
proper
extension.
Check
strut
barrel
for
corrosion,
pitting,
and cleanliness.
Check
shimmy
damper
and/or
bungees
for
operation, leakage,
and
attach
points
for
wear
and
security.
D
10
Nose
Gear
Fork
- Inspect
for
cracks, general
condition, and
security
of
attachment.
D
12
Nose
Gear Attachment
Structure
-
Inspect
for
cracks,
corrosion,
or
other
damage
and
security
of
attachment.
H
2
Elevator
Trim
System
-
Check
cables,
push-pull
rods,
bellcranks,
pulleys,
turnbuckles,
fairleads, rub strips,
etc.
for
proper
routing,
condition,
and
security.
J 1
Cowling
-
Inspect
for
cracks,
dents,
and
other
damage,
security of
cowl
fasteners,
and
cowl
mounted
landing
lights
for
attachment.
J
2
Engine
- Inspect
for
evidence
of
oil
and
fuel leaks.
Wash
engine
and check
for
security
of
accessories.
J
3
Engine
Controls
and
Linkage
-
Check
general
condition,
freedom
of
movement
through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks
for
proper
operation.
J
7
Induction
System
-
Check
security
of
clamps, tubes,
and
ducting.
Inspect
for
evidence
of
leakage.
J
10
Alternate
Induction
Air
System
-
Check
for
obstructions,
operation,
and
security.
J
11
Alternator,
Mounting
Bracket,
and
Electrical
Connections
-
Check
condition
and security.
Check
alternator
belts
for
condition
and proper
adjustment.
Check
belt
tension
per
Section
16,
Paragraph
16-38.
J
14
Oil
Cooler
-
Check
for
obstructions,
leaks,
and
security
of
attachment.
J
15
Exhaust
System
-
Inspect
for
cracks
and
security. Special
check
in
area
of
heat
exchanger.
Refer
to
Section
11,
Paragraph
11-73
for
inspection
procedures.
J
26
Hoses,
Metal
Lines,
and
Fittings
-
Inspect
for
signs
of
oil
and
fuel
leaks.
Check
for
abrasions,
chafing,
security,
proper
routing
and
support
and
for
evidence
of
deterioration.
J
29
Engine
Baffles
and
Seals
- Check
condition
and
security
of
attachment.
J
32
Engine
Oil
Without
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
clean
and
inspect
screens,
and
refill
with
recommended
grade
aviation
oil.
K
4
Fuel
Tank
or
Bay
Drains
-
Drain
water
and
sediment.
K
6
Fuel
Selector
Valve
- Check controls
for
detent
in
each
position,
security
of
attachment,
and
for
proper
placarding.
L 1
Propeller
Mounting
-
Check
for
security
of
installation.
L
2
Propeller
Blades
-
Inspect
for
cracks,
dents,
nicks,
scratches,
erosion, corrosion,
or
other
damage.
L 3
Spinner
-
Check
general
condition
and
attachment.
M
4
Pitot
Tube and
Stall
Warning Vane
- Check
for
condition
and
obstructions.
2-62
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
2
Registration
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
N 1
Vacuum
System
-
Inspect
for condition
and
security.
N
2
Vacuum
System
Hoses
-
Inspect
for
hardness,
deterioration, looseness, or collapsed
hoses.
N
4
Vacuum
System
Air
Filter
-
Inspect
for
damage,
deterioration
and
contamination.
Clean
or
replace,
if
required.
NOTE:
Smoking
will
cause
premature
filter
clogging.
N 5
Vacuum
System
relief
Valve
-
Inspect
for
condition
and
security.
N
6
Instruments
-
Check
general
condition
and
markings
for
legibility.
O
2
Instrument,
Cabin,
Navigation,
Beacon,
Strobe, and
Landing
Lights
-
Check
operation, condition
of
lens,
and
security
of
attachment.
O 3
Circuit
Breakers
and
Fuses
-
Check
operation
and
condition.
Check
for
required
number
of
spare fuses.
Q
1
Brakes
-
Test
toe
brakes
and
parking
brake
for
proper
operation.
Revision
3
2-63
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
2
INSPECTION
SPECIAL
INSPECTION AND
YEARLY
ITEMS
HOURS
YEARS
COMPLETED
BY
Please
review
each
of
these
items
for
required
compliance -
B
11
Upholstery, Headliner,
Trim,
and
Carpeting
-
Check
condition
EACH EACH
and
clean
as
required.
400
1
D
3
Brake
Lines,
Wheel
Cylinders,
Hoses,
Clamps, and
Fittings
-
EACH EACH
Check
for
leaks,
condition,
and
security
and
hoses
for
bulges
400
1
and
deterioration.
Check
brake
lines
and
hoses
for
proper
routing
and
support.
D
6
Wheel Fairings, Strut Fairings,
and
Cuffs
-
Check
for-cracks,
A
dents,
and condition
of
paint.
D
11
Wheel
Bearings
-
Clean,
inspect
and
lube.
B
E
4
Autopilot
Rigging
-
Check
per
Avionics
Installation
Manual.
C
H
5
Elevator
Trim
Tab
Actuator
-
Clean,
lubricate,
and
check free-
D
play.
-J
3
Engine
Controls
and
Linkage
-
Check
general
condition,
E
freedom
of
movement
through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear. Check
friction
locks
for
proper operation.
J
9
Induction
Air Filter
-
Remove
and
clean.
Inspect
for
damage,
F
and
service
per
Paragraph
2-22
and
2-22A.
J
12
Alternator
-
Check
brushes,
leads, commutator
or
slip
ring
for
G
wear.
J
13
Starter,
Starter
Solenoid,
and
Electrical
Connections
-
Check
for
H
condition
of
starter brushes,
brush leads,
and
commutator.
J
18
Magnetos
-
Check
external
condition,
security,
and
electrical
I
leads
for
condition.
Check
timing
to
engine
and
internal
timing
if
engine
timing
requires adjustment.
J
19
Magnetos
-
Check
impulse
coupling
and
stop
pins
for condition,
J
replace as required.
J
20
Magnetos
-
Inspection,
lubrication
and
overhaul
procedures.
K
J
31
Engine
Oil
With
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
replace
L
filter,
and
refill
witn
recommended grade
aviation
oil.
J
32
Engine
Oil
Without
Oil Filter
-
Drain
oil
sump
and
oil cooler,
L
clean
and
inspect
screens,
and
refill
with
recommended
grade
aviation
oil.
K
2
Fuel
Tanks
or
Integral
Fuel
Bays
-
Drain
fuel
and
check
tank
M
interior
and
outlet screens.
K
8
Fuel
Quantity
Indicators
-
Check
for
damage,
security
of
EACH
installation,
and
perform
accuracy
test.
1
M
1
Ventilation
System
-
Inspect
clamps,
hoses,
and
valves for
400
EACH
condition
and
security.
1
N
4
Vacuum
System
Air Filter
-
Inspect
for
damage,
deterioration
N
and
contamination.
Clean
or
replace,
if
required.
NOTE:
Smoking
will
cause
premature
filter
clogging.
N
5
Vacuum
System
relief
Valve
-
Inspect
for condition
and
security.
0
N
10
Airspeed
Indicator,
Vertical
Speed Indicator,
and
Magnetic
EACH
Compass
-
Calibrate.
2
N
11
Altimeter
and
Static
System
-
Inspect
in
accordance
with
FAR
EACH
Part
91.411.
2
0 4
Battery
-
Check
general
condition
and
security. Check level
of
P
electrolyte.
2-64
Revision
3
MODEL 172 SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
2
Special
Inspections
Legends:
A. If
the
airplane
is
flown
from
surfaces
with mud,
snow,
or
ice,
the main
gear
speed
fairings
should be
checked
that
there
is
no
accumulation
which
could prevent
normal
wheel
rotation.
B.
First
100
hours
and each
500
hours
thereafter.
More
often
if
operated
under
prevailing
wet
or
dusty
conditions.
C.
Each
600
hours
or
1
year,
whichever
comes
first.
D.
Lubrication
of
the actuator
is
required
each
1000
hours or
3
years,
whichever
comes first.
See
fig-
ure
2-5
for
grease
specification.
E.
Lubricate
each
50
hours
(except
in
extreme
dusty conditions). These
controls
are
not
repairable
and
should
be replaced
every
1500
hours
or
whenever
maximum
linear movement
exceeds
.050
inch.
F.
Model
172Q:
Replace
polyurethane
foam
filter
every
200 hours
or
on
condition.
Model
172
Series:
Filter
may
be
washed
20
times
maximum,
cleaned
by
compressed
air
30
times maximum.
Replace
filter
each
500
hours
or
1
year,
whichever
comes
first.
G.
Inspect
each 500
hours.
H.
Check
solenoid
and
electrical
connections
each
100
hours,
inspect
the
commutator
and
brushes
each 500
hours.
I. If
timing
to
engine
is
within
tolerance
-plus
zero
degrees, minus
two
degrees, internal
timing
will not
require
checking.
Model
172
with
0-320-H2AD engine
(1977
thru
1980):
Check
magnetos at
first
25
hours,
first
50
hours,
first
100
hours,
and
each
100
hours
thereafter.
Model
172
with
0-320-D2J
en-
gine
(1981 and
ON),
Model 172Q
with
0-360-A4N
engine
(1983
and
ON): Check
magnetos
at
first
100
hours,
and
every
100
hours
thereafter
or
each
one
year,
whichever occurs
first.
J.
Compliance
with
Bendix
Service
Bulletin
425B
is
required.
Model
172
with
0-320-H2AD
engine
(1977
thru
1980):
Each
500
hours.
K. 1.
Inspect
contact
points
for
condition
and
adjust
or
replace
as
required.
2.
Inspect
carbon
brush,
high-tension
lead,
and
distributor
block
for
condition
and
clean
or
replace
as
required.
3.
Inspect impulse
coupling
and
pawls
for
condition
and
replace
as required.
Use
light
pressure
only,
do
not
force
pin
(or
drill
bit)
when
checking
pawls.
4.
Inspect
bearings
and
lubricate, replace bearings,
if required.
5.
Lubricate
contact
point
cam.
6.
Completely
overhaul,
or replace
existing
magneto
with
a
new
or
rebuilt exchange
magneto,
at
every
engine
overhaul. Refer
to
Overhaul
and
Maintenance
Manual,
Publication
No.
1037C1-13,
covering
Model
4200/6200
series
magnetos.
Manual
No.
1037C1-13
is
available from
Cessna
Supply
Division.
Effectivity,
Model
172
with
0-320-0-2J
engine
(1981
and
ON)
and
Model 172Q
with
0-360-A4N
engine
(1983
and ON);
Each
500
hours
and
every
engine
overhaul.
L.
Model
172
with
0-320-H2AD
engine
(1977
thru
1980):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace oil
filter,
and
refill with
MIL-L-22851
ashless
dispersant
oil.
If
oil must
be added
during
first
25
hours,
use
MIL-L-6082
aviation
grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an
oil
filter, change
oil
and
clean
pressure
screen
at
50
hours,
and
each
50
hours
thereafter.
If
engine
is
equipped with
an
oil
filter,
change
oil
and
filter
at
50
hours,
and
each
100
hours
thereafter.
Model
172
with
0-320-D2J engine
(1981
and
ON)
and
Model 172Q
with
0-360-A4N
engine
(1983
and
ON):
First
25
hours.
Drain
oil
sump, clean
pressure
screen
or
replace
oil
filter,
and
refill
with
MIL-L-6080
aviation
grade
straight
mineral
oil.
If
engine
is
not equipped
with
an
oil
filter,
change
oil
and
clean
pressure
screen
at 50
hours and
each
50
hours
there
after.
If
engine
is
equipped
with
an
oil
filter,
change oil
and
filter
at
50
hours
and
each
100
hours
there after.
Beginning with
the
50-hour
oil
change
and
thereafter,
refill
oil
sump
with
MIL-L-22851
ashless
dispersant
oil.
M.
Each
1000
hours.
N.
Replace
every
500
hours.
O.
Replace
filter each
100
hours.
P.
Check
electrolyte level
and
clean
battery
box
each
100
hours
or
90
days.
Revision
3
2-65
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
3
Registration No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
B
13
Aileron,
Elevator,
and
Rudder
Stops
-
Check for damage
and
security.
B
15
Seat
Tracks
and
Stops
-
Inspect
seat
tracks
for
condition
and
security
of
installation.
Check
seat
track
stops for
damage
and
correct
location.
Ensure
inspection
of
seat
rails
for
cracks
EACH
50
HOURS.
Refer
to
Section
3.
C
1
Wing
Surfaces
and
Tips
-
Inspect
for
skin
damage,
loose
rivets,
and
condition of
paint.
C
2
Wing
Struts and
Strut Fairings
-
Check
for
dents, cracks,
loose
screws
and
rivets,
and
condition
of
paint.
C
3
Wing
Spar
and
Wing
Strut
Fittings
-
Check
for evidence
of
wear.
Check attach
bolts for
indications
of looseness
and
retorque
as
required.
C
4
Wing
Structure
-
Inspect
spars,
ribs,
skins,
and
stringers
for
cracks,
wrinkles,
loose
rivets,
corrosion,
or
other
damage.
C
5
Metal
Lines,
Hoses,
Clamps,
and
Fittings
-
Check
for
leaks,
condition,
and
security.
Check
for
proper routing
and
support.
C
6 Wing
Access
Plates
-
Check
for
damage
and
security
of
installation.
C
7
Vertical
and
Horizontal
Stabilizers,
Tips and
Tailcone
-
Inspect
externally
for
skin
damage
and
condition
of
paint.
C
8
Vertical
and
Horizontal
Stabilizers
and
Tailcone structure
-
Inspect
bulkheads,
spars,
ribs,
and
skins
for
cracks,
wrinkles,
loose rivets, corrosion,
or
other
damage.
Inspect
vertical
and
horizontal
stabilizer
attach
bolts for
looseness.
Retorque
as
necessary.
Check
security of inspection
covers,
fairings,
and
tips.
E 1
Ailerons
and
Hinges
-
Check
condition,
security
and
operation.
E
2
Aileron
Structure,
Control
Rods,
Hinges,
Balance
Weights,
Bellcranks,
Linkage,
Bolts,
Pulleys,
and
Pulley
Brackets
-
Check
condition,
operation, and
security of
attachment.
E
3
Ailerons
and
Cables
-
Check
operation
and
security
of
stops.
Check
cables
for
tension,
routing,
fraying,
corrosion,
and
turnbuckle
safety.
Check
travel
if
cable
tension
requires
adjustment
or if
stops
are
damaged.
Check
fairleads
and
rub
strips
for
condition.
E 5
Aileron
Controls
-
Check
freedom
of movement
and
proper
operation
through
full
travel
with
and
without
flaps
extended.
F 1
Flaps
-
Check
tracks,
rollers,
and
control
rods
for
security
of
attachment.
Check operation.
F
2
Flap
Actuator
Threads
-
Clean
and
lubricate.
Refer
to
paragraph
2-43
for
detailed
instructions.
F
3
Flap
Structure,
Linkage,
Bellcranks, Pulleys,
and
Pulley
Brackets
-
Check for
condition,
operation
and
security.
F
4
Wing
Flap
Control
-
Check
operation
through
full
travel
and
observe
Flap
Position
indicator
for
proper
indication.
F 5
Flaps
and
Cables
-
Check
cables
for
proper tension,
routing,
fraying,
corrosion,
and
turnbuckle
safety.
Check
travel
if cable tension
requires
adjustment.
2-66
Revision
3
MODEL
172
SERIES SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
3
Registration
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
F
7
Flap
Motor,
Actuator,
and
Limit
Switches (electric
flaps)
-
Check
wiring
and
terminals
for
condition
and
security.
Check
actuator
for
condition
and
security.
G 1
Elevator
Control
-
Check
freedom
of
movement
and
proper
operation
through
full
travel
with
and
without
flaps
extended.
G
2
Elevator,
Hinges,
and
Cable
Attachment
-
Check
condition,
security,
and
operation.
H 1
Elevator
Trim
Tab
and
Hinges
-
Check
condition,
security,
and
operation.
H
4
Elevator
Trim
Tab
Stop
Blocks
-
Inspect
for
damage
and
security.
H
6
Elevator
Trim Tab
Actuator
-
Free-Play
limits
inspection.
Refer
to
Section 9
for cleaning,
inspection,
and
repair
procedures.
I 1
Rudder
-
Inspect
the
rudder
skins
for
cracks
and
loose
rivets, rudder
hinges
for
condition,
cracks
and
security;
hinge
bolts,
hinge
bearings,
hinge
attach
fittings,
and
bonding
jumper for
evidence
of
damage
and
wear,
failed
fasteners,
and
security.
Inspect
the
rudder
hinge
bolts
for
proper
safetying
of
nuts
with cotter
pins.
Inspect
balance
weight
for
looseness
and
the
supporting
structure
for
damage.
I
3
Rudder,
Tips,
Hinges,
and
Cable
Attachment
-
Check
condition,
security,
and
operation.
I
4
Rudder
-
Check
internal
surfaces
for
corrosion,
condition
of
fasteners,
and
balance
weight
attachment.
J
1
Cowling
-
Inspect
for
cracks,
dents,
and other
damage,
security
of
cowl
fasteners,
and
cowl
mounted
landing
lights
for
attachment
J
2
Engine
-
Inspect
for
evidence
of
oil
and fuel
leaks.
Wash
engine
and
check
for
security
of
accessories.
J
3
Engine
Controls
and
Linkage
-
Check
general
condition,
freedom
of movement through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks
for
proper
operation.
J
4
Ignition
Switch
and Electrical
Harness -
Inspect
for
damage,
condition,
and
security.
J
7
Induction
System
-
Check
security
of
clamps,
tubes,
and
ducting.
Inspect
for
evidence
of
leakage.
J
8 Induction Airbox,
Valves,
Doors,
and
Controls
-
Remove
air
filter
and
inspect
hinges,
doors,
seals,
and
attaching
parts
for
wear
and
security.
Check operation.
Clean and
inspect
air
filter.
J
9
Induction
Air
Filter
-
Remove
and
clean. Inspect
for
damage,
and
service
per
Paragraph
2-22
and
2-22A.
J
10
Alternate
Induction
Air
System
-
Check
for
obstructions,
operation,
and
security.
J
11
Alternator,
Mounting
Bracket,
and
Electrical
Connections
-
Check
condition
and
security.
Check
alternator
belts
for
condition
and
proper adjustment.
Check
belt
tension
per
Section
16,
Paragraph
16-38.
Revision
3
2-67
MODEL 172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
3
Registration No. Airplane
Model
and
SN Airplane
Time
INSPECTION
COMPLETED
BY
J
13
Starter,
Starter
Solenoid,
and
Electrical
Connections
-
Check
for condition
of
starter
brushes,
brush
leads,
and
commutator.
J
14
Oil
Cooler
-
Check
for
obstructions,
leaks,
and
security
of
attachment.
J
15
Exhaust
System
- Inspect
for
cracks
and
security.
Special
check
in
area
of
heat
exchanger.
Refer
to
Section
11,
Paragraph
11-73
for
inspection
procedures.
J
16
Auxiliary
(Electric)
Fuel
Pump (172Q)
-
Check
pump
and
fittings
for
condition, operation,
security.
Remove
and
clean
filter
(as
applicable).
J 17
Engine-Driven
Fuel
Pump
-
Check
for evidence
of
leakage,
security
of
attachment,
and
general
condition.
J
18
Magnetos
-
Check
external
condition,
security,
and
electrical
leads
for
condition.
Check
timing
to
engine
and
internal
timing
if
engine
timing
requires
adjustment.
J
21
Ignition
Harness
and
Insulators
-
Check
for
proper
routing,
deterioration,
and
condition
of
terminals.
J
22
Spark
Plugs
-
Remove,
clean,
analyze,
test,
gap,
and rotate
top
plugs-to-bottom
and bottom
plugs-to-top.
J
24
Carburetor
-
Drain
and
flush
carburetor
bowl,
clean
inlet
strainer,
and
drain
plug.
Check
general
condition
and
security.
J
25
Engine
Primer
-
Check
for
leakage,
operation,
and
security.
J
26
Hoses,
Metal
Lines, and
Fittings
-
Inspect
for
signs
of
oil
and
fuel
leaks.
Check
for
abrasions,
chafing,
security,
proper
routing
and
support
and
for
evidence
of
deterioration.
J
27
Cold
and
Hot
Air
Hoses
-
Check
condition,
routing,
and
security.
J
28
Engine
Cylinders,
Rocker
Box
Covers,
and
Pushrod
Housings
-
Check
for
fin
damage,
cracks,
oil
leakage,
security
of
attachment,
and
general
condition.
J
29
Engine
Baffles
and
Seals
-
Check
condition
and security
of
attachment.
J
30
Crankcase,
Oil
Sump,
and
Accessory
Section
-
Inspect
for
cracks
and evidence
of
oil
leakage.
Check
bolts
and
nuts
for
looseness
and
retorque
as
necessary.
Check
crankcase
breather lines
for
obstructions,
security,
and
general
condition.
J
31
Engine
Oil
With
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
replace
filter,
and
refill
with
recommended
grade
aviation
oil.
J
32
Engine
Oil
Without
Oil Filter
-
Drain
oil
sump
and
oil
cooler,
clean
and
inspect
screens,
and
refill
with
recommended
grade
aviation
oil.
K 1
Fuel
Tanks
or
Integral
Fuel
Bays
-
Check
for
evidence
of
leakage
and
condition
of
fuel caps,
adapters,
and
placards.
K
3 Fuel
System
-
Inspect
plumbing
and
components
for
mounting
and
security.
K
4
Fuel
Tank
or
Bay
Drains
-
Drain
water
and
sediment.
K
5
Fuel
Tank
Vent
Lines
and
Vent
Valves
-
Check
vents
for
obstruction
and
proper
positioning.
2-68
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
3
Registration
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
K
7
Fuel
Strainer,
Drain Valve,
and
Controls
-
Check
freedom
of
movement,
security, and
proper
operation.
Disassemble,
flush,
and
clean
screen
and
bowl.
L
1 Propeller
Mounting
-
Check
for
security
of
installation.
L 2
Propeller
Blades
-
Inspect
for
cracks, dents,
nicks,
scratches,
erosion,
corrosion,
or
other
damage.
L 3
Spinner
-
Check
general
condition
and
attachment.
L 4
Spinner
and
Spinner Bulkhead
-
Remove
spinner,
wash,
and
inspect for
cracks
and
fractures.
M
2
Heater
Components, Inlets,
and
Outlets
-
Inspect
all
lines,
connections,
ducts,
clamps,
seals,
and
gaskets
for
condition,
restriction,
and
security.
M
4
Pitot
Tube and
Stall
Warning Vane
-
Check
for
condition
and
obstructions.
N 3
Vacuum
Pump
-
Check
for
condition
and
security.
Check
vacuum
system
breather
line for obstructions,
condition,
and
security.
O 4
Battery
-
Check general
condition
and
security.
Check
level
of electrolyte.
O
5
Battery
Box
and Cables
-
Clean
and
remove
any
corrosion.
Check
cables
for
routing,
support,
and security of
connections.
Revision
3
2-69
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION NO.
3
INSPECTION
SPECIAL INSPECTION
AND
YEARLY
ITEMS
HOURS
YEARS
COMPLETED
BY
Please
review
each
of
these
items
for
required compliance
B
11
Upholstery,
Headliner, Trim,
and
Carpeting
-
Check
condition
EACH
EACH
and
clean
as
required.
400
1
D
3
Brake
Lines,
Wheel Cylinders,
Hoses,
Clamps,
and
Fittings
-
EACH
EACH
Check
for leaks,
condition,
and
security
and
hoses
for
bulges
400
1
and
deterioration.
Check
brake lines
and hoses
for
proper
routing
and
support.
D
6
Wheel
Fairings,
Strut
Fairings,
and
Cuffs
-
Check
for
cracks,
A
dents,
and
condition
of
paint.
D
11
Wheel
Bearings
-
Clean,
inspect
and
lube.
B
E
4
Autopilot
Rigging
-
Check
per
Avionics
Installation Manual.
C
H
5
Elevator
Trim
Tab
Actuator
-
Clean,
lubricate,
and
check
free-
D
play.
-J
3
Engine
Controls
and
Linkage
-
Check
general
condition,
E
freedom
of movement
through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear. Check
friction locks
for
proper
operation.
J
9
Induction
Air
Filter
-
Remove
and
clean. Inspect
for
damage,
F
and
service
per
Paragraph
2-22
and
2-22A.
J
12
Alternator
-
Check
brushes,
leads,
commutator
or
slip
ring
for
G
wear.
J
13
Starter,
Starter
Solenoid,
and
Electrical
Connections
-
Check
for
H
condition
of
starter
brushes,
brush
leads,
and commutator.
J 18
Magnetos
-
Check
external
condition, security,
and
electrical
leads
for
condition.
Check
timing
to engine
and
internal
timing
if
engine
timing
requires
adjustment.
J
19
Magnetos
-
Check
impulse
coupling
and
stop
pins
for condition,
J
replace
as
required.
J
20 Magnetos
-
Inspection,
lubrication
and
overhaul
procedures.
K
J
31
Engine
Oil
With
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
replace
L
filter,
and
refill
with
recommended
grade
aviation oil.
J
32
Engine Oil
Without
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
L
clean
and
inspect
screens, and
refill with recommended
grade
aviation
oil.
K
2
Fuel
Tanks
or
Integral
Fuel
Bays
-
Drain
fuel
and
check
tank
M
interior
and
outlet
screens.
K
8
Fuel
Quantity
Indicators
-
Check for damage,
security
of
EACH
installation,
and
perform
accuracy
test.
1
M
1
Ventilation
System
-
Inspect
clamps,
hoses,
and
valves
for
400
EACH
condition
and
security.
1
N
4
Vacuum
System
Air
Filter
-
Inspect
for
damage,
deterioration
N
and
contamination.
Clean
or
replace,
if
required.
NOTE:
Smoking
will
cause premature
filter
clogging.
N
5
Vacuum
System
relief Valve
-
Inspect
for
condition
and
security.
O
N
10
Airspeed
Indicator,
Vertical Speed
Indicator,
and
Magnetic
EACH
Compass
-
Calibrate.
2
N
11
Altimeter and Static System
-
Inspect
in
accordance with
FAR
EACH
Part
91.411.
2
O
4
Battery
-
Check
general
condition
and
security.
Check
level
of
P
electrolyte.
2-70
Revision
3
MODEL 172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION NO.
3
Special
Inspections
Legends:
A.
If
the
airplane
is
flown
from
surfaces
with
mud,
snow,
or
ice,
the
main
gear
speed fairings
should
be
checked that there
is
no
accumulation
which
could prevent
normal
wheel
rotation.
B.
First
100
hours
and
each 500 hours
thereafter.
More often
if
operated
under
prevailing
wet
or
dusty
conditions.
C.
Each
600
hours
or
1
year,
whichever comes
first.
D.
Lubrication
of
the
actuator
is
required each
1000
hours
or
3
years,
whichever comes first.
See fig-
ure
2-5
for
grease
specification.
E.
Lubricate
each
50
hours
(except
in
extreme
dusty
conditions).
These
controls
are
not
repairable
and
should be
replaced
every
1500
hours
or
whenever
maximum
linear
movement
exceeds
.050
inch.
F.
Model 172Q:
Replace
polyurethane
foam
filter
every
200
hours
or
on
condition.
Model
172
Series:
Filter may
be
washed
20
times
maximum,
cleaned
by compressed
air
30
times
maximum.
Replace
filter
each
500
hours
or
1
year,
whichever
comes
first.
G.
Inspect each
500
hours.
H.
Check
solenoid
and
electrical
connections
each
100
hours,
inspect
the
commutator
and
brushes
each 500
hours.
I. If
timing
to
engine
is
within
tolerance -
plus
zero
degrees,
minus
two
degrees,
internal
timing
will
not
require
checking.
Model
172
with 0-320-H2AD
engine
(1977
thru
1980):
Check
magnetos
at
first
25
hours,
first
50
hours,
first
100
hours,
and
each
100
hours
thereafter.
Model
172
with
0-320-D2J en-
gine
(1981
and
ON),
Model
172Q
with
0-360-A4N
engine
(1983
and
ON): Check
magnetos
at
first
100
hours,
and
every
100
hours thereafter
or
each
one
year,
whichever
occurs
first.
J.
Compliance
with
Bendix
Service
Bulletin
425B
is
required.
Model
172
with
0-320-H2AD
engine
(1977
thru
1980):
Each
500
hours.
K 1.
Inspect
contact
points
for
condition
and
adjust
or
replace
as
required.
2.
Inspect
carbon
brush, high-tension
lead,
and
distributor
block
for
condition
and
clean
or
replace
as
required.
3.
Inspect impulse coupling
and
pawls
for
condition
and
replace
as
required.
Use
light
pressure
only,
do
not
force
pin (or
drill bit)
when
checking
pawls.
4.
Inspect
bearings
and
lubricate,
replace
bearings,
if
required.
5.
Lubricate
contact
point
cam.
6.
Completely
overhaul, or
replace
existing
magneto
with
a
new
or
rebuilt
exchange
magneto,
at
every
engine
overhaul. Refer
to
Overhaul
and
Maintenance
Manual,
Publication
No.
1037C1-13,
covering
Model
4200/6200
series
magnetos.
Manual
No.
1037C1-13
is
available
from
Cessna
Supply Division.
Effectivity,
Model 172
with
0-320-0-2J
engine
(1981
and
ON)
and Model
172Q
with
0-360-A4N
engine
(1983
and
ON);
Each
500
hours
and
every
engine
overhaul.
L
Model
172
with
0-320-H2AD engine
(1977
thru
1980): First
25 hours.
Drain
oil
sump,
clean
pressure
screen
or replace
oil
filter,
and
refill with
MIL-L-22851
ashless
dispersant
oil.
If
oil
must
be
added
during
first
25 hours,
use
MIL-L-6082
aviation grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an
oil
filter,
change
oil
and
clean
pressure screen
at
50
hours,
and
each
50
hours thereafter.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at
50
hours,
and
each
100
hours
thereafter.
Model
172
with
0-320-D2J
engine
(1981
and
ON)
and
Model
172Q
with
0-360-A4N
engine
(1983
and ON): First 25
hours.
Drain
oil
sump, clean
pressure screen
or
replace
oil
filter,
and
refill
with
MIL-L-6080 aviation
grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an
oil
filter,
change
oil
and
clean
pressure
screen
at 50
hours
and
each
50
hours
there
after.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at 50
hours
and
each
100
hours
there
after.
Beginning
with
the
50-hour
oil
change
and
thereafter,
refill
oil
sump
with
MIL-L-22851
ashless
dispersant
oil.
M.
Each
1000
hours.
N.
Replace
every
500
hours.
O.
Replace
filter
each
100
hours.
P.
Check
electrolyte
level
and
clean
battery
box
each
100
hours
or
90
days.
Revision
3
2-71
MODEL
172 SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE CARE
MODEL
172
OPERATION
NO.
4
Registration
No.
Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
A
1
Placards
and Decals
-
Inspect
presence,
legibility,
and
security.
Consult
Pilot's Operating
Handbook
and
FAA-
Approved
Airplane
Flight
Manual
for
required
placards.
B 1
Fuselage
Surface
-
Inspect
for
skin damage, loose
rivets,
condition
of paint,
and
check
pitot-static
ports
and
drain
holes
for obstruction.
Inspect
covers
and
fairings
for
security.
B
2
Internal
Fuselage
Structure
-
Inspect
bulkheads,
doorposts,
stringers, doublers,
and
skins
for
corrosion, cracks,
buckles,
and
loose rivets,
bolts
and
nuts.
B
3
Control
Wheel
Lock
-
Check
general
condition
and
operation.
B
4
Fuselage
Mounted
Equipment
-
Check
for
general
condition
and
security
of
attachment.
B
5
Antennas
and Cables
-
Inspect
for
security
of
attachment,
connection,
and
condition.
B
6 Emergency
Locator
Transmitter
-
Inspect for
security
of
attachment and
check
operation
by
verifying
transmitter
output.
Check
cumulative
time
and
useful
life
of
batteries
in
accordance
with
FAR
Part
91.207.
Refer
to
Section
16
-
Emergency Locator
Transmitter
-
Checkout
Interval.
B
7
Instrument
Panel
Shock
Mounts, Ground
Straps,
and
Covers
-
Inspect for
deterioration, cracks,
and
security
of
attachment.
B
8
Pilot's
and
Copilot's
Inertia
Reels
-
Inspect
for
security
of
installation,
proper operation,
and
evidence
of
damage.
B
9 Seats,
Seat
Belts,
and
Shoulder
Harnesses
-
Check
general
condition
and
security.
Check
operation
of
seat
stops
and
adjustment
mechanism.
Inspect
belts
for
condition
and
security
of
fasteners.
B
10
Windows,
Windshield,
Doors,
and
Seals
-
Inspect
general
condition.
Check latches,
hinges,
and
seals
for
condition,
operation, and
security
of
attachment.
B
12
Flight
Controls
-
Check
freedom
of
movement
and
proper
operation
through
full travel
with
and
without
flaps
extended. Check
electric
trim
controls
for
operation
(as
applicable).
B
14
Portable
Hand
Fire
Extinguisher
-
Inspect for
proper
operating
pressure,
condition,
security
of
installation,
and
servicing
date.
B
15
Seat
Tracks
and
Stops
-
Inspect
seat
tracks for
condition
and
security
of
installation.
Check
seat
track
stops
for
damage
and
correct
location.
Ensure
inspection
of
seat
rails
for
cracks
EACH
50
HOURS.
Refer to
Section
3.
B
16
Control
Column
-
Inspect
pulleys,
cables,
sprockets,
bearings,
chains,
bungees,
and
turnbuckles for
condition
and
security.
B
17
Fuel
Line
and
Selector
Valve
Drain(s)
-
Remove
plug
and
drain.
D 1
Brakes,
Master
Cylinders,
and Parking
Brake
-
Check
master
cylinders
and
parking
brake
mechanism for
condition
and
security.
Check fluid
level
and
test
operation
of toe
and
parking
brake.
-
2-72
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
Registration No. Airplane
Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
D
2
Main
Gear
Tubular
Struts
-
Inspect
for
cracks,
dents,
corrosion,
condition of
paint
or
other
damage. Check
axles
for
condition
and
security.
D
4
Wheels,
Brake
Discs,
and
Linings
-
Inspect
for
wear,
cracks,
warps,
dents,
or
other damage.
Check
wheel
through-bolts
and
nuts
for
looseness.
D 5
Tires
-
Check
tread
wear
and
general
condition.
Check
for
proper
inflation.
D
6
Wheel
Fairings,
Strut
Fairings,
and
Cuffs
-
Check
for
cracks,
dents,
and condition
of
paint.
D
7
Main
landing Gear
Attachment Structure
-
Check
for
damage,
cracks,
loose
rivets, bolts
and
nuts
and
security
of
attachment.
D
9
Nose
Gear
-
Inspect
torque
links,
steering
rods,
and
boots
for condition and
security
of
attachment.
Check
strut
for
evidence
of
leakage
and
proper
extension.
Check
strut
barrel
for
corrosion, pitting,
and
cleanliness.
Check
shimmy
damper
and/or
bungees
for
operation,
leakage, and
attach points
for
wear
and
security.
D
12
Nose
Gear
Attachment
Structure
-
Inspect
for
cracks,
corrosion,
or
other
damage
and
security
of
attachment.
G
3
Elevator
Control
System
-
Inspect
pulleys, cables,
sprockets,
bearings,
chains,
and
tumbuckles
for
condition,
security,
and
operation.
H
2
Elevator
Trim
System
-
Check
cables,
push-pull
rods,
bellcranks,
pulleys,
tumbuckles.
fairleads,
rub
strips,
etc.
for
proper
routing, condition,
and
security.
H
3
Trim
Controls
and
Indicators
-
Check
freedom
of
movement
and
proper
operation
through
full travel.
Check
pulleys,
cables, sprockets,
bearings,
chains, bungees,
and
tumbuckles
for condition
and
security.
Check
electric
trim
controls
for
operation
as
applicable.
2
Rudder
Pedals
and
Linkage
-
Check
for
general
condition,
proper
rigging,
and
operation.
Check
for
security
of
attachment.
J
1
Cowling
-
Inspect
for
cracks,
dents,
and
other
damage,
security
of
cowl
fasteners,
and
cowl
mounted
landing
lights
for
attachment.
J
2
Engine
-
Inspect
for
evidence
of
oil
and
fuel
leaks.
Wash
engine
and
check
for security
of
accessories.
J
3
Engine
Controls
and
Linkage
-
Check
general
condition,
freedom
of
movement
through
full
range.
Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks
for proper
operation.
J
7
Induction
System
-
Check
security
of
clamps,
tubes, and
ducting.
Inspect
for
evidence
of
leakage.
J
10
Alternate
Induction
Air
System
-
Check
for
obstructions,
operation,
and
security.
J
11
Alternator,
Mounting
Bracket,
and
Electrical Connections
-
Check
condition
and
security.
Check alternator
belts
for
condition
and
proper
adjustment.
Check
belt
tension
per
Section
16.
Paragraph
16-38.
J
14
Oil
Cooler
-
Check
for obstructions,
leaks,
and
security
of
attachment.
Revision
3
2-73
MODEL
172 SERIES
SERVICE
MANUAL
CESSNA PROGRESSIVE CARE
MODEL
172
OPERATION
NO.
4
Registration
No.
Airplane Model
and
SN
Airplane
Time
INSPECTION
COMPLETED
BY
J 15
Exhaust
System
-
Inspect
for
cracks
and
security.
Special
check
in
area
of
heat
exchanger.
Refer
to
Section
11,
Paragraph
11-73
for inspection
procedures.
J 26
Hoses,
Metal
Lines,
and
Fittings
-
Inspect
for
signs
of
oil
and
fuel
leaks.
Check
for
abrasions,
chafing,
security,
proper
routing
and
support
and
for
evidence
of
deterioration.
J
29
Engine
Baffles
and
Seals
-
Check
condition
and
security
of
attachment.
J
32
Engine
Oil
Without
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
clean
and
inspect
screens,
and
refill
with
recommended
grade
aviation
oil.
K
4
Fuel
Tank
or
Bay
Drains
-
Drain
water
and
sediment.
K
6
Fuel
Selector
Valve
-
Check
controls
for detent
in
each
position,
security
of attachment,
and
for
proper placarding.
L 1
Propeller
Mounting
-
Check
for
security
of
installation.
L
2
Propeller
Blades
-Inspect
for
cracks,
dents,
nicks,
scratches,
erosion,
corrosion,
or
other
damage.
L
3
Spinner
-
Check
general
condition
and
attachment.
M
3
Cabin
Heat
and
Ventilation
Controls
-
Check
freedom
of
movement
through
full
travel. Check
friction
locks
for
proper operation.
M
4
Pitot
Tube
and
Stall Warning
Vane
-
Check
for
condition
and
obstructions.
N
1
Vacuum
System
-
Inspect
for
condition
and
security.
N
2 Vacuum
System
Hoses
-
Inspect
for hardness,
deterioration,
looseness,
or
collapsed
hoses.
N
4
Vacuum
System
Air
Filter
- Inspect
for
damage,
deterioration
and
contamination.
Clean
or
replace, if
required.
NOTE:
Smoking
will
cause
premature
filter
clogging.
N
5
Vacuum
System
relief
Valve
-
Inspect
for
condition
and
security.
N
6
Instruments
-
Check general
condition
and
markings for
legibility.
N
7
Instrument
Lines, Fittings, Ducting,
and
Instrument
Panel
Wiring
-
Check
for
proper routing,
support,
and
security
of
attachment.
N
8
Static
System
-
Inspect
for security
of
installation,
cleanliness,
and
evidence
of
damage.
N
9
Navigation
Indicators,
Controls,
and
Components
-
Inspect
for
condition
and security.
N
12
Instrument
Panel Mounted
Avionics
Units
(Including
Audio
Panel,
VHF
Nav/Com(s),
ADF,
Transponder,
DME,
and
Compass
System)
-
Inspect
for
deterioration,
cracks,
and
security
of instrument panel
mounts.
Inspect
for
security
of
electrical
connections,
condition,
and
security
of
wire
routing.
N
13
Avionics
Operating
Controls
-
Inspect
for security
and
proper
operation of
controls
and
switches
and
ensure
that
all
digital
segments
will
illuminate
properly.
2-74
Revision
3
MODEL 172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
Registration
No.
Airplane
Model
and
SN
Airplane Time
INSPECTION
COMPLETED
BY
N
14
Remote
Mounted
Avionics
-
Inspect
for
security
of
units
and
electrical connectors,
condition
and
security
of
wire
routing.
Also,
check
for
evidence of
damage
and
cleanliness.
N
15
Microphones, Headsets,
and
Jacks
-
Inspect
for
cleanliness, security,
and
evidence of
damage.
N
16
Magnetic
Compass
-
Inspect
for
security of
installation,
cleanliness,
and
evidence
of
damage.
O
1
General
Airplane
and
System
Wiring
-
Inspect
for
proper
routing,
chafing,
broken
or
loose
terminals,
general
condition,
broken
or
inadequate
clamps,
and
sharp
bends
in
wiring.
O 2
Instrument,
Cabin,
Navigation,
Beacon, Strobe,
and
Landing
Lights
-
Check
operation,
condition of
lens,
and
security
of
attachment.
O 3
Circuit
Breakers
and
Fuses
-
Check operation
and
condition.
Check
for
required
number
of
spare
fuses.
O
6
Switch
and
Circuit
Breaker
Panel, Terminal
Blocks,
and
Junction
Boxes
-
Inspect
wiring
and
terminals
for
condition
and
security.
O
8
Switches
-
Check
operation,
terminals, wiring,
and
mounting
for conditions,
security,
and
interference.
O 9
Instrument
Panel
and
Control
Pedestal
-
Inspect
wiring,
mounting,
and
terminals
for
condition
and
security.
Check
resistance
between
stationary
panel
and
instrument
panel
for
proper
ground.
Q
1
Brakes
-
Test
toe
brakes
and
parking
brake
for
proper
operation.
Revision
3
2-75
MODEL
172
SERIES SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
INSPECTION
SPECIAL
INSPECTION AND
YEARLY
ITEMS
HOURS
YEARS
COMPLETED
BY
Please
review each
of these
items
for
required compliance
·
B
11
Upholstery,
Headliner,
Trim,
and
Carpeting
-
Check
condition
EACH
EACH
and
clean
as
required.
400
1
D
3
Brake
Lines,
Wheel
Cylinders,
Hoses,
Clamps,
and
Fittings
-
EACH
EACH
Check
for
leaks,
condition,
and
security
and
hoses
for
bulges
400
1
and
deterioration.
Check
brake
lines
and
hoses
for
proper
routing
and
support.
D
6
Wheel-Fairings,
Strut
Fairings,
and
Cuffs
-
Check
for
cracks,
A
dents,
and
condition
of
paint.
D
11
Wheel
Bearings
-
Clean,
inspect
and
lube.
B
E
4
Autopilot
Rigging
-
Check per
Avionics
Installation
Manual.
C
H
5
Elevator
Trim
Tab
Actuator
-
Clean,
lubricate,
and
check
free-
D
play.
J
3
Engine
Controls
and
Linkage
-
Check
general
condition,
E
freedom
of
movement
through
full
range. Check
for
proper
travel,
security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks
for
proper
operation.
J
9
Induction
Air
Filter
-
Remove
and
clean.
Inspect
for
damage,
F
and
service
per Paragraph 2-22
and
2-22A.
J
12
Alternator
-
Check
brushes,
leads,
commutator
or
slip
ring for
G
wear.
J 13
Starter,
Starter
Solenoid,
and
Electrical
Connections
-
Check
for
H
condition
of
starter
brushes,
brush
leads,
and
commutator.
J
18
Magnetos
-
Check
external
condition,
security,
and
electrical
leads
for
condition.
Check
timing
to
engine
and
internal
timing
if
engine
timing
requires
adjustment.
J
19
Magnetos
-
Check
impulse
coupling
and
stop
pins
for
condition,
J
replace
as
required.
J
20
Magnetos
-
Inspection,
lubrication
and
overhaul
procedures.
K
J
31
Engine
Oil
With
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
replace
L
filter,
and
refill
with
recommended
grade
aviation
oil.
J 32
Engine
Oil
Without
Oil
Filter
-
Drain
oil
sump
and
oil
cooler,
L
clean
and
inspect
screens,
and
refill
with
recommended
grade
aviation
oil.
K
2
Fuel
Tanks
or
Integral
Fuel
Bays
-
Drain
fuel
and
check
tank
M
interior
and
outlet
screens.
K
8
Fuel
Quantity
Indicators
-
Check for
damage,
security
of
EACH
installation,
and
perform
accuracy
test.
1
M
1
Ventilation
System
-
Inspect
clamps,
hoses,
and
valves
for
400
EACH
condition
and
security.
1
N
4 Vacuum
System
Air
Filter
-
Inspect
for
damage,
deterioration
N
and
contamination.
Clean
or
replace,
if
required.
NOTE:
Smoking will
cause
premature filter
clogging.
N
5
Vacuum
System
relief
Valve
-
Inspect
for
condition
and
security.
O
N
10
Airspeed
Indicator,
Vertical
Speed
Indicator,
and
Magnetic
EACH
Compass
-
Calibrate.
2
N
11
Altimeter
and
Static
System
-
Inspect
in
accordance
with
FAR
EACH
Part
91.411.
2
O
4
Battery
-
Check
general
condition
and
security.
Check
level of
P
electrolyte.
2-76
Revision
3
MODEL
172 SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
Special
Inspections
Legends:
A.
If
the
airplane
is
flown
from
surfaces
with
mud,
snow,
or
ice,
the
main
gear
speed fairings
should
be
checked
that
there
is no
accumulation
which
could
prevent
normal
wheel
rotation.
B.
First
100
hours and
each
500
hours
thereafter.
More
often
if
operated
under
prevailing
wet
or
dusty
conditions.
C.
Each
600
hours
or
1
year,
whichever
comes
first.
D.
Lubrication
of
the actuator
is
required
each
1000
hours
or
3
years, whichever comes first. See
fig-
ure
2-5
for
grease
specification.
E.
Lubricate
each
50
hours
(except
in
extreme dusty conditions).
These controls
are
not
repairable
and
should
be
replaced
every
1500
hours
or
whenever
maximum
linear
movement exceeds .050
inch.
F.
Model
172Q:
Replace polyurethane
foam
filter
every 200
hours or
on
condition.
Model
172
Series:
Filter may
be
washed
20
times
maximum,
cleaned
by
compressed
air
30
times
maximum.
Replace
filter
each
500
hours
or
1
year,
whichever
comes
first.
G.
Inspect
each
500
hours.
H.
Check
solenoid
and
electrical
connections
each
100
hours,
inspect
the
commutator
and
brushes
each
500 hours.
I.
If
timing
to
engine
is within
tolerance - plus
zero
degrees,
minus
two
degrees.
internal
timing
will
not
require
checking.
Model
172
with 0-320-H2AD
engine
(1977 thru
1980):
Check magnetos
at
first
25
hours,
first
50
hours, first
100
hours, and each
100
hours
thereafter.
Model
172
with
0-320-D2J
en-
gine
(1981
and
ON),
Model
172Q
with
0-360-A4N
engine
(1983
and
ON):
Check
magnetos
at
first
100
hours,
and
every
100
hours
thereafter
or
each one
year,
whichever
occurs
first.
J.
Compliance
with
Bendix
Service
Bulletin 425B
is
required.
Model
172
with
0-320-H2AD
engine
(1977 thru
1980):
Each
500
hours.
K.
1.
Inspect
contact
points
for
condition
and
adjust
or
replace
as
required.
2.
Inspect
carbon
brush,
high-tension
lead,
and
distributor
block
for
condition
and
clean
or
replace
as
required.
3.
Inspect
impulse coupling
and
pawls
for
condition
and
replace
as
required.
Use
light
pressure
only,
do
not
force
pin
(or
drill
bit)
when checking
pawls.
4.
Inspect bearings
and
lubricate,
replace
bearings,
if
required.
5.
Lubricate
contact
point
cam.
6.
Completely
overhaul,
or
replace existing
magneto with
a
new
or
rebuilt
exchange magneto,
at
every
engine
overhaul.
Refer
to
Overhaul
and
Maintenance
Manual,
Publication
No.
1037C1-13,
covering
Model
4200/6200
series magnetos.
Manual
No.
1037C1-13
is
available from Cessna
Supply Division.
Effectivity,
Model
172
with
0-320-0-2J
engine
(1981
and
ON)
and
Model
172Q
with
0-360-A4N
engine
(1983
and
ON);
Each 500
hours
and
every
engine overhaul.
L.
Model
172
with
0-320-H2AD
engine
(1977
thru
1980):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace
oil
filter,
and
refill
with
MIL-L-22851
ashless dispersant
oil.
If
oil
must
be
added
during
first
25
hours,
use
MIL-L-6082
aviation
grade
straight
mineral
oil.
If
engine
is
not
equipped
with
an oil
filter,
change
oil
and
clean
pressure
screen
at
50
hours,
and
each
50
hours
thereafter.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at
50
hours,
and each
100
hours
thereafter.
Model
172
with
0-320-D2J
engine
(1981
and
ON)
and
Model
172Q
with
0-360-A4N
engine
(1983
and
ON):
First
25
hours.
Drain
oil
sump,
clean
pressure
screen
or
replace
oil
filter,
and
refill
with
MIL-L-6080
aviation
grade
straight
mineral
oil.
If
engine
is
not equipped
with
an
oil
filter,
change
oil
and
clean
pressure screen
at
50
hours
and
each
50
hours
there
after.
If
engine
is
equipped
with
an
oil
filter,
change
oil
and
filter
at
50 hours
and
each
100
hours
there
after.
Beginning
with
the
50-hour
oil
change
and
thereafter,
refill
oil
sump with
MIL-L-22851
ashless
dispersant
oil.
M.
Each
1000
hours.
N.
Replace every
500
hours.
O.
Replace
filter
each
100
hours.
P.
Check
electrolyte level
and
clean
battery
box
each
100
hours
or
90
days.
Revision
3
2-77
(2-78
blank)
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
CABIN
1.
Control
Wheel
Lock
- Check
security
and
operation.
2.
Flight
Controls
-
Check
freedom
of
movement
and
proper
operation
through
full
travel
with
and
with-
out
flaps
extended.
Check
electric
trim
controls
for
operation.
3.
Control
Column
-
Inspect
pulleys,
cables,
sprockets,
bearings,
chains,
bungees
and
turnbuckles
for
con-
dition
and
security.
4.
Elevator
Control
-
Check
freedom
of
movement
and
proper
operation
through
full
travel
with
and
with-
out flaps extended.
5.
Trim
Control
and
Indicator
-
Check
freedom
of
movement
and
proper
operation through
full
travel.
Check
pulleys,
cables, sprockets, bearings,
chains,
bungees,
and
turnbuckles
for
condition
and
secu-
rity.
Check
electric
trim
controls for
operation
as
ap-
plicable.
6.
Wing
Flap
Control
- Check
operation
through
full
travel
and
observe
Flap
Position
Indicator
for
proper
indication.
7.
Rudder
Pedals
and
Linkage
-
Check
for
general
con-
dition, proper
rigging,
and
operation.
Check
for
se-
curity
of
attachment.
8.
Pilot's
and
Copilot's
Inertia
Reels
-
Inspect
for
secu-
rity
of
installation,
proper
operation,
and
evidence
of
damage.
9.
Seats,
Seat
Belts,
and
Shoulder
Harnesses
-
Check
general
condition
and
security.
Check
operation
of
seat
stops
and
adjustment
mechanism.
Inspect
belts
for condition
and
security
of
fasteners.
10.
Seat
Tracks and
Stops
-
Inspect
seat
tracks
for
con-
dition
and
security
of
installation.
Check
seat
track
stops
for
damage
and
correct
location.
11.
Portable
Hand
Fire
Extinguisher
-
Inspect
for
proper
operating
pressure,
condition,
security
of
installa-
tion,
and
servicing
date.
Sheet
3
of
12
Revision
1
2-79
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
12.
Fuel
Selector Valve
-
Check
controls
for
detent
in
each
position, security
of
attachment,
and
for
prop-
er
placarding.
13.
Switches
-
Check
operation,
terminals,
wiring,
and
mounting
for condition,
security,
and
interference.
14.
Circuit
Breakers
and
Fuses
-
check
operation
and
condition.
Check
for
required
number
of
spare
fuses.
15.
Switch
and
Circuit
Breaker Panel,
Terminal
Blocks,
and
Junction
Boxes
-
Inspect
wiring
and
terminals
for
condition
and
security.
16.
Ignition
Switch
and Electrical
Harness
-
Inspect for
damage,
condition,
and
security.
17.
Engine
Controls, and
Linkage
- Check
general
con-
dition,
freedom
of
movement
through
full
range.
Check
for
proper
travel, security
of
attachment,
and
for
evidence
of
wear.
Check
friction
locks
for
proper
operation.
18.
Heater
Components,
Inlets,
and
Outlets
-
Inspect
all
lines,
connections,
ducts,
clamps,
seals, and
gaskets
for condition, restriction,
and
security.
19.
Cabin
Heat
and
Ventilation
Controls
- Check
free-
dom
of
movement
through
full
travel.
Check
friction
locks
for
proper
operation.
20.
Instrument,
Cabin,
Navigation,
Beacon,
Strobe,
and
Landing
Lights
- Check
operation,
condition
of
lens,
and
security
of
attachment.
21.
Microphones,
Headsets,
and
Jacks
-
Inspect
for
cleanliness,
security,
and
evidence
of
damage.
22.
Instrument
Lines,
Fittings,
Ducting,
and
Instrument
Panel
Wiring
- Check
for
proper
routing,
support,
and
security
of
attachment.
23.
General
Airplane
and
System
Wiring
-
Inspect
for
proper
routing, chafing,
broken
or
loose
terminals,
general
condition,
broken
or
inadequate
clamps,
and
sharp bends
in
wiring.
Sheet
4
of
12
12-80
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
24.
Instrument
Panel
and
Control
Pedestal
-
Inspect
wir-
ing,
mounting,
and
terminals for
condition
and
se-
curity.
Check
resistance between
stationary
panel
and
instrument
panel
for
proper ground.
25.
Navigation
Indicators,
Controls,
and
Components
-
Inspect
for condition
and
security.
26.
Instrument
Panel
Mounted
Avionics
Units
(Including
Audio
Panel,
VHF
Nav/Com(s),
ADF,
Transponder,
DME,
and
Compass
System
-
Inspect
for
deteriora-
tion,
cracks, and
security of instrument
panel
mounts. Inspect
for
security
of
electrical
connec-
tions,
condition,
and
security
of
wire
routing.
27.
Avionics
Operating
Controls
-
Inspect
for security
and
proper
operation
of
control
and
switches
and
ensure
that
all
digital
segments
will
illuminate
prop-
erly.
28.
Vacuum
System
-
Inspect
for
condition
and
security.
29.
Vacuum
System
Hoses
-
Inspect
for
hardness,
de-
terioration,
looseness,
or
collasped
hoses.
30.
Vacuum
System Relief Valve
-
Inspect
for
condition
and
security.
31.
Vacuum
System
Air
Filter
-
Inspect
for
damage,
de-
terioration,
and
contamination.
Clean
or
replace,
if
required.
32.
Instrument
Panel
Shock
Mounts,
Ground Straps,
and
Covers
-
Inspect
for
deterioration,
cracks,
and
security
of
attachment.
33.
Instruments
- Check
general
condition
and
markings
for
legibility.
34.
Windows,
Windshield,
Doors,
and
Seals -
Inspect
general
condition.
Check
latches,
hinges,
and
seals
for
condition,
operation,
and
security
of
attachment.
35.
Placards
and Decals
-
Inspect
presence,
legibility,
and
security.
Consult
Pilot's
Operating
Handbook
and
FAA-approved
Airplane
Flight
Manual
for
re-
quired placards.
36.
Magnetic
Compass
-
Inspect
for security
of
installa-
tion,
cleanliness,
and
evidence
of
damage.
Sheet
5
of
12
Revision
1
2-81
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION NO.
4
MECHANIC
INSPECTOR
REMARKS
ENGINE
1.
Cowling
-
Inspect
for
cracks, dents,
and
other
dam-
age,
security
of
cowl
fasteners,
and
cowl
mounted
landing
lights for
attachment.
2.
Engine
-
Inspect
for
evidence
of
oil
and
fuel
leaks.
Wash
engine
and
check
for
security
of
accessories.
3.
Induction
System
- Check
security
of
clamps,
tubes,
and
ducting.
Inspect
for
evidence
of
leakage.
4.
Induction
Airbox,
Valves, Doors,
and
Controls
-
Re-
move
air
filter
and
inspect
hinges, doors,
seals,
and
attaching
parts
for
wear
and
security.
Check
oera-
tion.
Clean
and
inspect air
filter
and
re-oil
if flock-
coated.
5.
Induction
Air
Filter
-
Remove
and
clean.
Inspect
for
damage,
and
service
per
paragraphs
2-22
and
2-
22A.
6.
Alternate
Induction
Air
System
- Check
for
obstruc-
tions,
operation,
and
security.
7.
Oil Cooler
- Check
for
obstructions,
leaks,
and
secu-
rity
of
attachment.
8.
Hoses,
Metal
Lines, and
Fittings
-
Inspect
for
signs
of
oil
and
fuel
leaks.
Check
for
abrasions,
chafing,
security,
proper
routing
and
support
and
for
evi-
dence
of
deterioration.
9.
Firewall
Structure
-
Inspect
for
wrinkles,
damage,
cracks,
sheared
rivets,
etc.
Check
cowl
shock
mounts
for condition
and
security.
10.
Fuel
Strainer,
Drain
Valve,
and
Control
- Check
free-
dom
of
movement,
security,
and
proper
operation.
disassemble,
flush,
and
clean
screen
and
bowl.
11.
Vacuum Pump
-
Check
for
condition
and
security.
Check
vacuum system breather line
for
obstruc-
tions,
condition,
and
security.
12.
Engine
Shock
Mounts,
Engine
Mount
Structure,
and
Ground
Straps
-
Check
condition,
security,
and
alignment.
Sheet
6
of
12
2-82
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION NO.
4
MECHANIC
INSPECTOR
REMARKS
13.
Alternator,
Mounting
Bracket,
and Electrical
Connec-
tions
- Check
condition
and
security.
Check
alter-
nator belts
for
condition
and
proper
adjustment.
Check
belt tension
per
paragraph
16-38.
14.
Alternator
Control
Unit
-
Inspect
wiring,
mounting,
condition,
and
wire
routing.
15.
Auxiliary
(Electric)
(172Q)
Fuel
Pump
-
Check
pump
and
fittings
for
condition,
operation,
security.
Re-
move
and
clean
filter
(as
applicable).
16.
Engine-Driven
Fuel
Pump
-
Check
for
evidence
of
leakage,
security
of
attachment,
and
general
condi-
tion.
17.
Engine
Baffles
and
Seals
- Check
condition
and
se-
curity
of
attachment.
18.
Exhaust System
-
Inspect
for
cracks
and
security,
special
check in
area
of
heat
exhanger.
19.
Heater
Components
-
Inspect
all
components
for
condition
and
security.
20.
Ignition
Harness
and
Insulators
-
Check
for
proper
routing,
deterioration,
and
condition
of
terminals.
21.
Spark
Plugs
-
Remove, clean
analyze,
test,
gap,
and
rotate
top plugs-to-bottom
and
bottom
plugs-to-top.
22.
Carburetor
-
Drain
and
flush
carburetor
bowl
and
clean
inlet
strainer.
Check
general
condition
and
se-
curity.
23.
Engine
Primer
-Check
for
leakage,
operation,
and
security.
24.
Engine
Cylinders,
Rocker
Box
Covers, and
Pushrod
Housings
- Check
for
fin
damage,
cracks,
oil
leak-
age,
security
of
attachment,
and
general
condition.
25.
Crankcase,
Oil
Sump,
and
Accessory
Section
-
In-
spect
for
cracks
and
evidence of
oil
leakage.
Check
bolts
and
nuts
for
looseness
and
retorque
as
neces-
sary.
Check
crankcase
breather
lines
for
obstruc-
tions,
security,
and
general
condition.
Sheet
7
of
12
Revision
1
2-831
MODEL
172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
26.
Cold and
Hot
Air
Hoses - Check
condition,
routing,
and
security.
27.
Cylinder
Compression
-
Perform
differential
com-
pression
test.
PROPELLER
1.
Propeller
Blades
-
Inspect
for
cracks, dents,
nicks,
scratches,
erosion,
corrosion,
or
other
damage.
2.
Spinner
-
Check
general
condition
and
attachment.
3.
Spinner
and
Spinner
Bulkhead
-
Remove
spinner,
wash,
and
inspect
for
cracks and
fractures.
4.
Propeller
Mounting
- Check
for
security
of
installa-
tion.
5.
Propeller
Mounting
Bolts
-
Inspect
mounting
bolts
and
safety-wire
for
signs
of
looseness.
Retorque
mounting bolts
as
required.
6.
Propeller
Hub
-
Check
general
condition.
WINGS
1.
Wing
Surfaces and
Tips
-
Inspect
for
skin
damage,
loose
rivets,
and
condition
of paint.
2.
Wing
Struts
and
Strut
Fairings
-Check
for
dents,
cracks, loose
screws
and
rivets,
and
condition
of
paint.
3.
Wing
Spar
and
Wing
Strut
Fittings
-
Check
for
evi-
dence
of wear.
Check
attach
bolts
for
indications
of
looseness
and
retorque
as
required.
4.
Wing
Access
Plates
- Check
for
damage
and
security
of
installation.
5.
Pitot
Tube and
Stall
Warning
Vane
-
Check
for
con-
dition
and
obstructions.
6.
General
Airplane
and
System
Wiring
-
Inspect
for
proper routing,
chafing,
broken
or
loose
terminals,
general
condition,
broken
or inadequate
clamps,
and
sharp
bends
in
wiring.
Sheet
8
of
12
2-84
Revision
1
MODEL 172
SERIES
SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
7.
Metal Lines,
Hoses,
Clamps,
and
Fittings
- Check
for
leaks,
condition,
and
security.
Check
for
proper
rout-
ing
and
support.
8.
Fuel
Tank Vent
Lines
- Check
vent
lines
for
obstruc-
tion
and
proper
positioning.
9.
Fuel
System
-
Inspect
plumbing
and
components
for
mounting
and
security.
10.
Fuel
Tank
or
Bay
Drains
-
Drain
water
and
sediment.
11.
Fuel
Tanks
or Integral
Fuel
Bays
- Check
for
leakage
and
condition
of
fuel
caps,
adapters,
and
placards.
12.
Wing
Structure
-
Inspect
spars, ribs,
skins,
and
stringers
for
cracks,
wrinkles,
loose
rivets,
corro-
sion, or
other
damage.
13.
Placards
and
Decals
-
Inspect presence,
legibility,
and
security.
Consult
Pilot's
Operating
Handbook
and
FAA-Approved
Airplane
Manual
for
required
placards.
14.
Aileron
Structure,
Control
Rods,
Hinges,
Balance
Weights,
Bellcranks,
Linkage,
Bolts,
Pulleys,
and
Pulley
Brackets
-
Check
condition,
operation,
and
se-
curity of
attachment.
15.
Ailerons
and
Hinges
- Check
condition,
security,
and
operation.
16.
Aileron
Controls
-
Check
freedom
of
movement
and
proper
operation
through
full
travel
with
and
with-
out
flaps
extended.
17.
Ailerons
and
Cables
- Check
operation
and
security
of
stops.
Check
cables
for
tension,
routing,
fraying,
corrosion,
and
turnbuckle
safety.
Check
travel if
cable
tension
requires
adjustment or
if
stops
are
damaged.
Check
fairleads
and
rub
strips
for
condi-
tion.
18.
Flap
Structure,
Linkage,
Bellcranks,
Pulleys,
and
Pul-
ley
Brackets
- Check
for
condition,
operation,
and
security.
19.
Flaps -
Check
tracks,
rollers,
and
control
rods
for
se-
curity
of
attachment.
Check
operation.
Sheet
9
of
12
Revision
1
2-851
MODEL
172
SERIES SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
20.
Flaps and
Cables
-
Check
cables
for
proper
tension,
routing,
fraying, corrosion,
and
turnbuckle
safety.
Check
travel if
cable
tension requires
adjustment.
21.
Flap
Motor,
Actuator,
and
Limit
Switches (electric
flaps)
-
Check
wiring
and
terminals
for
condition
and
security.
Check
actuator
for
condition
and
secu-
rity.
22.
Flap
Actuator
Threads
-
Clean
and
lubricate.
LANDING
GEAR
1.
Nose
Gear
Attachment Structure
-
Inspect
for
cracks,
corrosion,
or
other
damage.
Check
for
secu-
rity
of attachment.
2.
Nose
Gear
-
Inspect
torque
links,
steering
rods,
and
boots
for
condition
and
security
of
attachment.
Check
strut
for
evidence
of
leakage
and
proper
ex-
tension.
Check
strut
barrel
for
corrosion,
pitting,
and
cleanliness.
Check
shimmy
damper
and/or bungees
for
operation,
leakage,
and
attach
points
for
wear
and
security.
3.
Nose
Gear Fork
-
Inspect
for
cracks, general
condi-
tion,
and
security
of
attachment.
4.
Nose
Gear
Steering
Mechanism
- Check
for
wear,
security,
and
proper
rigging.
5.
Tires
-
Check
tread wear
and general
condition.
Check
for proper
inflation.
6.
Wheels,
Brake
Discs, and
Linings
-
Inspect
for
wear,
cracks,
warps,
dents,
or
other
damage.
Check
wheel
through-bolts
and
nuts
for
evidence
of
looseness.
7.
Brakes
-
Test
toe
brakes
and
parking
brake
for
prop-
er
operation.
8.
Brakes,
Master
Cylinders,
and
Parking
Brake
-
Check
master
cylinders
and
parking
brake
mechanism
for
condition
and
security.
Check
fluid
level
and
test
op-
eration.
Sheet
10
of
12
2-86
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
CESSNA
PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC
INSPECTOR
REMARKS
EMPENNAGE
1.
Vertical
and
Horizontal
Stabilizers,
Tips and
Tailcone
-
Inspect
externally
for
skin
damage
and
condition
of
paint.
2.
Vertical
and
Horizontal
Stabilizers
and
Tailcone
Structure
-
Inspect
bulkheads,
spars, ribs,
and
skins
for
cracks,
wrinkles,
loose
rivets, corrosion,
or
other
damage.
Inspect
vertical
and
horizontal
stabilizer
at-
tach
bolts
for
looseness.
Retorque
as
necessary.
Check
security
of
inspection
covers,
fairings,
and
tips.
3.
Elevator,
Hinges, and
Cable
Attachment
-
Check
condition,
security,
and
operation.
4.
Elevator
Trim
Tab
and
Hinges
- Check
condition,
se-
curity,
and
operation.
5.
Elevator
Trim
Tab
Actuator
-
Free-play
limits
inspec-
tion.
6.
Elevator
Trim
System
- Check
cables,
push-pull
rods,
bellcranks,
pulleys,
turnbuckles,
fairleads,
rub
strips,
etc.
for proper
routing, condition,
and
secu-
rity.
7.
Elevator
Control
System
-
Inspect
pulleys,
cables,
sprockets,
bearings,
chains,
and
turnbuckles
for
condition,
security,
and
operation.
8.
Rudder -
Inspect
the
rudder
skins
for
cracks
and
loose
rivets,
rudder
hinges
for
condition,
cracks
and
security; hinge
bolts,
hinge bearings, hinge
attach
fittings,
and
bonding
jumper
for
evidence
of
dam-
age
and
wear,
failed
fasteners,
and
security.
Inspect
the
rudder
hinge
bolts for
proper
safetying
of
nuts
with cotter
pins.
Inspect
balance
weight
for
loose-
ness
and
the
supporting
structure
for
damage.
9.
Rudder,
Tips,
Hinges,
and
Cable
Attachment
-
Check
condition,
security,
and
operation.
10.
Rudder
-
Check
internal
surfaces
for
corrosion,
con-
dition
of
fasteners,
and
balance
weight
attachment.
11.
General
Airplane
and System
Wiring
-
Inspect for
proper
routing,
chafing,
broken
or
loose
terminals,
general
condition,
broken
or
inadequate
clamps,
and
sharp
bends
in
wiring.
Sheet
11
of
12
Revision
1
2-87
MODEL
172 SERIES
SERVICE
MANUAL
CESSNA PROGRESSIVE
CARE
MODEL
172
OPERATION
NO.
4
MECHANIC INSPECTOR
REMARKS
SPECIAL INSPECTION
ITEMS
1.
Check
and
accomplish
all
Special
Inspection
items
due.
POST
INSPECTION
1.
Replace
all
fairings,
doors,
floorboard
and
wing
ac-
cess
covers.
Ground
check
engine,
alternator charg-
ing
rate
(28
volts minimum),
oil
pressure/oil
temper-
ature, fuel
quantity
indicator,
rpm
indicator,
flight
instruments,
and
general
operating
components.
SERVICE
BULLETINS/AIRWORTHINESS
DIRECTIVES
1.
Check
that
all
applicable
Cessna
Service
Bulletins
Service
Newsletters,
and
Supplier
Service
Notices
are
complied
with.
2.
Check
that
all
applicable
Airworthiness
Directives
and
Federal
Aviation
Regulations
are
complied
with.
3.
Ensure
all
Maintenance
Record
Entries
required
by
Federal
Aviation
Regulations
are
completed
before
returning the
airplane
to
service.
OPERATION
NO.
4
COMPLETED
AIRPLANE MODEL/SERIAL REGISTRATION
NO.
AIRPLANE
HOURS
DATE
I
certify that
this
operation
was
performed
on
the
above
airplane
and
that
this
airplane
is ap-
proved
for return
to
service.
SUPERVISOR
MECHANIC AIRPLANE
INSPECTOR
CERTIFICATE NO.
CERTIFICATE
NO.
COMPANY
NAME
ADDRESS
CITY
STATE
Sheet
12
of
12
2-88
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
3
FUSELAGE
Page
No.
TABLE
OF CONTENTS
Aerofiche/
Manual
FUSELAGE
................
1F9/3-1
Installation
of
Lock
Windshield/Windows
........
1F9/3-1
Assembly
..............
1F24
3-12B
Description
.............
1F9/3-1
Installation
of
Cable
Cleaning/Waxing
.........
F12/3-4
Assembly
..............
1F24/3-12B
Windshield/Window
Rigging
Cable
Assembly
....
1G1/3-12C
Installation
Techniques
...
1F12/3-4
Rigging
Inside
Door
Repair
.................
1F13/3-4A
Handle
................
G13-12C
Scratches
...............
1F13/3-4A
Replacing
Lock Assembly
...
1G3/3-12E
Cracks
.................
1F15/3-5
Indexing
Inside
Door
Windshield
...............
1F15/3-5
Handle
................
1G3/3-12E
Removal
............
1F15/3-5
Baggage
Door
.............
1G3/3-12E
Installation
..........
1F16/3-6
Removal/Installation
.......
1G3
3-12E
Windows
...............
1F16/3-6
Weatherstrip
............
1G3
3-12E
Movable
................
1F16/3-6
Seats
....................
1G3/3-12E
Removal/Installation
.....
1F16/3-6
Pilot
and
Copilot
..........
1G3
3-12E
Wrap-Around Rear
........
1F16/3-6
Description
............
1G3
3-12E
Removal/Installation
.....
1F16/3-6
Removal/Installation
.....
1G5
3-13
Overhead
...............
1F16/3-6
Center
.................
1G5
3-13
Removal/Installation
.....
1F16/3-6
Description
............
1G5
3-13
Fixed
..................
1F16/3-6
Removal/Installation
.....
1G5 3-13
Cabin
Doors
..............
1F17/3-7
Auxiliary/Fold
Up
.........
1G5
3-13
Description
.............
1F17/3-7
Description
............
1G5
3-13
Removal/Installation
.......
1F17/3-7
Removal/Installation
.....
1G5
3-13
Adjustment
.............
1F17/3-7
Repair
................
1G5
3-13
Weatherstrip
............
1F17/3-7 Cabin
Upholstery
........
1G5
3-13
Latches
(Thru
17275034
&
Materials
and
Tools
.......
1G19
3-25
F17202134)
............
1F17/3-7
Soundproofing
...........
1G19 3-25
Description
......... ...
1F17/3-7 Cabin
Headliner
..........
1G19
3-25
Adjustment
............
1F17/3-7
Removal
Installation
.....
1G19
3-25
Lock
..................
1F21/3-11
Upholstery
Side
Panels
....
1G19
3-25
Indexing
Inside
Door
Handle.
1F21/3-11
Carpeting
...............
1G19
3-25
Latches
(Beginning
with
Safety
Provisions
.........
1G19
3-25
17275035
&
F17202135)
...
1F21/3-11
Cargo
Tie-Downs
........
1G19
3-25
Description
.............
1F21/3-11
Safety
Belts
............
1G19
3-25
Installation, Rigging,
and
Shoulder
Harness
.......
1G20
3-26
Adjustment
Procedures
....
1F24
3-12B
Glider
Tow
Hook
.........
1G20 3-26
Installation
of
Lock
on Rear
View
Mirror
.........
1G20
3-26
Latch
Assembly
.........
1F24/3-12B
Seat
Rail
Inspection
.......
1G20
3-26
3-1.
FUSELAGE.
3-2.
WINDSHIELD AND
WINDOWS.
(See
figure
3-1.)
3-3.
DESCRIPTION.
The
windshield
and
windows
are
single-piece,
acrylic
panels,
set
in
sealing
strips
and
held
by
formed
retaining
strips,
secured
to
the
fuselage
with
screws and
rivets.
FS-4291
sealer
(TMK01
Kit,
Supply
Division
Cessna
Aircraft
Company,
P.O.
Box
949,
Wichita,
KS
67201
316/685-9111,
Telex
417-489)
is
applied
to
all
edges
of
the windshield
and
windows,
with
exception
of
the
wing
root
area.
The
wing
root
fairing
has
a
heavy
strip
that
completes
the
windshield sealing.
Revision
1
3-1
MODEL
172
SERIES SERVICE
MANUAL
4
Detail
B
NOTE
No.
579.
6
sealer
(Inmont
Corp.,
St.
Louis,
Missouri)
and
EC-1202
reinforced
tape
sealant
should
be
applied
to
overhead
cabin
windows.
2
Detail
A
B
Detail
A
1
2
4
2
Detail
D
4
Detail
E
NOTE
10
10
Apply
H.B.
Fuller
FS-4291
to all
edges
of
windshield
and
windows
under
outer
retainer
(4).
1
1.
Inner
Retainer
2.
Windshield
3.
Felt
Seal
4.
Outer
Retainer
4
5.
Cabin
Top
Skin
6.
Overhead
Cabin
Window
7.
External
Centerstrip
8.
Rear
Window
Sealer
TYPICAL
METHODS
OF
RE-
9.
Fuselage
Structure
TAINING
FIXED
WINDOWS
10.
Window
11.
Cover
Figure
3-1.
Windshield
and
Fixed
Window
Installation
3-2
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
CORRECT
-
INCORRECT
STOP
DRILLED
CRACK
REINFORCEMENT
RUBBER
OR
WOOD
AVOID
SHARP
CORNERS
TRIM
DAMAGED
AREA
,
AND ROUND
ALL
CORNERS
BEVELED
EDGE
SURFACE PATCH
FOR
,
,IRREGULAR
SHAPED
DAMAGE
SURFACE
PATCH-
ROUND
HOLE
PATCH
SHOULD
BE
THICKER
BEVELED
EDGE
PATCHES
SURFACE
PATCH
FOR
ROUND
HOLES
PATCH
TAPERED
ON
SHARPER
ANGLE
THAN
MATERIAL-
DRILLED
PATCH
AND HOLE
DURING CEMENTING.
PRESSURE
SHOULD
BE TRIMMED
NEED
BE
APPLIED
ONLY
ON
TOP
CRACK
WITH
TAPERED
EDGES.
SURFACE.
TAPER
ASSURES
EQUAL
PRESSURE
ON
ALL
SIDES.
HEAT
EDGES
OF
SURFACE
PATCH PATCH
UNTIL
SURFACE
PATCH
FOR
CRACKS
SOFT
AND
FORCE
IT
INTO HOLE.
HOLD
IT
IN
PLACE
UNTIL
-
COOL AND
HARDTO
ASSURE
PERFECT
FIT.
AFTER
CEMENT
HAS
HARDENED
THEN
REMOVE PATCH
SAND
OR
FILE
EDGES
LEVEL
FOR
CEMENTING
BATH.
WITH
SURFACE
Figure
3-2.
Repair
of
Windshield
and
Windows
3-3
MODEL
172
SERIES
SERVICE
MANUAL
3-4.
CLEANING
and
WAXING.
(Refer
to
Section
2.)
3-5.
WINDSHIELD
AND
WINDOW
INSTALLATION
TECHNIQUES:
Special
drills
must
be
used
when
drilling
holes
in
acrylic.
Standard
drill
will
cause
the
hole
to
be
oversized,
distorted,
or
excessively
chipped.
Whenever possible,
a
coolant
such
as
a
plastic
drilling
wax
should
be
used
to
lubricate
the
drill
bit.
Cessna
recommends
"Reliance"
drill
wax or
Johnson
No. 140
Stick Wax.
Drilled
holes
should
be
smooth
with
a
finish
of
125
rhr.
The
feed
and
speed
of
the
drill
is
critical.
The following
chart
indicates drill
speed
for
vari-
ous
thicknesses
of
acrylic.
Material
Thickness
Drill
Speed
1/16"
to
3/16"
1500
to
4500
rpm
1/4"
to
3/8"
1500
to
2000
rpm
7/16" 1000
to
1500
rpm
1/2"
500
to
1000
rpm
3/4"
500
to
800
rpm
1"
500
rpm
Specifications for
the
twist
drill
used
to
drill
acrylics
is
as
follows:
NOTES
Shallow
holes
-
when
hole
depth
to
hole
diameter
ratio
is
less
than
1.5
to
1,
the
drill shall
have
an
included
tip
angle
of
55
degrees
to 60
degrees
and
a
lip
clearance
angle
of
15
degrees
to
20
degrees.
Medium
deep
holes
-
when
hole
depth
to
hole
diameter
ratio
is
from
1.5
to
1
up
to
3
to
1,
the
drill
shall
have
an
included
tip
angle
of
60
degrees to
140
degrees
and
a
lip
clearance
angle
of
15
degrees
to
20
degrees.
Deep
holes
-
when
hole
depth to
hole
diameter
ratio
is
greater
than
3.0
to
1,
the
drill
shall
have
an
included
tip
angle
of
140
degrees and
a
lip
clearance
of
12
degrees
to
15
degrees.
Parts
which
must
have
holes
drilled
shall
be
backed
up
with
a
drill fixture.
Holes
may
be
drilled
through
the
part
from
one
side.
However,
less
chipping
around
holes
will
occur
if
holes
are
drilled
by
drilling the
holes
from
both
sides. This
is
accomplished
by
using
a
drill
with
an
acrylic
backup
piece
on
the
opposite
side.
Remove
the
drill
from
the
hole
and
switch
the
backup
plate
and finish
drilling
from
the
opposite
side.
3-4
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
3-6.
REPAIR. (See
figure
3-2.)
Replace
extensively
damaged
transparent
plastic
rather
than
repair
whenever
possible,
since
even
a
carefully
patched
part
is
not
the equal
of
a
new
section,
either
optically
or
structurally.
At
the
first
sign
of
crack
development,
drill
a
small
hole
at
the extreme
end
of
the crack as
shown
in
figure
3-1.
This
serves
to
localize the
cracks
and
to
prevent further
splitting
by
distributing
the
strain
over
a
large
area.
If
the
cracks
are
small,
stopping
them
with
drilled
holes will
usually
suffice
until
replacement
or
more
permanent
repair
can
be
made.
The
following
repairs
are
permissible;
however,
they
are
not
to
be
located
in
the
pilot's
line
of
vision
during
landing
or
normal
flight.
a.
SURFACE PATCH. If
a
surface
patch
is
to
be
installed,
trim
away
the
damaged
area
and
round
all
corners.
Cut
a
piece
of
plastic
of
sufficient
size
to
cover
the
damaged
area
and extend
at
least
3/4-inch
on
each
side
of
the
crack or
hole.
Bevel
the
edges
as
shown
in
figure
3-1.
If
the
section
to
be
repaired
is
curved,
shape
the
patch
to
the
same
contour
by
heating
it in
an
oil
bath at
a
temperature
of
248
°
to
302°F.,
or
it
may
be
heated
on
a
hot
plate
until
soft.
Boiling
water
should
not
be
used
for
heating.
Coat
the
patch
evenly
with
plastic
solvent
adhesive
and
place
immediately
over
the
hole.
Maintain
a
uniform
pressure
of
from
5
to
10
psi
on
the
patch
for
a
minimum
of
three
hours.
Allow
the
patch
to
dry
24
to
36
hours
before
sanding
or
polishing
is
attempted.
b.
PLUG
PATCH.
In
using
inserted
patches
to
repair
holes
in
plastic
structures, trim
the
holes
to
a
perfect
circle
or
oval
and
bevel
the edges
slightly.
Make
the
patch
slightly
thicker
than
the
material
being
repaired,
and
similarly
bevel
the
edges.
Install
patches
in
accordance
with
procedures
illustrated
in
figure
3-1.
Heat
the
plug
until
soft
and
press
into
the
hole
without
cement
and
allow
to
cool
to
make
a
perfect
fit.
Remove
the
plug,
coat
the
edges
with
adhesive,
and then
reinsert
in
the
hole.
Maintain
a
firm
light
pressure
until
the
cement
has
set,
then sand or
file
the
edges
level
with
the
surface;
buff
and
polish.
3-7.
SCRATCHES.
(See
figure
3-2.)
Scratches
on
clear
plastic
surfaces
can
be
removed
by
hand-
sanding operations,
followed
by
buffing and
polishing,
if
the steps
below
are
followed
carefully.
a.
Wrap
a
piece
of
No.
320
(or
finer)
sandpaper
or
abrasive
cloth around
a
rubber
pad
or
wood
block.
Rub
surface around
scratch
with
a
circular
motion,
keeping
abrasive
constantly
wet
with
clean
water
to
prevent
scratching
surface
further.
Use
minimum
pressure
and
cover
an
area
large
enough
to
prevent
formation
of
"bull's-eyes"
or
other
optical
distortions.
CAUTION
Do
not
use
a
coarse grade
of
abrasive.
No.
320
is
of
maximum
coarseness.
b.
Continue
sanding
operation,
using
progressively
finer
grade
abrasives
until
scratches
disappear.
c.
When
scratches
have
been
removed,
wash
area
thoroughly
with
clean
water
to
remove
all
gritty
particles.
The
entire
sanded
area will
be
clouded with
minute
scratches
which
must
be
removed
to
restore
transparency.
d.
Apply
fresh tallow
or buffingcompound
to
amotor-driven
buffingwheel.
Hold
wheel
against
plastic
surface,
moving
it
constantly
over
damaged
area
until
cloudy
appearance
disappears.
A
2000-foot-per-minute
surface
speed
is
recommended
to
Revision
1
3-4A/(3-4B
blank)
MODEL
172
SERIES
SERVICE
MANUAL
prevent
overheating
and
distortion.
(Example:
750
rpm
polishing
machine with
a
10-
inch
buffing
bonnet)
NOTE
Polishing
can
be
accomplished
by
hand, but
will
require
a
considerably
longer
period
of
time
to
attain
the
same
result
as
produced
by
a
buffing wheel.
e.
When
buffing
is
finished,
wash
area
thoroughly
and
dry
with
a
soft
flannel
cloth.
Allow
surface
to
cool
and
inspect
area
to
determine
if
full
transparency
has
been
restored.
Apply
a
thin
coat
of
hard
wax
and
polish
surface
lightly
with
a
clean
flannel
cloth.
NOTE
Rubbing
plastic
surface
with
a
dry
cloth
will
build
up
an
electrostatic
charge
which
attracts
dirt
particles
and
may
eventually
cause
scratching
of
surface.
After
wax
has
hardened,
dissipate
this
charge
by
rubbing
surface
with
a
slightly
damp
chamois. This
will
also
remove
dust
particles
which
have
collected
while
wax
is
hardening.
f.
Minute
hairline
scratches
can
often
be
removed
by
rubbing
with
commercial
automobile
body
cleaner
or
fine-grade
rubbing
compound.
Apply
with
a
soft,
clean,
dry cloth
or
imitation
chamois.
3-8.
CRACKS.
(See
figure
3-2.)
a.
When
a
crack appears,
drill
a
hole
at
end
of
crack
to
prevent
further
spreading.
Hole
should
be
approximately
1/8-inch
diameter,
depending
on
length
of
crack
and
thickness
of
material.
b.
Temporary
repairs
to
flat
surfaces
can
be
accomplished
by
placing
a
thin
strip
of
wood
over
each
side
of
the
surface
and
inserting
small
bolts
through
the
wood
and
plastic.
A
cushion
of
sheet rubber
or
aircraft
fabric should
be
placed
between
wood
and
plastic
on
both
sides.
c.
A
temporary
repair
can
be
made
by
drilling
small
holes
along
both
sides
of
crack.
1/ 4
to
1/8-inch
apart
and
lacing
edges
together
with
soft
wire.
Small-stranded
antenna
wire
makes
a
good
temporary
lacing
material.
This
type
of
repair
is
used
as
a
temporary
measure
ONLY,
and
as
soon
as
facilities
are
available, panel
should
be
replaced.
3-9.
WINDSHIELD.
(See
figure
3-1.)
3-10.
REMOVAL.
a.
Remove
wing fairings.
b.
Remove
air
vent
tubes.
CAUTION
If
windshield
is
to
be
reinstalled,
be
sure
to
protect
windshield
during
removal.
c.
With
two
people
sitting
in
the
airplane placing
their
feet
against the
windshield,
just
above
the
centerline,
press
upward
on
windshield
forcing
it
out
of
lower
retainers.
d.
Clean
sealer from
inner
sidewalls
and
bottom
of
retainers.
Revision
1
3-5
MODEL
172
SERIES
SERVICE
MANUAL
3-11.
INSTALLATION.
a.
If
windshield
is
to
be
reinstalled,
clean
off
old
sealer
and
felt,
then
install
new
felt
around
edges
of
windshield.
b.
If
new
windshield
is
to
be
installed,
remove
protective
cover
and clean,
take
care
not
to
scratch
windshield.
c.
Apply
new
felt
to
edges
of
windshield.
d.
Apply
a
strip
of
sealer
(H.B.
Fuller
FS-4291)
along
the
sides
and
bottom
of
felt.
e.
Position
the
bottom
edge
of
windshield
into
lower
retainer.
f.
Using
a
piece of
bent
sheet
metal
(8
in.
wide
x
length
of
top
edge
of
windshield)
placed
under
top
edge of
upper
retainer,
bow
windshield
and
guide
top
edge
of
windshield
into upper
retainer
using
bent
sheet
metal
in
a
shoe
horn
effect.
g.
Install
air
vent
tube.
h.
Install wing
fairings.
3-12.
WINDOWS.
(See
figures
3-1
and
3-3.)
3-13.
MOVABLE
WINDOW. (See
figure
3-3.)
A
movable
window,
hinged at the
top,
is
installed
in
the
left
cabin
door,
and
optionally
installed
in
the
right
cabin
door.
3-14.
REMOVAL
AND
INSTALLATION.
(See
figure
3-3.)
a.
Disconnect
window
stop
(5).
b.
Remove
pins
from
window
hinges
(6).
c.
Reverse
preceding
steps
for
installation.
To
remove frame
from
plastic
panel,
drill
out
blind
rivets
at frame
splice.
When
replacing
plastic
panel
in
frame, ensure
sealing
strip
and
an
adequate
coating
of
Presstite
No.
579.6
sealing
compound
is
used
around
all
edges
of
panel.
3-15.
WRAP-AROUND
REAR
WINDOW.
(See
figure
3-1.)
The
rear
window
is a
one-piece,
acrylic
plastic
panel,
set
in
sealing
strips
and held
in
place
by
retaining
strips.
3-16.
REMOVAL
AND
INSTALLATION.
(See
figure
3-1.)
a.
Removal
external centerstrip
(7).
b.
Remove
upholstery as
necessary
to
expose
retainer
strips
inside
cabin.
c.
Drill
out
rivets
as
necessary
to
remove
outer retainer
strip
along
aft edge
of
window.
d.
Remove
window
by
lifting
aft
edge
and
pulling
window
aft.
If
difficulty
is
encoun-
tered,
rivets
securing
retainer
strips
inside
cabin
may also
be
drilled
out
and
retainer
strips
loosened
or
removed.
e.
Reverse
preceding
steps
for
installation.
Apply
felt
strip
and
sealing
compound
to
all
edges
of
window
to
prevent
leaks.
Check
fit
and
carefully
file
or
grind
away
excess
plastic.
Use
care
not
to
crack
plastic
while
installing.
3-17.
OVERHEAD
WINDOW.
(See
figure
3-1.)
Overhead
cabin
windows, located
in
the
cabin
top,
may
be
installed.
These windows
are
one-piece,
acrylic
plastic panels,
set
in
sealing
strips
and
held
in
place
by
retaining
strips.
3-18.
REMOVAL
AND
INSTALLATION.
(See
figure
3-1.)
a.
Remove
headliner
and
trim
panels.
b.
Drill
out
rivets
as
necessary
to
remove
retainer strips.
c.
Reverse
preceding
steps
for
installation.
Apply
felt
strip
and
sealing
compound
to
all
edges
of
window
to
prevent
leaks.
Check
fit
and
carefully
file
or grind
away
excess
plastic.
Use
care not
to
crack
plastic
when
installing.
3-19.
FIXED.
(See
figure
3-1.)
Fixed windows,
mounted
in
sealing
strips
and
sealing
compound,
are
held
in
place
by
various
retainer
strips.
To
replace
side
windows,
remove
upholstery
and
trim
panels
as
necessary,
and
drill
out
rivets
securing retainers.
Apply
felt
strip
and
sealing
3-6
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
compound
to
all
edges
of
window
to
prevent
leaks.
Check
fit
and
file
or
grind
away excess
plastic.
Use
care not
to
crack
plaster
when
installing.
3-20.
CABIN
DOORS.
(See
figure
3-3.)
3-21. DESCRIPTION.
A
cabin
door
is
installed on
each side
of
the
aircraft consisting
of
a
sheet-
outer
skin
chemically
bonded to
a
formed
inner
pan
assembly.
To
this
rigid
structure
are
at-
tached
the
door
latch
assembly,
a
remote inside
handle,
a
pair
of
external hinges,
and
an
in-
tegral
doorstop
assembly.
An
openable
window
is
installed
on
the
LH
door
and
may
also
be
optionally
installed
on
the
RH
door.
3-22.
REMOVAL
AND
INSTALLATION.
(See
figure
3-3.)
Removal
of
cabin
doors
is
accomplished
either
by
removing screws
attaching the
door
hinges
or
by
removing
hinge pins.
NOTE
Ensure clevis
pin
(index
21,
figure
3-3)
is
removed
before
removing
door.
During
reinstallation
permanent-type
hinge
pins may
be
replaced
with
clevis
pins
secured
with
cotter
pins.
3-23.
ADJUSTMENT.
Cabin
doors
should
be
adjusted
so
that
door
skin
fairs
smoothly
with
fuselage
skin.
Slots
at
door
latch
plate
permit
re-positioning
of
latch
assembly
and
bolt
engagement
with
rotary
clutch
on
door
post.
If
fitting
a
new
door
assembly.
some
trimming
of
door
flange
may
be
necessary,
but
gap
between
door
skin
and
fuselage
skin
should
be
0.09-
inch
or
less.
CAUTION
Reforming
of
bonded
door
flange
by
striking
with
soft
mallet,
etc.
is
NOT
permissible,
due
to
possible
damage
to
bonded
areas.
3-24.
CABIN
DOOR
WEATHERSTRIP.
A
hollow,
fluted-type,
rubber
weatherstrip
is
cemented
around
all edges
of
the
cabin
door.
When
replacing
weatherstrip,
ensure
that
contact
sur-
faces
are
clean
and
dry.
Cut
new
weatherstrip
to
length,
using
old
weatherstrip
as
a
guide.
Cut
small
notch
in
butt
ends
of
new
weatherstrip
to
allow
for
drainage.
Position
splice with
notch
at
door
low
point
and
apply
a
thin,
even
coat
of EC-1300L
adhesive
(3M
Company)
or
equivalent
to
both
surfaces.
Allow
to
dry until
tacky
before
pressing
into
place
on
door.
Do
not
stretch weatherstrip
around
door
corners.
3-25.
LATCHES
(Thru
17275034
and
F17202134).
(See
figure
3-4.)
3-26.
DESCRIPTION.
The
cabin
door
latch
is a
push-pull
bolt
type,
utilizing
a
rotary
clutch
for
positive
bolt
engagement.
As
door
is
closed,
teeth
on
underside
of
bolt
engage
gear
teeth
on
clutch.
The
clutch
gear
rotates
in
one
direction
only
and
holds
door
until
handle
is
moved
to
LOCK
position,
driving
bolt
into
slot.
3-27.
ADJUSTMENT.
Adjustment
of
latch
or
clutch
cover
is
afforded
by
oversize
and/or
slotted
holes.
This
adjustment
ensures
sufficient
gear-to-bolt
engagement
and
proper
alignment.
Revision
1
3-7
MODEL
172
SERIES
SERVICE
MANUAL
NOTE 24
14
Right-hand
door
installation
is
shown.
10
Openable
window
is
optional
equipment
on
RH
door
and
standard
equipment
on
LH
door.
Refer
To
Figure
3-4
Lock
(12)
installed
in
LH
door
only.
23
As
required
for
good
seal
18
23
(Typical
entire
perimeter)
Detail
D
THRU
1979
MODELS
View
E-E
1.
Lower
Hinge
7.
Latch
Striker
Plate
13.
Washer
19.
Doorstop
Bracket
2.
Upper
Hinge
8.
Door
Structure
14.
Latch
Handle
20.
Doorstop
Spring
3.
Upholstery
Panel
9.
Window
Frame
15.
Hinge
Pin
21.
Clevis
Pin
4.
Spring
10.
Window
16.
Inside
Handle
22.
Clevis
Pin
5.
Window
Stop
11.
Cam
17.
Armrest
23.
Weatherstrip
6.
Window
Hinge
12.
Lock
Assembly
18.
Washer
24.
Latch
Bracket
Figure
3-3.
Cabin
Door
Installation
(Sheet
1
of
2)
3-8
MODEL
172
SERIES
SERVICE
MANUAL
Section
A-A
Section
B-B
B
Section
D-D
Section
E-E
BEGINNING WITH
1980
MODELS
1.
Trim
Panel
7.
Latch
Assembly
13.
Latch Assembly
2.
Arm
Rest
8.
Weatherstrip
14.
Channel
3.
Inside
Handle
9.
Push-Pull
Rod
15.
Hinge
Pin
4.
Escutcheon
10.
Window
Assembly
16.
Upper
Hinge
5. Door
Pull
Assembly
11.
Hinge
Assembly
17.
Base
Plate
6.
Lock
Assembly
Mounting
12.
Spring
18.
Lower
Hinge
Hole
19.
Upholstery
Clip
Figure
3-3. Cabin Door
Installation (Sheet
2
of
2)
3-9
MODEL
172
SERIES
SERVICE
MANUAL
22
24
14
BEGINNING
WITH
1982
MODELS
on
RH
door
and
standard
equipment
on
(Typical
entire
2.
Upper
Hinge
8.
Door
Structure
14.
Latch
Handle
20.
Doorstop
Spring
3.
Upholstery
Panel
9.
Window
Frame
15.
Hinge Pin
21.
Clevis
Pin
4.
Spring
10.
Window
16.
Inside Handle
22.
Clevis
Pin
5.
Window
Stop
11.
Cam
17.
Armrest
23.
Weatherstrip
6.
Window Hinge
12.
Lock
Assembly
18.
Washer
24.
Latch
Bracket
Figure
3-3.
Cabin Door
Installation
(Sheet
3
of
3)
3-10
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Lubricate
door
latch
per
Section
2.
No
lubrication
is
recommended
for
the
rotary
clutch.
3-28.
LOCK.
In
addition
to
interior
locks,
a
cylinder
and
key-type lock
is
installed
on
left
door.
If
lock
is
to
be
replaced,
the
new
lock
may
be
modified
to
accept
the
original
key.
This
is
desirable,
as
the
same
key
is
used
for
ignition
switch
and
cabin
door
lock.
After
removing
old
lock
from
door,
proceed
as
follows:
a.
Remove
lock
cylinder
from
new
housing.
b.
Insert
original
key
into
new
cylinder
and
file
off
any
protruding
tumblers
flush
with
cylinder.
Without
removing
key,
check
that
cylinder
rotates
freely
in
housing.
c.
Install
lock
assembly
in
door
and
check
lock
operation
with door
open.
d.
Destroy
new
key and
disregard
code
number
on
cylinder.
3-29.
INDEXING
INSIDE
DOOR
HANDLE.
(See
figure
3-4.)
When
inside
door
handle
is
removed.
reinstall
in
relation
to
position
of
bolt
(7),
which
is
spring-loaded
to
the
CLOSE
position.
The
following
procedure
may
be
used.
a.
Temporarily
install
handle
(17)
on
shaft
assembly
(12).
approximately vertical.
b.
Move
handle
(17)
back
and
forth
until
handle centers
in
spring-loaded
position.
c.
Without
rotating
shaft
assembly
(12),
remove
handle
(17)
and
install
placard
(18)
with
CLOSE
index
at top.
d.
Install
handle
(17)
to
align
with
CLOSE
index
on
placard
(18),
using
screw
(16).
e.
Install
arm
rest
(15)
on
upholstery
panel
(14).
3-29A.
LATCHES
(Beginning
with
17275035
and
F17202135).
(See
figure
3-4A).
3-29B.
DESCRIPTION.
The
cabin
door
latch
consists
of
a
two-piece
nylon
latch
base,
exterior
han-
dle,
spring-loaded
latch
bolt/pull-bar
assembly,
and
a
spring-loaded
catch/trigger
pin
assem-
bly.
The
interior
handle
base plate
assembly
is
directly
connected
to
the cabin
door
latch
by
means
of
an
adjustable
push
rod
assembly.
This
push
rod
assembly
has
one
clamp
on
the
main
rod.
This
clamp
is
used
to
operate
a
cable
assembly
that
drives a
cable
pin
from
the
upper
aft
end
of
the
cabin
door into
the
aft
upper
door
sill. When the
cabin
door
is
open,
the
door
latch
exterior
handle
should
be
extended
(out),
held
in
this
position
by
means
of
the
spring-loaded
latch
catch
engaged
with the latch
bolt
through
the
beveled
hole
in
the
bolt.
The
push
rod
assembly
will
be
moved
forward,
and
the
attached
cable
assembly
will
be
re-
tracted
from
the
upper
door
sill
with the
cable
pin
recessed
in
the
pin
guide,
located
in
the
upper aft corner
of
the
door.
The
interior
handle,
being
directly
connected
by
means
of
the
push
rod,
will
be
moved
approximately
15
°
aft
of
the
vertical
position.
Closing
the
cabin
door
drives
the
trigger
pin
over
the
nylon
actuator
attached
to
the
cover
plate,
located
on
the
rear
doorpost.
As
the
trigger
pin
is
driven
forward,
it
disengages the
latch
catch
from
the
latch
bolt
The extended
extension
springs,
attached
to
the
latch
handle
and
bolt/pull
bar assem-
bly,
compress,
pulling the latch
handle
in,
and
driving
the
latch
bolt
over
the
latch
striker.
located
on
the
rear
doorpost.
Pushing
the
exterior
handle
flush
with the
fuselage
skin.
The
push
rod
assembly,
attached
to
the
latch
bolt/pull
bar
assembly,
moves
aft,
which also
drives
the
cable
pin
from
the
pin
guide
in
the
door
into
the
upper
aft
door
sill
receptacle.
The
inter-
ior
door
handle
has
now
moved
from
approximately
15
°
aft
of
vertical
to
approximately
45
°
forward
of
vertical.
Pushing
the
interior
handle
to
the
horizontal
position,
flush with
the
arm
rest,
will
overcenter
the
door
latch,
securing
the
door
for
flight.
The cabin
door
latch
assembly
also
incorporates
a
locking
arm
and locking
pin,
used
with a
key
lock
to
secure
the
aircraft
after
use.
With
the
cabin
door
closed,
and
the
exterior
latch
handle
flush,
actuat-
ing
the
key
lock
drives
the
locking
pin
into
the
exterior
latch handle, locking
the
aircraft.
It
is
important
to
note
that
since
the
cabin
door
latch
assembly
and
the
interior
handle
base
plate
assembly
are
directly
connected
by
the
push
rod
assembly,
that
any amount
of
force
3-11
MODEL
172
SERIES SERVICE
MANUAL
17267585
thru
17275034
F17201515
thru
F17202134
Adjust
door
bolt
by
changing
length
of
push-rod.
-
1.
Bearing Assembly
2.
Nut
3.
Spacer
A
4.
Push-Pull
Rod
5.
Base
Plate
6.
Roll
Pin
7.
Bolt
8.
Housing
9.
Outside
Handle
10.
Spring
2
4
11.
Support
12.
Shaft
Assembly
13.
Screw
13
14.
Upholstery
Panel
15.
Armrest
16.
Screw
17.
Inside
Handle
18.
Placard
19.
Pivot
Base
Plate
19
Rotated
180
17
Figure
3-4.
Door
Latch
Installation
Detail
A
Rotated
180°
Figure
3-4.
Door
Latch
Installation
3-12
MODEL
172
SERIES
SERVICE
MANUAL
1.
-Bearing
Assembly
8
2.
Nut
A
3.
Spacer
4.
Push-Pull
Rod
5.
Pivot
Base
Plate
7
6.
Bolt
7.
Cable
8.
Pin
9.
Inside
Handle
10.
Screw
4
11.
Armrest
12.
Base
Assembly
13.
Screw
14.
Outside
Handle
15.
Spring
29
17.
Washer
18.
Push
Rod
19.
Pin
20.
Pull
Bar
21.
Catch 5
22.
Pin
23.
Cotter
Pin
24.
Locking
Arm
25.
Pin.
26.
Pin
27.
Cam
Assembly
28.
Clamp
29.
Clamp
Bolt
30.
Cover
Assembly
31.
Pin
17
20
26 22
25
3-12A
3-
12A
MODEL
172
SERIES
SERVICE
MANUAL
applied
to
the
outside
handle
is
subsequently
applied
to
the
inside
handle.
If
the
push
rod
as-
sembly
is
not
properly
adjusted.
it
is
possible
to
lock one's
self
out
of
the
aircraft
by
apply-
ing
too
much
force
to
the
exterior
handle
when
closing
the
cabin
door.
Therefore,
it
is
im-
portant
to
adhere
to
all
of
the
rigging
and
adjustment
specifications
pertaining
to
the
pre-
load
forces
of
the
interior
door
handle.
Refer
to
the
rigging
and
adjusting
procedures
in
the
following
paragraphs.
3-29C. INSTALLATION,
RIGGING
AND
ADJUSTMENT
PROCEDURES.
(See
figure
3-4A.)
3-29D.
INSTALLATION
OF
LOCK
ASSEMBLY
ON
LATCH
ASSEMBLY.
(See
figure
3-4A.)
a.
Assemble
locking
arm
(24)
with
pin
assembly
(25)
by
placing one
washer
on
each
side
of
locking
arm
(24). Swage
pin
(25)
so
that
there
is a
minimal
amount
of
loose-
ness
between
parts.
Cut
excessive
material
from
pin
(25).
b.
Place
pin
(25)
in
1/8-inch
hole
of
base
assembly
(12).
c.
Align
.099-inch
hole of
locking
arm
(24)
with
.094-inch
hole
in
latch
base
(12),
and
install
pin.
d.
Assemble
cam
assembly
(27)
to
locking
arm
(24).
Cam
should
be
on
latch
side
of
locking
arm.
Use
3
washers
between
cam
(27)
and
locking
arm.
3-29E.
INSTALLATION
OF
LOCK ASSEMBLY.
(See
figure
3-4A)
NOTE
Install
with
latch
in
CLOSED
position.
a.
Install
latch
assembly
between
door
pan and
door
skin.
b.
Cable
assembly
(7)
should
be
forward
of
latch
base
attach
plate,
and
inboard
of
latch
base
cup.
c.
Extend
latch
handle
through
cutout
in
door
skin. This
will
pull
latch
bolt
back far
enough
to
allow latch
to
fall
into
place.
d.
Push
latch
assembly
aft
so
that
bolt
(20)
and
push
rod
(18)
extend
through
their
re-
spective
holes.
e.
Trip
push
rod
(18)
so
that
bolt
(20)
is
fully extended
and
handle
(14)
is
flush.
f.
Secure
latch
to
door
pan
with
four
NAS220-5
screws
(13)
through
base
assembly
(12)
and
two
AN525-10R6
screws
through
aft
flange
of
door
pan.
g.
Ensure
door
skin
fits properly
around
latch
assembly,
then
drill
eleven
.128-inch
holes
to
align
with
latch
base.
NOTE
Do
not
oversize
holes
in
the latch
base
and
do
not
rivet
base
to
skin at
this
time.
3-29F.
INSTALLATION
OF
CABLE
ASSEMBLY.
(See
figure
3-4A.)
a.
On
pin
end
of
cable
assembly
(7),
attach
clamp
(28)
and
nut,
oneinch
from
end
of
casing.
b.
Insert
pin
end
of
cable
between
door
pan and
door
skin
at
aft
end
of
door. Push
pin
end
of
cable
to top
of
door.
c.
Remove
plug
button
(30,
figure
3-1
of
this
Supplement)
and
align
pin
on
cable
with
pin
guide,
and
insert pin through
guide.
Access
is
gained
through
.875-inch
diame-
ter
hole
after
removal
of
plug
button
(30).
d.
Align
clamp
on
cable
casing
with
hole
located
one-inch
below
.875-inch
hole
and
in-
stall
screw.
3-12B
MODEL
172
SERIES
SERVICE
MANUAL
e.
Check
operation
of
cable.
If
sluggish
operation
of
cable
is
encountered,
add
S1450-
2A4-062
washers
as
required
to
facilitate
smoother
cable
operation.
3-29G.
RIGGING
CABLE
ASSEMBLY.
(See
figure
3-4A.)
a.
Pull
excess
slack
out
of
cable
(7).
Attach
clamp
(28)
and
nut
to
cable
so
that
it
aligns
with
.193-inch
hole
in
door
pan,
and
attach.
NOTE
Make
sure
door
latch
is in
OPEN
position
before proceed-
ing.
b.
Cut
casing
of
cable
assembly
approximately
two
inches
from
clamp bolt
(29) on
push
rod assembly
(4).
.
Insert
core
of
cable
through
clamp
(29).
d.
Pull
core
through
clamp bolt
so
that
pin
(8)
extends
approximately
1/8-inch
from
door
pan
contour.
e.
Cut
core
approximately one
inch
forward
of
push
rod
clamp
(29).
f.
Secure
two
nuts
to
push
rod
clamp
bolt.
g.
Operate
latch
several
times
to
ensure
latch
works
freely.
If latch
binds
up
and
will
not
work
freely,
remove
cable
core
from
clamp
(29)
and operate
latch.
If
cable oper-
ates
easily
without
cable
attachment,
check
cable
for
possible
adjustments
to facilitate
case
of
operation.
h.
After cable
operates
freely,
install
cover
assembly
(30)
and
recheck
cable
for
opera-
tion.
3-29H.
RIGGING
INSIDE
DOOR HANDLE.
(See
figure
3-4A.)
a.
With
latch
secured
to door
pan,
attach push
pull
rod
assembly
(4)
to
catch
(21),
and
secure
with
pin
(31).
NOTE
Do
not install
cotter
pin
(23).
b.
Ensure
that
latch
is
in
CLOSED
position.
c.
By
removing
pin
(31)
that
connects
push
pull
rod
to
latch
base
assembly,
rotate
rod
in
or
out
(180°)
for
adjustment.
Adjust
rod
so
that
it
takes
a
load
of
6
pounds
to
12
pounds
at
the
end
of
the
inner
handle
to
move
it
from
closed
position
to
overcenter
position.
NOTE
Rod
must
be
attached
to
latch
assembly
before
rigging
can
be
accomplished.
d.
For fine
adjustment
for
overcentering latch assembly,
proceed
as
follows:
1.
Cabin
door
must
be
installed
and
completely
fitted
to
fuselage.
2.
Cabin
door
latch
must
be
in
OPEN
position.
Latch
must
operate
smoothly
and
freely.
3.
Adjust
striker
plate
forward
by
installing
shims
as
required,
so
that
there
is
a
minimal
clearance
between
pull
bar
(20)
and
striker
plate.
3-12C
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
This
adjustment
will
ensure
that
when
the
door
is
opened
from
the
outside, the
push
rod
will
engage
the
latch
catch,
and
the
exterior
handle
will
stay
open
until
the
door
is
closed
again.
NOTE
If
cabin
door is
located
too
far
forward
such
that
the
door
latch
will
not operate,
this
will
not
allow
latch
asembly
push
rod
(18)
to
ride
up
on
actuator
and
trgger
the
pull
bar
(20).
Install
shims
as
required
beneath
actuator,
lo-
cated
on cover
assembly.
4.
Close
the
cabin
door from
inside
the
aircraft.
When
latch
is
overcentered.
the
ex-
terior
handle
should
pull
flush.
If
it
does
not
pull
flush, the
connecting push
pull
rod
from
the
door
latch
to
the
inside handle
assembly
should
be
adjusted
"out"
(lengthened).
NOTE
When
making
this
adjustment on
the overcentering
of
the
latch,
it
may
be
noticed
that
there
is
a
sharp,
loud
canning noise
when
the
inside
handle
is
pushed
down.
It
is
preferred
that
the
outside
door
handle
be
flush,
even if
the
canning
noise
is
noticeable.
5.
When
adjusting push
pull
rod
(4),
it
may
need
only
be
adjusted
1/2
turn.
To
accomplish
this,
base
plate
should
be
removed.
6.
To
make
1/2
turn
adjustment,
remove
smaller end
of
push
pull rod
(4)
and
turn
it
over
(180°).
Then
reinstall
base
plate
assembly
(5).
7.
When
closing
cabin
door
from
the outside,
by
using
a
large,
sharp
force
on
the
outside
handle,
it
is possible
to
overcenter
the inside handle,
thus
locking
one's
self
out.
To
prevent
this
from
occurring
when
adjusting
the
push
pull
rod
in
step
"4",
adjust
the
push
pull
rod
so
there
is
sufficient
force
(6
to
12
pounds)
against
the
inside
handle
to
prevent it
from
overcentering
when closing
the
door
from
the
outside.
8.
Do
not
file,
grind
or
sand
any
portion
of
the
pull
bar
(20).
9.
Recheck
clamps
that
secure
cable.
There
must
not
be
any
slippage
between cable
casing
and
clamp.
10.
After
overcenter
adjustment
has
been made,
install
cotter
pin
(23)
in
clevis
pin
(22).
e.
Rivet
latch
base
(12)
to
door
skin
with
MS20426A4-3
rivets.
f.
Attach
lock
assembly
casing
(13,
figure
3-3)
to
door
skin
with
nut
provided.
g.
Install
tumblers
and
attach
cam
to
tumblers
with
screw
and
lockwasher
provided.
NOTE
After
installing
cam,
seal
over
head
of
screw
and
washer
3-12D
MODEL
172
SERIES
SERVICE
MANUAL
washer
with
RTV-102
(white) or
RTV-103
(black)
silicone
rubber
sealant
(General Electric,
Waterford,
N.
Y.).
h.
Operate
lock
several
times
to
assure
that
all
components
function properly.
NOTE
Steps
"f",
"g"
and
"h"
apply
to
LH
door
only.
3-29L
REPLACING
LOCK ASSEMBLY.
a.
Remove
look
cylinder
from
new
housing.
b.
Insert
original
key
into
new
cylinder
and
file
off
any
protruding
tumblers
flush
with
cylinder.
Without
removing
key,
check
that
cylinder
rotates
freely
in
housing.
c.
Install
lok
assembly
in
door
and
check
lock
operation
with
door open.
d.
Destroy new
key
and
disregard
code
number
on
cylinder.
3-29J.
INDEXING
INSIDE
DOOR
HANDLE.
When
inside door
handle
is
removed,
reinstall
and
index
as
noted
in
paragraph
3-27A.
3-30.
BAGGAGE
DOOR.
(See
figure
3-5).
3-31.
REMOVAL
AND
INSTALLATION. (See
figure
3-5.)
a.
Remove
door-pull
handle.
b.
Disconnect
door-stop
chain
(8).
c.
Remove
buttons
securing
upholstery
panel
and
remove
panel.
d.
Remove
bolts
(9)
securing
door
to
hinges.
e.
Reverse
preceding
steps
for
installation.
CAUTION
Reforming
of
bonded
door
flange
by
striking
with
soft
mallet
etc.,
is
NOT
permissible,
due
to
possible
damage
to
bonded
areas.
3-32.
BAGGAGE
DOOR
WEATHERSTRIP.
A
rubber
weatherstrip
is
cemented
around
the
edge
of
the
baggage
door and
seals
the
door
to
the
fuselage
structure
when
the
door
is
closed.
A
new
seal
can
be
installed
after
carefully
cleaning
door and
weatherstrip
contact
surfaces.
Apply
a
thin,
even
coat
of
EC-880
adhesive
(3M
Co.)
or
equivalent
and
allow
to
dry
until
tacky
before
pressing
into
place.
3-33.
SEATS.
(See
figure
3-6.)
3-34.
PILOT
AND COPILOT.
a.
RECLINING
BACK/FORE-AND-AFT
ADJUST.
b.
ARTICULATING
RECLINE/VERTICAL
ADJUST.
3-35.
DESCRIPTION.
These
seats
are manually
operated
throughout their
full range
of
operation.
Seat stops
are
provided
to
limit
fore-and-aft
travel.
3-12E
MODEL
172
SERIES
SERVICE
MANUAL
17267585
thru
17273534
*
17273535
&
On
F17201515
thru
F17202029
F17202030
&
On
Detail
B
12
4
13
22
19
21
20
*18
Detail
A
1.
Handle
10.
Washer
18.
Cam
2.
Spacer
11.
Nut
19.
Latch
3.
Shim
12.
Baggage
Door
20.
Screw
4.
Screws
13.
Cam
21.
Lock
Assembly
5.
Hinge
14.
Screw
22.
Washer
6.
Hinge
Bracket
15.
Washer
23.
Nut
7.
Scuff
Plate
16.
Nut
24.
Lock
Assembly
8.
Chain
17.
Washer
25.
Mounting
Pad
9.
Bolt
26.
Latch
Assembly
Figure
3-5.
Baggage Door
Installation
3-12F
MODEL
172
SERIES SERVICE
MANUAL
3-36.
REMOVAL
AND
INSTALLATION.
(See
figure
3-6.)
a.
Remove
seat stops
from
rails.
b.
Disengage
seat
belts
by
slipping
buckle
ends
through
seat belt
retainer.
c.
Crank
vertical
adjust
seats
to
their
maximum
height.
d.
Slide
seat
forward
to
disengage
front
rollers
from
seat rails.
e.
Slide
seat
aft
to
disengage
rear
rollers
from
seat
rails.
f.
Lift
seat
out.
g.
Reverse
preceding
steps
to
install
seat.
Ensure
that
all
seat
stops
are
installed.
WARNING
It
is
extremely
important
that
pilot's
seat
stops
are
installed,
since
acceleration
and
deceleration
could
pos-
sibly
permit
seat
to
become
disengaged
from
seat
rails
and
create
a
hazardous
situation, especially
during
takeoff
and
landing.
3-37.
CENTER.
(See
figure
3-6.)
a.
DOUBLE-WIDTH
BOTTOM
AND
BACK/SINGLE
RECLINING
BACK.
b.
DOUBLE-WIDTH
BOTTOM/INDIVIDUAL
RECLINING
BACKS.
3-38.
DESCRIPTION.
These
seats
are
permanently
bolted to
the
cabin
structure
and
incorporate
no
adjustment
provisions
other
than
manually-adjustable
three
position
backs.
3-39.
REMOVAL
AND INSTALLATION. (See
figure
3-6.)
a.
Remove
bolts
securing
seat
to
cabin
structure.
b.
Lift
seat
out.
c.
Reverse
preceding
steps for
installation.
3-40.
AUXILIARY/FOLD
UP.
(See
figure
3-6.)
3-41.
DESCRIPTION.
These
seats
are
permanently
bolted
to
the
cabin
structure
and
have
no
adjustment
provisions.
The
seat
structure
is
mounted
on
hinge brackets
with
pivot
bolts,
thus
allowing seat
to
be
pivoted
upward
to
acquire more
baggage
area.
3-42.
REMOVAL
AND
INSTALLATION. (See
figure
3-6.)
a.
Remove
bolts
securing
seat
structure
to
hinge
brackets.
b.
Lift
seat
out.
c.
Reverse
preceding
steps
for
installation.
3-43.
REPAIR.
Replacement
of
defective
parts
is
recommended
in
repair
of
seats.
3-44.
CABIN
UPHOLSTERY.
Due
to
the
wide
selection
of
fabrics,
styles
and
colors,
it
is
impossible
to
depict
each
particular
type
of
upholstery.
The
following
paragraphs
describe
general
pro-
cedures which
will
serve
as guides
in
removal
and replacement
of
upholstery.
Major
work,
if
possible,
should
be
done
by
an
experienced
mechanic.
If
the
work
must
be
done
by
a
mechanic
unfamiliar
with upholstery
practices,
the
mechanic
should make careful
notes
during
removal
of
each
item
to
facilitate replacement
later.
NOTE
Repair
kits
are
available
for
the
repair
of
cracks
in
ABS,
PBC,
PVCP,
graphite
and
fiberglass
material.
(Cessna
Supply
Division,
P.O.
Box
949, Wichita,
KS
67201,
316/
685-9111,
Telex
417-489.)
Revision
1
3-13
MODEL
172
SERIES
SERVICE
MANUAL
PILOT
AND
COPILOT
(STANDARD)
(THRU
1979
MODELS)
1.
Seat
Back
Adjust
Link
2.
Torque
Tube
3.
Seat
Back
Adjustment
Cam
4.
Bushing
5.
Spacer
6.
Spring
2
7.
Seat
Adjustment
Pawl
8.
Roller
9.
Bracket
RECLINING
BACK/
4
16
NOTE
See
figure
3-7
for
seat
back
cam
re-
placement.
12
6
11
10
10.
Washer
11.
Pin
12.
Adjustment
Pin
4 NOTE
13.
Seat
Stop
Refer
to
sheets
9
and
10
14.
Seat
Rail
15.
Fore/Aft
Adjustment
Handle
for seat
stop
installa-
16.
Recline
Handle
tion.
17.
Roll
Pin
18.
Seat
Belt
Retainer
19.
Trim
Figure
3-6.
Seat
Installtion
(Sheet
1
of
11)
3-14
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
PILOT
AND
COPILOT
SEATS
1.
Vertical
Adjustable
21.
Fwd
Torque
Tube
(OPTIONAL)
Handle
22.
Fwd
Torque
Tube
34
2.
Pin Bellcrank
THRU
1979
3.
Bearing
Block
23.
Aft
Torque
Tube
MODELS
4.
Bearing
Bellcrank
5.
Collar
24.
Aft
Torque
Tube
6.
Vertical
Adjust
25.
Seat
Pivot
Bracket
Screw
26.
Seat
Skirt
Trim
7.
Vertical
adjust
27.
Seat
Back
Trim
32
Nut
28.
Pocket
-
8.
Seat
Adjust
Handle
29.
Seat Back
Retainer
16
9.
Seat
Adjust Pin
30.
Clip
10.
Spring
(LH
Side
Only)
31.
Former
Bracket.
31
11.
Seat
Back
Adjust
32.
Former
Assembly
Handle
33.
Bracket
30
12.
Jack
Screw
34.
Head
Rest
Assembly
17
13.
RH
Crank
Assembly
15
14.
LH
Crank
Assembly
15.
Seat Adjust
Bellcrank
16.
Cover
29
INFINITELY
ADJUSTABLE
28
12
14
17.
Cushion
18.
Seat
Stop
11
19.
Torque
Tube
Intercon-
nect
Channel
NOTE
20.
Pedestal Install
seat
stop
in
first
and
thir-
teenth
holes
from
front
of
outboard
seat
rail.
16
9
26
8
19
25
Detail
A
9
24
attached
directly
to
seat frame
with
four
screws.
3-15
Beginning with
17268914
&
F17201640,
seat
belt
Detail
B
retainer
(*) is
separate
from
trim
(26),
and
is
attached
directly
to
seat
frame
with
four
screws.
Figure
3-6. Seat
Installation
(Sheet
2
of
11)
3-15
MODEL
172
SERIES
SERVICE
MANUAL
CENTER
SEAT
(STANDARD)
4
7
5
10
9
8
3
Detail
A
DOUBLE
WIDTH
BOTTOM/
SINGLE
RECLINING
BACK
1.
Recline
Shaft
2.
Seat
Bottom
3.
Seat
Back
4.
Trim
5.
Headrest
6.
Recline
Pawl
7.
Lnk
A
8.
Bushing
9.
Bellcrank
10.
Knob
Figure
3-6.
Seat
Installation
(Sheet
3
of
11)
3-16
MODEL
172
SERIES SERVICE
MANUAL
CENTER
SEAT
THRU
1979
(OPTIONAL)
1.
Set
Bottom
2.
Spring
3.
Spacer
4.
Seat
Back
5.
Headrest
6.
Bushing
7.
Recline
Handle
4
8.
Pawl
9.
Control
Shaft
3
DOUBLE
WIDTH BOTTOM/
INDIVIDUAL
RECLINING
BACKS
Detail
A
9
Figure
3-6.
Seat
Installation
(Sheet
4
of
11)
3-17
MODEL
172
SERIES
SERVICE
MANUAL
1.
Attach
Bracket
2.
Seat
Bottom
Structure
3.
Seat
Bottom
4.
Seat
Back
5.
Floorboard
6.
Mounting
Bracket
Detail
A
6
Figure
3-6.
Seat
Installation
(Sheet
5
of
11)
3-18 Revision
1
MODEL
172
SERIES SERVICE
MANUAL
SEAT
PEDESTAL
ASSEMBLY
BEGINNING
WITH
1980
MODELS
8
2
1.
Seat
Back
Adjust
8.
Torque
Tube
Bellcrank
Bellcrank
9.
Forward
Torque
Tube
2.
Pivot
Bracket
10.
Aft
torque
Tube
3.
Bellcrank
11.
LH
Crank Assemble
4.
Spring
12.
Splice
5.
Seat
Adjust
Pin
13.
Jack
Screw
6.
Vertical
Adjust
Handle
14.
Seat
Back
Adjust
7.
Seat
Adjust
Handle
15.
RH
Crank
Assembly
Figure
3-6. Seat
Installation
(Sheet
6
of
11)
3-19
MODEL
172
SERIES
SERVICE
MANUAL
PILOT
AND
COPILOT
SEAT
ASSEMBLY
BEGINNING
WITH 1980
MODELS
1.
Seat
Handle
Pin
2.
Spring
3.
Sea
t
Adjust
Handle
4.
Cushion
5.
Cover
6.
Grommet
7.
Head
Rest
8.
Former
Bracket
4
9.
Former
Assembly
10.
Bracket
11.
Clip
12.
Pocket
13.
Bolt
and
Spacer
14.
Lock
Cylinder
15
Frame
16.
Bracket
17.
Pin
18.
Roller
19.
Spring
20.
Link
21.
Clevis
Pin
22.
Lock
Cylinder
Control
Figure
3-6. Seat Installation (Sheet 7 of 11)
3-20
MODEL
172
SERIES
SERVICE
MANUAL
5
6
INFINITELY-ADJUSTABLE
SEAT
ASSEMBLY
BEGINNING
WITH
1980
MODELS
26
31
0
BEGINNING
WITH
11
1983
MODELS
1.
Cushion
2.
Seat
Bottom Cover
3.
Cushion
12
4.
Seat
Back
Cover
5.
Head
Rest
6.
Head
Rest
Cover
7.
Former
Bracket
8.
Former
Assembly
9.
Bracket
10.
Clip
11.
Seat
Back
Retainer
12.
Seat
Back
Trim
13.
Pocket
Assembly
14.
Seat
Belt Retainer
15.
Trim
16.
RH
Crank
Assembly
17.
Splice
20
18.
LH
Crank
Assembly
15
19.
Aft
Torque
Tube
16
20.
Pivot
Bracket
21.
Seat Back
Adjust
Bellcrank
17
22.
LH
Pedestal
23.
Bellcrank
24.
Vertical
Adjust
Handle
27
20
25.
Forward
Torque
Tube
26.
Seat
Handle
Adjust
27.
Seat
Back Adjust
Handle
21
28.
RH
Pedestal
26
29.
Seat
Adjust
Pin
30.
Jack
Screw
31.
Spring
32.
Link
33.
Clevis
Pin
Figure
3-6.
Seat
Installation
(Sheet
8
of
11)
3-21
MODEL
172
SERIES
SERVICE
MANUAL
SEAT
STOP
INSTALLATION
-
STANDARD
SEAT
1
ELEVENTH
SEAT
STOP
1.
Screw
HOLE
FROM
FWD EDGE
2.
Seat
Stop
OF
OUTBD
PILOTS
&
3.
Seat
Rail-Outboard
COPILOTS
SEAT
RAILS
4.
Seat
top
5.
Pin
6.
Cotter
Pin
17267585
thru
17272884
F17201515
thru
F17201909
FIRST
SEAT
STOP
HOLE
PILOT'S
&
COPILOTS
OUTBD
SEAT
RAILS
17272885
thru
17276517
F17201910
thru
F17202238
EXTREME
AFT
OUTBD
PILOT'S
&
COPILOT'S
SEAT
RAILS.
3
2
17276518
&
ON
14.75"X
F17202239
&
ON
WARNING
It is
extremely
important
that
pilot's
seat
stops
are
instal-
led,
since acceleration
and
deceleration could
possibly
permit
seat
to
become
disengaged
from
seat
rails
and
create
a
hazardous
situation,
especially
during
takeoff
and
landing.
Figure
3-6.
Seat
Installation
(Sheet
9
of
11)
3-22
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
SEAT STOPS
INSTALLATION
-
OPTIONAL
INFINITE-ADJUST
SEAT
SECOND SEAT
STOP
HOLE
PILOTS
&
COPILOTrS OUTBD
SEAT
RAILS
17267585
thru
17272384
-. . .
F17201515
thru
F17201909
EXTREME
AFT
OUTBD
PILOTS
&
COPILOTS
SEAT RAILS.
2
3
1
FIRST
SEAT
STOP
HOLE
PILOTS
&
COPILOT'S
OUTBD
SEAT
RAILS
17272885
thru
17276517
EXTREME
AFT
OUTBD
F17201910
thru
F17202238
-
PILOTS
&
COPILOTS
SEAT
RAILS.
4
6
1.
Screw
4
2.
Seat
Stop
3.
Seat
Rail-Outboard
4.
Seat
Stop
5.
Pin
3
6.
Cotter
Pin
5
5.13
17276518
&
ON
F17202239
&
ON
WARNING
It
is
extremely
important that
pilot's
seat
stops
are
instal-
led,
since
acceleration
and
deceleration
could
possibly
permit
seat
to
become
disengaged
from
seat
rails
and
create
a
hazardous
situation,
especially
during
takeoff
and
landing.
Figure
3-6.
Seat
Installation
(Sheet
10
of
11)
Revision
1
3-22A
MODEL
172
SERIES
SERVICE
MANUAL
6
5
SPLIT
BACK
REAR
SEAT
2
BEGINNING WITH
1980
MODELS
6
A
1.
Cover
4
2.
Cushion
3.
Skirt
Detail
A
4.
Lock
-
5.
Grommet
6.
Back Panel
7.
Head
Rest
15
8.
Seat
Bottom
9.
Seat
Back
Legs
10.
Seat
Belt
Stirrup
11.
Bracket
12.
Link
13.
Spacer
14.
Spacer
15.
Hex
Nut
16.
Lock
Cylinder
17.
Spacer
Detail
B
18.
Spacer
Figure
3-6.
Seat
Installation
(Sheet
11
of
11)
3-22B
MODEL
172
SERIES
SERVICE
MANUAL
THRU
1979 MODELS
CLEVIS BOLT
(REF)
SEAT
BACK
(REF)
2.
50"
R.
(CONSTANT
AT
EACH
NOTCH)
REPLACEMENT
CAM
PAWL
(REF)
INDENT
PROFILE
.120"
(TYP)
.170"
MINIMUM-(TYP)
NOTE
Ensure
replacement
cam
conforms
to
dimensions
shown in
Detail
A
before
installation.
172
&
F172
SERIES
ONLY
060"R
(TYP)
Detail
A
REPLACEMENT
PROCEDURE:
a.
Remove
seat
from
aircraft.
b.
Remove
plastic
upholstery
panels
from
aft
side
of
seat
back,
then
loosen
upholstery
retaining
rings
and
upholstery
material
as required
to
expose
rivets
retaining
old
cam
assembly.
c.
Drill
out
existing
rivets
and
insert
new
cam
assembly
(2).
Position
seat
back
so
pawl
(3)
en-
gages
first
cam
slot
as
illustrated.
d.
Position
cam
so
each
slot
bottom
aligns
with the
2.
50"
radius
as
illustrated.
e.
Clamp
securely
in
this
position
and
check
travel
of
cam.
Pawl
must
contact
bottom
of
each
cam
slot.
Using
existing holes
in
seat
frame.
drill
through
new
cam
and
secure
with
MS20470AD6
rivets.
f.
Reinstall
upholstery.
upholstery
panels
and
seat.
Figure
3-7.
Seat
Back
Cam
Replacement
Revision
1
3-23
MODEL
172
SERIES
SERVICE
MANUAL
4
PROVISIONS
FOR
OPTIONAL
3
INERTIA
REEL INSTALLATION
2
2
Spar
Shield
3.
Headliner
Assembly
7
4.
Tiara
5.
Cover
6.
Retainer
7.
Cover
8.
Skylight
Retainer
9.
Wire
10.
Zipper
PROVISIONS
FOR
INERTIA REEL
-
INSTALLATION
9
Figure
3-8.
Cabin
Headliner
Installation
3-24
MODEL
172
SERIES
SERVICE
MANUAL
3-45.
MATERIALS
AND
TOOLS.
Materials
and
tools
will
vary
with the
job.
Scissors
for
trimming
upholstery
to
size,
and
a
dull-bladed
putty
knife
for
wedging
material
beneath
retainer strips
are
the only
tools
required
for
most
trim
work.
Use
industrial
rubber
cement
to
hold soundproofing
mats
and
fabric
edges
in
place.
Refer
to
Section
18
for
repair
of
glass-
fiber
constructed components.
3-46.
SOUNDPROOFING. The
aircraft
is
insulated
with spun
glass
mat-type
insulation
and
a
sound-deadener compound
applied
to
inner
surfaces
of
skin
in
most
areas
of
cabin
and
baggage
compartment.
All
soundproofing
material
should
be
replaced
in
its original
position
anytime
it is
removed.
A
soundproofing
panel
is
placed
in
gap
between
wing
and
fuselage
and
held
in
place
by
wing
root
fairings.
3-47.
CABIN
HEADLINER. (See
figure
3-8.)
3-48.
REMOVAL
AND
INSTALLATION.
(See
figure
3-8.)
a.
Remove
sun visors,
all
inside
finish
strips
and
plates,
overhead
console,
upper
doorpost
shields
and
any
other
visible
retainers
securing
headliner.
b.
Remove
molding
from
fixed windows.
c.
Remove
screws
securing
headliner
and
carefully
take
down
headliner.
d.
Remove
spun
glass
soundproofing panels
above
headliner.
NOTE
The
lightweight
soundproofing
panels
are
held
in
place
with
industrial
rubber
cement.
e.
Reverse
preceding
steps
for
installation.
Before
installation,
check
all
items
con-
cealed
by
headliner
for
security.
Use wide
cloth
tape
to
secure
loose
wires
to
fuselage
and
to
seal
openings
in
wing
roots.
3-49.
UPHOLSTERY
SIDE PANELS.
Removal
of
upholstery
side
panels
is
accomplished
by
removing
seats for
access,
then
removing
parts
attaching
panels.
Remove
screws,
retaining
strips,
arm
rests
and
ash
trays
as required
to
free
panels.
Automotive-type
spring
clips
attach
most
door
panels.
A
dull
putty
knife
makes
an
excellent
tool
for
prying
clips
loose.
When
installing
side
panels,
do
not
over-tighten
screws. Larger
screws
may
be
used
in
enlarged
holes
as
long as
the
area
behind
the
hole
is
checked
for
electrical wiring,
fuel
lines
and
other
components
which
might
be
damaged
by
using
a
longer screw.
Ensure
that,
after
all
seats
are
reinstalled,
seat
stops
are
properly
and
securely
installed.
3-50.
CARPETING.
Cabin
area
and
baggage
compartment
carpeting
is
held
in
place
by rubber
cement,
small
sheet metal
screws
and
retaining
strips.
When
fitting
a
new
carpet,
use
old
carpet
as
a
pattern
for
trimming
and
for
marking
screw
holes.
3-51.
SAFETY PROVISIONS.
3-52.
CARGO TIE-DOWNS.
(See
figure
3-9.)
Cargo tie-downs are
used
to
ensure
baggage
cannot
enter
seating
area during
flight.
Methods
of
attaching
tie-downs
are
illustrated
in
the
figure.
The
eyebolt
and
nutplate
can
be
located at
various
points.
The
sliding
tie-down
lugs
also
utilize
eyebolts
and
attach
to
seat
rails.
3-53.
SAFETY
BELTS.
(See
figure
3-11.)
Safety
belts
should
be
replaced
if
frayed
or
cut,
latches
are
defective
or
stitching
is
broken.
Attaching
parts
should
be
replaced
if
excessively
worn
or
defective.
A
seat
belt
shortening
kit
is available
for
aircraft
serials
17266047
thru
17274009.
Refer
to
SK172-76.
Revision
1
3-25
MODEL
172
SERIES
SERVICE
MANUAL
3-54.
SHOULDER
HARNESS.
(See
figure
3-11.)
Individual
shoulder harnesses may
be
installed
for
each
seat.
Each
harness
is
connected
to
the
upper
fuselage
structure
and
to
the
seat
safety
belt
buckle.
Component
parts
should
be
replaced
as
outlined
in
the
preceding
para-
graph.
3-55.
GLIDER
TOW-HOOK.
A
glider
tow-hook,
which
is
mounted
in
place
of
the tail
tie-down
ring,
is
available
for
all
models.
3-56.
REAR
VIEW
MIRROR. (172
AND
F172
SERIES
ONLY.)
(See
figure
3-10.)
A
rear
view
mir-
ror
may
be
installed
on
the
cowl
deck
above
the
instrument
panel.
The
figure
illustrates
de-
tails
for
removal
and installation
of
rear
view
mirror.
3-57.
SEAT
RAIL
INSPECTION.
A
special
inspection
of
seat
rails
should
be
conducted
each
50
hours.
See
figure
3-12
for
inspection
procedures.
CARGO
TIE-DOWN
RING
CARGO
TIE-DOWN
LUG
SLIDE
ASSEMBLY
SEAT
RAIL
Figure
3-9.
Cargo Tie-Down
Rings
2
1
3
4
OPTIONAL
(THRU
17271034
&
F17201749)
1.
Cover
2.
Mirror
5
3.
Grommet
4.
Nut
5.
Washer
172
& F172 SERIES
ONLY
6.
Deck
Skin
6
Figure
3-10.
Rear
View
Mirror
Installation
3-26
Revision 1
MODEL
172
SERIES
SERVICE
MANUAL
2
4
Detail
B
10
172Q
Models
1.
Shoulder
Harness
10
2.
Spacer
3.
Washer
4.
Cover
5.
Bolt
6.
Inertia
Reel
Assembly
7.
Spar
8.
Mounting
Plate
9.
Latch
Assembly
Detail
E
Split
Back
Seat
Beginning
with
10.
Belt
Left-Hand
Only 1980
Models
11.
Bracket
Beginning
with
12.
Link
17265685
and
13.
Cover
F17201385
2
Detail
Eand
F
DetailG
Beginning
with
1982
Models
on
aircraft
equipped
with
air
conditioning
Figure
3-11.
Seat
Belt
and
Shoulder
Harness
Installation
Revision
1
3-27
MODEL 172
SERIES
SERVICE
MANUAL
1
Counts
as
one
crack.
Usable
if
not
closer
than
one
inch.
REPLACE
SEAT
RAIL
WHEN:
a.
Any
portion
of
web
or
lower
flange
is
cracked (index
2).
b.
Any
crack
in
crown of
rail
is
in
any
direction
other
than right
angle
to
length
of
rail.
c.
Number
of
cracks
on
any
one
rail
exceeds
four,
or any
two
cracks
(index
1)
are
closer
than
one
inch.
NOTE
Use
of
seat
rail
cargo
tie-downs
is
not
permissible
on
seat
rails
with
cracks.
Figure
3-12.
Seat Rail
Inspection
3-28
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
4
WINGS
AND EMPENNAGE
Page
No.
TABLE
OF CONTENTS
Aerofiche/
Manual
WINGS
AND
EMPENNAGE
....
1H5/4-1
Description
.............
1H13
4-9
Wings
...................
1H5/4-1
Removal
................
1H13
4-9
Description
.............
1H5/4-1
Repair
.................
1H144-10
Removal
................
1H5/4-1
Installation
.............
1H14
4-10
Repair
. ................
H8/4-4
Horizontal
Stabilizer
........
1H14
4-10
Installation
.............
1H8/4-4
Description
.............
1H14
4-10
Adjustment
.............
1H12/4-8
Removal/Installation
.......
H14
4-10
Wing
Struts
..............
1H13/4-9
Repair
.................
1H17/4-11
Description
.............
113/4-9
Stabilizer Abrasion
Boots
.....
1H17/4-11
Removal/Installation
.......
1H13/4-9
Description
.............
1H17
4-11
Repair
. ................
1H13/4-9
Removal
................
1H17
4-11
Fin
.....................
1H13/4-9
Installation
.............
1H17
4-11
4-1.
WINGS
AND
EMPENNAGE.
4-2.
WINGS.
(See
figure
4-1.)
4-3.
DESCRIPTION.
Each
all-metal
wing
is a
semicantilever,
semimonocoque
type, with
two
main
spars
and
suitable ribs
for
the
attachment
of
the
skin.
Skin
panels
are
riveted
to
ribs.
spars
and
stringers
to
complete the
structure.
An
all-metal,
piano-hinged
aileron,
flap
and
a
detachable
wing
tip
are
mounted
on
each
wing
assembly.
A
single
metal
fuel
tank
is
mounted
between
the
wing
spars
at
the inboard
end
of
each
wing.
Beginning
with
1981
Models,
an
optional
installation,
consisting
of
an
integral
fuel bay,
formed
between the
wing
spars
at the
inboard end
of
each
wing,
is
available.
Colored
navigation
lights
are
mounted
at
each
wing
tip.
Beginning
with
1982
Models,
the
aircraft
landing lights
are
located
in
the
left
hand
wing leading edge.
4-4.
REMOVAL.
Wing
panel
removal
is
most
easily
accomplished
if
four
men
are
available
to
handle
the wing.
Otherwise,
the
wing
should
be
supported
with
a
sling
or
maintenance
stand
when
the
fastenings
are
loosened.
a.
Remove
wing
root fairings
and
fairing
plates.
b.
Remove
all
wing
inspection
plates.
c.
Drain
fuel
from
tank
or
bay
of
wing
being
removed.
d.
Disconnect:
1.
Electrical wires
at
wing
root
disconnects.
2.
Fuel
lines
at
wing
root.
(Refer
to
precautions
outlined
in
Section
12.)
3.
Pitot
line
(left
wing
only)
at
wing
root.
4.
Cabin
ventilator
hose
at
wing
root.
e.
Reduce
aileron
cable
tension
by
loosening
turnbuckles
and
disconnect
cables
at
aileron
bellcranks.
Disconnect flap
cables at
turnbuckles
above
headliner,
and
pull
cables
into
wing
root area.
Revision
1
4-1
MODEL
172
SERIES
SERVICE
MANUAL
A
300
LB
IN 12
18
690
LB
IN
(MAX)
Beginning
with
17275035
and
F1722135
&
On
Detail
B
1.
Fairing
8.
Eccentric
Bushings
15. Wing
Mounted
Landing
Light
2.
Fuel
Tank
9.
Washer
16. Wing
Assembly
3.
Lower
Rear
Fairing
10.
Nut
17.
Cover
Plate
4.
Inspection
Plate
11.
Wing
Flap
18.
Stall
Warning
Unit
5.
Fuel
Tank
Cover
12.
Aileron
19.
Washers
6.
Fuel
Gage
Access
Cover
13.
Wing
Tip
20.
Nut
7.
Bolt
14.
Navigation
and
Strobe
Lights
Figure
4-1.
Wing
Installation
(Sheet
1
of
2)
4-2
MODEL
172
SERIES
SERVICE
MANUAL
TORQUE:
300
LB
IN
(MIN)
500
LB
IN
(MAX)
9
690
LB
IN
(MAX)
BEGINNING
WITH
17275035
1.
Fairing
5.
Wing
Tip
9.
Bolt
3.
Wing
Flap
7.
Courtesy
Light
11.
Washers
4.
Aileron
8.
Fuel
Filler
Cap
12.
Nut
13.
Wing
Mounted
Landing
Light
Figure
4-1.
Wing
Installation
(Sheet
2
of
2)
4-3
MODEL
172
SERIES SERVICE
MANUAL
NOTE
To
ease
rerouting
the
cables.
a
guide
wire
may
be
att-
ached
to
each cable
before
it
is
pulled
free
from
the wing.
Cable
may
then
be
disconnected
from
the
wire.
Leave
the
guide wire routed
through
the
wing;
it
may
be
attached
again
to
the
cable
during installation.
and
used
to
pull
the
cable into
place.
f.
Remove
screws
from
strut
fairings
and
slide
fairings
toward
center
of
strut.
g.
Support
wing
at
outboard
end and
remove
strut-to-wing
attach
bolt.
h.
Lower
strut
carefully
to
avoid
damage
to
lower
strut-to-fuselage
fitting.
NOTE
Tape
flaps
in
the
streamlined
position
during
wing
removal.
This
will
prevent
flap
damage due
to
the
unse-
cured
free-swinging
action
when
handling
the
wing.
i.
Mark
position
of
wing-attachment
eccentric
bushings
(See
figure
4-1.)
These
bushings
are
used
to
rig
out
"wing heaviness".
j.
Remove
nuts.
washers, bushings
and
bolts
attaching
wing
spars
to
fuselage.
NOTE
It
may
be
necessary
to
rock
the
wings
slightly
and/or
to
use
a
long
drift
punch
to
remove
attaching
bolts.
k.
Remove
wing
and
lay
on
padded
stand.
NOTE
Plans
for
fabrication
of
padded
wing
support stands
are
illustrated
in
Section
18
of
this
manual.
4-5.
REPAIR.
A
damaged
wing
panel
may
be
repaired
in
accordance
with
instructions
outlined
in
Section
18,
which
supplements
Federal
Aviation
Regulation.
Part43.
Extensiverepairs
of
wing
skin
and
structure
are
best
accomplished
by
using
the
wing
alignment
repair
jig.
which
may
be
obtained
from
Cessna.
The
wing
jig
serves
not only
as
a
holding
fixture.
making
work
on
the
wing
easier,
but also
assures
absolute
alignment
of
the
repaired
wing.
4-6.
INSTALLATION.
(See
figure
4-1.)
NOTE
The
forward
wing
spar
fittings
are
attached
to
the
fuse-
lage
fittings
with
AN8-23
bolts. and
the
aft
wing
spar
fittings
are
attached
to the
fuselage
fittings
with
AN7-24
bolts.
Minimum
torque
on
the
AN8-23
bolts
is
300
lb-in
and the
maximum
torque
is
690
lb-in.
Minimum
torque
on
the
AN7-24
bolts
is
300
lb-in, and
the
maximum
torque
is
500
lb-in.
4-4
MODEL
172
SERIES
SERVICE
MANUAL
*
NOTE
Lubricate
bolt
and
hole
per
Section
2.
NOTE
Seal
across
top
of
lower
strut
fitting
at
skin cutout
with
576.
1
Permagum.
1. Wing
Strut
2.
Tie-Down
Ring
3.
Wing
Attachment
Fitting
4.
Spacer
5.
Screw
6.
Upper
Fairing
7.
Lower
Fairing
8.
Fuselage
Attachment
Fitting
Figure
4-2.
Wing
Strut
4-5
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Fairing
(1)
and
Dorsal
(2)
are
riveted
to
Fuselage
(13).
6
Detail
A
NOTE
Tighten
forward
stabilizer
attach
bolts
first,
install required
thick-
ness
of
washers
to
allow
a
maximum
.010
gap
between
washer
and
stab-
ilizer
rear
spar
(washer
required
Detail
2
places),
9
.
Detail
C
1.
Fairing
2.
Dorsal
3.
Upper
Right
Fairing
4.
Nutplates
5.
Fin
Assembly
6.
Fin
Tip
7.
Upper
Rudder
Hinge
8.
Center
Rudder
Hinge
9.
Lower
Rudder
Hinge
10.
Shim
14
11.
Tailcone
12
12.
Upper Left
Fairing
13.
Fuselage
14.
Washer
13
Figure
4-3.
Vertical
Fin
4-6
MODEL
172
SERIES
SERVICE
MANUAL
4
Detail
A
NOTE
See
figure
4-3
for
stabilizer
NOTE
rear
attach
bolt
installation.
A
kit
is
available
from
the
Cessna
Supply
Division
for
installation
of
abrasion
boots
on
aircraft
not so
equipped.
1.
Stabilizer
Tip
4.
Inboard
Elevator
Hinge
8.
Horizontal
Stabilizer
2.
Outboard
Elevator
Hinge
5.
Bracket
9.
Forward Left
Fairing
3.
Bushing
6.
Upper
Right
Fairing
10.
Forward
Right
Fairing
7.
Upper
Left
Fairing
11.
Abrasion
Boot
Figure
4-4.
Horizontal
Stabilizer
4-7
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Upon
installation
of
bolts,
coat
holes
and
bolts
lightly
with
Electro-Moly
No.
11
(MIL-G-121164)
grease.
a. Hold
wing
in
position
and
install
bolts.
bushings. washers
and
nuts
attaching
wing
spars
to
fuselage
fittings.
Ensure
eccentric
bushings
are
positioned
as
marked.
Torque
nuts
to
values
stipulated
in
note
preceding
this
step.
b.
Install
bolts,
spacers.
and
nuts
to
secure
upper
and
lower
ends
of
wing
strut
to
wing
and
fuselage
fittings.
NOTE
Upon
installation
of
bolts,
coat holes
and
bolts
lightly
with
Electro-Moly
No.
11
(MIL-G-121164)
grease.
NOTE
Seal
opening
in
fuselage
skin
around
lower wing
strut
fitting
with
579.6
Sealer
(Inmont
Corp..
St.
Louis.
Mis-
souri)
or
equivalent.
c.
Route
flap
and
aileron
cables.
using
guide
wires.
(See
note
in
paragraph
4-4)
d.
Connect:
1.
Electrical
wires
at
wing
root
disconnects.
2.
Fuel
lines
at
wing
root.
(Refer
to
precautions
outlined
in
Section
12.)
3.
Pitot
line
(if left
wing
is
being
installed.)
e.
Rig
aileron
system
(Section
6).
f.
Rig
flap
system
(Section
7).
g.
Refuel
wing
tank
or
bay
and
check
for
leaks.
(Refer
to
precautions
outlined
in
Section
12.)
h.
Check
operation
of
wing
tip
lights.
i.
Check
operation
of
fuel
gage.
j.
Seal
all openings
common
to
fuselage root
rib
and
adjacent
to
fuel
cell
with
cloth-
backed
waterproof
tape.
Tapes
recommended for
usage
are:
Polyken
224.
230
or
231.
Permacel
P-69.
P-670
or
P-672,
or
Tuck
92T.
k.
Install
wing
root
fairings.
NOTE
Be
sure
to
insert
soundproofing
panel
in
wing
gap,
if
such
a
panel
was
installed
originally,
before
replacing
wing
root fairings.
1.
Install
all
wing
inspection
plates.
interior
panels
and
upholstery.
4-7.
ADJUSTMENT
(Correcting
"Wing-Heavy" Condition).
(See
figure
4-1.)
If
considerable
control wheel
pressure
is
required
to
keep
the
wings
level
in
normal
flight,
a
"wing-heavy"
condition
exists.
a.
Remove
wing
fairing
strip
on
the
"wing-heavy"
side
of
the
aircraft
b.
Loosen
nut
(10)
and
rotate
bushings
(8)
simultaneously
until
the
bushings
are
positioned with
the
thick
side
of
the
eccentrics
up.
This will lower
the
trailing
edge
of
the
wing,
and
decrease
"wing-heaviness"
by
increasing
angle-of-incidence
of
the
wing.
4-8
MODEL
172
SERIES SERVICE
MANUAL
CAUTION
Be
sure
to
rotate
the
eccentric
bushings
simultaneously.
Rotating
them
separately
will
destroy the alignment
between
the
off-center
bolt
holes
in
the
bushings,
thus
exerting
a
shearing
force
on
the bolt,
with
possible
damage
to
the
hole
in
the
wing
spar.
c.
Torque
nut
(10)
and
reinstall
fairing
strip.
d.
Test-fly the
aircraft.
If
the
"wing-heavy"
condition
still
exists,
remove
fairing
strip
on
the
"lighter" wing.
loosen
nut,
and
rotate
bushings
simultaneously
until
the
bushings
are
positioned with
the
thick
side
of
the
eccentrics
down.
This
will
raise
the
trailing
edge of
the wing,
thus
increasing
"wing-heaviness"
to
balance
heaviness
in
the
opposite
wing.
e.
Torque
nut
(10),
install
fairing
strip,
and
repeat
flight
test.
4-8.
WING
STRUTS.
(See
figure
4-2.)
4-9.
DESCRIPTION.
Each
wing
has
a
single
lift
strut
which
transmits
a
part
of
the
wing
load
to
the
lower
portion
of
the
fuselage.
The
strut
consists
of
a
streamlined
tube
riveted
to
two
end
fittings
for
attachment
at
the fuselage
and
wing.
4-10.
REMOVAL
AND
INSTALLATION.
a.
Remove
screws
from
strut
fairings
and
slide
fairings
along
strut.
b.
Remove
fuselage
and
wing
inspection
plates
at
strut
junction
points.
c.
Support
wing
securely, then
remove
nut
and
bolt
securing
strut
to
fuselage.
d.
Remove
nut,
bolt
and
spacer
used to
attach
strut
to
wing.
then
remove
strut
from
aircraft.
e.
Reverse
preceding
steps
to
install
strut.
NOTE
Seal
opening
in
fuselage
skin
around
lower
wing
strut
fitting
with
579.6
Sealant
(Inmont
Corp..
St.
Louis,
Mis-
souri)
or
equivalent.
4-11.
REPAIR.
a.
For
grooves
in
wing
strut
caused
by
strut
fairings,
the
following
applies.
1.
If
groove
exceeds .010
inch
in
depth
and
is
less
than
.75
inch
from
a
rivet
center.
the
strut
should
be
replaced.
2.
If
groove
is
more
than
.75
inch
from
a
rivet center and
groove
depth
exceeds
.030
inch,
strut
should
be
replaced.
3.
If
groove
depth
is
less
than
.030
inch
and
is
more
than
.75
inch
from
a
rivet
cen-
ter,
strut
should
be
repaired
by
tapering
gradually
to
the
original
surface
and
burnishing
out
to
a
smooth
finish.
The
local
area
should
be
checked
with
dye
penetrant
to
insure
that
no
crack
has
developed.
4-9
MODEL
172
SERIES
SERVICE
MANUAL
b.
The
following
applies
to
wing
struts
with
grooves
worn
in
the lower
trailing
edge.
This
type
damage
can
occur
after
extensive
cabin
door
usage
with
a
missing
or
im-
properly adjusted
door
stop
which
allows
the
door
to
bang
against
the
aft
edge
of
the
strut
at
the
lower
end.
NOTE
Struts
with
a
groove
deeper
than
50%
of
the
original
ma-
terial
thickness
should
be
replaced. Lesser
damage
may
be
repaired
as
follows:
1.
Without
making
the
damage
deeper,
remove
strut
material
on
each
side
of
groove
to
reduce
notch
effect
of damage.
Smooth
and
blend
the surface
to
provide
a
gradual transition
of
strut
tube material
thickness
in
damaged
area.
The
local
area
should
be
checked
with
dye
penetrant
to
insure
that
no
crack
has
developed.
2.
Apply
brush
alodine
or
zink
chromate
primer
and
repaint
area.
3.
Re-rig
the
door
stop
and/or
re-form
the
lower
portion
of
the
door
pan
and
skin
in-
board
to
prevent
the
door
from
rubbing
the
strut
tube.
If
these
actions
prove
to
be
ineffective,
install
some
form
of
protective
bumper,
either
on
strut
or
lower
por-
tion
of
door,
to
prevent
further
damage.
A
short,
hard
rubber
strip
bonded
to
the
trailing
edge
of
the
strut
where the
door
comes
close
to
strut
is a
possibilty.
NOTE
It
should
be
noted
that
the
above
disposition
applies
only
to
the
damage
caused
by
strikes
from
cabin
door.
The
criteria set
forth
for strut
fairing
damage
still
applies
as
a
general
criteria
for
the
remainer
of
the
strut.
c.
Tie-downs
and
attaching
parts
may
be
replaced.
If
the
strut
is
severly
dented,
cracked
or
deformed,
it
should
be
replaced.
4-12.
FIN.
(See
figure
4-3.)
4-13.
DESCRIPTION.
The
fin
is
primarily
of
metal
construction,
consisting
of
ribs
and
spars
covered
with skin.
Fin
tips
are
of
ABS
construction.
Hinge
brackets
at
the
fin
rear
spar
attach
the
rudder.
4-14.
REMOVAL.
The
fin
may
be
removed
without
first
removingthe
rudder.
However, for
access
and
ease
of
handling,
the
rudder may
be
removed
in
accordance
with
procedures
outlined
in
Section
10
of
this
manual.
Remove
fin
as
follows:
a.
Remove
fairings
on
either
side
of
fin.
b.
Disconnect
flashing
beacon
lead,
tail
navigation
light
lead.
antennas
and
antenna
leads,
and
rudder
cables,
if
rudder
has
not
been
removed.
4-10
MODEL
172
SERIES SERVICE
MANUAL
NOTE
The
flashing
beacon
electric
lead
that
routes
into
the
fuselage
may
be
cut,
then
spliced (or
quick-disconnects
used)
at installation.
c.
Remove
screws
attaching dorsal
to
fin.
d.
Disconnect
elevator
cable from
elevator
bellcrank.
e.
Remove
bolts
attaching
fin
rear
spar
to
fuselage
fitting.
Remove
upper
elevator stop
bolts.
f.
Remove
bolts
attaching
fin
front
spar
to
fuselage
bulkhead,
and
remove
fin.
g.
Retain
any
shims installed
between
the
rear
spar
of
the fin
and
the
fuselage
fitting.
4-15.
REPAIR.
Fin
repair
should
be
accomplished
in
accordance
with
applicable
instructions
outlined
in
Section
18.
4-16.
INSTALLATION.
Reverse
the
procedures
outlined
in
paragraph
4-14
to
install
the
vertical
fin.
Be
sure
to check
and
reset
rudder
and
elevator
travel.
a.
Reinstall
any
shims
removed
from
between
the fin
rear
spar
and
the
fuselage
fitting.
If a
new
fin
is
being
installed,
measure
any
gap
existing
between
the
fin
rear
spar
and
the
fuselage
fitting
and
use
shims
as
follows:
.000"
to
.030"
gap
..............................
No
Shim
.030"
to
.050"
gap
.............................
0531115-1
Shim
(.020")
.050"
to
.070"
gap
.............................
0531115-2
Shim
(.040")
A
maximum
of
one
shim
per
bolt
is
permissible.
4-17.
HORIZONTAL
STABILIZER.
(See
figure
4-4.)
4-18.
DESCRIPTION.
The
horizontal
stabilizer
is
primarily
of
all-metal construction,
consisting
of
ribs
and
spars
covered
with
skin.
Stabilizer
tips
are
of
ABS
construction.
A
formed
metal
leading
edge
is
riveted
to
the
assembly
to
complete
the
structure.
The
elevator
trim
tab
actuator
is
contained
within
the
horizontal
stabilizer.
The
underside
of
the
stabilizer
contains
a
covered
opening
which
provides
access
to
the
actuator.
Hinges
are
located
on
the
rear
spar
assembly
to
support
the
elevators.
4-19.
REMOVAL
AND
INSTALLATION.
a.
Remove
elevators
and
rudder
in
accordance
with
procedures
outlined
in
Sections
8
and
10.
b.
Remove
vertical
fin
in
accordance
with
procedures
outlined
in
paragraph
4-14.
c.
Disconnect
elevator
trim
control
cables
at
clevis
and
turnbuckle
inside
tailcone.
remove
pulleys
which route
the
aft
cables
into
horizontal
stabilizer.
and
pull
cables
out
of
tailcone.
d.
Remove
bolts
securing
horizontal
stabilizer
to
fuselage.
e.
Remove
horizontal
stabilizer.
f.
Reverse
preceding
steps
to
install
horizontal
stabilizer.
4-10A/(4-10B
blank)
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Tighten
forward
stabilizer-attach
bolts
first.
Install
re-
quired
thickness
of
washers
to
allow
a
maximum
.010-
inch
gap
between
washer
and
stabilizer
rear
spar.
Washers
are
required
in
2
places.
The
following
washers
are
available
from
the
Cessna
Supply
Division.
S1450-5A20-100
S1450-5A20-080
S1450-5A20-063
g.
Check
operation
of
tail
navigation
light
and
flashing
beacon.
h.
Rig
control
systems
as
necessary.
4-20.
REPAIR.
Horizontal
stabilizer
repair
should be
accomplished
in accordance
with
applica-
ble
instructions
outlined
in Section
18.
4-21.
STABILIZER
ABRASION
BOOTS.
(See
figure
4-4.)
NOTE
An
Accessory
Kit
(AK182-217)
is
available
from
the
Cessna
Supply
Division
for
installation
of
abrasion
boots
on
aircraft
not
so
equipped.
4-22.
DESCRIPTION.
The
aircraft
may
be
equipped
with
two extruded rubber
abrasion
boots.
one
on
the
leading
edge
of
each
horizontal
stabilizer.
These
boots
are
installed
to
protect
the
stabilizer
leading
edge
from damage
caused
by
rocks
thrown
back
by
the
propeller.
4-23.
REMOVAL
The
abrasion
boots
can
be
removed
by loosening
one
end
of
the
boot
and
pulling
it
off
the
stabilizer
with
an even
pressure.
Excess
adhesive
or
rubber
can
be
removed with
Methyl-Ethyl-Ketone.
4-24.
INSTALLATION.
Install
abrasion
boots
as
outlined
in
the
following
procedures.
.
Trim
boots
to
desired
length.
b.
Mask
off
boot
area
on
leading
edge
of
stabilizer
with
1-inch
masking
tape.
allowing
1/4-inch
margin.
c.
Clean
metal
surfaces
of
stabilizer,
where
boot
is
to
be
installed
with
Methyl-Ethyl-
Ketone.
d.
Clean
inside
surface
of
abrasion
boot
with
Methyl-Ethyl-Ketone
and
a
Scotch
brite
pad
to
ensure
complete
removal
of
paraffin/talc.
Then
a
normal
wipe
down
with
ME
K
on a
cloth
will
leave
surface
suitable
for
bonding
to
the
aluminum.
NOTE
Boots
may
be
applied
over
epoxy primer,
but
if
the
surface
has
been
painted,
the
paint
shall
be removed
from
the
bond
area.
This
shall
be
done
by
wiping
the
surfaces
with
a
clean,
lint-free
rag,
soaked
with
solvent,
and
then
wiping
the
surfaces
dry,
before
the
solvent
has
time
to
evaporate,
with
a
clean,
dry
lint-free
rag.
e.
Stir
cement
(EC-1300
Minnesota
Mining
and Manufacturing
Co.)
thoroughly
f.
Apply
one
even
brush
coat
to
the
metal
and
the
inner
surface
of
the
boot.
Allow
4-11
MODEL
172
SERIES
SERVICE
MANUAL
cement
to
air-dry
for
a
minimum
of
30
minutes.
and
then
apply
a
second
coat
to
each
surface.
Allow at
least
30
minutes
(preferably
one-hour)
for
drying.
g.
After
the
cement
has
thoroughly
dried.
reactivate
the surface
of
the
cement
on
the
stabilizer
and
boot.
using
a
clean,
lint-free
cloth.
heavily moistened
with
toluol.
Avoid
excess
rubbing
which
would
remove
the
cement
from
the
surfaces.
h.
Position
boot
against
leading
edge.
exercising
care
not
to
trap
air
between
boot
and
stabilizer.
NOTE
Should
boot
be
attached
"off-course".
pull
it
up
imme-
diately
with
a
quick
motion.
and
reposition properly.
i.
Press
or
roll entire
surface
of
boot
to
assure
positive
contact
between
the
two
surfaces.
j.
Apply
a
coat
of
GACO
N700A
sealer,
or equivalent.
conforming
to
MIL-C-21067.
along the
trailing
edges
of
the
boots
to
the
surface
of
the
skin
to
form
a
neat,
straight
fillet.
k.
Remove
masking
tape
and
clean
stabilizer
of
excess
material.
1.
Mask
to
the
edge
of
boot
for
painting
stabilizer.
4-12
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
5
LANDING
GEAR,
WHEELS
AND
BRAKES
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
LANDING
GEAR
............
1I2/5-2
Speed
Fairing
Installation
...
/5-23
Description
...............
1I2/5-2
Wheel
Removal
...........
1J3/5-25.
Trouble
Shooting
...........
1I2/5-2
Disassembly
(McCauley)
....
1J3/5-25
Main
Landing
Gear
.........
1I3/5-3
Inspection/Repair
Description
.............
1I3/5-3
(McCauley)
............
1J3/5-25
Removal
................
1I5/5-5
Reassembly
(McCauley)
....
1J4/5-26
Installation
.............
1I5/5-5
Disassembly
(Cleveland)
....
1J5/5-27
Step
Bracket
Installation
....
1I6/5-6
Inspection/Repair
Fairings
................
1I6/5-6
(Cleveland)
.............
1J6/5-28
Description
............
1I6/5-6
Reassembly
(Cleveland)
.....
1J6/5-28
Removal/Installation
.....
1I6/5-6
Wheel
Installation
........
1J6/5-28
Speed
Fairing
Removal
...
1I11/5-11
Wheel
Balancing
.........
1J7/5-29
Speed
Fairing
Installation
.
1I11/5-11
Strut
Disassembly
.......
1J7/5-29
Wheel
Removal
...........
1I11/5-11
Strut
Inspection/Repair
.....
1J9/5-31
Disassembly
(McCauley)
Strut
Reassembly
.........
1J9/5-31
Two-Piece)
.............
1I12/5-12
Torque
Link
............
1J10/5-32
Inspection/Repair
(McCauley
Description
............
1J10/5-32
Two-Piece)
.............
1112/5-12
Removal
..............
J10/5-32
Reassembly
(McCauley
Inspection/Repair
.......
1J10/5-32
Two-Piece)
...........
1I12/5-12
Installation
.........
1J11/5-33
Disassembly
(Cleveland
Shimmy
Damper
.........
1J12/5-34
Wheel)
................
1I13/5-13
Description
............
1J12/5-34
Inspection/Repair
Removal
...........
1J12/5-34
(Cleveland
Wheel)
........
1I13/5-13
Disassembly/Reassembly
. .
1J12/5-34
Reassembly
(Cleveland
Installation
............
1J12/5-34
Wheel)
................
1I14/5-14
Steering
System
..........
1J13/5-35
Disassembly
(McCauley
with
Description
...........
1J13/5-35
Hub
and
Capscrews)
......
1I14/5-14
Steering
Rod
Assemblies
..
1J13/5-35
Inspection/Repair
(McCauley
Description
..........
1J13/5-35
with
Hub
and
Capscrews)
..
1I14/5-14
Adjustment
............
1J13/5-35
Reassembly
(McCauley
with
Brake
System
.............
1J13/5-35
Hub
and
Capscrews)
......
1I15/5-15
Description
.............
1J13/5-35
Wheel
Installation
........
1I15/5-15
Trouble
Shooting
.........
1J13/5-35
Wheel
Axle
Removal
.......
1I16/5-16
Brake
Lines
.............
1J14/5-36
Wheel
Axle
Installation.....
1I16/5-16
Description
............
1J14/5-36
Bonded Axle
Removal
......
1I16/5-16
Brake
Assemblies
.........
1J14/5-36
Bonded Axle
Installation
....
1I18/5-18
Description
............
1J14/5-36
Wheel
Alignment
Check
....
1I19/5-19
Removal
..............
1J14/5-36
Wheel
Balancing
.........
1I19/5-19
Disassembly
...........
1J14/5-36
Nose
Gear
................
1I19/5-19
Inspection/Repair
.......
1J14/5-36
Description
.............
1I19/5-19
Reassembly
............
1J17/5-39
Trouble
Shooting
.........
1I23/5-21
Installtion
............
1J17/5-39
Removal
................
1I23/5-21
Checking
Lining
Wear
....
1J17/5-39
Installation
.............
1I23/5-21
Lining
Installation
......
1J17/5-39
Speed
Fairing
Removal
.....
1J1/5-23
System
Bleeding
........
1G14/5-40
Revision
1
5-1
MODEL
172
SERIES
SERVICE
MANUAL
Brake
Master
Cylinder
........
1J18/5-40
Inspection/Repair
Description
.
................
1J185-40
(Beginning
with
1979)
..
1J19/5-41
Removal
...................
1J18/5-40
Reassembly
(Beginning
Disassembly
(Thru
1978)
....
1J18/5-40
with
1979)
.............
1J19/5-41
Inspection/Repair
...........
Installation
.............
1J20/5-42
(Thru
1978)
...............
1J19/5-41
Brake
Lining
Burn-In
......
1J20/5-42
Reassembly
(Thru
1978)
.....
1J19/5-41
Parking
Brake
System
......
1J20/5-42
Disassembly
(Beginning
.....
Description
..............
1J20/5-42
with
1979)
................
1J19/5-41
Removal/Installation
.....
1J20/5-42
5-1.
LANDING
GEAR.
5-2.
DESCRIPTION.
The
aircraft
is
equipped
with
a
fixed
tricycle
landing
gear, consisting
of
tubular
spring-steel
main
gear
struts,
and
an
air/oil
steerable
nose
gear
shock
strut.
Wheels
with
disc-type
brakes and
tube-type
tires
are
installed
on
the
main
landing gear
struts,
and
a
two-piece,
die-cast
alu-
minum
wheel
is
mounted
on
the
nose
gear
strut.
The
nose
wheel
is
steerable
with
the
rudder
pedals
up
to
a
maximum
pedal deflection,
after
which
it
becomes
free-swiveling,
up to
a
maximum
of
30
de-
grees,
each
side
of
center.
Nose
and
main
wheel
speed
fairings are
available
for
installation.
5-3.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
AIRCRAFT
LEANS
TO
ONE
Incorrect
tire
inflation.
Inflate
to
pressure
specified
SIDE.
in
figure
1-1.
Landing
gear
attaching
Tighten
loose
parts; replace
parts
not
tight.
defective
parts
with
new
parts.
Landing
gear spring
Remove
and
install
new
excessively
sprung.
part(s).
Bent
axle(s).
Install
new
part(s).
TIRES
WEAR
EXCESSIVELY.
Incorrect
tire
inflation.
Inflate
to
pressure
specified
in
figure
1-1.
Main
wheels
out
of Remove
and
install
new
alignment.
part(s).
Landing
gear
spring
Remove
and
install
new
excessively
sprung.
part(s).
Bent
axle(s).
Install
new
part(s).
Dragging
brakes.
Refer
to
paragraph
5-67.
Wheel
bearings
excessively
Adjust
properly.
tight.
5-2
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
5-3.
TROUBLE SHOOTING.
(Cont.)
TROUBLE
PROBABLE
CAUSE
REMEDY
TIRES
WEAR
EXCESSIVELY
Loose
torque
links.
Add
shims
or
install
new
(Cont.)
parts
as
required.
WHEEL
BOUNCE
EVIDENT
Out
of
balance
condition.
Refer
to
paragraph
5-30.
ON
SMOOTH
SURFACE.
5-4.
MAIN
LANDING
GEAR. (See
figure
5-1.)
5-5.
DESCRIPTION.
The
tubular,
spring-steel
main
landing
gear
struts
are
attached
to
the
AFT
LANDING
GEAR BULKHEAD
4
6
STA.
65.33
FUSELAGE
STA.
56.70
FWD
LANDING GEAR
BULKHEAD
1.
Inboard
Forging
3.
Outboard
Forging
5.
Bushing
Retainer
Ring
2.
Bolt
4.
Bushing
6.
Tubular
Strut
Figure
5-1.
Main
Landing
Gear
Installation
(Sheet
1
of
2)
5-3
MODEL
172
SERIES
SERVICE
MANUAL
Apply
Y-8560
(3M
Corporation)
polyurethane
tape
(1"
wide)
to
upper and
lower
surface
of
spring
and
above
and below
step
bracket
to
prevent
chaf-
ing
of
spring
faring.
1.
Inboard
Forging
2.
Bolt
3.
Outboard
Forging
4.
Bushing
5.
Bushing
Retainer
Ring
6.
Tubular Strut
1
17
7.
Brake
Line
8.
Clamp
9. Step
10.
Step
Bracket
11.
Axle
12.
Brake Torque
Plate
13.
Nut
14.
Hub
Cap
15.
Wheel
Assembly
16.
Wheel
Brake
Assembly
18
17.
Fuselage
Fairing
18.
Tubular
Strut
Fairing
19.
Cap
Fairing
20.
Brake
Fairing
21.
Elbow
22.
Nut
23.
O-Ring
19
SECTION
A-A
Torque
bolt
(2)
to
1100-1300
lb,
in.
Torque
elbow
to
a
maximum
of
60
lb.
in.
13
Lube/seal
with
Liquid-O-Ring
#404
(Oil
Center
Research,
P.O.
Box
51971,
14
Lafayette,
Louisiana
70501).
(Elbow
(*)
installed thru
1981
Models).
USED
ONLY
WITH
WHEEL
FAIRINGS
Fuselage
fairings
(17)
are
split
thru
aircraft
22
serials
17271034
and
F17201749.
Beginning
15
with
aircraft
serials
17271035
and F17201750,
23
one-piece
fairings
areinstalled.
However,
ser-
vice
replacement
fairings,
ordered
through
the
Beginning
with
1982
Models.
Cessna
Supply
Division, will
be
split,
and
can
be
installed
without
disassembling
the
main
landing
gear.
Figure
5-1. Main
Landing
Gear Installation
(Sheet
2
of
2)
5-4
MODEL
172
SERIES SERVICE
MANUAL
aircraft
at inboard
and
outboard
forgings,
located
in
the
belly
of
the
aircraft.
A
bracket
is
bonded
to
each
strut
for
attachment
of
a
step. Hydraulic
brake lines
are
routed
down
and
clamped
to
each
main
gear
strut.
The
axles, main
wheels
and
brake
assemblies
are
installed
at
the
lower end
of
each
strut.
5-6.
MAIN
LANDING
GEAR
REMOVAL. (See
figure
5-1.)
NOTE
The
following
procedure
removes
the
landing
gear
as
a
complete
assembly.
Refer
to
applicable
paragraph
for
removal
of
individual
components.
a.
Remove
floorboard
access
covers
over
inboard
and
outboard
landing
gear
forgings
(1)
and
(3).
b.
Hoist
or
jack
aircraft
in
accordance
with
procedures
outlined
in
Section
2.
c.
Remove
screws
attaching
fairing
(17)
to
fuselage.
Remove
screws
at
splice
in
fairing
and
work
fairing
off
strut
fairing.
d.
Drain
hydraulic
fluid
from
brake line
(7)
on
strut
being
removed.
e.
Disconnect
hydraulic
brake
line
(7)
at
fitting
where
brake line
emerges
from
fuselage
skin
Cap
or
plug
disconnected
fittings.
f.
Remove
nut,
washer
and
bolt
attaching
inboard
end
of
tubular
strut
to
the inboard
landing
gear
bulkhead
fitting.
g.
Pull
tubular
strut
from
fitting
and
bushing.
Use
care
when
removing
strut
to
prevent
damage
to hydraulic
brake
line.
NOTE
The
tubular
strut
is a
compression
fit
in
the
bushing
in
the
outboard
landing gear
forging
(3).
5-7.
MAIN
LANDING
GEAR
INSTALLATION. (See
figure
5-1.)
NOTE
The
following
procedure
installs
the
landing
gear
as
a
complete assembly.
Refer
to
applicable
paragraphs
for
installation
of
individual
components.
a.
Install
all
parts
removed
from
strut.
b.
Apply
Dow
Corning
Compound
DC-7
to
approximately
11
inches
on
upper
end
of
tubular
strut.
NOTE
Avoid
use
of
Dow
Corning
DC-7
on
surfaces
to
be
painted.
DC-7
contains
silicone
which
is
harmful
to
painted
areas.
c.
Slide
tubular strut
into
place
through
bushing
in
outboard
strut
fitting
and
into
inboard
strut
fitting.
d.
Align
tubular
strut
in
inboard
fitting
and
install
bolt
through
fitting
and
strut.
Install
washer
and
nut
on
bolt
and
tighten
to
torque
value
of
1100-1300
lb.in.
e.
Connect
hydraulic
brake
line
to
fitting.
Fill
and
bleed
brake
system
in
accordance
with
paragraph
5-79.
5-5
MODEL
172
SERIES
SERVICE
MANUAL
f.
Install
fuselage
fairing.
g.
Lower
aircraft
and
install
floorboard
access
covers.
5-8.
STEP
BRACKET INSTALLATION.
(See
figure
5-1.)
NOTE
The
step
bracket
is
secured
to
the
tubular
gear
strut
with
EA9309.
EC2216,
EC2214,
EC3445,
or
a
similar
epoxy
base
adhesive.
a.
Mark
position
of
the
bracket
so
that
the
new
step
bracket
will
be
installed
in
approximately
the
same
position
on
the
strut.
b.
Remove
all
traces
of
the
original
bracket
and
adhesive
as
well
as
any
rust,
paint
or
scale
with
a
wire
brush
and
coarse
sandpaper.
c.
Leave
surfaces
slightly
roughened
or
abraded,
but
deep
scratches or
nicks
should
be
avoided.
d.
Clean
surfaces
to be
bonded
together
thoroughly.
If
a
solvent
is
used.
remove
all
traces
of
the
solvent
with
a
clean,
dry
cloth.
It is
important
that
the
bonding
surfaces
be
clean
and dry.
e.
Check
fit
of
step
bracket
on
the
tubular
strut.
A
small
gap
is
permissible
between
bracket
and
tubular
strut.
f.
Mix
adhesive
(any
of
those
listed
in
note
preceding
step
"a")
in
accordance with
manufacturer's
directions.
g.
Spread
a
coat
of
adhesive
on
bonding
surfaces,
and
place
step
bracket
in
position
on
the
tubular
strut.
Clamp
bracket
to
strut
to
ensure
a
good,
tight
fit.
h.
Form
a
small
fillet
of
the
adhesive
at
all
edges
of
the
bonded
surfaces.
Remove
excess
adhesive
with
lacquer
thinner.
i.
Allow
adhesive
to
cure
thoroughly
according
to
manufacturer's
recommendations
before
flexing
the
tubular
gear
strut
or
applying
loads
to
the
strut.
j.
Paint
tubular
strut
and
step
bracket
after
curing
is
complete.
5-9
MAIN
LANDING
GEAR
FAIRINGS.
(See
figures
5-1
and
5-2.)
5-10.
DESCRIPTION.
Some
aircraft
are
equipped
with
fuselage
fairings.
attached
to
the
fuselage
and
the
tubular strut fairings
with
screws.
The
tubular
strut
fairings
cover the
tubular
landing
gear
struts,
and
attach
to
the
fuselage
fairings
atthe
upper
end
and
to
fairingcaps
at
the
lower
end.
The
fairing
caps
attach
to
the
tubular
strut fairings
at
the
upper
end
and
are
clamped
to
the
tubular
struts
at the
lower
end.
Brake
fairings
are
installed
at
the
lower
end
of
the
tubular
strut
fairings
and
are
attached
to
the
wheel speed
fairings
by
screws
around
their
outer
perimeters.
The
speed
fairings
are
installed
over the
wheels
and
are
attached
to
mounting
plates,
attached
to
the
axles.
The
wheel
fairings are
equipped
with adjustable
scrapers,
installed
in
the
lower
aft
part
of
the
fairings, directly
behind
the wheels.
5-11.
REMOVAL AND
INSTALLATION.
(See
figure
5-1.)
a.
To
remove
brake
fairings,
proceed
as
follows.
1.
Remove
screws
from
perimeter
of
fairing.
2.
Remove
screws from
nutplates holding
two
halves
of
fairing
together:
remove
fairing
halves.
3.
Reverse
preceding
steps
for
installation.
b.
To
remove
cap
fairings,
proceed
as
follows:
1.
Remove
screws
attaching
fairing
to
tubular
spring
strut.
2.
Disconnect clamp from
tubular
strut
and
spring
clamp over strut;
remove
cap
fairing.
5-6
MODEL
172
SERIES
SERVICE
MANUAL
17263459
thru
17271569
17271570
thru
17273369
17273370
thru
17276574
F17201235
thru
F17201794
F17201795
thru
F17202029
F17202030
And
On
17276575
&
On
1.
Stiffener
,
2.
Mounting
Plate
7
3.
Doubler
4.
Fairing
-,,
.
5.
Scraper
6.
Axle
Nut
6
,
7.
Door,
Access
8.
Latch
* 7
9.
Plug
Figure
5-2.
Main
Wheel
Speed
Fairings
3.
Reverse
preceding
steps
for
installation.
c.
To
remove
fuselage
fairings,
proceed
as
follows:
1.
Remove
screws
attaching
fairings
to
fuselage.
2.
Slide
fairings
down
tubular strut fairings
and,
thru
aircraft
serials
17271034
and
F17201749,
remove
screws
from
nutplates
holding
fairings
together;
spring
fairings
over
strut
fairings.
Beginning
with
aircraft
serials
17271035
and
F17201750,
fairings
are one-piece
and
cannot
be
sprung
apart.
3.
Reverse
preceding
steps
for
installation.
d. To
remove
tubular
strut
fairing,
proceed
as
follows:
1.
Remove
brake
fairing
per
step
"a".
2.
Remove
cap
fairing
per
step
"b".
3.
Remove
fuselage
fairing
per
step
"c".
4.
Remove
screws
from
nutplates
on
strut
fairing.
5.
Spring
fairing
over
tubular
gear
strut.
Revision
3
5-7
MODEL
172
SERIES
SERVICE
MANUAL
9
5
1-
Retaining
Ring
2.
Grease
Seal
Retainer
3.
Grease
Seal
Felt
4.
Grease
Seal
Retainer
5.
Bearing
Cone
6.
Wheel
Half
7.
Tire
MC
CAULE
WHEEL
8.
Tube
(Two-Piece)
9.
Washer
10.
Nut
11.
Brake
Disc
Beginning
with
12.
Torque
Plate
1982
Models
13.
Pressure
Plate
14.
Anchor
Bolt
16.
Brake
Cylinder
28
17.
Bolt
18.
Bleeder
Screw
19.
Dust
Cover
21.
Piston
O-Ring
22.
Brake
Piston
23.
Lining
24.
Thru-Bolt
25.
Washer
26.
Back
Plate Torque
to
100-110
27.
Bearing
Cup
Torque
to
100-110
28. Elbow
in.-lbs.
Safety
29.
Nut
wire.
30.
O-Ring
22
Maximum
torque
on
elbow
(15)
to
be
60
lb,
in.
21
Lube/seal
elbow
(15)
with
Liquid-O-Ring
#
404
20
(Oil
CenterResearch,
P.O.
Box
51871,
Lafayette, Louisiana
70501.)
Elbow
(15)
installed
thru
1981
Models.
19
Figure
5-3.
Main
Wheel
and
Brake
(Sheet
1
of
3)
5-8
MODEL
172
SERIES SERVICE
MANUAL
2
3
2
7
CLEVELAND
WHEEL
1.
Snap
Ring
2.
Grease
Seal
Ring
23
3.
Grease
Seal
Felt
4.
Bearing
Cone
11
5.
Nut
6.
Washer
7.
Wheel
Half
22
8.
Bearing
Cup
9.
Tire
21
10.
Tube
20
11.
Lining
Torque
to
80-90
in.
-lbs.
12.
Brake
Disc
19
13.
Torque
Plate
14.
Torque
Plate
Bushing
15.
Pressure
Plate
16.
Anchor
Bolt
17.
Brake
Cylinder
18.
Bolt
19.
Bleeder
screw
20.
Piston
O-Ring
21.
Brake
Piston
22.
Thru-Bolt
23.
Back
Plate
Figure
5-3.
Main Wheel
and
Brake
(Sheet 2
of
3)
5-9
MODEL
172
SERIES
SERVICE
MANUAL
28
10
1.
Snap
Ring
2.
Grease
Seal
Retainer
(Outboard)
19
3.
Grease
Seal
Felt
(Outboard)
4.
Grease
Seal
Retainer
(Outboard)
5.
Bearing
Cone
6.
Wheel
Flange
17.
Anchor
Bolt
7.
Phenolic
Spacer
27
8.
Tire
9.
Tube
10.
Wheel Hub
11.
Bearing
Cup(Race)
12.
Grease
Seal Retainer
(Inboard)
13.
Grease
Seal
Felt
(Inboard)
14.
Brake
Disc
15.
Torque
Plate
16.
Pressure
Plate
17.
Anchor
Bolt
18.
Elbow
19.
Brake
Cylinder
20. Bolt
Maximum
torque
on
elbow
(18)
to
be
60
lb.
in.
21.
Bleeder
Screw
Lube/seal
elbow
(18)
with
Liquid-O-Ring
#404
22. Dust
Cup
(Oil
Center
Research,
P.O.
Box
51871,
23.
Bleeder
Fitting Lafayette,
Louisiana
70501.)
Elbow
(18)
installed
24.
Piston
O-Ring
thru
1981
Models.
25.
Brake Piston
26.
Brake
Lining
27.
Capacrew
28.
Washer
Figure
5-3.
Main
Wheel
and
Brake
(Sheet
3
of
3)
5-10
MODEL
172
SERIES
SERVICE
MANUAL
6.
Reverse
preceding
steps
for
installation.
e.
To
remove
step
bracket
cover,
proceed
as
follows:
1.
Remove
tubular
strut
fairing
per
step
"d".
2.
Slide
step bracket
cover from
step
bracket
on
tubular
gear
strut.
3.
Reverse
preceding
steps
for
installation.
5-12.
MAIN
WHEEL
SPEED
FAIRING
REMOVAL.
(See
figure
5-2.)
a.
Remove
wheel
brake
fairing
(item
20,
figure
5-1)
by
removing
screws around
perimeter
of
fairing,
then
removing
screws
from
nutplates
holding
two
halves
of
brake
fairing
together.
b.
Remove
screws
attaching
stiffener
(1)
and
inboard
side
of
wheel
speed
fairing
(4)
to
attach
plate
(2),
which
is
bolted
to
the
axle.
c.
Remove
bolt
securing
outboard
side
of
fairing
to
axle
nut.
d.
Loosen
scraper,
if
necessary,
and
work
speed
fairing
from
wheel.
5-13.
MAIN
WHEEL
SPEED
FAIRING
INSTALLATION.
(See
figure
5-2.)
a.
Work
speed
fairing
down
over
wheel.
b.
Install
bolt
securing
outboard
side of
fairing
to
axle nut.
c.
Install
screws
attaching
stiffener
(1)
and
inboard
side
of
wheel
speed
fairing
(4)
to
mounting
plate
(2),
which
is
bolted
to
the
axle.
d.
Install
wheel
brake
fairing
(item
20,
figure
5-1)
by
installing
screws
in
nutplates
holding
two
halves
of
brake
fairing
together,
then
install
screws
around
perimeter
of
fairing.
e.
After
installation,
check
scraper-to-tire
clearance
for
a
minimum
of
0.25-inch
to
a
maximum
of
0.50-inch.
Elongated
holes
are
provided
in
the
scraper
for
clearance
ad-
CAUTION
Always
check
scraper-to-tire clearance
after
installing
speed
fairings,
whenever
a
tire
has
been
changed,
and
whenever
scraper
adjustment
has
been
disturbed.
If
the
aircraft
is
flown from
surfaces
with
mud,
snow,
or
ice,
the
speed
fairings
should
be
checked
to
make
sure
there
is
no
accumulation
which
could
prevent
normal
wheel
rota-
tion.
Wipe
fuel and
oil
from
speed
fairings
to
prevent
stains
and
deterioration.
5-14.
MAIN
WHEEL
REMOVAL. (See
figure
5-1.)
NOTE
It
is
not necessary
to remove
the
main
wheel
to
reline
brakes or
to
remove
brake
parts,
other
than
the
brake
disc
on
the
torque
plate.
a.
Hoist
or
jack
aircraft
in
accordance
with procedures
outlined
in
Section
2.
b.
Remove
speed
fairing,
if
installed, as
outlined in
paragraph
5-12.
c.
Remove
hub
caps,
if
installed,
cotter
pin
and
axle
nut.
d.
Remove
bolts
and
washers
attaching
brake
back
plate
to
brake
cylinder,
and
remove
back
plate.
e.
Pull
wheel
from
axle.
5-11
MODEL
172
SERIES
SERVICE
MANUAL
5-15.
MAIN
WHEEL
DISASSEMBLY.
(McCauley
Two-Piece
Wheel.)
(See
figure
5-3.
Sheet
1
of
3.)
a.
Completely
deflate
tire and
tube
and
break
loose
tire
beads.
Extreme
care
must
be
exercised
to
prevent
tire
tool
damage
when
removing
tire
from
wheel
halves
(6).
WARNING
Serious
injury
can
result
from
attempting
to
separate
wheel
halves
with
tire
and
tube
inflated.
b.
Remove
nuts
(10)
and
washers
(9).
c.
Remove
thru-bolts
(24)
and
washers
(25).
d.
Separate
and
remove
wheel halves
(6)
from
tire
and
tube.
e.
Remove
retaining
rings
(1),
grease
seal
retainers
(2)
grease
al
felts
(3),
grease
seal
retainers
(4)
and
bearing
cones
(5)
from
both
wheel
halves
(6).
NOTE
Bearing cups (races)
(27)
are
a
press
fit
in
wheel
halves
(6),
and
should
not
be
removed
unless
a
new
part
is
to
be
installed.
To
remove
bearing cups. heat
wheel
half
in
boiling
water
for
30
minutes.
or
in
an
oven.
not
to
exceed
121°C
(250°F).
Using
an
arbor
press,
if
available,
press
out
bearing
cup
and
press
in a
new
bearing
cup
while
wheel
half
is
still
hot.
5- 6.
MAIN
WHEEL
INSPECTION
AND
REPAIR.
(McCauley
Two-Piece
WheeL)
(See
figure
5-3
Sheet
1
of
3.)
a.
Clean
all
metal
parts
and
grease
seal
felts
in
Stoddard
solvent or
equivalent,
anddry
thoroughly.
NOTE
A
soft
bristle
brush
may
be
used
to
remove
hardened
grease.
dust
or dirt.
b.
Inspect
wheel
halves
(6)
for
cracks
or
damage.
c.
Inspect
bearing
cones
(5),
cups
(27),
retaining rings
(1),
grease
seal
retainers
(2),
grease seal
felts
(3)
and
grease
seal retainers
(4)
for
wear
or
damage.
d.
Inspect
thru-bolts
(24)
and
nuts
(10)
for
cracks
in
threads
or
cracks
in
radius
under
bolt
head.
e.
Replace
cracked
or
damaged
wheel
half
(6).
f.
Replace
damaged
retainer
rings
(1)
and
seals
(2),
(3)
and
(4).
g.
Replace
worn
or
damaged
bearing
cups
(27)
and
cones
(5).
h.
Replace
any
worn
or
cracked
thru-bolts
(24)
or
nuts
(10).
i.
Remove
any corrosion
or
small
nicks.
j.
Repair
reworked
areas
of
wheel
by
cleaning
thoroughly,
then
applying
one
coat
of
clear
lacquer
paint.
k.
Pack
bearings
with
grease
specified
in
Section
2.
L
Inspect
brakes
per
paragraph
5-81.
5-17.
MAIN
WHEEL
REASSEMBLY.
(McCauley Two-Piece
Wheel.)
(See
figure
5-3.
Sheet
1
of
3.)
a.
Assemble
bearing
cone
(5),
grease
seal
retainer
(4),
grease seal
felt
(3),
grease
seal
retainer
(2)
and
retaining ring
(1)
into
each
wheel
half
(6).
b.
Insert
tube
in
tire,
aligning
index
marks
on
tire
and
tube.
5-12
MODEL
172
SERIES
SERVICE
MANUAL
c.
Place wheel
half
(6)
into
tire
and
tube
(side
opposite
valve
stem).
With
washer
(25)
under
head
of
thru-bolt
(24),
insert
bolt
through
wheel
half
(6).
d.
Place wheel
half
(6)
into
other
side
of
tire
and
tube.
aligning
valve
stem
in
valve
slot.
e.
Insert
washers
(9)
and
nuts
(10)
on
thru-bolts
(24),
and
pre-torque
to
10-15
lb.
in.
CAUTION
Uneven
or
improper
torque
of
the
nuts
can
cause
failure
of
the
bolts
with
resultant
wheel
failure.
f.
Prior
to
torquing
nuts
(10),
inflate
tube
with
approximately
10-15
psi
air
pressure
to
seat
tire.
CAUTION
Do
not
use impact
wrenches
on
thru-bolts
or
nuts.
g.
Dry
torque
all
nuts
(10)
evenly
to
a
torque value
of
140-150
lb.
in.
h.
Inflate
tire
to
correct
pressure
specified
in
figure
1-1.
5-18.
DISASSEMBLY.
(Cleveland
Wheel.)
(See
figure
5-3,
Sheet
2
of
3.)
a.
Remove
valve
core
and
deflate
tire
and
tube.
Break
tire
beads loose
from
wheel
rims.
WARNING
Injury
can
result
from
attempting
to
separate
wheel
halves
with
tire
inflated.
Avoid
damaging
wheel
flanges
when
breaking
tire
beads
loose.
A
scratch,
gouge
or
nick
in
the
wheel
may
cause wheel
failure.
b.
Remove
thru-bolts
and
separate
wheel
halves,
removing
tire,
tube
and
brake
disc
c.
Remove
grease
seal
rings,
felts
and
bearing
cones
from
wheel
halves.
NOTE
Bearing cups
(races)
are
press-fit
in
the
wheel
halves
and
should
not
be
removed
unless
a
new
part
is
to
be
installed.
To
remove
bearing
cups, heat
wheel
halves
in
boiling
water
for
30
minutes
or
in
an
oven not
to exceed
149
C
(300°F).
Using
an
arbor press,
if
available,
press
out
bearing
cup and
press
in
new
bearing
cup
while
wheel
half
is
still
hot.
5-19.
MAIN
WHEEL
INSPECTION
AND
REPAIR.
(Cleveland
Wheel.)
(See
figure
5-3,
Sheet
2
of
3.)
a.
Clean
all
metal
parts
and
grease seal
felts
in
solvent
and
dry
thoroughly.
b.
Inspect
wheel
halves
for
cracks.
Cracked
wheel
halves
should
be
discarded
and
new
parts
used.
Sand out
nicks,
gouges
and
corroded areas.
When
protective
coating
has
been
removed,
the
area
should
be
cleaned
thoroughly,
primed
with
zinc
chromate
and
painted
with
aluminum
lacquer.
c.
Inspect
brakes
per paragraph
5-81.
d.
Carefully
inspect bearing
cones and
cups
for
damage
and
discoloration.
After
cleaning,
pack
bearing
cones
with
clean
aircraft
wheel
bearing
grease.
as
outlined
in
Section
2,
before
installing
in
wheel
half.
5-13
MODEL
172
SERIES
SERVICE
MANUAL
5-20.
MAIN
WHEEL
REASSEMBLY.
(Cleveland
Wheel.)
(See
figure
5-3,
Sheet
2
of
3.)
a.
Insert
thru-bolts
through
brake
disc and
position
disc
in
the
inner
wheel
half.
using
thru-bolts
to
guide
the disc.
Ascertain
that
the
disc
is
bottomed
in
the wheel
half.
b.
Position tire
and
tube
on
outboard
wheel
half
with
tube
inflation
valve
through
hole
in
wheel
half.
c.
Place
inner
wheel
half
in
position
on
outboard
wheel
half.
Apply
a
light
force
to
bring
wheel
halves
together.
While
maintaining
the
light
force,
assemble
a
washer
and nut
on
thru-bolt
and
tighten
to
maintain
force.
Assemble
remaining washers
and
nuts
to
thru-bolts.
Tighten
nuts
evenly
to
the
torque
value
of
90
lb.
in.
CAUTION
Uneven
or
improper
torque
of
thru-bolt
nuts
can
cause
failure
of
bolts,
with
resultant
wheel
failure.
d.
Clean and
pack
bearing
cones
with clean
aircraft
wheel
bearing
grease.
as
outlined
in
Section
2.
e.
Assemble
bearing
cones,
grease
seal
felts
and
rings
into
wheel
halves.
f.
Inflate
tire
to
seat
tire
beads,
then
adjust
to
correct
tire
pressure.
Refer
to
chart
in
Section
1
for
correct
tire
pressure.
5-21.
MAIN
WHEEL
DISASSEMBLY.
(McCauley
Wheel
with
Hub
and
Capscrews.)
(See
figure
5-
3,
Sheet
3
of
3.)
WARNING
Injury
can
result
from
attempting
to
remove
wheel
flanges
with
tire
and
tube
inflated.
Avoid
damaging
wheel
flanges
when
breaking tire
beads
loose.
A
scratch,
gouge
or nick
in
wheel
flange
could cause
wheel
failure.
a.
Remove
valve
core
and
deflate
tire
and
tube.
Break
tire
beads loose
from
wheel
flanges.
b.
Remove
capscrews
and
washers
from
outboard
wheel
flange.
c.
Remove
capscrews
and
washers
from
inboard
wheel flange.
d.
Remove
brake
disc.
e.
Remove
wheel
hub
from
tire.
g.
Remove
retainer
rings,
grease
seal
retainers,
grease
seal
felts
and
bearing
cones.
NOTE
Bearing
cups
(races)
are
a
press
fit
in
the
wheel
hub
and
should
not
be
removed
unless
a
new
part
is
to
be
installed.
To
remove
the
bearing
cup,
heat
wheel
hub
in
boiling
water
for
30
minutes.
or
in
an
oven
not
to
exceed
121°C
(250°F).
Using
arbor
press,
if
available,
press
out
the
bearing
cup
and
press
in
the
new
bearing
cup
while
the
wheel
hub
is
still
hot.
5-22.
MAIN
WHEEL
INSPECTION
AND
REPAIR.
(McCauley
Wheel
With Hub
and
Capscrews.)
(See
figure
5-3,
Sheet
3
of
3).
a.
Clean
all
metal
parts,
grease
seal
felts
and
phenolic
spacers
in
cleaning
solvent
and
dry thoroughly.
5-14
MODEL
172
SERIES SERVICE
MANUAL
b.
Inspect
wheel
flanges
and
wheel hub
for
cracks.
Cracked
wheel
flanges
or
hub
shall
be
discarded and
new
parts
installed.
Sand
out smooth
nicks,
gouges
and
corroded
areas.
When
the
protective
coating
has
been
removed,
the
the
area
should
be
cleaned
thoroughly, primed
with
zinc
chromate
and
painted
with
aluminum
lacquer.
c.
Inspect brakes
per paragraph
5-81.
d.
Carefully
inspect
bearing
cones
and
cups
for
damage
and
discoloration.
After
cleaning,
pack
bearing
cones
with
clean
aircraft
wheel
bearing
grease.
Refer
to
Section
2
for
grease
type.
5-23.
MAIN
WHEEL
REASSEMBLY.
(McCauley
Wheel
With
Hub
and
Capscrews.)
(See
figure
5-3,
Sheet
3
of
3.)
a.
Place
wheel
hub
in
tire
and
tube
with
tube
inflation
stem
in
hole
of
wheel
hub.
b.
Place
spacer
and wheel
flange
on
inboard
side
of
wheel
hub
(opposite
of
tube
inflation
stem).
c.
Place
washer
under
head
of
each
capscrew.
insert
capscrew
through
brake
disc.
wheel
flange
and
spacer,
and
start
capscrews into
wheel
hub
threads.
CAUTION
Be
sure
that
spacers,
wheel
flanges
and
brake
disc
are
seated
on
flange of
wheel hub.
Uneven
or
improper
torque
of
capscrews
can
cause
failure
of
capscrews
or
hub
threads
with
resultant
wheel
failure.
d.
Tighten
capscrews
evenly
and
torque
to
190
to
200
lb.
in.
e.
Place
spacer
and
wheel
flange
on
outboard side
of
wheel
hub
and
align
valve
stem
hole
in
wheel
flange.
f.
Place
washer
under
head
of
each
capscrew,
insert
capscrew
through
wheel flange
and
spacer.
Start
capscrews into
wheel hub
threads.
g.
Tighten
capscrews
evenly
and
torque
to
190
to
200
lb.
in.
h.
Clean
and
pack
bearing
cones
with
clean
aircraft
wheel
bearing
grease.
Refer
to
Section
2
for
grease
type.
i.
Assemble
bearing
cones,
grease seal
filts
and
retainer
into
wheel
hub.
j.
Inflate
tire
to
seat
tire
beads,
then
adjust
to
correct
pressure.
Refer
to
chart
in
Section
1
for
correct
tire
pressure.
5-24.
MAIN
WHEEL
INSTALLATION.
(See
figure
5-1.)
a.
Place
wheel
assembly
on
axle.
b.
Install
axle
nut
and
tighten
axle
nut
until
a
slight
bearing
drag
is
obvious
when
the
wheel
is
rotated. Back
off
nut
to
nearest
castellation and
install
cotter pin.
c.
Place
brake
back
plate
in
position
and
secure
with
bolts
and
washers.
d.
Install
hub
cap.
Install
speed
fairing
(if
used)
as
outlined
in
paragraph
5-13.
CAUTION
Always
check
scraper-to-tire
clearance
after
installing
speed
fairings,
whenever
a
tire
has
been
changed,
and
whenever
scraper
adjustment
has
been
disturbed
If
the
aircraft
is
flown
from
surfaces
with mud,
snow,
or
ice,
the
fairing
should
be
checked
to
make
sure
there
is
no
accumulation
which
could
prevent
normal
wheel
rota-
tion.
Refer
to
paragraph
5-13
for
correct scraper-to-tire
clearance.
5-15
MODEL
172
SERIES
SERVICE
MANUAL
5-25.
MAIN
WHEEL
AXLE
REMOVAL.
(See
figure
5-1.)
NOTE
This
procedure should
be
used
if
the
axle
is
not
bonded
to
the
tubular
strut.
If
the
axle
is
bonded
to
the
strut,
refer
to
paragraph
5-27.
a.
Remove
speed
fairing,
if
installed,
in
accordance
with
paragraph
5-12.
b.
Remove
wheel
in
accordance
with
paragraph
5-14.
c.
Disconnect,
drain
and cap
or
plug hydraulic
brake
line
at
the
wheel
brake
cylinder.
d.
Remove
bolts
attaching
brake
torque
plate
and
speed
fairing
mounting plate
to
axle.
e.
Remove
cotter
pin,
nut,
washer
and
bolt
attaching
axle
to
tubular
strut.
f.
Remove
axle
from
spring-strut.
5-26.
MAIN
WHEEL
AXLE
INSTALLATION.
(See
figure
5-1.)
NOTE
This procedure should
be
used
if
the
axle
is
not
to
be
bonded
to
the
tubular
strut.
If
the
axle
is
to
be
bonded to
the
strut,
refer
to
paragraph
5-28.
a.
Install
axle
on
spring-strut,
using
wet
primer
on
faying
surfaces
of
axle
and
spring-strut.
Axle
is
installed
with
tapered
edges
to
bottom.
b.
Install
bolt,
washer
and
nut
attaching
axle
to
spring-strut.
After
tightening
nut,
install
cotter
pin.
c.
Install
brake
components
and
speed
fairing
mounting
plate
to
axle.
d.
Install
wheel
on
axle
in
accordance
with
paragraph
5-24.
e.
Connect
hydraulic brake
line
to
wheel
brake
cylinder.
f.
Fill
and
bleed
hydraulic
brake
system
in
accordance
with
paragraph
5-79.
g.
Install
speed
fairing,
if
used,
in
accordance
with
paragraph
5-13.
5-27.
BONDED MAIN
WHEEL AXLE
REMOVAL.
(See
figure
5-4.)
NOTE
On
some
aircraft,
due
to
axle
looseness,
axles
have
been
bonded
to
the
tubular
landing
gear
strut.
The
following
procedure
should
be
used
to
remove
a
bonded
axle.
a
Remove
speed
fairings,
if
installed,
accordingto
procedures
outlined
in
paragraph
5-
12.
b.
Remove
wheels
in
accordance
with
procedures
outlined
in
paragraph
5-14.
c.
Disconnect,
drain
and
cap
or
plug
hydraulic
brake
line at
the
wheel
brake
cylinder.
d.
Remove
cotter
pin,
nut
and
bolt
attaching
axle
to
spring
strut.
e.
Remove
brake components
and speed
fairing
plate
from
axle.
5-16
MODEL
172
SERIES
SERVICE
MANUAL
WARNING
Due
to
aging
of
aluminum
axle,
caused
by
the
heating
2
tape,
a
new
axle
will
have
to
be
installed.
CAUTION
Do
not
place
tape
in
direct
contact
with
tubular
gear
spring
1.
Axle
2
Tubular
Gear
Strut
3.
Electrical
Heating
Tape
4.
Plug
Figure
5-4
Bonded
Main
Wheel
Axle
Removal
NOTE
Axles
are
bonded
to
the
struts
of
some
tubular
gear
aircraft
with EA9309-25GR
adhesive,
which
is
avail-
able
from
the
Cessna
Supply
Division.
The
bond
is
too
strong
to
allow
the
axle
to
be
removed
without
first
weakening
the bond
strength.
The
only
methods
of
weakening the
bond
are
with
heat
or
cryogenic
cold;
heat
being
the
most
practical.
A
temperature
of
approximately
500°F
is
sufficient
to
weaken
the bond
so
the
axle
can
be
removed.
This
is
still
a
low
enough
temperature
to
prevent
damage
to the
tubular
strut.
f.
Remove
axles
as
follows:
NOTE
Axles
should
be
removed
from
strut,
using
electric
heating
tape. Heating
tape,
P/N
135-459,
can
be
obtained
from
the
Cessna
Supply
Division.
g.
Wrap
heating
tape
around
axle
from
base
head
to
outer
end
of
axle
and
tie
it
on
with
string
provided
with
the
tape,
as
shown
in
figure
5-4.
5-17
MODEL
172
SERIES
SERVICE
MANUAL
5
NOTE
Holes
in
gear
strut
and
3
axle
must
not
exceed
dia-
2
meter
of
mounting
bolts
by
more
than
0.0023/inch.
1.
Tire
2.
Attaching
Bolt
3.
Axle
4.
Tubular Gear
Strut
5.
Brake
Line
6.
Brake
Figure
5-5.
Installation
of
Main
Wheel
Strut
to
Axle
Mounting
Bolts.
CAUTION
Do
not
place
tape
in
direct contact
with
tubular
gear
spring.
h.
Plug
electric
tape
into
110
volt
wall
socket
and
heat
for
20
to
30
minutes.
i.
Unplug
tape
and
remove
from
axle.
Remove
axle
by
striking
axle
base
head
with
a
few
sharp
blows.
j.
Clean
any
old
adhesive
off
landing
gear
spring
with
a
wire
brush.
Brush
strokes
should
run
lengthwise along
the
spring.
After
old
adhesive
has
been
removed,
wipe
with clean
rag
saturated
with
acetone
or
alcohol.
Immediately
wipe
drywith
a
clean.
lint
free
cloth.
WARNING
Due
to
aging
of
the
aluminum
axle.
caused
by the
heating
tape,
a
new
axle
will
have
to
be
installed.
5-28.
BONDED
MAIN
WHEEL
AXLE
INSTALLATION.
(See
figure
5-4.)
NOTE
If
hole
diameters
in
gear
strut
and
axle
exceed
diameter
of
mounting
bolts
by
more
than
0.0023
/inch,
it
is permissible
to
bond
the
axle
to
the
strut.
Do
not
allow
adhesive
to
enter
the
holes
in
gear
strut
or
axle,
or
to
contact bolt
threads.
5-18
MODEL
172
SERIES
SERVICE
MANUAL
The
following
procedure
outlines
the
correct
method
for
bonding
axle
to
strut.
a.
Prior
to
installing
new
axle,
wipe
outer
surface
of
tubular
gear
and
inside
of
axle
with
solvent,
drying
immediately
with
a
clean,
lint
free
cloth.
b.
Mix
EA9309-25GR
adhesive, available from
the
Cessna
Supply
Division,
in
accordance
with
instructions
in
the
package.
Spread
adhesive
thinly
and
evenly
on
outer
surface
of
landing
gear
spring
in
area
that will
be
be
covered
by
axle.
c.
Place
axle
on
gear
spring
and
rotate
axle
to
assure
even
coverage
between
inner surface
of
axle
and
outer
surface
of
spring.
d.
Install
retaining
bolt,
washers,
nut
and
cotter
pin.
Tighten
nut
securely.
e.
Allow
24
hours
at
75°F
for
adhesive
to
cure,
or
30
minutes
at
250°F,
if
heating equipment
is
available.
f.
Install
brake
components
and
speed
fairing
mounting
plate
to
axle.
g.
Install
wheel
on
axle
in
accordance
with
procedures
outlined
in
paragraph
5-24.
h.
Connect
hydraulic
brake
line
to
wheel
brake
cylinder.
i.
Fill
and
bleed
hydraulic brake
system
in
accordance
with
paragraph
5-79.
j.
Install
speed
fairings,
if
used,
in
accordance
with
paragraph
5-13.
5-29.
MAIN
WHEEL
ALIGNMENT
CHECK.
(See
figure
5-6.)
No
provisions
are
made
for
aligning
the
nose
wheel.
Figure
5-6
contains
procedures
for
check-
ing
toe-in
and
camber.
Toe-in
limitations
are
.
00"
to
+.
18".
Camber
limi-
tations
are
2°
to
4
° .
If
wheel
alignment
is
out
of
these
limitations,
a
new
tubular
spring
strut
will
have
to
be
installed.
5-30.
WHEEL
BALANCING.
Since
uneven
tire
wear
is
usually
the
cause
of
wheel
unbalance,
replacing
the
tire
will
probably
correct
this
condition.
Tire
and
tube
manufacturing
tolerances
permit
a specified
amount
of
static
unbalance.
The
light-weight
point
of
this
tire
is
marked
with
a
red
dot
on
the
tire
side-
wall
and
the
heavy-weight
point
of
the
tube
is
marked
with
a
contrasting
color
line
(usually near
the
inflation
valve stem).
When
installing
a
new
tire,
place
these marks
adjacent
to
each
other.
If
a wheel
shows
evidence
of unbalance
during
service,
it
may
be
statically
balanced.
Wheel
balancing
equipment
is
available
from
the
Cessna
Supply
Division.
5-31.
NOSE
GEAR.
(See
figure
5-7.)
5-32.
DESCRIPTION.
A
steerable
nose
wheel,
mounted
in
a
fork,
attached
to
an
air/oil
(oleo)
shock
strut,
make
up
the
nose
gear.
The
shock
strut
is
attached
to
the
firewall with
upper
and
lower
strut
fittings.
Nose
wheel
steering
is
accomplished
by
two
steering
tubes
lining
the
nose
gear
steering
collar
to
the
rudder
pedal
bars.
A
hydraulic
fluid-filled
shimmy
dampener
is
provided
to
minimize
nose
wheel
shimmy.
A
nose
wheel
speed
fairing
may
be
installed
on
some
aircraft.
5-19
MODEL 172
SERIES
SERVICE
MANUAL
NOTE
ENSURE
FLOOR
IS
LEVEL
IN
WORK
AREA.
SUSPEND
PLUMB
BOB
FROM TAIL TIE-DOWN
RING
(AFT)
AND
FROM FORWARD
INSPECTION
COVER
PLATE
ATTACH
SCREW
OF
INSPECTION
HOLE
LOCATED
JUST
AFT
OF
NOSE GEAR
ON
BOTTOM
OF
FUSELAGE.
VALUES.
.
PERPENDICULAR
GREASED
PLATES
Figure 5-6.
Main
Wheel
Alignment
Check
(Sheet
1
of
2)
5-20
5-20
MODEL 172
SERIES
SERVICE
MANUAL
TOP
VIEW
OF
TOE-IN
CHECK
FRONT
VIEW
OF
CAMBER
CHECK
Measure
toe-in
at
edges
of
wheel
flange.
Differ-
Measure camber
by
reading
protractor
level
ence
in
measurements
is
toe-in
for
one
wheel.
held
vertically
against
outboard flanges
of
(half
of
total
toe-in.)
wheel.
NEGATIVE CAMBER
CARPENTER'S
SQUARE
POSITIVE
CAMBER
FORWARD
-STRAIGHTEDGE
NOTE
These
procedures
are
specifically
for
checking
main
wheel
alignment.
No
provisions
are
made
for
aligning
the
nose
wheel.
Refer
to
paragraph
5-29 or
the
chart
in
figure
1-1
of
this
manual
for
camber
and
toe-in
limitations.
Figure
5-6.
Main
Wheel
Alignment
Check (Sheet
2
of 2)
5-20A/5-20B
blank)
MODEL
172
SERIES
SERVICE
MANUAL
5-33.
TROUBLE
SHOOTING.
TROUBLE PROBABL
CAUSE
REMEDY
NOSE
WHEEL
SHIMMY
.
Nose
strut
attaching
bolts
Tighten
nose
strut
attaching
(Also
refer
to
Service
Letter
loose.
bolts.
SE84-21.)
Loose
or
worn
nose
wheel
Tighten.
Replace
defective
steering
linkage.
parts
with
new
parts.
Nose
wheel
out
of
balance.
Refer
to
paragraph
5-46.
Wheel
bearings
too
loose.
Adjust
properly.
Defective
himmy
Repair,
or
install
new
damper.
damper.
Shimmy
damper
fluid
Service
in
accordance
with
low.
Section
2.
Loose
torque
links.
Add
shims,
or
install
new
parts
as
required.
NOSE
STRUT DOES
NOT
Defective
or
loose
air
Check
gasket
and
tighten
HOLD
AIR
PRESSURE. filler
valve.
loose
valve.
Install
new
valve
if
defective.
Defective
strut
seals.
Install
new
seals.
HYDRAULIC
FLUID
LEAK-
Defective
strut
seals.
Install
new
seals.
AGE
FROM
NOSE
STRUT.
5-34.
NOSE
GEAR
REMOVAL.
(See
figure
5-7.)
a.
Remove
cowling for
access.
b.
Weight
or tie
down
tail
of
aircraft
to
raise
nose
wheel
off
the floor.
c.
Disconnect
nose
wheel
steering
tubes
from
nose
gear
steering
collar.
d.
Remove
strut
clamp
cap
and
shims
at
lower
strut
fitting.
WARNING
Be
sure
strut
is
deflated
completely
before
removing
bolt
or
roll pin
at
top
of
strut.
e.
Deflate
strut
completely
and
telescope
strut
to
its shortest
length.
f.
Remove
bolt
at
top
of
strut.
g.
Pull
the
strut
assembly
down
out
of
upper
attach
forging.
5-35.
NOSE
GEAR
INSTALLATION.
(See
figure
5-7.
)
a.
Before inflating
nose
gear
strut,
insert
top
of
strut
in
upper
attach
forging
and
attach
with
bolt.
b.
Telescope
strut
to
mate
strut
clamp
cap
with
lower
strut
fitting
on
firewall.
5-21
MODEL
172
SERIES
SERVICE
MANUAL
3
..
...
6
8
7
8
If
rivets
that
attach the
upper
nose
gear
20
fitting(4) to
firewall
work
loose,
it
is
permissible
to
replace
the
AD5
rivets
with
the
appropriate
length
AN3
bolts
and
MS
20365-
1032
nuts.
The
exist-
ing
rivet
holes
should
be
enlarged
to
CAUTION
.193
inch
to
accomodate
the
bolts.
When
installing
cap
(14),
check
gap
between
cap and
strut
fitting before
attaching
bolts
are
tightened.
Gap
tolerance
is
.010"
minimum
and
.016"
maximum.
If
gap
exceeds
maximum
tolerance,
install
shims
(16),
Part
No.
0543042-1
(.016")
and
Part
No.
0543042-2 (.
032"),
as
required,
to
obtain
gap
tolerance.
Replace
cap
if
gap
is
less
than
mini-
mum,
using
shims
to
obtain
proper
gap.
Install
shims
as
equally
as
possible
between
sides.
1.
Bolt
8.
Lower
Strut
Fitting
15.
Shimmy
Dampener
2.
Strut
Assembly
9.
Bolt
16.
Shim
3.
Bolt
10.
Rod
End
17.
Rivet
4.
Upper
Nose
Gear Fitting
11.
Steering
Arm
Assembly
18.
Ball
Joint
Section
D-D
5.
RH
Steering
Tube
12.
Wheel
Assembly
19.
Nut
6.
LH
Steering
Tube
13.
Shimmy
Dampener Arm
20.
Check
Nut
7.
Clamp
14.
Strut
Clamp
Cap
21.
Clevis
Figure
5-7.
Nose
Gear
Installation
5-22
MODEL
172
SERIES SERVICE
MANUAL
c.
Install
shims
and
strut
clamp
cap
attachig
strut
to
lower
strut
fitting,
observing
the
CAUTION
in
figure
5-7.
d.
Inflate
and
service
shock
strut
in
accordance
with
procedures outlined
in
Section 2.
e.
Rig
nose
wheel
steering
tubes
as
outlined
in
appliable
paragraph
in
Section
10.
5-36.
NOSE
WHEEL
SPEED
FAIRING
REMOVAL.
(See
figure
5-8.)
WARNING
Nose
wheel
fairing
cover
plate
(3)
is
secured
by
the
lower
torque
link
attaching
bolt.
Maitain
weight
of
airplan
on
nose
gear
while
removing
this
bolt
and
cover
plate.
a.
Remove
bolt
securing
cover
plate
(3)
and
fairing
(1)
to
strut
and
remove
cover
plate.
Reinstall
torque
link
attach
bolt
b.
Weight
or
tie
down
tail
of
airplane
to
raise
nose
wheel
off the
floor.
c.
Remove nose
wheel axle
stud
(6).
WARNING
Bolt
(4)
securing
tow
bar
spacers
(2)
also
holds strut
cy-
linder
base
plug
retaining
spacer
in
place.
Ensure
spacer
does
not
disengage from
strut
when
removing bolt
(4).
See
figure
5-10.
d.
Remove
bolt
(4)
securing speed
fairing
(1)
and
tow
bar
spacers
(2)
to strut.
e.
Slide
speed
fairing
up
and
remove
nose
wheel.
Loosen
scraper
as
necessary.
f.
Rotate
speed
fairing
90
degrees
and
work
fairing
down
over
the
fork to
remove.
5-37.
NOSE
WHEEL
SPEED
FAIRNG
INSTALATION.
(See
figure
5-8.)
a.
Rotate
speed
fairing
90
degrees
and
work
fairing
up
over
nose
gear
fork
to
install.
b.
Slide
fairing
up
and
install
nose
wheel;
install
axle
stud
(6).
c.
Tighten
axle
stud
nut
until
a
slight
bearing
drag
is
obvious
when
the
wheel
is
ro-
tated.
Back
off
nut
to
the
nearest
castellation
and
install
cotter
pins.
d.
Install
bolt
(4),
tow
bar
spacers
(2),
washers,
and
nut
attaching
fairing
to
strut.
e.
Adjust
wheel
scraper
clearance
in
accordance
with
the
following
caution.
CAUTION
Always
check
scraper
clearance
after
installing
speed
fairing,
whenever
a
tire has
been
changed,
and
whenever
scraper
adjustment
has
been
disturbed.
Set
clearane
be-
twen
tire
and
scraper for a
minimum
of
0.25-inch
to
a
maximum
of
0.50-inch.
Elongated
holes
are
provided
in
the
scraper
for adjustment.
If
the
airplane
is
flown
from
surfaces
with
mud,
snow,
or
ice,
the
speed
fairing
should
be
checked
to
make
sure
there
is
no accumulation
which
could
prevent
normal
wheel
rotation.
Wipe
fuel
and
oil
from
speed
fairing
to
prevent stains
and
deterioration.
f.
Lower
nose
of
airplane
to
floor.
g.
Install
cover
plate
and
bolt
attaching
cover
plate
to
strut.
5-23
MODEL
172
SERIES
SERVICE
MANUAL
17263459
thru
17271569
17271570
thru
17273369
17273370
thru
17276574
F17201235
thru
F17201794
F17201795
thru
F17202029
F17202030
And
On
17276575
&
On
9
10
-
1.
Speed
Fairing
2.
Tow
Bar
Spacer
3.
Cover
Plate
4.
Fork
Bolt
5.
Scraper
6.
Axle
Stud
7.
Ferrule
8.
S2111-1
Washer
9.
Door,
Access
10.
Latch
11.
Plug
Figure
5-8.
Nose
Wheel
Speed
Fairing
5-24
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
5-38.
NOSE
WHEEL
REMOVAL.
(See
figure
5-7.)
a.
Weight
or
tie
down
tail
of
aircraft
to
raise
the
nose
wheel
off
the
floor.
b.
Remove
nose
wheel
axle
stud.
c.
Pull
nose
wheel
assembly
from fork
and remove
axle
tube
from
nose
wheel.
Loosen
wheel
scraper
if
necessary,
if
wheel
is
equipped
with
a
speed
fairing.
5-39.
DISASSEMBLY (McCauley.)
(See
figure
5-9,
sheet
1.)
WARNING
Serious
injury
can
result
from
attempting
to
separate
wheel
halves
with
tire
and
tube
inflated.
a.
Completely
deflate
tire
and
tube
and
break
loose
tire
beads.
Extreme
care
must
be
exercised
to
prevent tire
tool
damage
when
removing
tire
from
wheel
halves
(6).
b.
Remove
nuts
(4)
and
washers
(5).
c.
Remove
thru-bolts
(8)
and
washers
(5)
d.
Separate
and remove
wheel
halves
(6)
from
tire
and
tube.
e.
Remove
retaining
rings
(1),
grease
seal
retainer
(2),
felt
grease
seal
(3).
grease
retainer
(2)
and
bearing
cone
(9)
from
each wheel
half
(6).
NOTE
Bearing
cups
(races)
(7)
are
a
press
fit
in
wheel
half
(6)
and
should
not
be
removed
unless
a
new
part
is
to
be
installed.
To
remove
bearing
cups,
heat
wheel
half
in
boiling
water
for
30
minutes.
or
in
an
oven,
not
to
exceed
121°C
(250°F).
Using
an
arbor
press,
if
available, press
out
bearing
cup and
press
in
new
bearing
cup
while
wheel
half
is
still
hot.
5-40.
INSPECTION
AND
REPAIR.
(McCauley.)
(See
figure
5-9.
sheet
1.)
a.
Clean
all
metal
parts
and felt
grease seals
in
Stoddard
solvent
or
equivalent,
and
dry
thoroughly.
NOTE
A
soft
bristle
brush
may
be
used
to
remove
hardened
grease, dust
or
dirt.
b.
Inspect
wheel
halves
(6)
for
cracks or
damage.
c.
Inspect
bearing
cones
(9),
cups
(7).
retaining
rings
(1)
and
seals
(2)
and
(3),
for
wear
or
damage.
d.
Inspect
thru-bolts
(8)
and
nuts
(4)
for
cracks
in
threads or
cracks
in
radius
of
bolt
heads.
e.
Replace
cracked
or
damaged
wheel
half
(6).
f.
Replace
damaged
retaining
rings
(1)
and
seals
(2)
and
(3).
g.
Replace
any
worn
or
cracked
thru-bolts
(8)
or
nuts
(4).
h.
Replace
worn
or damaged
bearing
cups
(7)
or
cones
(9).
i.
Remove
any
corrosion
or
small
nicks.
j.
Repair
reworked
areas
of
wheel
by
cleaning
thoroughly,
then
applying
one
coat
of
clear
lacquer
paint.
5-25
MODEL
172
SERIES
SERVICE
MANUAL
MC
CAULEY
WHEEL
1.
Retaining
Ring
2.
Grease
Seal
Retainer
3.
Felt
Grease Seal
4.
Nut
5.
Washer
6.
Wheel
Half
7.
Bearing
Cup
8.
Bolt
10
9.
Bearing
Cone
10.
Tube
11.
Tire
Figure
5-9.
Nose
Wheel
and
Tire
(Sheet
1
of
2)
k.
Pack
bearings
with
grease
specified
in
Section
2.
5-41.
REASSEMBLY.
(McCauley.)
(See
figure
5-9,
sheet
1.)
a.
Assemble
bearing
cone
(9).
grease
seal
retainer
(2),
felt
grease
seal
(3),
grease
seal
retainer
(2)
and
retaining ring
(1)
into
both
wheel
halves
(6).
b.
Insert
tube
in
tire,
aligning
index
marks
on
tire
and
tube.
c.
Place
wheel
half
(6)
into
tire
and
tube
(side
opposite
valve
stem).
With
washer
(5)
under
head
of
thru-bolt
(8),
insert
bolt
through
wheel
half
(6).
d.
Place
wheel
half
(6)
into
other
side
of
tire
and
tube,
aligning
valve
stem
in
valve slot.
e.
Install
washers
(5)
and
nuts
(4)
on
thru-bolts
(8)
and
pre-torque
to
10-50
lb.
in.
CAUTION
Uneven
or
improper
torque
of
the
nuts
can
cause
failure
of
the
bolts
with
resultant
wheel
failure.
5-26
MODEL
172
SERIES
SERVICE
MANUAL
1
2
1.
Snap
Ring
4.
Bearing
Cone
5.
Outer
Wheel
Half
6.
Tire
7.
Tube
8.
Inner
Wheel
Half
10
9.
Bearing
Cup
10.
Thru-Bolt
CLEVELAND
WHEEL
Figure
5-9.
Nose
Wheel
and
Tire (Sheet
2
of
2)
f.
Prior
to
torquing
nuts
(4),
inflate
tube
with
approximately
10-15
psi
air
pressure
to
seat
tire.
CAUTION
Do
not
use impact
wrenches
on
thru-bolts
or
nuts.
g.
Dry
torque
all
nuts
(4)
evenly
to
a
torque
value
of
140-150
lb.
in.
h.
Inflate
tire
to
correct
pressure
specified
in
chrt
in
Section
1.
5-42.
DISASSEMBLY.
(Cleveland.)
(See
figure
5-9.
sheet
2.)
5-27
MODEL
172
SERIES
SERVICE
MANUAL
WARNING
Injury
can
result
from
attempting
to
separate
wheel
halves
with tire
inflated.
Avoid
damaging
wheel
flanges
when
breaking
tire
beads loose.
a.
Deflate
tire and break
tire
beads loose.
b.
Remove
thru-bolts
and
separate
wheel
halves.
c.
Remove
tire
and
tube.
d.
Remove
snap
ring.
grease
seal
felt,
grease seal
rings
and
bearing
cones
from
both
wheel
halves.
NOTE
Bearing
are
a
press-fit
in
the
wheel
halves
and
should
not
be
removed
unless
replacement
is
necessary.
To
remove
bearing
cups.
heat
wheel
half
in
boiling
water
for
15
minutes.
Using
an
arbor
press,
if
available,
press
out
bearing
cup
and
press
in
new
cup
while
wheel
is
still
hot.
5-43.
INSPECT
AND
REPAIR.
(Cleveland.)
(See
to
figure
5-9,
sheet
2.)
a.
Clean
all
metal
parts
and
grease
seal
felts
in
solvent
and
dry
thoroughly.
b.
Inspect
wheel
halves
for
cracks.
Cracked wheel
halves
must
be
replaced. Sand
out
nicks,
gouges
and
corroded
areas.
Where
protective coating
has
been
removed,
area
should
be
cleaned
thoroughly.
primed
with
zinc
chromate
primer
and
painted
with
aluminum
lacquer.
c.
Bearing cups
and
cones
must
be
inspected
carefully
for
damage
and
discoloration.
After
cleaning,
repack
cones
with
clean
aircraft
wheel
bearing
grease
(Section
2)
before
installation
in
the
wheel.
To
replace
bearing
cups. refer
to
note
in
paragraph
5-
42.
5-44.
REASSEMBLY.
(Cleveland.)
(See
figure
5-9.
sheet
2.)
a.
Insert
tire
in
tube.
aligning
index
marks
on
tire
and
tube.
b.
Place
tire
and
tube
on
wheel
half
and
position valve
stem
through
hole
in
wheel
half.
c.
Insert
thru-bolts, position
other
wheel
half.
and
secure
with
nuts
and
washers.
Take
care
to
avoid
pinching
tube
between wheel
halves.
Torque
bolts
to
90
lb-in.
CAUTION
Uneven
or
improper
torque
on
thru-bolt
nuts
may
cause
bolt
failure
with
resultant
wheel
failure.
d.
Clean
and
repack
bearing
cones
with
clean
aircraft
wheel
bearing
grease.
(Section
2.)
e.
Assemble
bearing
cones,
seals
and
retainers
into
wheel
halves.
f.
Inflate
tire
to
seat tire
beads,
then
adjust
to
correct
pressure
(Section
1).
g.
Install
wheel
in
accordance
with
paragraph
5-45.
5-45.
NOSE
WHEEL
INSTALLATION.
(See
figure
5-7.)
a.
Install
axle tube
in
nose
wheel.
b.
Install
nose
wheel
assembly
in
fork
and
install
nose
wheel
axle
stud.
c.
Tighten axle
stud
until
a
slight
bearing
drag
is
obvious
when
wheel
is
rotated.
Back
the
nut
off
to
the
nearest
castellation
and
insert
cotter
pins.
5-28
MODEL
172
SERIES SERVICE
MANUAL
CAUTION
On
aircraft
equipped
with
speed
fairings,
always
check
scraper-to-tire
clearance
after
installing
speed
fairing,
whenever
a
tire
has
been
changed,
or
whenever
scraper
adjustment
has
been
disturbed.
Set
scraper
clearance
in
accordance
with
instructions
outlined
in
paragraph
5-37.
5-46.
WHEEL
BALANCING.
Since
uneven
tire
wear
is
usually
the
cause
of
wheel
unbalance,
replacing
the
tire
will
probably
correct
this
condition.
Tire
and
tube
manufacturing
tolerances
permit
a
specified
amount
of
static
unbalance.
The
light-weight
point
of
the
tire
is
marked
with
a
red
dot
on
the
tire
side-
wall,
and
the
heavy-weight
point
of
the
tube
is
marked
with
a
contrasting
color
line
(usually
near
the
inflation
valve
stem).
When
installing
a
new
tire,
place
these
marks
adjacent
to
each
other.
If
a
wheel
shows
evidence
of
unbalance
during
service,
it
may be
statically
balanced.
Wheel
balancing
equipment
is
available
from
the
Cessna
Supply
Division.
5-47.
NOSE
GEAR
SHOCK STRUT
DISASSEMBLY. (See
figure
5-10.)
NOTE
The
following
procedures apply
to
the
nose
gear
shock
strut
after
it
has
been
removed
from
the
aircraft,
and
the
speed
fairing
and nose
wheel
have
been
removed.
In
many
cases,
separation
of
the
upper
and
lower
strut
will
permit inspection
and
parts
installation
without removal
or complete
disassembly
of
the
strut.
WARNING
Be
sure
shock
strut
is
completely
deflated
before
remov-
ing
lock
ring
in
lower
end
of
upper
strut,
or
disconnecting
torque
links.
a.
Remove
shimmy
dampener.
b.
Remove
torque
links.
Note
position
of
washers,
shims
and
spacers.
c.
Remove
lock
ring
from
groove
inside
lower
end
of
upper
strut.
A
small
hole
is
provided
at
the
lock
ring
groove
to
facilitate
removal
of
the lock
ring.
NOTE
Hydraulic
fluid
will drain
from
strut
halves
as
lower
strut
is
pulled
from
upper strut.
d.
Using
a
straight, sharp
pull
separate
upper
and
lower
struts.
Invert
lower
strut
and
drain hydraulic
fluid.
e.
Remove
lock
ring
and
bearing
at
upper
end
of
lower
strut
assembly.
Note
top
side
of
bearing.
f.
Slide
packing support
ring,
scraper ring,
retaining
ring
and
lock
ring
from
lower
strut,
noting
relative
position
and
top
side
of
each
ring:
wire
or
tape
together.
if
desired.
g.
Remove
O-ring
and
back-up
rings
from
packing support
ring.
h.
Remove bolt
securing
tow
bar
spacers.
5-29
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
.
Use
shims
(2)
as
required
between
steer-
ing
arm assembly
(4)
and
washer
(1)
to
provide
a
snug
fit
with
retainer
ring
(5)
installed.
Also.
adjust
rod
ends
(3)
to
provide
dimension
shown
in
detail
A-A.
14-
16
15
SECTION
A-A
NO.
40
(.098)
HOLE
1.
Washer
10.
Filler
Valve
19.
O-Ring
2.
Shim
(As
Required)
11.
Lock Ring
20.
O-Ring
21
3.
Rod
End
12.
Bearing
21.
Base
Plug
4.
Steering
Arm
Assembly
(Collar)
13.
Lower
Strut
22.
Fork
5.
Retaining
Ring
14.
Packing
Support
Ring
23.
Retaining
Spacer
6.
Decal
15.
Scraper
Ring
24.
Back-Up
Ring
7.
Upper
Strut
16.
Retaining
Ring
25.
O-Ring
8.
Orifice
Piston
Support
17.
Lock
Ring
26.
O-Ring
9.
O-Ring
18.
Metering
Pin
27.
Tow
Bar
Spacer
Figure
5-10.
Nose
Gear
Shock
Strut
Assembly
1.
Washer
10.
Filler
Valve
19.
O-Ring
2.
Shim
(As
Required)
11.
Lock
Ring
20.
O-Ring
21
3.
Rod
End
12.
Bearing
21.
Base Plug
21
4.
Steering
Arm
Assembly
(Collar)
13.
Lower
Strut
22.
Fork
5.
Retaining
Ring
14.
Packing
Support
Ring
23.
Retaining
Spacer
6.
Decal
15.
Scraper
Ring
24.
Back-Up
Ring
7.
Upper
Strut
16.
Retaining
Ring
25.
O-Ring
8.
Orifice
Piston
Support
17.
Lock
Ring
26.
O-Ring
9.
O-Ring
18.
Metering
Pin
27.
Tow
Bar
Spacer
Figure
5-10.
Nose
Gear
Shock
Strut
Assembly
5-30
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Bolt
attaching
tow
bar
spacers
also
holds
bushing
and
base
plug
in
place.
i.
Remove
bolt
attaching
fork
to
strut
barrel
and
remove base
plug
and
metering
pin
from
lower
strut.
Remove O-rings
and
metering pin
from
base
plug.
NOTE
Lower
strut
barrel
and
fork
are
a
press
fit,
drilled
on
assembly.
Separation
of
these
parts
is
not
recommended,
except for
installation
of
a
new
part.
j.
Remove
retaining ring
securing
steering
arm
assembly
on
upper
strut,
and
remove
steering
arm assembly,
shims
(if
installed)
and
washer.
If
shims are
installed.
note
number
and
position
of
each
shim.
k.
Push
orifice
support
from
upper
strut
and
remove
O-ring.
1.
Remove
filler
valve
from
orifice
support
5-48.
NOSE
GEAR
SHOCK
STRUT
INSPECTION
AND
REPAIR.
(See
figure
5-10.)
a. Thoroughly
clean
all
parts
in
cleaning
solvent
and
inspect
them
care-
fully.
b.
All worn
or
defective
parts
and
all
O-rings
and
back-up
rings
must
be
replaced
with
new
parts.
c.
Sharp
metal
edges
should
be
smoothed
with
No.
400
emery
paper,
then
cleaned
with
solvent.
5-49.
NOSE
GEAR
SHOCK
STRUT
REASSEMBLY.
(See
figure
5-10.)
Assemble
these
parts,
lubricated
with
a
film
of
Petrolatum
VV-P-236,
Hydraulic
Fluid
MIL-H-
5606,
or
Dow-Corning
DC-7.
Do
not
use
DC-7
on
surfaces
to
be
painted.
a.
Install
washer
(1)
and
shim(s),
(2),
if
installed.
b.
Lubricate
needle
bearings
in
steering
collar
(4),
as
shown
in
Section
2,
and
install
collar
and
retaining
ring
(5).
c.
Check
steering
collar
for
snug
fit
against
washer.
Shims
of
variable
thicknesses
are
available
from
the
Cessna
Supply
Division
to
provide
a
snug
fit
for
collar
against washer.
NOTE
If
shims
are
required,
remove
retaining
ring
and
steering collar
and
add
shims
as
necessary
to
provide
a
snug
fit
with
steering
collar
retaining
ring
installed.
Shims
are
available
in
the
following
part
numbers
and
thicknesses:
1243030-5
(.
006
inch),
1243030-6
(.
012
inch),
and
1243030-7
(.
020
inch).
5-31
MODEL
172
SERIES
SERVICE
MANUAL
d.
Install
rod
ends
(3)
in
steering
collar
(4)
and
adjust
rod
ends
to
dimension
specified
in
Section
A-A
in
figure
5-10.
e.
Install
O-ring
(9)
and
filler
valve
(10)
in
orifice
piston
support
(8)
and
install
orifice
piston
support
in
upper
strut
(7).
f.
Install
O-ring
(20)
and
metering
pin
(18)
with
O-ring
(19)
in
base plug
(21);
secure
with
nut.
NOTE
If
base
plug
(21)
is
to
be
replaced,
new
part
will
need
to
be
line-drilled
to
accept
NAS75-5
bushing.
g.
Install
bushing
(23)
(if
removed)
in
base
plug
(21),
and
install
base
plug
assembly
in
lower
strut
(13).
h.
Align
holes
of
bushing,
hole
in
lower
strut,
and hole
in
fork.
Install
tow
bar
spacer
under
head
of
bolt,
and
install
bolt
through
fork,
lower
strut
and
bushing
which
is
installed
in
base
plug.
Install
tow
bar
spacer
on
threaded
end
of
bolt.
install
and
tighten
nut.
i.
Install
lock
ring
(17).
retaining
ring
(16)
and
scraper ring
(15)
on
lower
strut.
making
sure
they
are
installed
in
same
positions
as
they
were
removed.
j.
Install
O-rings
(25)
and
(26)
and
back-up
rings
in
packing
support ring
(14);
slide
packing
support
ring
over
lower
strut
(13).
k.
Install
bearing
(12)
and
lock
ring
(11)
at
upper
end
of
lower
strut
assembly.
Note
top
side
of
bearing.
1.
Install
upper
strut
assembly
over
lower
strut
assembly.
m.
Install
lock
ring
(17)
in
groove
in
lower
end
of
upper
strut.
Position
lock
ring
so
that
one
of
its
ends
covers the
small
access
hole
in
the lock
ring
groove (Section
view
C-
C.)
n.
Install
torque
links,
positioning
washers.
shims
and
spacers
exactly
in
positions
as
removed.
o.
Install
shimmy
dampener.
p.
After
shock
strut
assembly
is
complete.
install strut
on
aircraft
as
outlined
in
paragraph
5-35.
q.
After
strut
is
installed
on
aircraft,
fill
and
inflate shock
strut
in
accordance with
procedures outlined
in
Section
2.
5-50.
TORQUE
LINKS.
(See
figure
5-11.)
5-51.
DESCRIPTION.
Torque
links
keep
the
lower
strut
aligned
with
the
nose
gear
steering
system,
but
permit
shock
strut
action.
5-52.
TORQUE
LINK
REMOVAL.
(See
figure
5-11.)
WARNING
Completely
deflate
strut
before
removing
torque
links.
a.
Completely deflate
shock
strut.
b.
Disconnect
upper
and
lower
attaching
bolts.
spacers,
shims
and
nuts:
remove
torque
links.
5-53.
TORQUE
LINK
INSPECTION
AND
REPAIR.
(See
figure
5-11.)
Torque
link
bushings
should
not
be
removed except
for
replacement
of
parts:
replace
if
excessively
worn.
5-32
MODEL
172
SERIES
SERVICE
MANUAL
10
NOTE
Tighten
bolts
(8)
to
20
to
25
pound
inches.
then
safety
the
bolts
by
bending
tips
of
safety
lug
(10).
7
Tighten
nuts
(7)
snugly,
then
tighten
to
align
next
castel-
lation
with
cotter
pin
hole.
4
Shims
(3)
are
available
to
use
as
required
to
remove
any
looseness.
1.
Spacer
2.
Grease
Fitting
3.
Shim
9
4.
Bushing
4
5.
Stop
Lug
3
6.
Upper
Torque Link
2
7.
Nut
8.
Bolt
9.
Lower
Torque
Link
10.
Safety
Lug
Figure
5-11.
Torque Links
5-54.
TORQUE LINK
INSTALLATION.
(See
figure
5-11.)
NOTE
If
bolts
(8),
safety
lug
(10)
and
stop
lug
(5)
were
removed,
upon
installation.
tighten
bolts
(8)
to
20-25
pound-inches.
then safety the
bolts
by
bending
tips
of
safety
lug
(10).
a.
With
shock
strut
completely
deflated,
install
upper
and
lower
torque
link
assemblies.
b.
Install
bolt
attaching upper
and
lower
assemblies.
c.
Tighten
nuts
(7)
snugly,
then
tighten
to
align
next
castellation
with
cotter
pin
hole
in
bolt.
d.
Check
upper
torque
link
(6)
and
lower torque
link
(9)
for
looseness.
If
looseness
is
apparent,
remove
nuts
(7)
and
bolts
and
install
shims
(3)
as
necessary
to
take
up
any
looseness.
This
will
assist
in
preventing
nose
wheel shimmy.
e.
Retighten
nuts
(7)
snugly,
then
tighten
to
align
next
castellation
with
cotter
pin
hole
in
bolt;
install
cotter
pin.
f.
Fill
and
inflate shock
strut
in
accordance
with procedures
outlined in
Section
2.
5-33
MODEL
172
SERIES
SERVICE
MANUAL
1.
O-Ring
2.
Barrel
2
3.
Snap
Ring
4.
Bearing
Head
5.
Piston
Rod
6.
Roll
Pin
7.
Piston
5
4
Figure
5-12.
Shimmy
Damper
5-55.
SHIMMY
DAMPER.
(See
figure
5-12.)
5-56.
DESCRIPTION.
The
shimmy damper,
provided
for
the
nose
gear,
offers
resistance
to
shimmy
by
forcing hydraulic
fluid
through
small orifices
in
a
piston.
The
damper
piston
shaft
is
secured
to
a
bracket,
welded
on
the
bottom
of
the
upper
strut
tube.
The
shimmy
damper
housing
is
secured
to
the
steering
arm
assembly,
which
moves
as
the
nose
wheel
is
turned,
causing
relative motion
between
the
damper
shaft
and
housing.
5-57.
SHIMMY
DAMPER
REMOVAL.
(See
figure
5-7.)
a.
Remove
cotter
pin,
nut,
washers
and
bolt
attaching
piston shaft
clevis
to
bracket
welded
on
bottom
of
upper
strut
tube.
b.
Remove
cotter
pin,
nut,
spacer
and
bolt
attaching
housing
to
steering
arm
assembly.
c.
Remove
shimmy
dampener.
5-58.
DISASSEMBLY
AND
REASSEMBLY.
(See
figure
5-12.)
Refer
to
figure
for disassembling
and
reassembling
the
shimmy
damper.
When
reassembling
damper,
install
all
new
O-rings.
Lubricate
all
parts
with
clean
hydraulic
fluid,
Petrolatum
VV-P-236,
or
Dow
Corning
DC-7.
Keep
DC-7
away from
painted
surfaces.
When
damper
is
completely assembled,
service
in
ac-
cordance
with
procedures
outlined
in
Section
2.
5-59.
SHIMMY
DAMPER
INSTALLATION.
(See
figure
5-7.)
a.
Attach
shimmy
damper
housing
to
steering
arm
assembly
with
bolt,
spacer,
nut
and
cotter
pin.
b.
Attach
shimmy
damper
piston
rod
clevis
to
bracket
welded
on
bottom
of
upper
strut
tube
with
bolt,
washers
(as
required)
and
nut.
5-34
MODEL
172
SERIES SERVICE
MANUAL
5-60.
NOSE
WHEEL
STEERING
SYSTEM.
(See
figure
5-7.)
5-61.
DESCRIPTION.
Nose wheel
steering
is
accomplished
through
use
of
the
rudder
pedals.
Spring-loaded
steering
rod
assemblies
connect
the
nose
gear
steering
arm
assembly
to
arms
on
the
rudder
bars.
Steering
is
afforded
up
to
approximately
10
degrees
each
side
of
neutral.
after
which
brakes
may
be
used
to
gain
a
maximum
deflection
of
30
degrees
right
or
left
of
center.
A
flexible
boot
seals
the
fuselage
entrance
of
the
steering
rod
assembly.
5-62.
NOSE
WHEEL
STEERING
ROD
ASSEMBLIES. (See
figure
5-7.)
5-63.
DESCRIPTION.
The
steering
rods
are
connected
by
a
clevis
to
the
rod
ends
extending
from
the
nose
gear
steering
arm,
and
to
an
arm
on
the
rudder
pedal
crossbars.
5-64.
NOSE
WHEEL
STEERING
ADJUSTMENT.
Before
attaching
nose
wheel
steering
rods
to
the
rod
ends
protruding
from
the
steering
arm assembly,
adjust
rod
ends
to
the
dimension
specified
in
section view
A-A
in
figure
5-10.
Since the nose
wheel
steering
system
and
the
rudder system
are
interconnected,
adjustment
to
one
system
might
affect
the
other
system.
Refer
to
Section
10
for
instructions
for
rigging
the
nose wheel
steering
and
the
rudder
system.
5-65.
BRAKE
SYSTEM. (See
figure
5-3.)
5-66.
DESCRIPTION. The
hydraulic
brake
system is
comprised
of
two
master
cylinders,
located
immediately
forward
of
the
pilot's
rudder
pedals,
brake
lines
and
hose
connecting
each
master
cylinder
to
its
wheel
brake
cylinder,
and
the
single-disc, floating
cylinder-type
brake
assembly.
located
at
each
main landing
gear
wheel.
5-67.
TROUBLE
SHOOTING.
TROUBLE PROBABLE
CAUSE
REMEDY
DRAGGING
BRAKES.
Brake
pedal
binding.
Check
and
adjust properly.
Parking
brake
linkage
hold-
Check
and
adjust
properly.
ing
brake
pedal
down.
Worn
or
broken
piston Repair,
or
install
new
return spring
(in
master
cylinder.
cylinder.)
Insufficient clearance
at
Adjust
as
outlined
in
para-
Lock-O-Seal
or
incorrect
graph
5-84.
(Thru
aircraft
adjustment
of
cylinder
serials
17271034
and
overall
length.
F17201749.)
Restriction
in
hydraulic
Drain brake line
and
clean
lines
or
restrictions
in
the
inside
of
the
brake
line
compensating
port
in
with filtered
compressed
air.
brake
master
cylinder.
If
cleaning
the
lines fails
to
give
satisfactory
results,
the
master
cylinder may
be
faulty
and
should
be
re-
paired.
5-35
MODEL
172
SERIES SERVICE
MANUAL
5-67.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
DRAGGING
BRAKES.
Worn.
scored or warped
Install
new
disc
and
brake
Cont).
brake disc. linings.
Damaged or
accumulated
Clean
and
repair
or
install
dirt
restricting
free move-
new
parts
as
necessary.
ment
of
wheel
brake
parts.
BRAKES FAIL
TO
Leak
in
system.
If
brake
master
cylinders
or
OPERATE.
wheel
cylinder assemblies
are
leaking,
repair,
or
in-
stall
new
parts.
Air
in
system.
Bleed
system.
Lack
of
fluid
in
master
Fill
and
bleed
system.
cylinders.
Defective
master
cylinder. Repair,
or
install
new
parts.
5-68.
HYDRAULIC
BRAKE
LINES.
5-69.
DESCRIPTION.
The
brake
lines
are
rigid
tubing,
except
for
flexible
hose
used
at
the
brake
master
cylinders.
A
separate
line
is
used
to
connect each brake
master
cylinder
to
its
corresponding
wheel
brake
cylinder.
5-70.
WHEEL
BRAKE ASSEMBLIES.
(See
figure
5-3.)
5-71.
DESCRIPTION.
(See
figure
5-3.)
The
wheel
brake
assemblies
use
a
floating
brake
assembly
and
a
disc
which
is
attached
to
the
main
wheel.
5-72.
WHEEL
BRAKE
REMOVAL.
(See
figure
5-3.)
Wheel
brake
assemblies
can
be
removed
by
dis-
connecting
the
brake
line
(drain
hydraulic
brake
fluid
when
disconnecting
line)
and
remov-
ing
the
brake
back
plate.
The
brake
disc is
removed
after
the
wheel is
removed
and
disas-
sembled.
To
remove
the
torque
plate,
remove
wheel
and
axle.
5-73.
WHEEL
BRAKE
DISASSEMBLY.
See
figure
5-3
for
a
breakdown
of wheel
brake
parts.
This
figure
may
be
used
as
a
guide
for
disassembling
the
wheel
brakes.
5-74.
WHEEL
BRAKE INSPECTION
AND
REPAIR.
(See
figure
5-3.)
a.
Clean
all
parts
except
brake
linings
and
O-rings
in
dry
cleaning
solvent
and
dry
thoroughly.
b.
Install
all
new
O-rings.
If
O-ring reuse
is necessary,
wipe
with
a
clean cloth
satu-
rated
in
hydraulic
fluid
and
inspect
for
damage.
NOTE
Thorough
cleaning
is
important.
Dirt
and chips
are
the
greatest
single
cause
of
malfunctions
in
the hydraulic
brake
system.
5-36
MODEL
172
SERIES
SERVICE
MANUAL
2
3
2
VENT HOLE
9
DO
NOTS
DAMAGE
9141312
11
THRU
1978
MODELS
3
16
15
ASSEMBLY
OF
PISTON
1.
Clevis
7.
Body
14.
Piston
2.
Jam
Nut
8.
Reservoir
15.
Lock-O-Seat
3.
Piston
Rod
9.
O-Ring
16.
Compensating
Sleeve
4.
Cover
10.
Cylinder
17.
Filler
Plug
5.
Setscrew
11.
Piston Return
Spring
18.
Screw
6.
Cover
Boss
12.
Nut
19.
Washer
13.
Piston
Spring
Figure
5-13.
Brake
Master
Cylinder
(Sheet 1
of
2)
5-37
MODEL
172
SERIES SERVICE
MANUAL
6
7
7
View
AA
1.
Clevis
2.
Nut
3.
Filler
Plug
4.
Cover
5.
Piston
6.
Back-up
Ring
7.
Packing
8.
Spring
9.
Cylinder
Body
BEGINNING
WITH
1979
MODELS
Figure
5-13.
Brake Master
Cylinder
(Sheet
2
of
2)
5-38
MODEL
172
SERIES SERVICE
MANUAL
c.
Check
brake
lining
for
deterioration
and
maximum
permissible
wear.
(Refer
to
applicable
paragraph
for
maximum
wear
limit.)
d.
Inspect
brake
cylinder
bore
for
scoring.
A
scored
cylinder
will
leak
or
cause
rapid
0-
ring
wear.
Install
a
new
brake
cylinder
if
the
bore
is
scored.
e.
If
the anchor
bolts
on
the
brake assembly
are
nicked
or
gouged,
they
shall
be
sanded
smooth
to
prevent
binding
with the
pressure
plate
or
torque
plate.
When new
anchor
bolts
are
to
be
installed,
press
out
old
bolts
and
install
new
bolts
with
a
soft
mallet.
f.
Inspect
wheel
brakes
disc
for
a
minimum
thickness
of
0.190
(McCauley)
or
0.205
(Cleveland).
If
brake
disc
is
below
minimum
thickness, install
a
new
part.
5-75.
WHEEL
BRAKE
REASSEMBLY.
(See
figure
5-3.)
NOTE
Lubricate
parts
with
clean
hydraulic
fluid
during
brake
reassembly.
a.
See
figure
5-3
for
reassembling
wheel
brakes.
b.
Thru
1981
Models,
torque
elbow
(18)
to
a
maximum
of
60
lb.
in.
Lube/seal
with
Liq-
uid
O-Ring
No.
404
(Oil
Research,
P.O. Box
51971, Lafayette,
La.
7050).
c.
Torque
bolt
(20)
to
120-130 lb.
in.
d.
Thru
1981
Models,
torque
bleeder
screw
(21)
to
30-40
lb.
in.
5-76.
WHEEL
BRAKE INSTALLATION.
a.
Place
brake
assembly
in
position
with
pressure
plate
in
place.
b.
Install
back
plate.
NOTE
If
torque
plate
was
removed,
install
as
the
axle
is
installed,
or
install
on
axle.
If
the
brake
disc
was
removed,
install
as
wheel
is
assembled.
5-77.
CHECKING
BRAKE
LINING
WEAR.
New
brake
lining
should
be
installed
when
the
existing lining
has
worn
to
a
minimum
thickness
of
3/32-inch.
A
3/32-inch
thick
strip
of
material
held
adjacent
to
each
lining
can
be
used
to
determine
amount
of
wear.
The
shank
end
of
a
drill
bit
of
the
correct
size can
also
be
used
to
determine
wear
of
brake
linings.
5-78.
BRAKE LINING
INSTALLATION.
(See
figure
5-3.)
a.
Remove
bolts
securing
back
plate,
and
remove
back
plate.
b.
Pull
brake
cylinder
out
of
torque plate
and
slide
pressure
plate
off
anchor
bolts.
c.
Place
back
plate
on
a
table
with
lining
side
down
flat.
Center
a
9/64-inch
(or
slightly
smaller)
punch
in
the
rolled
rivet,
and
hit
the
punch
sharply
with
a
hammer.
Punch
out
all
rivets
securing
the
linings
to
the
back
plate
and pressure
plate
in
the
same
manner.
NOTE
A
rivet
setting
kit,
Part
No.
199-00100,
is
available
from
the
Cessna
Supply
Division.
This
kit
consists
of
an
anvil
and
punch.
d.
Clamp
the
flat
side
of
the
anvil
in a
vise.
e.
Align
new
lining
on
back
plate
and
place
brake
rivet
in
hole
with rivet
head
in
the
Revision
1
5-39
MODEL
172
SERIES
SERVICE
MANUAL
lining. Place
the
head
against
the anvil.
f.
Center
rivet setting
punch
on
lips
of
rivet.
While
holding
back
plate
down
firmly
against
lining,
hit
punch
with
hammer
to
set
rivet.
Repeat
blows
on
punch
until
lin-
ing
is
firmly
against
back
plate.
g.
Realign
the
lining
on
the
back plate
and
install
and
set rivets
in
the
remaining
holes.
h.
Install
a new
lining
on
pressure
plate
in
the
same
manner.
i.
Position
pressure
plate
on
anchor
bolts
and
place
cylinder
in
position
so
that
anchor
bolts
slide
into
the
torque
plate.
j.
Install
back
plate with
bolts
and
washers.
k.
Refer
to
paragraph
5-90
for
brake
lining
burn-in
procedure.
5-79.
BRAKE
SYSTEM
BLEEDING.
NOTE
Bleeding
with
a
clean
hydraulic
pressure
source
connected
to
the
wheel
bleeder
is
recommended.
a.
Remove
brake
master
cylinder
filler plug
and
screw
flexible
hose
with appropriate
fit-
ting
into
the
filler
hole
at
top
of
the
master
cylinder.
b.
Immerse
opposite end
of
flexible
hose
in
a
container
with
enough
hydraulic
fluid
to
cover
the
end
of
the
hose.
c.
Connect
a
clean
hydraulic
pressure
source,
such
as
a
hydraulic
hand
pump
or
Hydro-
Fill
unit,
to
the
bleeder
valve
in
the
wheel
cylinder.
d.
As
fluid
is
pumped
into
the
system,
observe
the
immersed
end
of
the
hose
at
the
mas-
ter
brake
cylinder
for
evidence
of
air
bubbles
being
forced
from
the
brake
system.
When
bubbling
has
ceased,
remove
bleeder
source from
wheel cylinder
and
tighten
the
bleeder
valve.
5-80.
BRAKE
MASTER
CYLINDER.
5-81.
DESCRIPTION. The
brake
master
cylinders, located
immediately
forward
of
the
pilot's
rudder
pedals,
are
actuated
by
applying
pressure
at
the
top
of
the
rudder
pedals.
A
small
reservoir
is
incorporated
into
each
master
cylinder
for
the
fluid
supply.
When
dual
brakes
are
installed,
mechanical
linkage
permits the
copilot
pedals
to
operate
the
master
cylin-
ders.
5-82.
BRAKE
MASTER
CYLINDER
REMOVAL.
a.
Remove
front
seats
and
rudder
bar
shield
for
access to
the
brake
master
cylinders.
b.
Remove
bleeder
screw
at
wheel brake assembly
and
drain
hydraulic
fluid
from
brake
cylinders.
c.
Disconnect
parking
brake
and
disconnect
brake master
cylinders
from
rudder
pedals.
d.
Disconnect
hydraulic
hose
from
brake
master
cylinders
and
remove
cylinders.
e.
Plug
or
cap
hydraulic
fittings,
hose
and
lines,
to
prevent
entry
of
foreign
material.
5-83.
DISASSEMBLY.
(Thru
aircraft
serials
17271034
and
F17201749.)
(See
figure
5-13,
sheet
lof2.)
a.
Unscrew
clevis
(1)
andjamnut
(2).
h.
Remove
screw
(18)
and
washer
(19).
c.
Remove
filler
plug
(17)
and
setscrew(5).
d.
Unscrew
cover
(4)
and
remove up
over
piston
rod
(3).
e.
Remove
piston
rod
(3)
and
compensating
sleeve
(16).
f.
Slide
sleeve
(16)
up
over
rod
(3).
g.
Unscrew
nut
(12)
from
threads
of
piston
rod
(3).
h.
Remove
spring
(13)
and
0-ring
(9)
from
piston
(14).
5-40
Revision
3
MODEL
172
SERIES SERVICE
MANUAL
i.
Remove Lock-O-Seal
(15).
5-84.
INSPECTION
AND
REPAIR.
(Thru
aircraft serials
17271034
and
F17201749.)
(See
figure
5-
13,
sheet
1
of
2).
Repair
is
limited
to
installation
of
new
parts,
cleaning
and
adjusting.
(Refer
to
reassembly
paragraph
for
adjustment.)
Use
clean
hydraulic
fluid
(MIL-H-5606)
as
a
lubricant
during
reassembly
of
the
cylinders.
Inspect
Lock-O-Seal
(Parker
Seal
Co.
P/
N
800-
001-6)
and
replace
if
damaged.
Replace
all
O-rings.
Filler
plug
(17)
must
be
vented
so
pressure
cannot
build
up
in
the
reservoir
during
brake
operation.
Remove
plug
and
drill
1/16-inch
hole;
30
°
from
vertical
if
plug
is
not
vented.
5-85.
REASSEMBLY.
(Thru
aircraft serials
17271034
and
F17201749.)
(See
figure
5-13,
sheet
1
of
2.)
a.
Install
Lock-O-Seal
(15)
at
bottom
of
piston
rod
(3).
b.
Install
O-ring
(9)
in
groove
in
piston
(14);
insert piston
spring
(13)
into
piston.
and
slide
assembly
up
on
bottom
threaded
portion
of
piston
rod
(3).
c.
Run
nut
(12)
up
threads
to
spring
(13).
Tighten
nut
(12)
enough to
obtain
0.040
0.005-
inch
clearance
between top
of
piston
and
bottom
of
Lock-O-Seal
as
shown
in
the
figure.
d.
Install
piston
return
spring
(11)
into
cylinder
(10)
portion
of
body
(7).
e.
Install
piston
rod
end
(3)
through
spring
(11).
f.
Slide
compensating
sleeve
(16)
over
rod
(3).
g.
Install
cover
(4),
washer
(19)
and
screw
(18).
h.
Install
jamb
nut
(2)
and
clevis
(1).
i.
Install
filler
plug
(17), making
sure
vent
hole
is
open.
j.
Install
setscrew
(5).
5-86.
DISASSEMBLY.
(Beginning
with
aircraft
serials
17271035
and
F17201750.)
(See
figure
5-13.
sheet
2
of
2.)
a.
Unscrew
clevis
(1)
and
jamb
nut
(2).
b.
Remove
filler
plug
(3).
NOTE
A
special
tool,
brake
master
cylinder wrench
No.
34-101
is
available
from
the
Cessna
Supply
Division
to
accom-
plish
the
following
step.
c.
Unscrew
cover
(4)
and
remove
up
over
piston
(5).
d.
Remove
piston
(5)
and
spring
(8).
e.
Remove
packing
(7)
and
back-up
ring
(6)
from
piston
(5).
5-87.
INSPECTION
AND
REPAIR.
(Beginning
with
aircraft
serials
17271035
and
F17201750.)
(See
figure
5-13.
sheet
2
of
2.)
Repair
is
limited
to
installation
of
new
parts
and
cleaning.
Use
clean
hydraulic
fluid
(MIL-H-5606)
as
a
lubricant during
reassembly
of
the
cylinders.
Replace
packing
and
back-up
ring.
Filler
plug
(3)
must
be
vented
so
pressure
cannot
build
up
during
brake
operation.
Remove
plug
and
drill
1/16-inch
hole,
30
°
from
vertical.
if
plug
is
not
vented
Refer
to
view
A-A
for
location
of
vent
hole.
5-88.
REASSEMBLY.
(Beginning
with aircraft
serials
17271035
and
F17201750.)
(See
figure
5-13.
sheet
2
of
2.)
a.
Install
spring
(8)
in
cylinder
body
(9).
b.
Install
back-up
ring
(6)
and
packing
(7)
in
groove
of
piston
(5).
c.
Install piston
(5)
in
cylinder
body
(9).
d.
Install
cover
(4)
over
piston
(5)
and
screw
cover
into
cylinder
body
(9).
5-41
MODEL
172
SERIES
SERVICE
MANUAL
e.
Install
nut
(2) and
clevis
(1).
f.
Install
filler
plug
(3),
making
sure
vent
hole
is
open.
5-89.
BRAKE
MASTER
CYLINDER
INSTALLATION.
a.
Connect
hydraulic
hoses to
brake
master
cylinders
and
install
cylinders.
b.
Connect
brake
master
cylinders
to
rudder
pedals and
connect
parking
brake
link-
age.
c.
Install
bleeder
screw
at
wheel
brake
assembly
and
fill
and
bleed
brake
system
in
ac-
cordance
with
paragraph
5-79.
d.
Install
rudder
bar
shield
and
install
front seats.
NOTE
Ensure
that
seat stops
are installed
properly.
5-90.
BRAKE
LINING
BURN-IN.
The
brake
pads
are
equipped
with
either
a
non-asbestos
or-
ganic
lining or
an
iron
based
metallic
lining.
These
materials
must
be
properly
conditioned
(glazed)
in
order
to
provide
maximum
performance
and
service life.
This
is
accomplished
by
a brake
burn-in.
a.
Non-asbestos
organic
lining.
1.
Taxi
airplane
for
1500
feet
with
engine
at
1700
RPM
applying
brake
pedal
force
as
needed
to develop
a
5
to
9
knots taxi
speed.
2.
Allow
brakes
to
cool
for
10
to
15
minutes.
3.
Apply
brakes
and
check
to
see
if
a
high
throttle
static
run
up may
be
held
with
normal
pedal
force.
If
so,
burn-in
is
completed.
4.
If
static
run
up
cannot
be
held. repeat
steps
1
thru
3
as
needed
to
successfully
hold.
b.
Iron
based
metallic
lining.
1.
Perform
two
consecutive
full
stop
braking
applications
from
30
to
35
knots.
Do
not
allow
the
brake
discs
to
cool
substantially
between
stops.
NOTE
Light
brake
usage
can
cause
the
glaze
to
wear
off,
resulting
in
reduced
brake
performance.
In
such
cases,
the
lining
may
be
conditioned
again
following
the
instructions
set
forth
in
this
burn-in
procedure.
5-91.
PARKING
BRAKE SYSTEM.
(See
figure
5-14.)
5-92.
DESCRIPTION. The
parking
brake
system
employs
a
handle
and
a
ratchet
mechanism
connected
by
a
cable
to
linkge
at
the
brake
master
cylinders.
Pulling
out
on
the
handle
de-
presses both
master
cylinder
piston
rods,
and the
handle
ratchet
locks
the
handle
in
this
position
until
the
handle
is
turned
and
released.
5-93.
REMOVAL
AND INSTALLATION OF COMPONENTS.
See
figure
5-14
for
relative
loca-
tion
of
system
components.
The
figure
may
be
used
for
removal
and
installation
of
parts
of
the
system.
5-42
Revision
3
MODEL
172
SERIES SERVICE
MANUAL
brake
master
cy-
1.
Brake
Hos
e
2.
Brake
Master
Cylinder
3.
Control
Assembly
7.
Catch
Detail
B
8.
Handle
10
Housing
11.
Spring
12.
Tube
14.
Positioning
Rack
15.
Rudder
Pedals
17.
Pulley
18.
Bellcrank
19
Bracket
20.
Spring
21.
Brake
Line
F
i
gu
re
5
-1
4.
B
r
a
ke
S
yst
e
m
s
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
6
AILERON
CONTROL
SYSTEM
Page
No.
TABLE OF
CONTENTS
Aerofiche/
Manual
AILERON
CONTROL
SYSTEM
..
1K5/6-1
Repair
.................
1K11/6-7
Description
...............
1K5/6-1
installatiON
.............
1K11/6-7
Trouble
Shooting
...........
1K5/6-1
Cables
and Pulleys
..........
1K11/6-7
Control
"U"
...............
1K6/6-2
Removal/Installation
.......
1K11/6-7
Description
.............
1K6/6-2
Ailerons
.................
1K12/6-8
Removal/Installation
.......
1K7/6-3
Removal
................
1K12/6-8
Repair
.................
1K7/-3
Installation
.............
1K12/6-8
Aileron
Bellcrank
..........
1K7/3
Repair
.................
1K12/6-8
Removal
................
1K11/6-7
Rigging
.................
1K12/6-8
6-1.
AILERON
CONTROL
SYSTEM.
(See
figure
6-1.)
6-2.
DESCRIPTION.
The
aileron control
system
consists
of
two
control
wheels, one
for
the
pilot
and
one
for the
copilot,
attached
to
columns
and
linked
by
universal
joints
to
the
control
"U"
located
behind
the
instrument
panel.
Lateral
rotation
of
either
control wheel
is
transmitted
to
the
ailerons,
one
per wing,
via
a
series
of
sprockets.
chains,
pulleys,
cables, bellcranks
and
push-pull
tubes.
6-3.
TROUBLE
SHOOTING.
NOTE
Due
to
remedy
procedures
in
the
following
trouble
shoot-
ing
chart
it
may
be
necessary
to
rerig
system,
refer
to
paragraph
6-18.
TROUBLE
PROBABLE
CAUSE REMEDY
LOST MOTION
IN
CONTROL
Loose
control
cables.
Adjust
cables
to
proper
WHEELS.
tension.
Broken
pulley
or
bracket,
Replace
worn
or
broken
cable
off
pulley
or
worn
parts.
install
cables
rod end
bearings.
correctly.
Sprung
bellcrank.
Replace
bellcrank.
Loose
chains.
Adjust
chain
tension.
Revision
2 6-1
MODEL
172
SERIES SERVICE
MANUAL
6-3.
TROUBLE SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
RESISTANCE
TO
CONTROL
Cables
too
tight.
Adjust
cables
to
proper
WHEEL
MOVEMENT.
tension.
Pulleys
binding
or
cable
Replace
defective
pulleys.
off.
Install
cables
correctly.
Bellcrank distorted
or
Replace
bellcrank.
damaged.
Defective
U-joints.
Replace
defective
U-joints.
Clevis
bolts
in
system
too
Loosen.
then
tighten prop-
tight.
erly
and
safety.
Rusty
chain
or
chain
bind-
Replace
chain
or
defective
ing
with
sprocket.
parts.
CONTROL WHEELS
NOT
Improper
adjustment
of
Adjust
in
accordance
with
LEVEL
WITH
AILERONS
chains or
cables.
With
paragraph
6-18.
NEUTRAL.
control
wheel centered.
aileron
bellcrank
stop
bush-
ing
should
be
centered
in
slot
(both
left and
right
bellcranks).
Improper
adjustment
of
-
Adjust
in
accordance
with
aileron
push-pull
rods.
paragraph
6-18.
If
chains
and
cables
are
properly
rigged
and bellcrank
stop
bushings
are
not
centered
in
slots.
push-
pull
rods
are
adjusted
incorrectly.
DUAL
CONTROL
WHEELS
Chains
improperly
Adjust
in
accordance
with
NOT
COORDINATED.
adjusted.
paragraph
6-18.
INCORRECT AILERON
Push-pull
rods
not
Adjust
in
accordance
with
TRAVEL
adjusted
properly.
paragraph
6-18
Worn
bellcrank
stop
bush-
Replace
worn
parts.
ings
or
bellcrank
slots.
6-4.
CONTROL
"U".
(See
figure
6-2.)
6-5.
DESCRIPTION. The
control
"U"
transforms
rotation
of
the
control
wheels
into
pulling
motion
on
the
aileron
cables
by
means
of
sprockets
and
chains.
The
"U"
is
pivoted
at
the
lower
end
to
operate
the
elevator
control
system.
6-2
MODEL
172
SERIES SERVICE
MANUAL
6-6.
REMOVAL AND
INSTALLATION.
a.
Disconnect
battery
cables
and insulate
terminals
as
a
safety
precaution
b.
Remove
pedestal
cover
as outlined
in
paragraph
9-17.
c.
Remove
rudder
bar
shields,
carpeting
and
plates
as
necessary
for
access
to
lower
end
of
control
"U".
d.
Remove
radios,
radio cooling
plenums, dust
covers
and
associated
hardware
as
necessary.
e.
Remove
glove
box.
f.
Remove
cabin
air
cooling
hose
directly
below
right
hand
side
of
instrument
panel.
g.
Remove
engine
controls
and
cabin
air
controls
as necessary.
h.
Remove
right
hand
forward
side
upholstery panel.
i.
Remove
bolt
from
each
end
of
parking
brake
assembly
and
swing assembly
away
from
working
area.
j.
Remove
bolt
attaching
bearing
(11)
to
RH
side
of
control
"U"
and
remove bolt
attach-
ing
roller
(32)
(beginning
with
17265685
and
F17201385)
to
LH
side
of
control
"U".
Remove
bearing, roller
and
attaching
hardware.
k.
Drill
out rivets
attaching
instrument
panel
support
(after
completion
of
step "j")
and
remove
support.
1.
Drill
out
rivets
attaching
right
hand
side
panel
to
pedestal
structure
and
remove
panel.
m.
Remove
safety wire
and
disconnect
direct
cable
turnbuckles
(17).
n.
Remove
bolts
(12)
attaching
control
wheel
tubes
to
universal
joints
(13.)
o.
Remove
bolt
(19)
attaching push-pull
tube
(18)
to
control
"U".
p.
Remove
pivot
bolt
(20)
and
carefully
work control
"U"
out
from
under
right
hand
side
of
instrument
panel.
q.
Reverse preceding steps
for
reinstallation.
NOTE
To
prevent loss
of
strength
and
to
ease
reinstallation
of
right
hand
pedestal
structure
side
panel
machine
screws
and
nuts
may
be
installed
in
the
two
upper rivet
holes.
provided
at
least
No.
6
screws are
installed.
r.
Rig
aileron
control
system
in
accordance
with
paragraph
6-18
and
safety
turnbuck-
les
(17).
s.
Check
and/or rig
elevator
control
system
in
accordance
with
paragraph
8-14.
t.
Check
and/or
rig
all
engine
and
cabin
air
controls.
u.
Check
all
radios
and
electrical
components
which
may
have
been
disconnected
or
become
inoperative
while
performing
the
preceding
steps.
v.
Reinstall
all
items
removed
for
access.
6-7.
REPAIR.
Repair
consists
of
replacing
worn.
damaged
or
defective
shafts. bearings.
bushings,
sprockets,
roller
chains,
universal
joints
or
other
components. Refer
to
Section
2
for
lubrication requirements.
6-8.
AILERON
BELLCRANK.
(See
figure
6-3.)
6-3
MODEL
172
SERIES SERVICE
MANUAL
Figure
6-1.
Aileron
Control
System
(Sheet
1
of
2)
6-4
MODEL 172
SERIES SERVICE
MANUAL
1.
Spacer
2.
Pulley
3.
Cable
Guard
4.
Carry-Thru
Cable
Turnbuckle
5.
Carry-Thru
Cable
9
8
6.
Bellcrank
7.
Aileron
8.
Bushing
5
9.
LH
Direct
Cable
10.
RH
Direct
Cable
11.
Direct
Cable
12.
Pulley
Bracket
2
Detail
C
10
13.
LH
Direct
Cable
Turnbuckle
14.
RH
Direct
Cable
Turnbuckle
*
THRU
17269874
&
F17201829
17269875
&
ON
F17201830
THRU
F17202233
Detail
D
CAUTION
Maintain
specified
cable
tension.
Direct
and
follow-
thr
cables:
40
± 10
lbs
at
average
temperature
for
the
area.
Figure
6-1.
Aileron
Control
System
(Sheet
2
of
2)
6-5
MODEL
172
SERIES SERVICE
MANUAL
NOTES
Install
cable
drum
(8)
with
wide
groove
aft.
Primary
cable
(7)
is
wrapped
once
around
aft
groove
of
cable
drum
(8)
with
cable
lock
(9) on
bottom.
Direct
cable
(16)
is
installed
in
forward
groove
of
cable
drum
(8)
with
lock
(14)
on
top.
26
28
23
12
1.
Sprocket
2.
Bolt
3.
Spacer
4.
Chain
5.
Secondary
Cable
6.
Secondary
Cable
Turnbuckle
7.
Primary
Cable
8.
Cable
Drum
9.
Primary
Cable Lock
10.
Bushing
11.
Bearing
12.
Bolt
13.
Universal
Joint
.
14.
Direct
Cable
Lock
15.
Primary
Cable
Turnbuckle
16.
Direct
Cable
17.
Direct
Cable
Turnbuckle
Detail
A
18.
Elevator
Push-Pull
Tube
19.
Bolt
LH
AND
RH
CONTROLS
20.
Pivot
Bolt
*Bushing
(10),
bearing
(11),
and
washer
(30)
used
thru:
21.
Hose
17265684
and
F17201384.
22.
Copilot's
Control
Wheel
23.
Control
Tube
LH
CONTROLS
24.
Shaft
Spacer
(31)
and roller
(32)
beginning
serials:
25.
Retainer
17265685
and
ON.
26.
Pilot's
Control
Wheel
F17201385
thru
F17202233.
27.
Bearing
28.
Countersunk
Washer
NOTE
29.
Shaft
When
dual
controls are
NOT
installed,
spacer
(3)
replaces
30.
Washer
copilot's
control
wheel
(22),
control
tube
(23),
and
universal
31.
Spacer
joint
(13).
32.
Roller
Figure
6-2.
Control
"U"
Installation
6-6
MODEL
172
SERIES SERVICE
MANUAL
6-9.
REMOVAL.
a.
Remove
access
plate
inboard
of
each bellcrank
on
underside
of
wing.
b.
Relieve
control
cable
tension
by
loosening
turnbuckle
barrel
(17).
c.
Disconnect
control cables
from
bellcrank
Retain
all
spacers
(12).
d.
Disconnect
aileron
push-pull
rod
(8)
at
bellcrank.
e.
Remove
nuts,
washers
and
bolts
securing
bellcrank
stop
bushing
(15)
and
bellcrank
(7)
to
wing structure.
f.
Remove
bellcrank
through
access
opening,
using
care
that
bushing
(5)
is
not
dropped
from
bellcrank.
NOTE
Brass
washers
(11)
may
be
used
as
shims
between
lower
end
of
bellcrank
and
wing
channel
(9).
Retain these
shims.
Tape
open
ends
of
bellcrank
to
prevent
dust
and
dirt
from
entering
bellcrank
needle
bearings
(6).
6-10.
REPAIR.
Repair
of
bellcranks consists
of
replacement
of
defective
parts.
If
needle
bearings
are
dirty
or
in
need
of
lubrication,
clean
thoroughly
and
lubricate
as
outlined
in
Section
2.
6-11.
INSTALLATION.
a.
Place
bushing
(5)
and
stop-bushing
(15)
in
bellcrank
(7)
and
position bellcrank
in
wing.
b.
Install
brass
washers
(11)
between
lower
end
of
bellcrank
and
wing
channel
(9)
to
shim out
excess
clearance.
c.
Install
bellcrank
pivot
bolt
(4).
washers
and nut.
d.
Position bellcrank
stop-bushing
and
install
attaching
bolt
(16),
washers
and
nut.
e.
Connect
aileron
cables
and
push-pull
rod
to
bellcrank.
f.
Rig
aileron
system
in
accordance
with applicable
paragraph
in
this
section,
safety
turnbuckle
(17)
and
reinstall
all items
removed
for access.
6-12.
CABLES
AND
PULLEYS. (See
figure
6-1.)
6-13.
REMOVAL
AND
INSTALLATION.
a.
Remove
access
plates,
wing
root
fairings
and
upholstery
as
required
b.
Disconnect cables
from
aileron bellcranks
and
remove
cable
guards
and
pulleys
as
necessary
to
work
cables
free
of
aircraft
NOTE
To
ease
routing
of
cables,
a
length
of
wire
may
be
attached
to
end
of
cable
before
being
withdrawn
from
aircraft
Leave
wire
in
place.
routed
through
structure:
then
attach
cable
being
installed
and use
to
pull
cable into
position.
c.
After
cable
is
routed
install
pulleys
and cable
guards.
Ensure
cable
is
positioned
in
pulley
groove
before
installing
guard.
d.
Rig
aileron
system
in
accordance
with
applicable
paragraph
in
this
section.
safety
turnbuckles
and
install
access
plates,
fairings
and
upholstery
removed
in
step
"a"
6-7
MODEL
172
SERIES
SERVICE
MANUAL
6-14.
AILERONS.
(See
figure
6-3.)
6-15.
REMOVAL.
a.
Disconnect
push-pull
rod
(8)
at
aileron.
b.
Remove
screws
and
nuts
attaching
aileron
hinges
(2)
to
trailing
edge
of
wing.
c.
Using
care,
pull
aileron
out
and
down
to
slide
hinges
from
under
wing
skin
and
auxiliary
spar
reinforcements.
6-16.
INSTALLATION.
a.
Position
aileron hinges
between
skin
and
auxiliary
spar
reinforcements
and
install
screws
and
nuts
attaching
hinges
to
trailing
edge
of
wing.
b.
Attach
push-pull
rod
(8)
to
aileron.
NOTE
If
rigging
was
correct
and
push-pull
rod
adjustment
was
not
disturbed,
it
should
not
be
necessary
to
rig
system.
c.
Check
aileron
travel
and
alignment
rig
if
necessary,
in
accordance
with
applicable
paragraph
in
this
section.
6-17.
REPAIR.
Aileron
repair
may
be
accomplished
in
accordance
with
instructions
outlined
in
Section
18.
Before
installation,
ensure
balance
weights
and
hinges
are
securely
attached.
6-18.
RIGGING.
(See
figure
6-2.)
a.
Check
primary
cable (7)
is
in
aft
groove
of
cable
drum
(8)
and
wrapped
once
around
drum.
The
primary
cable
lock
(9)
is
installed
at
bottom
of
drum
and
direct
cable
look
(14)
is
installed
at
top.
b.
With
control
wheels
neutral,
check
chain
ends
(4)
are approximately
equidistant
from
center
of
sprockets
(1).
c.
Keeping
control
wheels
neutral,
tighten
secondary
cable
turnbuckles
(6)
so
control
wheels
are
level
in
neutral
position
(synchronized),
with enough
tension
on
cables
to
remove
slack
from
chains
(4),
without
binding.
Results
of
adjusting
turnbuckles
are
as
follows:
1.
Loosening
secondary
cable
turnbuckles
(6)
and
tightening
direct
cable
turnbuck-
les
(17)
at
center
of
control
"U"
will
move
inboard
sides
of
both
control
wheels
down.
2.
Tightening
either
primary
control
cable
turnbuckle
(15)
and
loosening
secondary
cable
turnbuckles
(6)
at
center
of control
"U"
will
move
outboard
side
of
applica-
ble
control
wheel
down.
d.
Tape
a
bar
across
both
control
wheels
to
hold
them
in
neutral position
e.
Adjust
direct
cable
turnbuckles
(17)
below
control
"U"
and
single
carry-thru
turnbuckle (index
17,
figure
6-3)
at
aileron
bellcrank
(index
7,
figure
6-3)
so
bellcrank
stop
bushings
(index
15,
figure
6-3)
are
centered
in
both
bellcrank
slots
with
40
±
10
pounds
tension
on
aileron
carry-thru
cable
(index
18.
figure
6-3).
Disregard
tension
on
direct
cables.
which
will
be
different
than tension
on
carry-thru
cable.
f.
Adjust
push-pull
rods (index
8.
figure
6-3)
at
each
aileron
until
ailerons
are
neutral
with reference
to
trailng
edge
of
wing
flaps.
Be
sure
wing flaps
are
fully
up
when
making
this
adjustment.
g.
Remove
bar
from
control
wheels.
6-8
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
A
NOTE
14
Carry-thru
cable
turnbuckle
(17)
is
located
at
RH
aileron
bellcrank
thru
17269874
and
F17201829.
Carry-thru
cable
turnbuckle
(17)
18
is
located
above
headliner
beginning
17269875
and
F17201830.
16
1.
Aileron
12
2.
Hinge
3.
Balance
Weight
4.
Pivot
Bolt
5.
Bushing
7.
LH
Bellcrank
8.
Push-Pull
Rod
9.
Channel
10.
Lower
Wing
Skin
11.
Brss
Washer
12.
Spacer
13.
Direct
Cable
14.
Bushing
15.
Bushing
16.
Bolt
17.
Carry-Thru
Cable
Turnbuckle
Detail
A
18.
Carry-Thru
Cable
19.
Washers
Figure
6-3.
Aileron
Installation(Sheet
1
of
3)
6-9
MODEL
172
SERIES
SERVICE
MANUAL
2.
Hinge
3.
Balance Weight
20.
Hinge
Pin
21.
Hinge
22.
Cotter
Pin
23.
Hinge
Pin
Detail
B
AILERON
HINGE
(TYP)
Used
through
Serials
17276254
and
F17202233.
AILERON HINGE
(TYP)
Beginning
Serial:
17276255
and
ON.
Detail
C
NOTE
Install
loop
of
hinge
pin
(23)
on
outboard end
of
hinge.
Figure
6-3.
Aileron
Installation
(Sheet
2
of
3)
6-10
MODEL
172
SERIES SERVICE
MANUAL
2
25
20
24
Detail
D
2.
Hinge
20.
Hinge
Pin
24.
0.89
Diameter
Drill
Rod
25.
MS24665
Cotter
Pin
NOTE
The
following
method
may
be
utilized
to
check
wear
on
aileron
hinges
used
prior
to
Serial
17276254
and
F17202233.
Refer
to
Service
Letter
SE83-18
for
specific
serials
affected.
(1)
Remove
cotter
pins
(22)
from
both
ends
of
hinge.
(2)
Push drill
rod
(24)
or
number
43
drill
bit
into
hole
past
holes
from
which
cotter
pins
(25)
were
removed.
(3)
Bend
one
leg
of
cotter
pin
(25)
back
and attempt
to
install
the
other
leg
into
the
cotter
pin
hole
past
drill
rod
(24).
If
leg
of
cotter
pin
(25)
GOES,
replace
hinge
(2).
If
NO
GO
condition
exits,
hinges are
not
worn
sufficiently
to
require
re-
placement.
(4)
Remove
drill
rods
(24)
and
replace
new
cotter
pins
(25)
in
hinges
(2).
Figure
6-3.
Aileron
Installation
(Sheet
3
of
3)
6-11
MODEL
172
SERIES
SERVICE
MANUAL
AVAILABLE
FROM
CESSNA
SUPPLY
DIVISION (TOOL
NO.
SE716)
Figure
6-4.
Inclinometer
for
Measuring
Control
Surface
Travel
h.
Check
ailerons
for
correct
travel
(figure
1-1)
using
an
inclinometer
(illustrated
in
figure
6-4).
Make
adjustments
if
necessary
and
check
that
the
bushing
travel
stops
are
properly
centered
in
the bellcranks.
i.
Safety
all
turnbuckles
by
the
single-wrap
method.
j.
Install
all
items
removed
for
access.
NOTE
Be
sure
ailerons
move
in
correct
direction
when
operated
by
control
wheel.
6-12
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
7
WING
FLAP
CONTROL
SYSTEM
Page
No.
TABLE
OF CONTENTS
Aerofiche/
Manual
WING
FLAP
CONTROL SYSTEM.
1K21/7-1
Flaps
................... 1L1/7-5
Description
...............
1K21/7-1
Removal/Installation
.......
1L1/7-5
Operation
Check
...........
1K21/7-1
Repair
.................
1L1/7-5
Trouble
Shooting
...........
1K22/7-2
Cable
and
Pulleys
..........
1L1/7-5
Motor
Transmission
Assembly
.
1K24/7-4
Removal/Installation
.......
1L1/7-5
Removal
Installation
.......
1K24/7-4
Rigging
..............
1L37-7
Repair
................. 1L1/7-5
Follow-Up
and Indicating
Drive
Pulleys
.............. 1L1/7-5
System
..................
1L6/7-10
Removal/Installation
.......
1L1/7-5
Description
.............
1L6/7-10
Repair
................. 1L1/7-5
Removal/Installation
.......
1L8/7-12
Rigging
................
1L8/7-12
7-1.
WING
FLAP
CONTROL
SYSTEM.
(See
figure
7-1.)
7-2.
DESCRIPTION.
The
wing
flap
control
system
is
comprised
of
an electric motor
and
transmission
assembly, drive
pulleys, push-pull
rods, cables
and a
follow-up
control.
Power
from
the
motor
and
transmission
assembly is
transmitted
to
the
flaps
by
a
system
of
drive
pulleys,
cables
and
push-pull
rods.
Electrical
power
to
the
motor
is
controlled
by
two
microswitches
mounted
on
a
floating arm assembly,
by
a
camming
lever
and
a
follow-up
control.
As
the
flap
control
lever is
moved to
the
desired
flap
setting,
the
attached
cam
trips
one
of
the
microswitches.
activating
the
flap
motor.
As
the
flaps move
to
the
position
selected,
the
floating arm is
rotated
by
the
follow-up
control
until the active
microswitch
clears
the
cam
breaking
the
circuit
and
stopping the
motor.
To
reverse
flap
direction,
the
control lever
is
moved
in
the
opposite
direction
causing
the cam to
trip
the
second
microswitch
which
reverses
the
flap motor.
The
follow-up
control
moves
the
cam
until
it
is
clear
of
the second
switch,
shutting
off
the flap
motor.
Limit
switches
at
the
flap
actuator
assembly
control
flap
travel
as
the
flaps
reach
the
full
UP
or
DOWN
positions.
7-3.
OPERATIONAL
CHECK.
a.
Operate
flaps through
their
full
range
of
travel observing
for
uneven
travel
or
jumpy
motion,
binding
or
lost
motion.
Ensure
flaps
are
moving
together
through
their
full
range
of
travel.
b.
Check for
positive
shut-off
of
motor
at
flap
travel
extremes
to
prevent
damage
to
actuator
assembly.
c.
With
flaps
full
UP,
mount
an inclinometer
on
one
flap and
set
to
0
°
.
Lower
flaps
to
full
DOWN
position
and
check
flap
angle
as
specified
in
figure
1-1.
Check
approximate
mid-range
percentage
setting
against
degrees
as
indicated
on
inclinometer.
Repeat
the
same procedure
for
the
opposite
flap.
NOTE
An
inclinometer
for
measuring
control
surface
travel
is
available
from
the
Cessna
Supply
Division.
See
figure
6-4.
Revision
1
7-1
MODEL
172
SERIES
SERVICE
MANUAL
d.
Remove
access
plates adjacent
to
flap
drive
pulleys
and
attempt
to
rock
pulleys
to
check
for
bearing
wear.
e.
Inspect
flap
rollers
and
tracks
for
evidence
of
binding
or
defective
parts.
7-4.
TROUBLE SHOOTING.
NOTE
Due
to
remedy
procedures
in
the
following
trouble
shoot-
ing
chart
it
may
be
necessary
to
rerig
system,
refer
to
parapaphs
7-16
and
7-20.
TROUBLE
PROBABLE
CAUSE REMEDY
BOTH
FLAPS
FAIL
TO
Open
circuit
breaker.
Reset
and
check
continuity.
MOVE.
Replace
breaker
if
defective.
Defective
switch.
Place
jumper
across
switch.
Replace
if
defective.
Defective
motor.
Remove
and
bench
test
motor.
Replace
if
defective.
Broken
or
disconnected
Run
a
continuity
check
of
wires.
wiring.
Connect
or
repair
wiring.
Defective
or
disconnected
Connect
transmission.
Remove.
transmission.
bench
best
and
replace
trans-
mission
if
defective.
Defective
limit
switch.
Check
continuity
of
switches.
Replace
switches
found
de-
fective.
BINDING
IN
SYSTEM
AS
Cables
not
riding
on Check
visually.
Route
FLAPS
ARE
RAISED
AND
pulleys.
cables
correctly
over
LOWERED.
pulleys.
Bind
in
drive
pulleys.
Check
drive
pulleys
in
motion.
Replace
drive
pul-
leys
found defective.
Broken
or
binding pulleys.
Check
pulleys
for
free
rotation
or
breaks.
Replace
defective
pulleys.
Frayed
cable.
Check
visually.
Replace
defective
cable.
Flaps
binding
on
tracks.
Observe
flap
tracks
and
rollers.
Replace defective
parts.
7-2
MODEL
172
SERIES SERVICE
MANUAL
Detail
A
12
A
SEE
FIGURE
7-2
SEE
FIGURE
7-3
SEE
FIGURE
7-5
SEE
FIGURE
7-5
1.
Cable
Guard
2.
Pulley
3.
Washer
4.
Direct
Cable
5.
Retract
Cable
6.
Turnbuckle
7.
Bolt
BEGINNING
17274125
8.
Screw
AND
F17202040
9.
Bracket
10.
Follow-Up
Control
11.
Flap
Control
Lever
12.
Flap
13.
Drive
Pulley
14.
Spacer
Detail
B
CAUTION
MAINTAIN
SPECIFIED
CONTROL
CABLE
TENSION.
CABLE
TENSION:
30 LBS
±
10
LBS
(AT
AVERAGE
TEMPER-
ATURE
FOR
THE
AREA.)
REFER
TO
FIGURE
1-1
FOR
TRAVEL.
Figure
7-1.
Wing
Flap
Control System
7-3
MODEL
172
SERIES SERVICE
MANUAL
LEFT FLAPS FAILS
TO
Disconnected
or
broken
Check
cable
tension.
Con-
MOVE.
cable. nect
or
replace
cable.
Disconnected
push-pull
Check
visually.
Attach
rod.
push-pull
rod.
INCORRECT
FLAP
TRAVEL.
Incorrect
rigging.
Refer
to
paragraph
7-16.
Defective
operating
switch.
Check
continuity
of
switches.
Replace
switches
found
de-
fective.
FLAPS
FAIL
TO
RETRACT.
Defective
or
disconnected
Check
continuity
of
switch.
flaps
UP
operating
switch.
Connect
or replace
switch.
FLAPS
FAIL
TO
EXTEND.
Defective
or disconnected
Check
continuity
of
switch.
flaps
DOWN
operating
Connect
or replace switch.
switch.
7-5.
FLAP
MOTOR AND
TRANSMISSION
ASSEMBLY.
7-6.
REMOVAL AND
INSTALLATION
(See
figure
7-2.)
a.
Run
flaps
to
full
DOWN
position.
b.
Disconnect
battery
ground
cable
and
insulate terminal
as
a
safety
precaution.
c.
Remove
access
plates
beneath
flap
motor
and
transmission
assembly
in
right
wing.
NOTE
Flap motor
(9).
transmission
(7),
hinge assembly
(10)
and
actuating
tube
(5)
are
removed from
the
aircraft
as
a
unit.
On
aircraft
equipped
with
long
range
fuel
tank.
it
may
be
easier
to
detach motor
and
transmission
assembly
before
removal
from
wing.
d.
Remove
bolt
(20)
securing
actuating
tube
(5)
to
drive
pulley
(13).
e.
Screw
actuating
tube
(5)
in
toward
transmission
(7)
as
far
as
possible
by
hand.
f.
Remove
bolt
(1)
securing
flap
motor
hinge
(10)
to
wing.
Retain
brass
washer
between
hinge
and
wing
structure
for
use
on
reinstallation.
g.
Disconnect
motor
electrical
leads
at
quick-disconnects.
h.
Disconnect
wiring at
limit
switches
(23
and
26).
i.
Carefully work
assembly
from
wing
through
access
opening.
j.
Reverse
preceding
steps
for
reinstallation.
If
hinge
assembly
(10)
was
removed
from
the
transmission
(7)
for
any reason,
ensure
that
short
end
of
hinge
is
reinstalled
toward
the
top.
k.
Use
Loctite
grade
CV
adhesive
on
threads
of
setscrew
(6)
and
collar
(24)
whenever
actuating
tube
(5)
is
removed.
Torque
setscrew
to
60
pound-inches.
l.
Complete
operational
check
as
outlined
in
paragraph
7-3
and
rerig
system
in
accordance
with
paragraph
7-16.
7-4
MODEL
172
SERIES
SERVICE
MANUAL
7-7.
REPAIR.
Repair
consists
of
replacement
of
motor,
transmission,
actuating
tube
and
associated
hardware.
Bearings
in
hinge assembly
may
also
be
replaced.
Lubricate
as
outlined
in
Section
2.
7-8.
DRIVE
PULLEYS.
(See
figure
7-2.)
7-9.
REMOVAL
AND
INSTALLATION.
a.
Remove
access
plate
adjacent
to
drive
pulley
(13)
in
right
wing.
b.
Unzip
or
remove
headliner
as
necessary
for
access
to
turnbuckles
(index
4.
figure
7-
1),
remove
safety
wire
and
loosen
turnbuckles.
c.
Remove
bolt
(19)
securing flap
push-pull
rod
(14)
to
drive
pulley
(13)
and
lower
RIGHT
flap
gently.
d.
Remove
bolt
(20)
securing
actuating
tube
(5)
to
drive
pulley
(13)
and
lower
LEFT
flap
gently.
Retain
bushing.
e.
Remove
cable
locks
(12)
securing
control
cables
to
drive
pulley
(13).
Tag
cables
for
reference
on
reinstallation.
f.
Remove
bolt
(11)
attaching
drive
pulley
(13)
to
wing
structure.
g.
Using
care,
remove
drive
pulley
through
access
opening,
being
careful
not
to
drop
bushing.
Retain
brass
washer
between
drive
pulley
and
wing
structure
for
use
on
reinstallation.
Tape open
ends
of
drive
pulley
after
removal
to
protect
bearings.
h.
To
remove
left
wing
drive
pulley,
use
this
same procedure
omitting
step
"d."
i.
Reverse
the
preceding steps
for
reinstallation.
Rig
system
in
accordance
with
paragraph
7-16,
safety
turnbuckles
and
reinstall
all
items
removed for
access.
7-10
REPAIR.
Repair
is
limited
to
replacement
of
bearings.
Cracked,
bent
or
excessively
worn
drive
pulleys
must
be
replaced.
Lubricate
bearings
as
outlined
in
Section
2.
7-11.
FLAPS.
(See
figure
7-3.)
7-12.
REMOVAL
AND
INSTALLATION.
a.
Run
flaps
to
full
DOWN
position.
b.
Remove
access
plates
(1)
from
top
leading
edge
of
flap.
c.
Disconnect
push-pull
rod
(6)
at
flap
bracket
(7).
d.
Remove
bolts
(5)
at
each
flap
track.
As
flap is
removed
from wing,
all
washers,
rollers
and
bushings
will
fall
free.
Retain
these
for
reinstallation.
e.
Reverse the
preceding
steps for
reinstallation.
If
push-pull
rod
(6)
adjustment
is
not
disturbed,
rerigging
of
system
should
not
be
necessary.
Check
flap
travel
and
rig
in
accordance
with
paragraph
7-16,
if
necessary.
7-13.
REPAIR.
Flap
repair
may
be
accomplished
in
accordance
with
instructions
outlined
in
Section
18.
7-14.
CABLES
AND
PULLEYS.
(See
figure
7-1.)
7-15.
REMOVAL
AND
INSTALLATION.
a.
Remove
access plates,
fairings, headliner
and
upholstery
as
necessary
for access.
b.
If
direct
cable
(4)
is
to
be
removed,
disconnect clamp
(index
7,
figure
7-5)
from
bellcrank
(index
2,
figure
7-5).
c.
Remove
safety
wire,
relieve
cable
tension, disconnect
turnbuckles
(6)
and
carefully
lower
LEFT
flap.
d.
Disconnect
cables
at drive
pulleys,
remove
cable
guards
and
pulleys
as
necessary
to
work cables
free
of
aircraft.
7-5
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Use
Loctite
grade
CV
adhesive
on
threads
of
setscrew
(6)
and
collar
(24)
whenever
actuating
tube
(5)
is
removed.
Torquesetscrew
to
60
pound-inches.
20.
Wing
Structure
5.
Actuating
Tube
7.
Transmission
Assembly
8.
Electrical
Wiring
9.
Motor
Assembly
10.
Hinge
Assembly
11.
Bolt
12.
Cable
Lock
18
13.
Drive
Pulley
14.
Push-Pull
Rod
15.
Attach
Bracket
16.
Bolt
17.
Direct
Cable
18.
Retract
Cable
19.
Bolt
20.
Bolt
21. Set
Screw
-
22.
Switch
Adjustment
Block
23.
Up-Limit
Switch
24.
Switch
Actuating
Collar
25.
Support
26.
Down-Limit
Switch
-
VIEW
A-A
Figure
7-2.
Flap
Motor
and
Transmission
Installation
7-6
MODEL
172
SERIES SERVICE
MANUAL
NOTE
To
ease
routing
of
cables,
a
length
of
wire
may
be
attached
to
the
end
of
cable
being withdrawn
from the
aircraft.
Leave
wire
in
place.
routed
through
structure;
then
attach
the
cable
being
installed
and
use
wire to
pull
cable
into
position.
e.
Reverse
the
preceding
steps
for reinstallation.
f.
After
cables are
routed
in
position.
install
pulleys
and
cable
guards. Ensure
cables
are
positioned
in
pulley
grooves
before
installing
guards
g.
Rerig flap
system
in
accordance
with
paragraph
7-16
and
safety
turnbuckles.
h.
Rerig
follow-up
system
in
accordance
with
paragraph
7-20
and
reinstall
all
items
removed
in
step
"a."
7-16.
RIGGING.
a.
(See
figure
7-1.)
Unzip
or
remove
headliner
as
necessary
for
access
to
turnbuckles
(6).
b.
With
flaps
in
the
full
UP
position.
disconnect follow-up
cable
(index
4.
figure
7-5)
by
removing
clevis
attaching
follow-up
cable
to
bellcrank
(index
2.
figure
7-5).
c.
(See
figure
7-1.)
Remove
safety
wire,
relieve cable
tension,
disconnect
turnbuckles
(6)
and
carefully
lower
left
flap.
d.
(See
figure
7-2.)
Disconnect
push-pull
rods
(14)
at
drive
pulleys
(13)
in
both
wings
and
lower
RIGHT
flap
gently.
e.
Disconnect
actuating
tube
(5)
from
drive
pulley
(13).
NOTE
If
control
cables
are
not connected
to
left and
right
drive
pulleys,
actuating
tube
(5)
and
push-pull
rods
(14)
must
be
disconnected
before
installing
cables.
If
drive
pulleys
(13)
are
not
installed
attach
control
cables
before
install-
ing
drive
pulleys
in
the
wings
as
illustrated
in
figure
7-4.
f.
Adjust
both
push-pullrods
(14)
to
8.83
±.12
inches
between
centers
of
rod
end
bearings
and
tighten
locknuts
on
both
ends.
Connect
push-pull
rods
to
flaps
and
drive
pulleys.
NOTE
Temporarily
connect
cables
at
turnbuckles
(index
6.
figure
7-1)
and
test
flaps
by
hand
to
ensure
both
flaps
extend and
retract
together.
If
they will
not,
the
cables
are
incorrectly
attached
to
the
drive
pulleys.
Ensure
that
the
right
drive
pulley
rotates
clockwise
when
viewed
from
below,
as
the
flaps
are
extended. Tag
cables
for reference
and
disconnect
turnbuckles
again.
7-7
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Beginning
with
Serial
17276296,
the
ac-
NOTE
cess
plates
(1)
are
attached with
recessed
head
screws
in
place of
truss
head
screws.
Bushings
(4),
rollers
(3)
and
spacers
(9)
are
first
positioned
through
slots
in flap
tracks,
*
Airplanes
17261445,17267585
and
On
and
then
are
secured
to
the
flap
roller
supports
(2)
F17201515
and
On
incorporating
SK180-44.
with
attaching
bolts,
washers
and
nuts.
Nylon
When
incorporating
SK180-44only
stainless
steel
plug
buttons
(11)
prevent
wing
flap
from
chafing
washers
(12)
are
used. wing
trailing
edge.
Position
spacers
(9)
and
direction
of
bolts
(5)
as
required
to
provide
adequate
flap
clearance
at
wing
root,
flap
well
skin
and
aileron.
Some
lat-
eral
movement
of
flap
is
inherant
due
to
the
width
of
rollers.
This
movement
should be
considered
when
positioning
spacers
and
direction
of
bolts.
C
Detail
B
1.
Access
Plate
9
2.
Flap
Support
3.
Roller
Assembly
4
4.
Bushing
9
5.
Bolt
6.
Push-Pull
Rod
7.
Flap
Bracket
9
8.
Bolt
9.
Spacer
9
Detail
C
10.
Plug
Button 4
11.
Nylon
Plug
Button
Detail
C
BEGINNING
WITH
12.
Stainless
Steel
Washer
THRU
1980
MODELS
1981
MODELS
OUTBOARD
HINGE
Figure
7-3.
Flap
Installation
7-8
Revision
3
MODEL
172
SERIES SERVICE
MANUAL
g.
(See
figure
7-2.)
Screw
actuating
tube
(5)
IN
toward
transmission
(7)
by
hand
to
.12
-
.05
inches
between
switch
actuating
collar
(24)
and
transmission
as
illustrated
in
View
A-A.
h.
Loosen
setscrew
(6)
securing
actuating
tube
(5)
to
switch
actuating
collar
(24)
and
hold
collar
to
maintain
.12
±
.05
inch
while
holding
RIGHT
flap
in
the
full
UP
position
and
adjust
actuating
tube
(5)
IN
or
OUT.
as
necessary
to
align
with
attachment
hole
in
drive
pulley
(13).
i.
Apply
Loctite
grade
CV
sealant
(or
equivalent)
to
threads
of
setscrew
(6)
and
torque
to
60
inch-pounds.
NOTE
If
actuating
tube
(5)
is
too
long
to
allow
attachment
to
drive
pulley
after
completion
of
step
"h".
proceed
to
step
j.
Disconnect
push-pull
rod
(14)
at
drive
pulley
(13)
to
allow
connecting
actuating
tube
(5)
to
drive
pulley.
k.
Manually
hold
RIGHT
flap
in
full
UP
position
and
readjust
push-pull
rod
(14)
to
align
with
attachment
hole
in
drive pulley.
Connect
push-pull
rod
and
tighten
locknuts
NOTE
The
right
flap
and
actuator
must
be
correctly
rigged.
before
cables
and
left
flap
can
be
rigged.
l.
With
flaps
in
full
UP
position,
loosen
setscrew
(21)
and
slide
up
limit
switch
adjustment
block
(22)
on
support
(25)
to
just
activate
switch
and
shut
off
electrical
power
to
motor at
this
position.
Tighten setscrew.
m.
Manually
hold
LEFT
flap.
full
UP
and connect
control
cables
at
turnbuckles
(index
6.
figure
7-1).
Remove
reference
tags
previously
installed.
n.
With
flaps
full
UP,
adjust
turnbuckles
to
obtain
30
±
10
pounds
tension
on
cables.
Adjust
retract
cable
(18)
first.
NOTE
Ensure
cables
are positioned
in
pulley
grooves and cable
ends
are
positioned correctly
at
drive
pulleys
before
tightening
turnbuckles.
o.
Disconnect
push-pull
rod
at
left
drive
pulley.
Run
motor
to
extend
flaps
approxi-
mately
20
°
and
check
tension
on
each
flap
cable.
If
necessary,
readjust
turnbuckles
to
maintain
30
±
10
pounds
tension
on
each
cable
and
safety
turnbuckles.
p.
Fully retract
right
flap.
Manually
hold
left
flap
in
full
UP
position
and
readjust
push-
pull
rod
to
align
with
attaching
hole
in
drive
pulley.
Connect
push-pull
rod
and
tighten
locknuts.
NOTE
An
inclinometer
for
measuring
control
surface
travel
is
available
from
the
Cessna
Supply
Divison.
See
figure
6-4.
7-9
MODEL
172
SERIES SERVICE
MANUAL
FLAP
MOTOR
AND
TRANSMISSION
FWD
DRIVE
PULLEY
DRIVE PULLEY
SETSCREW
TO LEFT
TO
RIGHT
VIEWED
FROM
ABOVE
Figure
7-4.
Flap
System
Schematic
TURNBUCKLES
WING
FLAP
WING
FLAP
VIEWED
FROM
ABOVE
Figure
7-4.
Flap
System
Schematic
q.
Mount
an
inclinometer
on
RIGHT
flap and
adjust
to
0°.
r.
Run
flaps
to
full
DOWN
position
and
adj
ust
DOWN
limit
switch
(32)
to
stop
motor
and
flap
at
the
degree
of
travel
specified
in
figure
1-1.
Repeat
check
on
LEFT
flap.
Recheck
limit
switch
through several
flap
cycles.
NOTE
All
flap
rollers
may
not bottom
in
the
flap
tracks
at
the
travel
extremes.
s.
Reconnect
and
rerig
the
flap
follow-up
system
in
accordance
with
paragraph
7-20.
Perform
an
operational
check
in
accordance with
paragraph
7-3.
recheck
all items
for
proper
safetying
and
replace
items
removed
for
access.
7-17.
FLAP
FOLLOW.UP
AND
INDICATING
SYSTEM. (See
figure
7-5.)
7-18.
DESCRIPTION.The
flap follow-up and
indicating
system
consists
of
a
sheathed
cable
assembly.
pointers
and
microswitches.
One
end
of
the cable
is
attached
to
the
flap
operating
switch operating
arm.
The
other
end
is
clamped
to
the
flap
direct
cable,
above
the
headliner
in
the
rear
cabin
area.
Motion of
the
flap
cable
is
transmitted
through
the
follow-up
control
to
the
pointer.
attached
to
the
switch
mounting
arm.
Pointer
moves
along
a
scale
as
the
flaps
are
extended
or
retracted.
When
the
motion
of
the
switch
mounting
arm
with
the attached
operating
switches
positions
the
"active" operating
switch
to
clear
the
cam
on
flap
lever,
flap
motor
circuit
is
broken
and
flaps
stop
at
selected
position.
7-10
MODEL
172
SERIES
SERVICE
MANUAL
A
Detail
A
NOTE
Lubricate
slots
of
guide
(1)
and
bellcrank
(2)
with
Lubri-Bond
"A"
or
Lubri-Bond
220
(Electrofilm
Inc.)
North
Hollywood,
California
or
Perma-Silk
(Everlube
Corp.,)
North
Holly-
wood,
California
Thru
17272169
&
F17201909
*
Beginning
17272170
&
F17201910
10
Detail
A
1.
Guide
13.
Flap
Lever
2.
Bellcrank
14.
Position
Indicator
3.
Mounting
Bracket
15.
Spacer
4.
Follow-Up
Cable
16.
Switch
Mounting
Arm
5.
Bushing
17.
Clamp
Bolt
6.
Flap
Direct
Cable
18.
Flaps
DOWN
Operating
Switch
7.
Clamp
19.
Cam
8.
Washer
20.
Flaps
UP
Operating
Switch
Detail
B
9.
Teflon
Washer
21.
Spring
10.
Support
22.
Clamp
Bolt Washer
11.
Bracket
23.
Insulator
12.
Knob
*
NOTE
Position
center
cable
of
flap
follow-
up
(4)
between
washers
(22)
Figure
7-5.
Flap
Follow-Up
Control
and
Position
Indicator
7-11
MODEL
172
SERIES
SERVICE
MANUAL
7-19.
REMOVAL AND INSTALLATION.
Figure
7-5
can
be
used
as
a
guide
to
removal
and
installa-
tion
of
the
flap
follow-up
and
indicating
system.
NOTE
If
knob
(12)
works
loose
on
flap
lever
(13),
remove
knob
and
clean
threads
on
flap
lever
with
MEK
or
equivalent.
After
threads
have
thoroughly
dried, prime
with
grade
T
primer,
and
allow
primer
to
flash
off
or
dry
from
three
to
five
minutes.
Apply
grade
CU
Loctite
(M1L-S-22473),
Loc-
tite
271.
STA-LOK
Catalog
No.
800.
or
equivalent
to
threads
of
flap
lever
(13).
Install
knob
(12)
and
allow
Loc-
tite
to cure
from
five
to
20
minutes
before
service
use.
7-20.
RIGGING.
(See
figure
7-5.)
a.
Flap
control system
must
be
rigged
in
accordance
with
paragraph
7-16
before
flap
follow-up
system
can
be
rigged.
b.
Disconnect
spring
(21)
from
switch
mounting
arm
(16).
c.
With
flaps
and
flap
lever
(13)
in
full
UP
position
and
holding
flap
position indicator
(14)
to
a
clearance
of
.03
inch
maximum
with
top
of
instrument
panel opening.
pull
center
cable
of
flap follow-up
(index
4,
detail
b)
to
remove
slack.
Connect
cable
thru
clamp
bolt
(17)
observing
note
of
figure
7-5.
d.
Connect
spring
(21)
to
switch
mounting
arm
(16).
e.
Adjust
switches
(18)
and
(20)
in
slotted holes
in
mounting
arm
(16)
until
cam
(19)
is
centered
between
switch
rollers.
f.
Mount
an
inclinometer
on
one
flap
and
set
to
0°
(flaps
full
UP).
Turn
master
switch
ON
and
move flap
lever
(13)
to
10°
position.
NOTE
An
inclinometer
for
measuring
control
surface
travel
is
available
from
Cessna Supply
Division.
See
figure
6-4.
.
Observe
inclinometer
reading
when
flaps
stop.
Adjust
flaps
DOWN
operating
switch
(18)
in
slotted
holes
on
mounting
arm
(16)
as
required
to
obtain
flap
travel
of
10°-0 °-
2°.
h.
Adjust
flaps
UP
operating
switch
(20)
to
obtain
positive clearance
with cam
(19)
when
flaps
DOWN
operating
switch has
just
opened
in
the
10°
position.
i.
Repeat
steps
g.
and
h.
for
20
°
flap
position
(travel
20
° +0°
-2°).
j.
Run
flaps
to
full
DOWN
position
at
the
degree
of
travel
specified
in
figure
1-1.
Check
that
flaps
DOWN
operating
switch
(18)
remains
closed
as
flap
motor
limit
switch
(index
26.
figure
7-2)
stops
flaps
in
full
DOWN
position.
k.
Check
flaps
through several
cycles, recheck
all
components
for
security
and
replace
items
removed
for access.
7-12
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
8
ELEVATOR
CONTROL
SYSTEM
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
ELEVATOR
CONTROL
SYSTEM
.
1L13/8-1
Forward
................
1L168-4
Description
...............
1L13/8-1
Removal/Installation
.....
1L16/8-4
Trouble
Shooting
...........
1L13/8-1
Rear
..................
1L16
8-4
Elevators
.................
1L16/8-4
RemovaL/Installation
.....
1L16
8-4
Removal
Installation
.......
1L16/8-4
Cables
and Pulleys
........
1L18
8-6
Repair
.................
1L16/8-4
Removal/Installation
.....
1L188-6
Bellcranks
................
1L16/8-4
Rigging
................
1L18/8-6
8-1.
ELEVATOR
CONTROL SYSTEM.
8-2.
DESCRIPTION.
The
elevators
are
operated
by
power
transmitted
through
forward
and
aft
movement
of
the control
"U".
This
power reaches
the
elevators
through
a
system
consisting
of
a
push-pull
tube,
cables
and
bellcranks.
The
elevator
control
cables,
at
their
aft
ends.
are
attached
directly
to
a
bellcrank.
installed
between
the
elevators.
This
bellcrank
serves as
an
interconnect
between
the
elevators
and
as
a
bearing
point
for
the
travel
stop
bolts.
A
trim
tab
is
installed
on
the
right
elevator
and
is
described
in
Section
9.
8-3
TROUBLE
SHOOTING
NOTE
Due
to
remedy
procedures
in
the
following
trouble
shoot-
ing
chart
it
may
be
necessary
to
rerig
system,
refer
to
paragraph
8-14.
TROUBLE
PROBABLE
CAUSE
REMEDY
NO
RESPONSE
TO
CON-
Forward
or
aft end
of
push-
Attach
push-pull
tube
TROL
WHEEL
FORE-AND-
pull
tube
disconnected.
correctly.
AFT
MOVEMENT.
Cables
disconnected.
Attach
cables
and
rig
system
in
accordance with
para-
graph
8-14.
Revision
1 8-1
MODEL
172
SERIES
SERVICE
MANUAL
-3.
TROUBLE
SHOOTING
(CoNt).
TROUBLE
PROBABLE
CAUSE
REMEDY
BINDING
OR
JUMPY
Defective
forward
or
rear
Move
to
check
for
play
or
MOTION
FELT
IN
MOVE-
bellcrank
pivot
bearing.
binding.
Replace
bellcrank.
MENT
OF ELEVATOR
SYSTEM.
Cables
slack.
Adjust
to
tension
specified
in
figure
8-1.
Cables
not
riding
correctly
Open
access
plates
and
ob-
on
pulleys.
serve
pulleys.
Route
cables
correctly
over
pulleys.
Nylon
bearing
on
instru-
Disconnect
universal
joint
ment
panel
binding.
and
check
for
binding.
Re-
place
bearing
if
binding
is
felt.
Defective
control
"U"
pivot Disconnect
elevator
push-
bearing.
pull
tube
at
lower
end
of
"U"
and
check
that
control
moves
freely.
Replace
bearing
if
found
defective.
Defective
elevator
hinges.
Move
elevators
by
hand
check-
ing
hinges.
Replace
defective
hinges.
Clevis
bolts
too
tight.
Readjust
to
eliminate
bolt binding.
Lubrication
needed.
Lubricate
in
accordance
with
Section
2.
Defective
pulleys or
cable
Replace
defective
parts
and
guards.
install
guards properly.
ELEVATORS
FAIL
TO
Stops
incorrectly
set.
Check
elevator
travel
with
ATTAIN
PRESCRIBED
inclinometer.
Rig
system
in
TRAVEL.
accordance
with
paragraph
8-14.
Cables
tightened
unevenly.
Rig
system
in
accordance
with
paragraph
8-14.
Interference
at
instru-
Rig
system
in
accordance
ment
paneL
with
paragraph
8-14.
8-2
MODEL
172
SERIES
SERVICE
MANUAL
FIGURE
8-2
SEF
FIGURE
6-2
1.
Pull
ey
2. Bolt
Detail
B
and
C
3.
Rear
Up
Cable
4.
Bolt
5.
Cable
Guard
6.
Rear
Down
Cable
7.
Rear
Bellcrank
8.
Forward
Up
Cable
9.
Forward
Down
Cable
10.
Push-Pull
Tube
11.
Forward
Bellcrank
12.
Bracket
13.
Turnbuckle
12
Detail
F
TRAVEL
Figure
8-1.
Elevator
Control System
8-3
MODEL
172
SERIES SERVICE
MANUAL
8-4.
ELEVATORS.
(See
figure
8-2.)
8-5.
REMOVAL
AND
INSTALLATION.
NOTE
This
procedure
is
written
primarily
for
the
right
elevator
since
the
trim
tab
is
attached
to
this
elevator.
a.
Disconnect
trim
tab
push-pull
channel
(3)
at
tab
actuator.
b.
Remove
bolts
(6)
securing
elevators
to
bellcrank
(9).
NOTE
If
trim
system
is
not
moved
and
actuator
screw
is
not
turned.
rigging
of
trim
system
should
not
be
necessary
after
installation
of
elevator.
c.
Remove
bolts
(16)
from
elevator
hinges.
d.
Using
care.
remove
elevator.
e.
To
remove
left
elevator
use
same procedure.
omitting
step
"a"
f.
Reverse
preceding
steps
for
installation.
Rig
system
in
accordance
with
paragraph
8-14
if
necessary.
8-6.
REPAIR.
Repair
may
be
accomplished
as
outlined
in
Section
18.
If
repair
has
affected
static
balance.
check
and rebalance
as required.
8-7.
BELLCRANKS.
8-8.
FORWARD.
(See
figure
8-1.)
8-9.
REMOVAL AND
INSTALLATION.
a.
Remove
seats,
upholstery
and
access
plates
as
necessary.
b.
Relieve cable
tension
at
turnbuckles
(13)
and
disconnect
cables
from
bellcrank
(11).
c.
Disconnect
push-pull
tube
(10)
from
bellcrank
(11).
d.
Remove
pivot
bolt
and remove bellcrank.
e.
Reverse
preceding
steps
for
installation.
Rig
system
in
accordance
with
paragraph
8-14.
safety
turnbuckles
and
reinstall
all
items removed
in
step
"a".
8-10.
REAR. (See
figure
8-2.)
8-11.
REMOVAL
AND
INSTALLATION.
a.
Remove
rudder. (Refer
to
Section
10.)
b.
Relieve
cable
tension
at
turnbuckles
(index
13,
figure
8-1)
and
disconnect
cables
from
rear
bellcrank
(9).
c.
Remove
bolts
(6)
securing
elevators
to
bellcrank.
d.
Remove
bellcrank pivot
bolt
(8)
and slide
bellcrank
from between
tube
assemblies
(7).
8-4
MODEL
172
SERIES
SERVICE
MANUAL
Do
not
paint
cable
terminals,
bolts,
or
ends
of
elevator
bellcrank
(9).
NOTE
Install
push-pull channel
(3)
with
channel
opening
up
on
all floatplanes
and
landplanes
through
Serials
17274009
3
and
F17202039.
Beginning
with
landplanes
Serials
17274010
and
F17202040,
install
push-pull channel
(3)
with
channel
opening
down.
Detail
A
NOTE
Install
upper
bolt
with
head
to
the
right
and
lower
bolt with head
to
the
left. The cable
end
clevises
must
be
free
to
swivel.
9.
7
1.
Elevator
Tip
2.
Elevator
Trim
Tab
3.
Push-Pull
Channel
4.
Trim
Tab Horn
15
5.
Balance
Weight
6.
Bolt
14
7.
Tube
Assembly
8.
Bolt
9.
Rear
Bellcrank
B
10.
Hinge
Bracket
Detail
B
11.
Bonding
Strap
12.
Horizontal
Stabilizer
13.
Screw
C
14.
Travel
Stop
Bolt
15.
Jamnut
13
10
12
10
Detail
D
Detail
C
Figure
8-2.
Elevator
Installation
Revision
3
8-5
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
It
may
be
necessary
to
remove
one
of
e
stabilizer
attaching
bolts
for
clearance
when
removing
the
bell-
crank
pivot
bolt.
e.
Reverse
preceding
steps
for
installation
Rig
system
in
accordance
with
paragraph
8-14.
safety
turnbuckles
and
resinstall
all
items
removed for
access
8-12.
CABLES AND
PULLEYS.
(See
figure
8-1.)
8-13.
REMOVAL
AND
INSTALLATION.
a. Remove
seats,
upholsteryand
access
plates
as
necessary.
b.
Relieve
cable
tension
at
turnbuckles
(13).
c.
Disconnect
cables
at
forward
bellcrank
(11).
d.
Disconnect
cables
at
rear
bellcrank
(7).
e.
Remove
cable
guards
and
pulleys
as
necessary
to
work
cables
free
of
aircraft.
NOTE
To
ease
routing
of
cables.
a length
of
wire
may
be
attached
to
end
of
cable
before
being
withdrawn
from-
aircraft.
Leave
wire
in
place.
routed
through
structure. attach
cable
being
installed
and
pull
cable
into
position.
f.
After
cable
is
routed
in
position.
install
pulleys
and
cable
guards.
Ensure
cable
is
positioned
in
pulley
groove
before
installing
guards.
g.
Rig
system
in
accordance
with
paragraph
8-14.
safety
turnbuckles
and
reinstall
all
items
removed
in
step
"a".
8-14.
RIGGING. (See
figure
8-1.)
a.
Lock
control
column
in
neutral
position
by
installing
neutral
rigging
tool
(index
2.
figure
8-3).
b.
Streamline elevators
to
neutral
with
horizontal
stabilizer.
NOTE
Neutral
position
measured
with
the
bottom
of
the
balance
area
flush
with
the
bottom
of
the
stabilizer.
c.
Holding
elevators
in
neutralposition.
adjust
turnbuckles
(13)
equally
to
obtain
30
±
10
lbs.
cable
tension.
d.
Mount
an
inclinometer
on
elevator
and,
keeping
elevator
streamlined
with
stabilizer.
set
inclinometer
to
00.
8-6
MODEL
172
SERIES
SERVICE
MANUAL
17276080
&
On
17267585,
17261445
F17202217
&
On
17261578
thru
17276079
F17201515
thru
F17202216
2
3
4
1. Support
2.
Neutral
Rigging
Tool
3.
Instrument
Panel
4.
Pilot's
Control
Column
.46
inch
Press
fit
.62
inch
.30
inch
Detail
A
Fabricate
from
.
125
inch
steel
plate
and
.209
inch
dia.
drill
rod
according
to
dim-
ensions
shown.
Figure
8-3.
Control
Column
Neutral
Rigging Tool
Revision
3
8-7
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
An
inclinometer
for
measuring
control
surface
travel
is
available
from
Cessna
Supply
Division.
See
figure
6-4.
e.
Remove
control
column
neutral rigging
tool
and
adjust
travel
stop
bolts
(index
14.
figure
8-2)
to
range
of
travel
specified
in
figure
1-1.
f.
Check
that
control
"U"
does
NOT
contact
instrument
panel
in
full
UP
position
or
firewall
in
the
full
DOWN
position.
g.
Safety
turnbuckles
(13)
and
travel
stop
bolts:
check
remainder
of
elevator
control
system
for
security
and
reinstall
all
items
removed
for
access.
WARNING
Be
sure
elevators
move
in
the
correct direction
when
operated
by
controls.
8-8
MODEL
172
SERIES SERVICE
MANUAL
SECTION
9
ELEVATOR
TRIM CONTROL
SYSTEM
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
ELEVATOR
TRIM CONTROL
Reassembly
.............
2A8/9-6
SYSTEM
..................
2A3/9-1
Tab
Free-Play
Description
...............
2A3/9-1
Inspection
...............
2A10/9-8
Trouble
Shooting
...........
2A3/9-1
Tab
Control
Wheel
..........
2A10/9-8
Trim
Tab
.................
2A7/9-5
Removal/Installation
.......
2A11
9-9
Removal
Installation
.......
2A7/9-5
Cables
and
Pulleys
..........
2A11/9-9
Tab
Actuator
..............
2A7/9-5
Removal/Installation
.......
2A11/9-9
Removal
Installation
.......
2A7/9-5
Pedestal
Cover.............
2A11/9-9
Disassembly
.............
2A7/9-5
Removal/Installation
.......
2A11/9-9
Cleaning,
Inspection and
Rigging
.................
2A11/9-9
Repair
................
2A8/9-6
9
1.
ELEVATOR
TRIM
CONTROL
SYSTEM.
(See
figure
9-1.)
9-2.
DESCRIPTION.
The
elevator trim
tab,
located
on
the
right
elevator,
is
controlled
by
a
trim
wheel
mounted
in
the
pedestal.
Power
to
operate
the
tab
is
transmitted
from the
trim
control
wheel
by
means
of
chains,
cables
and
an
actuator.
A
mechanical
pointer,
adjacent
to
the
trim
wheel
indicates
tab
position.
A
"nose-up"
setting
results
in a
tab-down
position.
9-3.
TROUBLE
SHOOTING.
NOTE
Due
to
remedy
procedure
in
the following
trouble
shoot-
ing chart
it
may
be
necessary
to
rerig
system,
refer
to
paragraph
9-18.
Revision
1
9-1
MODEL
172
SERIES
SERVICE
MANUAL
9-3.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
TRIM
CONTROL
WHEEL
Cable
tension
too
high. Adjust
tension
as
speci-
MOVES
WITH
EXCESSIVE
fied
in
figure
9-1.
RESISTANCE.
Pulleys
binding
or
rubbing.
Repair
or
replace
as
necessary.
Cables not
in
place
on
Install
cables
correctly.
pulleys.
Trim
tab
hinge
binding.
Disconnect
actuator
and
move
tab
to
check
resist-
ance.
Lubricate
or
replace
hinge
as
necessary.
Defective
trim
tab
actuator.
Remove
chain
from
actuator
sprocket
and
operate
act-
uator
manually.
Replace
act-
uator
if
defective.
Rusty
chain. Replace
rusty
chain.
Damaged
sprocket. Replace
damaged
sprocket.
Bent
sprocket
shaft.
Observe
motion
of
sprockets.
Replace
bent
sprocket
shaft.
LOST
MOTION
BETWEEN
Cable
tension
too
low.
Adjust
tension
as
specified
CONTROL
WHEEL
AND
in
figure
9-1.
TRIM TAB.
Broken pulley.
Replace
defective
pulley.
Cables
not
in
place
on
Install
cables
correctly.
pulleys.
Worn
trim
tab
actuator.
Remove
and
replace
worn
actuator.
Actuator
attachment
loose. Tighten.
TRIM
INDICATOR
FAILS
Indicator
incorrectly
engaged
Reset
indicator.
TO
INDICATE
CORRECT
on
wheel track.
TRIM
POSITION.
INCORRECT
TRIM
TAB
Stop
blocks
loose
or
Adjust stop
blocks
on
TRAVEL.
incorrectly
adjusted.
cables.
See
figure
9-2.
9-2
MODEL
172
SERIES
SERVICE
MANUAL
1.
Pulley
(Sheet
2)
2.
Chain
Guard
3.
Actuator
4.
Aft
Chain
5.
Left
Aft
Cable
.-4
6.
Left
Forward
Cable
7.
Right
Aft
Cable
8.
Turnbuckle
9.
Right
Forward
Cable
10.
Stop
Block
11.
Bushing
12.
Rear
Chain
(SEE
SHEET
2)
13.
Forward
Chain
14.
Trim
Wheel
15.
Sprocket
16.
Pointer
Detail
B
--
17.
Retainer
18.
Pedestal
19.
Roll
Pin
FIGURE
8-2
A1(SEE
SHEET
2)
Detail
A --
.-
CABLE
TENSION:
15
TO
20
LBS
(AT
AVERAGE
TEMPER-
SAFETY
WIRE
ROLL
PIN
(19)
Figure
9-1.
Elevator
Trim
Tab
Control
System
(Sheet
1
of
2)
9-3
MODEL
172
SERIES
SERVICE
MANUAL
Tab
Up
Tab
Up
Tab
Down
Tab
Down
Tab
Down
Tab
Up
Detail
A1
Detail
B1
Tab
Up
Tab
Up
Detail D1
Tab
Down
Tab
Down
Detail
H1
Detail
J1
Figure
9-1.
Elevator
Trim
Tab
Control
System
(Sheet
2
of
2)
HINGE
POINT
TRAILING
EDGE
CHORD
LENGTH
Detail
A
NEUTRAL
POSITION
FREE-PLAY
DOWN
TOTAL
FREE-PLAY
1.
Measure
chord
length
at
extreme
inboard
end
of
trim
tab
as
shown
in
detail
A.
2.
Mulitiply
chord
length
by
0.025
to
obtain
maximum
allowable
free-play.
3.
Measure
free-play
at
same
point
on
trim
tab
that
chord
length
was
measured.
4.
Total
free-play
must
not
exceed
maximum
allow-
able.
Refer
to
detail
B.
Figure
9-1A.
Trim
Tab
Free-Play
Inspection
9-4
MODEL
172
SERIES SERVICE
MANUAL
9-4.
TRIM
TAB.
(See
figure
8-2.)
9-5.
REMOVAL
AND
INSTALLATION.
a.
Disconnect
push-pull
channel
(3)
from
horn
assembly
(4).
b.
Drill
out
rivets
attaching
hinge
to
elevator.
NOTE
After
tab
has
been
removed
and
if
hinge
pin
is
to
be
removed,
it is
necessary
to
spread
the
crimped
ends
of
the
hinge
before
driving
out
pin.
When
a
pin
has
been
installed,
crimp
ends
of
hinge
to
prevent
pin
from
work-
ing
out.
c.
Reverse
preceding
steps
for
installation.
9-6.
TRIM TAB
ACTUATOR.
9-7.
REMOVAL
AND
INSTALLATION.
(See
figure
9-1.)
CAUTION
Position
a
support
stand
under
tail
tie-down
ring
to
prevent
tailcone
from
dropping
while
working
inside.
a.
Remove
baggage
compartment
aft
wall
for
access.
b.
Remove
safety wire
and
relieve
cable
tension
at
turnbuckle
(8).
c.
Disconnect
push-pull
tube
from
actuator
(3).
d.
Remove
access
plate
from
underside
of
right-hand
stabilizer
beneath
actuator.
e.
Remove
chain
guard
(2)
and
disengage
chain
(4)
from
actuator
sprocket.
f.
Remove
screws
attaching
actuator
clamps
to
bracket
and
carefully
work
actuator
out
through
access
opening.
g.
Reverse
the
preceding steps
for
reinstallation.
Rig
trim
system
in
accordance with
paragraph
9-18.
safety
turnbuckle
(8)
and
reinstall
all
items
removed
for
access.
9-8.
DISASSEMBLY.
(See
figure
9-3.)
a.
Remove
actuator
in
accordance
with
paragraph
9-7.
b.
Disassemble
actuator
assembly
(1)
as
illustrated
in
Detail
A
as
follows:
1.
Remove
chain guard
(3)
if
not
previously
removed
in
step
"e"
of
paragraph
9-7.
2.
Using
suitable
punch
and
hammer,
remove
groov-pins
(8)
securing
sprocket
(5)
to
screw
(9)
and
remove
sprocket
from
screw.
3.
Unscrew
threaded
rod
end
(15)
and remove
rod
end
from
actuator.
4.
Remove
groov-pins
(10)
securing
bearings
(6
and
14)
at
the
housing
ends.
5.
Lightly
tap
screw
(9)
toward
the sprocket
end
of
housing,
remove
bearing
(6)
and
collar
(7).
6.
Lightly tap
screw
(9)
in
the
opposite
direction from
sprocket end.
remove
bearing
(14).
O-ring
(13)
and
collar
(7).
7.
It
is
not
necessary
to
remove
retaining rings
(11).
9-5
MODEL
172
SERIES
SERVICE
MANUAL
9-9.
CLEANING.
INSPECTION
AND
REPAIR.
(See
figure
9-
3 .
)
a. DO
NOT
remove
bearing
(16)
from
threaded
rod
end
(15)
unless replacement
of
bearing
is
necessary.
b.
Clean
all
component
parts,
except
bearing
(16).
by
washing
in
Stoddard
solvent
or
equivalent.
Do
not
clean sealed
bearing
(16).
c.
Inspect
all
component
parts
for
obvious
indications
of
damage
such
as
stripped
threads.
cracks.
deep
nicks
and
dents.
d.
Check
bearings
(6
and
14),
screw
(9)
and
threaded
rod end
(15)
for
excessive
wear
and
scoring. Dimensions
of
the
parts
are
as
follows:
BEARING
(6)
INSIDE
DIAMETER
0.373"
MIN.
INSIDE
DIAMETER
0.374"
MAX.
BEARING
(14)
INSIDE
DIAMETER
SMALL HOLE
0.248"
MIN.
SMALL
HOLE
0.249"
MAX.
LARGE
HOLE
0.373"
MIN.
LARGE
HOLE
0.374"
MAX.
THREADED
ROD END
(15)
OUTSIDE DIAMETER
(SHANK)
0.245"
MIN.
0.246"
MAX.
SCREW
(9)
OUTSIDE DIAMETER
0.369"
MIN.
0.370"
MAX.
NOTE
Relative
linear
movement
between
internal
threaded
screw
(9)
and
bearing
(14)
should
be
0.004
to
0.010
inch
at
room
temperature.
e.
Examine
threaded
rod
end
(15)
and
screw
(9)
for
damaged
threads
or dirt particles
that
may
impair
smooth
operation.
f.
Check
sprocket
(5)
for
broken.
chipped
and/or
worn
teeth.
g.
Check
bearing
(16)
for
smoothness
of
operation.
h.
DO
NOT
attempt
to
repair
damaged
or
worn
parts
of
the actuator
assembly.
Discard
all
defective
items
and
install
new
parts
during
reassembly.
9-10.
REASSEMBLY.
(See
figure
9-3.)
a.
Always
discard
the
following
items
and
install
new
parts
during
reassembly:
1.
Groov-Pins
(8
and
10).
2.
O-Ring
(13).
3.
Nuts
(2).
b.
During reassembly,
lubricate
collars
(7),
screw
(9)
and
threaded
rod
end
(15)
in
accordance
with
procedures
outlined
in Section
2.
c.
Install
collar
(7)
and
bearing
(6)
on
screw
(9).
d.
Press
sprocket
(5)
into
the
end
of
screw
(9).
align
groov-pin
holes
and
install
new
groov-pins
(8).
9-6
MODEL
172
SERIES SERVICE
MANUAL
TURNBUCKLE
1.
With
elevators
in
neutral,
set
trim tab
to
neutral (streamlined).
2.
Position
stop
blocks
(2)
and
(3)
approximately 1/4"
fore-and-aft
of
turnbuckle
respectively,
and
secure
to
cable
A.
3.
Place inclinometer
on
trim
tab
and
run
tab
to
DOWN
TRAVEL
limit
listed
in
Section
1.
4.
Position
stop
block
(4)
against
stop
block
(3)
and
secure
to
cable
B.
5.
Run
trim
tab
to
UP
TRAVEL
limit
listed
in
Section
1,
place
stop
block
(1)
against
stop
block
(2)
and
secure
to
cable
B.
Figure
9-2. Elevator
Trim
Tab
Travel
Adjustment
A
1.
Actuator
Assembly
9.
Screw
2.
Nut
10.
Groov-Pin
3.
Chain
Guard
11.
Retaining
Ring
4.
Screw
12.
Housing
5.
Sprocket
13.
O-Ring
6.
Bearing
14.
Bearing
3
7.
Collar
15.
Threaded
Rod
End
2
8.
Groov-Pin
16.
Bearing
Figure
9-3.
Elevator
Trim
Tab
Actuator
Assembly
9-7
MODEL
172
SERIES
SERVICE
MANUAL
e.
Insert
screw
(9),
with
assembled
parts,
into
housing
(12)
until
bearing
(6)
is
flush
with
end
of
housing.
NOTE
When
inserting
screw
(9)
into
housing
(12),
locate
the
sprocket
(5)
at the
end
of
housing
which
is
farther
away
from
the
groove
for
retaining
ring
(11).
The
bearings
(6
and
14)
are
not
pre-drilled
and
must
be
drilled
on
assembly.
The
groov-pins
(10)
are
3/32
inch
in
diameter,
therefore, re-
quiring
a
3/32 (0.0937)
inch
drill.
f.
With
bearing
(6)
flush
with
end
of
housing
(12).
carefully drill
bearing
so
the
drill
will
emerge
from
the
hole
on
the
opposite
side
of
housing
(12).
DO
NOT
ENLARGE
HOLES IN
HOUSING.
g.
Press
new
groov-pins
(10)
into
pin
holes.
h.
Insert
collar
(7).
new
O-ring
(13)
and
bearing
(14)
into
opposite
end
of
housing
(12).
i.
Complete
steps
"f"
and
"g"
for
bearing
(14).
j.
If
a
new
bearing
(16)
is
required,
a
new
bearing
may
be
pressed
into
the
boss.
Be
sure
force
bears
against
the
outer
race
of
bearing.
k.
Screw
the
threaded
rod end
(15)
into
screw
(9).
l.
Install
retaining
rings
(11).
if
they
were
removed.
m.
Test
actuator
assembly
by
rotating
sprocket
(5)
with
fingers
while
holding
threaded
rod
end
(15).
The
threaded
rod
end
should
travel
in and
out smoothly,
with
no
indication
of
binding.
n.
Reinstall actuator
assembly
in
accordance
with
paragraph
9-7.
9-11.
TRIM
TAB
FREE-PLAY INSPECTION.
a.
Place
elevator
and
trim
tab
in
neutral
position
and
secure
elevator
from
movement.
b.
Determine
maximum amount
of
allowable
free
play
using
formula
shown
in
figure
9-
1A.
c.
Using moderate
hand
pressure
(up
and
down),
measure
free-play
at
trailing
edge
of
trim
tab.
d.
If
trim
tab
free-play
is
less than
maximum
allowable,
the
system
is
within
prescribed
limits.
e.
If
trim
tab
free-play
is
more
than
maximum
allowable,
check
the
following
items
for
looseness
while
moving trim
tab
up
and
down.
1.
Check
push-pull
channel
to
trim
tab
horn
assembly
attachment
for
looseness.
2.
Check
push-pull
channel
to
actuator
assembly
threaded
rod
end
attachment
for
looseness.
3.
Check
actuator
assembly
threaded
rod
end
for looseness
in
the
actuator
assem-
bly.
f.
If
looseness
is
apparent
while
checking
steps
e-1
and
e-2.
repair
by
installing
new
parts.
g.
If
looseness
is
apparent
while
checking
step
e-3.
refer
to
paragraphs
9-6
through
9-10.
9-12.
TRIM
TAB CONTROL
WHEEL.
(See
figure
9-1.)
9-8
MODEL
172
SERIES
SERVICE
MANUAL
9-13.
REMOVAL
AND
INSTALLATION.
a.
Relieve
cable
tension
at turnbuckle
(8).
CAUTION
Position
a
support
stand
under
tail
tie-down
ring
to
prevent
tailcone
from
dropping
while
working
inside.
b.
Remove
pedestal
cover
(12).
(Refer to
applicable
paragraph
in
this
section.)
c.
Remove
screws
attaching
control
wheel
retainer
(17).
d.
Remove
retainer
and
pointer
(16).
using
care
not
to
drop control
wheel
(14).
e.
Disengage
roller
chain
(13)
from
sprocket
(15)
and
remove
control
wheel.
f.
Reverse preceding
steps
for
installation.
Rig
system
in
accordance
with
applicable
paragraph
in
this
section.
safety
turnbuckle
and
reinstall
all
items
removed
for
access.
9-14.
CABLES AND PULLEYS.
(See
figure
9-1.)
9-15.
REMOVAL
AND
INSTALLATION.
a.
Remove
seats,
upholstery
and
access
plates as
necessary.
b.
Disconnect cables
at
turnbuckle
(8)
and
cable
ends
(5
and
6).
c.
Remove cable
guards
and
pulleys as necessary
to
work
cables free
of
aircraft.
NOTE
To
ease
routing
of
cables,
a
length
of
wire
may
be
attached
to
end
of
cable
before
being
withdrawn
from
aircraft
Leave
wire
in
place,
routed
through
structure,
attach
cable
being
installed
and
pull
cable
into
position.
d.
After cable
is
routed
in
position,
install
pulleys
and
cable
guards.
Ensure
cable
is
positioned
in
pulley
groove
before
installing
guards.
e.
Rig
system
in
accordance with
applicable
paragraph
in
this
section.
safety
turn-
buckle
and
reinstall all
items
removed
in
step
"a."
9-16.
PEDESTAL
COVER.
(See
figure
9-1.)
9-17.
REMOVAL
AND
INSTALLATION.
a.
Remove
fuel
selector
valve
handle
and
placard.
b.
Remove
mike
and
remove
mike
jack
mounting
nut.
c.
Remove
screws
attaching
pedestal
cover
to
structure
and
remove
cover.
9-18.
RIGGING.
(See
figure
9-1.)
CAUTION
Position
a
support
stand
under
tail
tie-down
ring
to
prevent
tailcone
from
dropping
while
working
inside.
a.
Remove
rear
baggage compartment
panel
and
access
plates
as
necessary.
b.
Loosen
travel
stop
blocks
(10)
on
cables.
c.
Disconnect
actuator
(3)
from
trim
tab
push-pull
channel.
d.
Check
cable
tension
and
readjust
turnbuckle
(8)
if
necessary.
9-9
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
If
chains
and/
or
cables
are
being
installed.
permit
actua-
tor
screw
to
rotate
freely
as
chains
and
cables
are
connected.
Set
cable
tension.
e.
Rotate
trim
wheel
(14)
full
forward
(nose
down).
Ensure
pointer
(16)
does
not
restrict
wheel
movement.
If
necessary, reposition
pointer
using
a
thin
screwdriver
to
pry
trailing
leg
of
pointer
out
of
groove.
NOTE
Full
forward
(nose
down)
position
of
trim
wheel
is
where
further
movement
is
prevented
by
chain
or
cable
ends
contacting
sprockets
or
pulleys.
f.
With
elevator
and
trim
tab
both
in
neutral
(streamlined),
place
inclinometer
on
tab
and
set
to
zero.
NOTE
An
inclinometer
for
measuring
control
surface
travel
is
available
from
Cessna
Supply
Division.
See
figure
6-4.
g.
Rotate
actuator
screw
in
or
out
as
required
to
place
tab
up
with
a
maximum
of
2°
overtravel.
with
actuator
screw
connected
to
push-pull
channel.
h.
Rotate
trim
wheel
to
position
tab
up
and
down.
readjusting
actuator
screw
as
required
to
obtain
overtravel
in
both
directions.
i.
Position
stop
blocks
(10)
and
adjust
as
illustrated
in
figure
9-2
to
limit
travel
as
specified
in
Section
1.
j.
Check
trim
wheel
pointer
travels
the
same distance
from
ends
of
slot
in
cover.
Reposition
trailing
leg
of
pointer
if
necessary
(refer
to
step
"d").
k.
Safety
turnbuckle
and
reinstall
all
items
removed
in
step
"a".
WARNING
Be
sure
trim
tab
moves
in
correct direction
when
oper-
ated
by
trim
wheel.
Nose
down
trim
corresponds
to
tab
up
position.
9-10
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
10
RUDDER
AND
RUDDER
TRIM
CONTROL
SYSTEMS
Page
No.
TABLE OF
CONTENTS
Aerofiche/
Manual
RUDDER
CONTROL
SYSTEM
...
2A17/10-1
Repair
.................
2A20
10-4
Description
...............
2A17/10-1
Cables
and
Pulleys
..........
2A20/10-4
Trouble
Shooting
...........
2A17/10-1
Removal/Installation
.......
2A20/10-4
Pedal
Assembly
............
2A18/10-2
Rigging
.................
2A20/10-4
Removal
Installation
.......
2A18/10-2
RUDDER TRIM
CONTROL
Rudder
..................
2A20/10-4
SY TEM
..................
2B1/10-9
Removal/Installation
.......
2A20/10-4
Description
...............
2B1/10-9
Rigging
.................
2B1/10-9
10-1.
RUDDER
CONTROL
SYSTEM.
(See
figure
10-1.)
10-2.
DESCRIPTION.
Rudder
control
is
maintained
through
use
of
conventional
rudder
pedals
which also
control
nose wheel
steering.
The
system
is
comprised
of
rudder
pedals.
cables
and
pulleys,
all
of
which
link
the
pedals
to
the
rudder
and
nose
wheel
steering.
Cable
tension
is
automatically
determined
when
the
rudder
pedals
are
rigged
against
return
springs
6.50
inches
from
firewall.
10-3.
TROUBLE
SHOOTING.
NOTE
Due to
remedy
procedures
in
the following
trouble
shoot-
ing
chart
it
may
be
necessary
to
rerig
system,
refer
to
paragraph
10-11.
TROUBLE
PROBABLE CAUSE
REMEDY
RUDDER
DOES
NOT
Broken
or
disconnected
Connect
or
replace cables.
RESPOND
TO
PEDAL
cables.
MOVEMENT.
Revision
1
10-1
MODEL
172
SERIES
SERVICE
MANUAL
10-3.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
BINDING
OR
JUMPY
MOVE-
Cables
too
tight.
See
figure
10-2
for
dist-
MENT
OF
RUDDER
PEDALS.
ance
between
firewall
and
pedals. Adjust
cable
tension
in
accordance
with
para-
graph
10-11.
Cables
not
riding
properly
Route
cables
correctly
over
on
pulleys.
pulleys.
Binding,
broken
or
defec-
Replace
defective
pulleys
tive pulleys
or
cable
and
install
guards
guards.
properly.
Pedal
bars
need
lubrication.
Refer
to
Section
2.
Defective
rudder
bar
If
lubrication
fails
to
eli-
bearings.
minate
binding,
replace
bearing
blocks.
Defective
rudder
hinge
Replace
defective
bushings.
bushings.
Clevis
bolts
too
tight.
Readjust
to
eliminate
binding.
Steering
rods
not
adjusted
Rig
system
in
accordance
properly.
with
paragraph
10-11.
LOST
MOTION
BETWEEN
Insufficient
cable
tension.
See
figure
10-2
for
distance
RUDDER
PEDALS
between
firewall
and
pedals.
AND
RUDDER.
Adjust
cable
tension
in
ac-
cordance
with
paragraph
10-11.
INCORRECT
RUDDER
Incorrect
rigging.
Rig
system
in
accordance
TRAVEL.
with
paragraph
10-11.
10-4.
RUDDER
PEDAL ASSEMBLY. (See
figure
10-2.)
10-5.
REMOVAL
AND
INSTALLATION.
a.
Remove
carpeting,
shields
and
soundproofing
from
pedal
and
tunnel
areas
as
necessary.
b.
Disconnect
master
cylinders
(12)
at
pilot
rudder
pedals.
c.
Disconnect
parking
brake
cables
at
master
cylinders.
d.
Remove
rudder pedals
(2)
and
brake
links
(5).
e.
Relieve
cable
tension
at clevises
(index
11.
figure
10-1).
f.
Disconnect
cables,
return
springs,
trim
bungee.
and
steering
tubes
from
rudder
bars.
g. Remove
bolts
securing
bearing
blocks
(8)
and
work
rudder
bars
out
of
tunnel
area.
10-2
MODEL
172
SERIES
SERVICE
MANUAL
1.
Shackle
10.
Rudder
Cable
15.
Right
Front
Cable
2.
Bellcrank
11.
Clevis
16.
Left
Front
Cable
3.
Travel
Stop
12.
Washer
4.
Right
Rear
Cable
13.
Bushing
5.
Left
Rear
Cable
14.
Stop
Nut
6.
Turnbuckle
7.
Cable
Guard
8.
Pulley
9.
Rudder
Bar
DetailB
4
Detail
A
Detail
B1
(Typical)
14
*
Safety
wire
rudder
travel
stop bolt
(3).
NOTE
10
Shaded
pulleys
used
in
this
system
only.
Detail
E--
REFER
TO
FIGURE
10-5
C1
D1
CABLE
TENSION:
REFER
TO
P
RAGRAPH
10-11.
REFER
TO
FIGURE
1-1
FOR
TRAVEL.
10-3
Detail
C
15
Detail
C1
(Typical)
CABLE
TENSION
CABLE
TENSION:
REFER
TO PARAGRAPH
10-11.
REFER
TO FIGURE
1-1
FOR
TRAVEL.
Figure
10-1.
Rudder
Control
System
10-3
MODEL
172
SERIES SERVICE
MANUAL
NOTE
Rudder
bar
assemblies
should
be
checked
for
excessive
wear
before
installation.
The
bearing
blocks
are
nylon
and
require
no
lubrication
unless
binding
occurs.
A
few
drops
of
general
purpose
oil
should
eliminate
such
bind-
ing.
h.
Reverse
preceding
steps
for
installation.
Rig
system
in
accordance
with applicable
paragraph
in
this
section.
Safety
turnbuckles
or
clevises,
as
applicable,
and
reinstall
all
items
removed
in
step
"a".
10-6.
RUDDER.
(See
figure
10-3.)
10-7.
REMOVAL
AND
INSTALLATION.
a.
Disconnect
tail
navigation light
quick-disconnect
(13).
b.
Relieve
cable
tension at
clevises
(index
11,
figure
10-1)
and
disconnect
clevises
from
rudder
bellcrank
(12).
c.
With
rudder
supported,
remove
hinge
bolts
(1)
and
lift
rudder
free.of
vertical
fin.
d.
Reverse
preceding
steps for
installation.
Rig
system
in
accordance
with
appropriate
paragraph
in
this
section
and
safety
turnbuckles
or
clevises,
as
applicable.
10-8.
REPAIR.
Repair
may
be
accomplished
as
outlined
in
Section
18.
Hinge
bushings
may
be
replaced as
necessary.
10-9.
CABLES.
AND
PULLEYS.
(See
figure
10-1.)
10-10.
REMOVAL
AND
INSTALLATION.
a.
Remove
seats,
upholstery
and
access
plates
as
necessary,
b.
Disconnect cable
at rudder
bar
(9)
and
bellcrank
(2).
c.
Remove
cable
guards
and
pulleys
as
necessary
to
work
cables
free
of
aircraft.
NOTE
To
ease
routing
of
cables,
a
length
of
wire may
be
attached
to
end
of
cable
before
being
withdrawn
from
aircraft.
Leave
wire
in
place,
routed
through structure,
attach
cable
being
installed
and
pull
cable
into
position.
d.
After
cable
is
routed
in
position,
install
pulleys
and cable
guards. Ensure
cable
is
positioned
in
pulley
groove
before
installing
guard.
e.
Rig
system
in
accordance
with
appropriate
paragraph
in
this
section.
Safety
turnbuckles
or
clevises,
as
applicable,
and
reinstall
all
items removed
in
step
"a".
10-11.
RIGGING.
(See
figure
10-1.)
a.
Adjust
travel stops
(3)
to
attain
travel
specified
in
Section
1.
Figure
10-4
illustrates
correct
travel
and
one
method
of
checking.
10-4
MODEL
172
SERIES
SERVICE
MANUAL
*
THRU
17276019
AND
F17202174
*
BEGINNING
WITH
17276020
18
2
AND
F17202175
FIREWALL
CLEARANCE
HOLE
ON
AFT
RUDDER
BAR
*
BEGINNING
WITH
17274931
AND
F17202135
CLEARANCE
HOLE
ON
FORWARD
RUDDER
BAR 12
8
1.
Shaft
18.
Shaft
10
2.
Rudder
Pedal
19.
Shim
3.
Anti-Rattle
Spring
14
4.
Spacer
.
15
5.
Brake
Links
6.
Pivot
Shaft
7.
Aft
Rudder
Bar
NOTE
8.
Bearing
Block
9.
Return
Spring
Brake
links
(5),
bellcranks
(15)
and
attaching
10.
Brake Torque
Tube
parts
are
replaced
with
hubs when
dual
controls
11.
Forward
Rudder
Bar
are
NOT
installed
12.
Master
Cylinder
Detail
B
13.
Bracket
14.
Bearing
Nylon
washers
may
be
installed
between
shaft
15.
Bellcrank
(1)
and
brake
link
(5)
as
required
to eliminate
16.
Single
Control
Hub
excessive
clearance
when
dual
controls
ARE
17.
Rudder
Pedal
Extension
installed.
Figure
10-2.
Rudder
Pedals
Installation
10-5
MODEL
172
SERIES SERVICE
MANUAL
1
BALANCE
WEIGHT
Detail
C
12
1.
Bolt
5.
Center
Hinge
10.
Trim
Tab
2.
Upper
Hinge
6.
Washer
11.
Lower
Tip
3.
Bushing
7.
Nut
12.
Bellcrank
4.
Nutplate
8.
Lower
Hinge
13.
Quick-Disconnect
9. Upper
Tip
Figure
10-3.
Rudder Assembly
10-6
MODEL
172
SERIES SERVICE
MANUAL
BLOCK
RUDDER
HALF
THE
DIS-
TANCE
BETWEEN
STRAIGHTEDGES
MEASURING
ESTABLISHING
NEUTRAL
RUDDER
POSITION
OF
RUDDER
TRAVEL
1.
Establish
neutral
position
of
rudder
by
clamping
straightedge
(such
as
wooden
2
X
4)
on
each
side
of
fin
and
rudder
and blocking
trailing
edge
of
rudder
half
the
distance
between
straightedges
as
shown.
2.
Tape
a
length
of
soft
wire
to
one
elevator
in
such
a
manner
that
it
can
be
bent
to
index
with
a
point
on
rudder
trailing
edge
just
above the
lower
rudder
tip
(disregard
fixed
trim
tab).
3.
Using
soft lead
pencil,
mark
rudder
at
point
corresponding
to
soft wire
indexing
point
(neutral).
4.
Remove
straightedges.
5.
Hold
rudder against
right,
then
left,
rudder
stop.
Measure
the
distance from
pointer
to
pencil
mark
on
rudder
in
each
direction
of
travel.
Distance
should
be
between
5.29"
and
5.91".
Figure
10-4.
Checking Rudder
Travel
10-7
MODEL
172
SERIES
SERVICE
MANUAL
b.
Disconnect
nose
wheel
steering
tubes (refer
to
section
5)
from
nose
strut.
c.
Adjust
cables
at
clevises
(11)
to
align
rudder
and
pedals
in
neutral
position.
6.50
inches
from
firewall
to
pedal
pivot
shafts
(index
6.
figure
10-2).
This
step
automati-
cally
determines
cable
tension
because
of
the
return
springs
(index
9.
figure
10-2)
attached
to the
rudder
bar.
NOTE
Due to
thickness
of
insulation
on
firewall.
it is
recom-
mended
that
a
piece
of
1/16
inch welding
rod
be
ground
to
a
sharp
point
and
notched
at
the
6.50
inch
dimension.
Pierce
insulation
on
firewall
and
use
notch
to
measure
proper
dimension.
d.
Tie
down
or
weight
tail
to
raise
nose
wheel
free
of
ground.
e.
Center
nose
gear
against
external
stop.
f.
Extend
steering
tubes
until
free
play
is
removed.
DO
NOT
COMPRESS
SPRINGS.
g.
Adjust
steering
tube
rod
ends
to
1.00
inch
dimension
between
steering
arm
assembly
and
bolt
hole
as
illustrated
in
section
5
and
tighten
jam
nuts.
h.
Adjust
steering
tube
clevises
to
align
with rod
end
bearings.
NOTE
Extend
steering
tubes
to
seat
rods
against
internal
springs
but
do
not
attempt
to
preload these
springs
by
shortening
rod
end
clevises
after
alignment. Preload
is
built
into
steering
tubes.
i.
Install
clevises
on
rod
ends.
NOTE
DO
NOT
adjust rudder
trim
with
steeringtubes.
Degree
of
steering travel
cannot
be
adjusted.
j.
Rig
rudder
trim
control
system
in
accordance
with
paragraph
10-14.
k.
Safety clevises
(11)
and
install
all
items
removed
for
access.
NOTE
Flight
test aircraft
to
determine
if
ground
adjustment
of
fixed
trim
tab
is
necessary.
DO
NOT
rig
rudder
"off-
center"
unless
trim
tab
does
not
provide adequate
correc-
tion.
WARNING
Be
sure
rudder
moves
in
correct
direction
when
operated
by
pedals.
10-6
MODEL
172
SERIES
SERVICE
MANUAL
10-12.
RUDDER
TRIM CONTROL
SYSTEM.
(See
figure
10-5.)
10-13.
DESCRIPTION.
A
lever
assembly.
actuated
by
the
pilot, is
linked via
a
bellcrank
to
a
rudder
trim
bungee
which
is,
in
turn
connected
directly
to
the
rudder
bar
assembly and hence
to
the
rudder
itself.
The
lever
assembly is
mounted
on
the
center
console
structure
and
utilizes
a
pin
to
positively
lock
the
trim
system
in
any
of
3
positions
left
or
right
of
the
center
of
"neutral'
trim
position.
The
lever
also
serves
as
the
trim
position
indicator.
10-14.
RIGGING.
(See
figure
10-5.)
NOTE
The
rudder control
system
MUST
be
rigged
according
to
paragraph
10-11
prior
to
rigging
the
rudder
trim
control
system.
a.
Tie
down
or
weight
tail
of
the
aircraft
to
raise
nose
wheel
clear
of
ground.
b.
Ensure
nose
wheel,
rudder
and
rudder
pedals
are
all
in
"neutral" position.
c.
Ensure
top
nut
on
bungee
assembly
is
adjusted
to
eliminate
end
play
between
shaft
and
housing.
d.
Install
bungee
(5)
between
rudder
bar
(6),
and
bellcrank
(7)
as
shown
in
figure
10-5.
detail
A.
e.
Make
sure
lever
assembly
(3)
is
in
neutral
position
or
center
hole
of
bracket
(4).
f.
Adjust
ball
ends
of
push
rod
(8)
so
that
ball
end
studs align
with
holes
in
bellcrank
(7)
and
lever
assembly
(3)
and
install
push
rod.
g.
Check
for
security
and
safetying
of
all
components
and
reinstall
all
items
removed
for
access.
WARNING
Be
sure rudder
trim
lever
moves
rudder
in
correct
direc-
tion.
10-9
MODEL
172
SERIES
SERVICE
MANUAL
1.
Console
Structure
2.
Knob
3.
Lever
4.
Bracket
5.
Trim
Bungee
8
6.
Rudder
Bar
7.
Bellcrank
8.
Pushrod
4.
Detail
A
Figure
10-5.
Rudder
Trim
Control
System
10-10
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
11
ENGINE
(O-320-H2AD)
WARNING
When
performing
any
inspection
or
maintenance
that
re-
quires
turning
on
the
master
switch,
installing
a
battery,
or
pulling
the
propeller through
by
hand,
treat
the
prop-
eller
as
if
the
ignition
switch
were
ON.
Do
not
stand,
nor
allow
any
one
else
to
stand,
within
the
arc
of
the
propel-
ler,
since
a
loose
or
broken
wire,
or
a
component
mal-
function,
could
cause
the
propeller
to
rotate.
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
ENGINE
COWLING
..........
2B8/11-2
Description
............
2C3/11-19
Description
...............
2B8/11-2
Removal/Installation
.....
2C3/11-19
Removal
Installation
........
2B8/11-2
Oil
Cooler
...............
2C3
11-19
Cleaning
Inspection
.........
2B11/11-3
Description
............
2C4
11-20
Repair
...................
2B1111-3
Fuel
System
..............
2C4
11-20
ENGIIE
...................
2B11/11-3
Description
.............
2C4'11-20
Description
...............
2B1111-3
Carburetor
..............
2C411-20
Engine
Data
.....
........
2B11/11-3
Removal/Installation
.....
2C4
11-20
Time
Between
Overhaul
(TBO)
.
2B12/11-4
Idle
Speed
and
Mixture
Overspeed
Limitations
.......
2B12/11-4
Adjustments
..........
2C4
11-20
Trouble
Shooting
...........
2B13/11-5
Induction
Air
System
........
2C5
11-21
Removal
..............
2B16/11-8
Description
.............
2C5/11-21
Cleaning
................
2B18
11-10
Removal/Installation
.......
2C5
11-21
Accessories
Removal
........
2B18,11-10
Ignition
System
............
2C6
11-22
Inspection
. .............
2B20/11-12
Description
.............
2C6
11-22
Build-Up
.. ...........
2B20
11-12
Trouble
Shooting
.........
2C6
11-22
Installation
..............
2B20
11-12
Magneto
............... .
2C7
11-23
Flexible
Fluid
Hoses
.....
.2B22/11-14
Description
............
2C7
11-23
Leak
Test
..........
2B22/11-14
Removal/Installation
.....
2C7
11-23
Replacement
...........
2B22/11-14
Internal
Timing
.........
2C8
11-24
Static
Run-up Procedures
....
2B22/11-14
Magneto-to-Engine Timing
. .
2C10
11-26
Baffles
..................
2B23/11-15
Maintenance
.............
2C11
11-27
Description
.... ......
2B23
11-15
Magneto
Check
...........
2C11
11-28
Cleaning
Inspection
......
2B23/11-15
Spark
Plugs
.............
2C13
11-29
Removal
Installation
.......
2B23/11-15
Controls
.................
2C13
11-29
Repair
................
2B23/11-15
Description
............ .
2C13
11-29
Mount
...................
2B23/11-15
Rigging
................
2C14
11-30
Description
.............
2B23/11-15
Throttle
Control
........
2C14
11-30
Removal
Installation
.......
2B23/11-15
Mixture
Control
........
2C15
11-31
Repair
.................
2B24/11-16
Carburetor
Heat
Control
. .
2C17'11-33
Shock-Mount
Pads
..........
2B24
11-16
Starting
System
...........
2C17
11-33
Oil
System
...............
2B24
11-16
Description
............ .
2C17
11-33
Description
.............
2B24
11-16
Trouble
Shooting
.........
2C18
11-34
Trouble
Shooting
.........
2B24/11-16
Primary
Maintenance
......
2C19
11-35
Full-Flow
Oil
Filter
........
2C3
11-19
Starter
Motor
............
2C19
11-35
Revision
1
11-1
MODEL
172
SERIES
SERVICE
MANUAL
RemovalInstallation
.....
2C19
11-35
Extreme
Weather
Maintenance
2C20
11-36
Exhaust
System
...........
2V19
11-35
Cold
Weather
...... ....
2C20
11-36
Description
.............
2C19
11-35
Dusty
Conditions
.....
2C22
11-38
Removal
Installation
.......
2C19
11-35
Seacoast
and
Humid
Areas
.2C22
11-38
Inspection
..............
2C20
11-36
7.
Firewall
Detail
B
11.
Nose
Cap
12.
Engine
Item
(13)
shim
(PN
0552227-1) can
be
installed as
re-
13.
Shim quired
(maximum
4)
between
snupper support
(10)
and
14.
Screw
snubber
(9)
to
obtain
a
maximum
gap
of
.125
inch
be-
tween
snubber
(9)
and
cowl
snubber bracket
(8).
8.
Cowl
Snubber Bracket
Detail
B
9.
Snubber
11.
Nose
Cap
11-2
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
11-1.
ENGINE
COWLING.
11-2.
DESCRIPTION.
The
engine
cowling
is
comprised
of
an
upper
and
lower
cowling
segment.
Instead
of
attaching
directly
to
the
fuselage.
the
cowling
attaches
to
shock
mounts, which
in
turn,
are
fastened
to
the
fuselage.
A
door
in
the
top
cowl
provides access
to
the
engine
oil
dipstick.
oil
filler
neck
and
strainer
drain
control.
Quick-disconnect
fasteners
are
used
at
the
cowling-to
shock
mounts
and
at
the
parting
surfaces
of
the
upper
and
lower
cowl
attach
points.
Machine
screws
secure
the
cowling
segments
together
at
the
nose
caps.
11-3.
REMOVAL
AND
INSTALLATION.
a.
Release
the quick-release
fasteners
attaching
the
cowling
to
the
shock
mounts
and
at
the
parting
surfaces
of
the
upper and
lower
cowling
segments.
(See
figure
11-1.)
b.
Remove
machine
screws
securing
the
cowling
nose
caps
together.
c.
Disconnect
electrical
wiring
at
back
of
landing
light.
d.
Remove
air
filter
cover
from
lower
cowl by
removing
4
attaching
screws
(Thru
Se-
rials
17273579
and
F17202029),
or
4
quick-release
fasteners (Serial
17273580
&
On,
and
F17202030
&
On).
e.
Release
the
4
quick-release
fasteners
from
the
air filter
and
remove
filter
from
cowl.
f.
Reverse
the preceding
steps
for
reinstallation.
Be
sure
that
the baffle
seals
are
turned
in
the
correct
direction
to
confine
and
direct
airflow
around the
engine.
The
vertical
seals
must
fold
forward
and
the
side
seals
must
fold
upward.
Revision
1
11-2A/(
1-2B
blank)
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
When
the
new
shock
mounts
or
brackets
are
being
installed,
careful
measurements
should
be
made
to
posi-
tion these
parts
correctly
on
the
firewall.
These
service
parts
are
not
pre-drilled
Install
shock
mounts
on
brackets
so
that
cowling
stud
and
shock
mount
re
correctly
aligned.
Sheet
aluminum
may
be
used
as
shims
between
bracket
halves
to
provide
proper
cowling
con-
tour.
11-4.
CLEANING
AND
INSPECTION.
Wipe
the
inner
surfaces
of
the
cowling
segments
with
a
clean
cloth
saturated
with
cleaning
solvent
(Stoddard
or
equivalent).
If
the
inside
surface
of
the
cowling
is
coated
heavily
with
oil
or
dirt,
allow
solvent
to
soak
until
foreign
material
can
be
removed.
Wash
painted
surfaces
of
the cowling
with
a
solution
of
mild
soap
and
water
and
rinse
thoroughly.
After
washing,
a coat
of
wax
may
be
applied
to
the
painted surfaces
to
prolong
paint
life.
After
cleaning,
inspect
cowling
for
dents,
cracks,
loose
rivets
and
spot
welds.
Repair
all
defects
to
prevent
spread
of
damage.
11-5.
REPAIR.
If
cowling
skins are
extensively
damaged, new complete
sections
of
the
cowling
should
be
installed.
Standard
insert-type
patches
may
be
used
for
repair
if
repair parts
are
formed
to
fit
contour
of
cowling.
Small
cracks
may
be
stop-drilled
and
small
dents
straightened
if
they
are
reinforced
on
the
inner
surface with
a
doubler
of
the
same
material
as
the
cowling
skin.
Damaged
reinforcement
angles
should
be
replaced
with
new
parts.
Due
to
their
small
size,
new
reinforcement
angles
are
easier
to
install
than
to
repair
the
damaged
part.
11-6.
ENGINE.
11-7.
DESCRIPTION.
On
1977
thru
1980 Models,
an
air
cooled,
wet-sump
four-cylinder,
horizon-
tally-opposed, direct-drive
carbureted
"Blue
Streak"
(Lycoming)
0-320-H
series
engine
is
used
to
power
the
airplane.
The
cylinders,
numbered
from
front
to
rear
are staggered
to
permit
a
separate
throw
on
the
crankshaft
for
each
connecting
rod.
The
right
front
cylinder
is
number
1
and
cylinders
on
the
right
side
are
identified
by
odd
numbers
1
and
3.
The
left
front
cylinder
is
number
2
and
the
cylinders
on
the
left side
are
identified
as
numbers
2
and
4.
Refer
to
paragraph
11-8
for
engine
data
For
repair
and
overhaul of
the
engine,
acces-
sories
and
propeller,
refer
to
the
appropriate
publications
issued
by
their
manufacturer's.
These
publications
are
available
from
the
Cessna
Supply
Division.
11-8.
ENGINE
DATA.
MODEL
(Lycoming)
O-320-H2AD
BHP
at
RPM
160
BHP
at
2700
RPM
Number
of
Cylinders
4
Horizontally-Opposed
Displacement
319.8
Cubic
Inches
Bore
5.125
Inches
Stroke
3.875
Inches
Compression
Ratio
9.0:1
11-3
MODEL
172
SERIES SERVICE
MANUAL
11-8.
ENGINE
DATA
(Cont).
Magnetos
Bendix
D4RN-2021*
Right
Magneto
Fires
25
°
BTC
1-3
Lower
and
2-4
Upper
Left
Magneto
Fires
25°
BTC
1-3
Upper
and
2-4
Lower
Firing
Order
1-3-2-4
Spark
Plugs
18mm
(Refer
to
Avco
Lycoming
Service
Instruction
No.
1042
for
factory approved
spark
plugs
and
required
gap.)
Torque Value
390
±
30
LB-IN.
Carburetor
(Marvel-Schebler)
MA-4SPA
Oil
Sump
Capacity
6
U.S.
Quarts
With
Filter
Change
7
U.S.
Quarts
Tachometer
Mechanical
Approximate
Dry
Weight
283
Pounds
(Weight
is
Approximate
With
Standard
Accessories
and
will
vary
with
optional
equipment
installed)
Oil
Pressure
Minimum
Idling
25
PSI
Normal
60
to
90
PSI
Maximum
115
PSI
Oil
Temperature
Normal
Operation
Within Green
Arc
Maximum
Permissible
Red
Line
(245°F)
Cylinder
Head
Temperature
500°F
Maximum
(Not
Indicated)
Right
rotating
rotor
as
viewed
from
propeller
end.
11-9.
TIME BETWEEN OVERHAUL
(TBO).
Refer
to
the
latest
Revision
of
Lycoming
Service
Instruction
No.
1009.
and
all
applicable
Service
Letters
or
Service
Bulletins,
for
recommen-
dations
applicable
to
0-320-H
series
engines.
At
the
time
of
overhaul
engine accessories
should
be
overhauled.
11-9A.
OVERSPEED LIMITATIONS.
The
engine
must
not
be
operated
above
specified
maximum
continuous
RPM.
However.
should
inadvertant
overspeed
occur refer
to
the
latest
issue
of
Avco
Lycoming
Service
Bulletin
No.
369
and
all
applicable
Service
Letters
and
Service
Instructions
for
obligatory
recommendations.
11-4
MODEL
172
SERIES
SERVICE
MANUAL
11-10.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE REMEDY
ENGINE
WILL
NOT
START.
Improper
use
of
starting
Refer
to
Pilot's
Operating
procedure.
Handbook.
Fuel
tanks
or
bays
Viually
inspect
tanks
or
empty.
bays.
Fill
with
proper
grade
and
quantity
of
gasolin
Mixture control
in
the
Move
control
to
the
full
IDLE
CUT-OFF
position.
RICH
position.
Fuel
selector
valve
in
Place selector
valve
in
the
OFF
position.
ON
position
to
a
tank
known
to
contain
gasoline.
Defective
carburetor.
Repair
or
replace
carburetor.
Carburetor
screen
or
fuel
Remove
carburetor
and
clean
strainer
plugged.
carburetor
screen
or
fuel
strainer
thoroughly.
Engine
flooded.
Refer
to
Pilot's
Operating
Handbook.
Water
in
fuel
system.
Open
fuel
strainer
drain
and
check
for
water.
If
water
is
present,
drain
fuel
tank
sumps,
lines.
strainer
and
carburetor.
Defective
magneto
switch
Check
continuity.
Repair
or
grounded
magneto
leads.
or
replace
switch
or
leads.
Spark
plugs
fouled.
Remove,
clean
and
regap
plugs.
Test
harness
cables
to
persistently
fouled
plugs.
Replace
if
defective.
11-5
MODEL
172
SERIES
SERVICE
MANUAL
11-10.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
STARTS
BUT
Idle
stop
screw
or
idle
mix-
Refer
to
paragraph
11-43.
DIES.
OR
WILL
NOT IDLE.
ture
incorrectly
adjusted.
Carburetor
idling
jet
Clean
carburetor
plugged.
idling jet.
Spark plugs
fouled
or
im-
Remove.
clean
and
regap
properly
gapped.
plugs.
Replace
if
defective.
Water
in
fuel
system.
Open
fuel
strainer
drain
and
check
for
water.
If
water
is
present,
drain
fuel
tank
sumps.
lines.
strainer
and
carburetor.
Defective
ignition
system.
Refer
to
paragraph
11-55.
Induction
air
leaks.
Check
visually.
Correct
the
cause
of
leaks.
Manual
primer
leaking.
Disconnect
primer
outlet
line.
If
fuel
leaks
through
primer. repair
or
replace
primer.
Leaking
float
valve or
Perform
an
idle
mixture
float
level
set
too
high. check.
Attempt
to
remove
any
rich indication
with
the
idle
mixture
adjustment.
If
the
rich indication cannot
be
re-
moved, the
float
valve
is
leaking
or the
float
level
is
set
too
high.
Replace
defec-
tive
parts,
reset
float
level.
Defective
carburetor.
If
engine will
start
when
primed
but
stops
when
priming
is
discontinued
with
mixture
control
in
full
RICH
position.
the
carburetor
is
defective.
Repair or
replace
carburetor.
MODEL
172
SERIES SERVICE
MANUAL
11-10.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
ENGINE
STARTS
BUT
Defective
engine.
Check
compression.
Liste
DIES.
OR
WILL
NOT
IDLE
for
unusual
engine
noises.
(Cont).
Engine
repair
is
required
ENGINE
RUNS
ROUGHLY
Restriction
n
aircraft
fuel Refer
to
Section
12.
OR
WILL
NOT
ACCEL-
system.
ERATE PROPERLY.
Worn
or
improperly
rigged
Check
visually.
Replace
throttle
or
mixture
control.
worn
linkage.
Rig properly.
Spark
plugs
fouled
or
im- Remove,
clean
and
regap
properly
gapped.
plugs.
Replace
if
defective.
Defective
ignition
system.
Refer
to
paragraph
11-55.
Defective
or
badly
adjusted
Check
setting
of
accelerator
accelerator
pump
in
carbu-
pump linkage
and
adjust
as
retor.
necessary.
Float
level
set
too
low.
Check
and
reset
float
level.
Defective
carburetor.
Repair
or
replace carburetor.
Defective
engine.
Check
compression.
Listen
for
unusual
engine
noises.
Engine
repair
is
required
Restricted
carburetor
air
Check
visually.
Clean
in
filter.
accordance
with
Section
2.
Cracked
engine
mount.
Inspect
and
repair
or
re-
place
mount
as
required.
Defective
mounting
bushings.
Inspect
and
install
new
bushings
as
required
11-7
MODEL
172
SERIES
SERVICE
MANUAL
11-10.
TROUBLE SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
POOR
IDLE
CUT-OFF. Worn
or
improperly
rigged
Check
that
idle cut-off
stop
mixture control.
on
carburetor
is
contacted.
Replace
worn
linkage.
Rig
properly.
Manual
primer
leaking. Disconnect
primer
outlet
line.
If
fuel
leaks
through
primer,
it is
defective.
Repair
or
replace
primer.
Defective
carburetor. Repair
or
replace
carburetor.
Fuel
contamination.
Check
all
screens
in
fuel
system.
Drain
all
fuel
and
flush
out
system.
Clean
all
screens, lines,
strainer
and
carburetor.
11-11.
REMOVAL. If
an
engine
is
to
be
placed
in
storage
or returned
to
the
manufacturer
for
overhaul,
proper
preparatory steps
should
be
taken
for
corrosion
prevention
prior
to
beginning
the
removal
procedure.
Refer
to
Section
2
for
storage
preparation.
The
following
engine
removal
procedure
is
based
upon
the
engine
being removed
from the
aircraft
with
the
engine
mount
attached
to
the
firewall.
NOTE
Tag
each item
when
disconnected
to
aid
in
identifying
wires,
hoses, lines and
control
linkages
when
engine
is
reinstalled.
Likewise,
shop
notes
made
during
removal
will
often
clarify
reinstallation.
Protect
openings,
exposed
as
a
result
of
removing
or disconnecting
units,
against
entry
of
foreign
material
by
installing
covers
or
sealing
with
tape.
a.
Place
all
cabin
switches
in
the
OFF
position.
b.
Place
fuel
selector
valve
in
the
OFF
position.
c.
Remove
engine
cowling
in
accordance
with
paragraph
11-3.
d.
Disconnect
battery
cables
and
insulate
terminals
as
a
safety
precaution.
e.
Drain
fuel
strainer
and
lines
with
strainer
drain
control.
11-8
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
During
the
following
procedures,
remove
any
clamps
or
lacings
which
secure
controls,
wires,
hoses
or
lines
to the
engine. engine mount or
attached brackets,
so
they
will
not interfere with
engine
removal.
Some
of
the
items
listed
can
be
disconnected
at
more
than
one
place.
It
may
be
desirable
to
disconnect
some
of
these
items
at
other
than
the
places
indiated
The
reason
for engine
removal
should
be
the governing
factor
in
deciding
at
which
point
to
disconnect
them.
Omit
any
of
the
items
which
are
not
present
on a
particular
engine
installation.
f.
Drain
the
engine oil
sump
and
oil
cooler.
g.
Disconnect
magneto
primary
lead
wires
at
magnetos.
WARNING
The
magnetos
are
in
a
SWITCH
ON
condition
when
the
switch wires are
disconnected.
Ground
the
magneto
points
or
remove
the
high
tension
wires
from
the
magne-
tos
or
spark
plugs
to
prevent
accidental
firing.
h.
Remove
the
spinner
and
propeller
in
accordance
with
Section
13.
i.
Disconnect
throttle
and
mixture
controls
at
carburetor.
Remove
clamps
attaching
controls
to
engine
and
pull
controls
aft clear
of
engine.
Use
care
to
avoid
bending
controls
too
sharply.
Note
EXACT
position,
size
and
number
of
attaching
washers
and
spacers
for
reference
on
reinstallation.
j.
Loosen
clamps
and
remove
flexible
duct
from
engine
baffle and
oil
cooler.
k.
Loosen
clamps
and
remove
flexible
duct
from
muffler shroud
and
heater
valve.
l.
Disconnect
carburetor
heat
control
at
airbox
and
remove
clamp
attaching
control
to
bracket.
Pull
control
aft
to
clear
engine.
m.
Disconnect
wires
and
cables as
follows:
1.
Disconnect
tachometer drive
shaft
at
adapter.
CAUTION
When
disconnecting
starter
cable
do
not
permit
starter
terminal
bolt
to
rotate.
Rotation
of
the
bolt
could
break
the
conductor
between
bolt
and
field
coils
causing
the
starter
to
be
inoperative.
2.
Disconnect
starter
electrical
cable
at
starter.
3.
Disconnect
cylinder
head
temperature
wire
at
probe.
4.
Disconnect
electrical
wires
and
wire
shielding
ground at
alternator.
5.
Disconnect
EGT
probe
(if
installed).
6.
Remove
all
clamps
and
lacings
attaching
wires
or cables
to
engine
and
pull
wires
and cables
aft
to
clear
engine.
n.
Disconnect
lines
and
hoses
as follows:
1.
Disconnect
vacuum
hose
at
firewall
fitting.
2.
Disconnect
engine breather
hose
at
top
of
accessory
case.
11-9
MODEL
172
SERIES
SERVICE
MANUAL
WARNING
Residual
fuel
and
oil
draining
from
disconnected
lines
and
hoses
constitutes
a
fire
hazard.
Use
caution
to
prevent accumulation
of
such
fuel
and
oil
when
lines
or
hoses
are
disconnected.
3.
Disconnect
oil
temperature
bulb
at
adapter.
4.
Disconnect
primer
line
at
firewall
fitting.
5.
Disconnect
fuel
supply
hose
at
carburetor.
6.
Disconnect
oil
pressure
line
at
firewall
fitting.
7.
Disconnect
oil
cooler hoses
at
cooler.
o.
Carefully check
the
engine
again
to
ensure
ALL
hoses.
lines,
wires,
cables, clamps
and
lacings
are
disconnected
or
removed which
would
interfere with
the
engine
removal.
Ensure
all
wires,
cables
and engine
controls
have
been
pulled
aft
to
clear
the
engine.
p.
Attach
a
hoist
to
the
lifting
eye
at
the
top
center
of
the
engine
crankcase.
Lift
engine
just
enough
to
relieve
the
weight
from
the
engine
mounts.
CAUTION
Place
a
suitable
stand
under
the
tail
tie-down
ring
before
removing
engine.
The
loss
of
engine weight
will
cause
the
aircraft
to
be
tail
heavy.
q.
Remove
bolts
attaching
engine
to
engine mount
and
slowly
hoist
engine
and
pull
it
forward,
checking for any
items
which
would
interfere
with the
engine
removal.
Balance the
engine
by
hand
and
carefully
guide
the
disconnected
parts
out
as
the
engine
is
removed.
11-12.
CLEANING.
Refer
to
Section
2
for
cleaning
of
the
engine.
11-13.
ACCESSORIES
REMOVAL.
Removal
of
engine
accessories
for
overhaul
or
for
engine
replacement
involves
stripping
the
engine
of
parts,
accessories
and
components
to
reduce
it
to
the
bare
engine.
During
the
removal
process,
removed
items
should
be
examined
carefully
and defective
parts
should
be
tagged
for
repair
or replacement with
new
compo-
nents.
NOTE
Items
easily
confused with
similar
items
should
be
tagged
to
provide
a
mean
of
identification
when
being
installed
on
a
new
engine.
All
openings
exposed by
the
removal
of
an
item
should
be
closed
by
installing
a
suitable
cover
or
cap
over the
opening.
This
will
prevent
entry
of
foreign
material.
If
suitable
covers
are
not
available,
tape
may
be
used
to
cover the
openings.
11-10
MODEL
172
SERIES
SERVICE
MANUAL
ENGINE-TO-MOUNT
6
MOUNT-TO-FIREWALL
(UPPER)
4
(UPPER)
TORQUE
MOUNT-TO-FIREWALL
BOLTS TO
160-190 LB-IN
9
2
7
4*
8
NOTE
When
installing
shock
mounts,
install
shock
mount
pad
(8)
as
shown
for
the
upper
and
lower
mounts.
2 4*
4
5
11
3
10
2
3
MOUNT-
TO-FIREWALL
(LOWER) 9
TORQUE ENGINE-TO-MOUNT
6
BOLTS
TO
450-500
LB-IN
ENGINE-TO-MOUNT
(LOWER)
*
BEGINNING
WITH
SERIAL
17267808(LOWER)
F17201518
1.
Nut
4.
Washer
8.
Shock
Mount
Pad
2.
Washer
5.
Firewall
9.
Shock
Mount
Dampener
3.
Engine
Mount
6.
Bolt
10.
Shock
Mount
Pad
7.
Engine
Mount
Foot
11.
Washer
Figure
11-2. Engine
Mount
Details
Temporary
Revision
4
-
Feb
16/96
Revision
3
11-11
MODEL
172
SERIES
SERVICE
MANUAL
11-14.
INSPECTION.
For
specific
items
to
be
inspected,
refer
to
the
engine
manufacturer's
man-
ual.
a.
Visually
inspect
the
engine
for
loose
nuts,
bolts,
cracks and
fin
damage.
b.
Inspect
baffles, baffle
seals and
brackets
for
cracks,
deterioration and breakage.
c.
Inspect
all hoses
for
internal
swelling,
chafing
through
protective
plys,
cuts,
breaks,
stiffness
damaged
threads
and
loose
connections.
Excessive
heat
on
hos-
es
will
cause
them
to
become
brittle
and
easily
broken.
Hoses
and
lines
are
most
likely
to
crack
or
break
near the
end
fittings and
support
points.
d.
Inspect
for
color
bleaching
of
the
end
fittings
or
severe
discoloration
of
the
hoses.
NOTE
Avoid
excessive
flexing
and
sharp
bends
when
exam-
ining
hoses
for
stiffness.
e.
Refer
to
Section
2
for
replacement intervals
for
flexible
fluid
carrying
hoses.
f.
For
major
engine
repairs,
refer
to
the
manufacturer's
overhaul
and
repair
man-
ual.
11-15.
BUILD-UP.
Engine
build-up consists
of
installation
of
parts,
accessories
and
components
to
the
basic
engine
to
build
up
an
engine
unit
ready
for
installation
on
the
aircraft.
All
safe-
ty
wire,
lockwashers,
nuts,
gaskets
and
rubber
connections
should
be
new
parts.
11-16.
INSTALLATION.
Before
installing
the
engine
on
the
aircraft,
install
any
items
which
were
removed
from
the
engine
or
aircraft
after
the
engine was
removed.
NOTE
Remove
all protective
covers,
plugs,
caps
and
identifi-
cation
tags
as each
item
is
connected
or
installed.
Omit any
items
not
present
on
a
particular
engine
in-
stallation.
a.
Hoist
the
engine
to
a
point
near
the
engine
mount.
b.
Install
engine shock-mount pads
as
illustrated
in figure
11-2.
c.
Carefully
lower
engine
slowly
into
place
on
the
engine
mount.
Route
controls,
lines,
hoses
and
wires
in
place
as
the
engine
is
positioned
on
the
engine
mount.
NOTE
Be
sure
engine
shock-mount
pads,
spacers
and
washers
are
in
place
as
the
engine
is
lowered
in-
to
position.
d.
Install
engine
mount
bolts,
washers
and
nuts,
then
remove
the hoist
and
tail
support
stand.
Torque bolts
to
450-500
lb-in.
e.
Route
throttle,
mixture
and
carburetor heat controls
to
the
carburetor
and
airbox and
connect.
Secure
controls
in position
with
clamps.
11-12
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Throughout the
aircraft
fuel
system.
from
the
tanks
to the
carburetor,
use
NS-40
(RAS-4)
(Snap-On-Tools
Corp..
Kenosha,
Wisconsin),
MIL-T-5544
(Thread
Compound
Antiseize,
Graphite
Petrolatum).
USP
Petrolatum
or
engine
oil
as
a
thread
lubricator or
to
seal
a
leaking
connection.
Apply
sparigly
to
male
threads,
exercising
extreme
caution
to
avoid
"stringing"
sealer
across
the
end
of
the
fitting.
Always
ensure that
a
compound.
the
residue
from
a
previously
used
compound,
or
any other
foreign
material
cannot
enter
the
system.
f.
Connect
lines
and
hoses
as
follows:
1.
Connect
oil
cooler
hoses
at
cooler.
2.
Connect
oil
pressure
line
at firewall
fitting.
3.
Connect
fuel
supply
hose
at
carburetor.
4.
Connect
primer
line at
firewall fitting.
5.
Connect oil
temperature
bulb
at
adapter.
6.
Connect
engine
breather
hose at
top
of
accessory
case.
7.
Connect
vacuum
hose at
firewall
fitting.
8.
Install
clamps
and
lacings
attaching
lines
and
hoses to
engine,
engine mount
and
brackets.
g.
Connect
wires
and
cables
as
follows:
1.
Connect
electrical
wires
and wire
shielding
ground
at
alternator.
2.
Connect
cylinder
head
temperature
wire
at
probe.
Do
not
exceed
4
lb-in.
torque.
CAUTION
When
connecting
starter
cable,
do
not
permit
starter
terminal
bolt
to
rotate.
Rotation
of
the
bolt
could
break
the
conductor
between
bolt
and
field
coils
causing
the
starter
to
be
inoperative.
3.
Connect
starter
electrical
cable
at
starter.
4.
Connect
tachometer
drive
shaft
at
adapter.
Be
sure
drive
cable
engages
drive
in
adapter.
Hand
tighten,
then
torque
1/4
turn.
5.
Connect
EGT
probe
(if
installed).
6.
Install
clamps
and
lacings securing wires
and
cables
to
engine.
engine
mount
and
brackets.
h.
Install
flexible
duct
to
heater valve
and engine
baffle
and
install
clamps.
i.
Install
flexible
duct
to
engine
baffle
and
oil
cooler
and
install
clamps.
j.
Install
propeller
and
spinner
in
accordance
with
instructions
outlined
in
Section
13.
k.
Complete
a
magneto
switch ground-out
and
continuity
check,
then
connect
primary
lead
wires
to
the
magnetos.
Remove
the
temporary
ground
or
connect
spark
plug
leads,
whichever
procedure
was
used
during
removal.
WARNING
Be
sure
magneto
switch
is in
OFF
position
when
connect-
ing
switch
wires
to
magnetos.
11-13
MODEL
172
SERIES SERVICE
MANUAL
l.
Clean
and
install
induction air
filter.
m.
Service engine
with
proper
grade
and
quantity
of
engine
oil.
Refer
to
Section
2
if
engine
is
new.
newly
overhauled
or
has
been
in
storage.
n.
Check
all
switches
are
in
the
OFF
position,
and
connect
battery
cables.
o.
Rig
engine
controls
in
accordance with
paragraphs
11-61.
11-62
and
11-63.
p.
Inspect
engine
installation
for
security,
correct
routing
of
controls.
lines,
hoses
and
electrical
wiring,
proper
safetying
and
tightness
of
all
components.
q.
Install
engine
cowling
in
accordance
with
paragraph
11-3.
r.
Perform
an
engine
run-up
and
make
final adjustments
on
the
engine
controls.
11-17.
FLEXIBLE
FLUID
HOSES.
11-18.
LEAK
TEST.
a.
After each
100
hours
of
engine
operation. all
flexible
fluid
hoses
in
the
engine
compartment
should
be
checked
for
leaks
as
follows:
1.
Examine
the
exterior
of
hoses
for
evidence
of
leakage
or
wetness.
2.
Hoses
found
leaking
should
be
replaced.
3.
Refer
to
paragraph
11-14
for
detailed
inspection
procedures
for
flexible
hoses.
11-19.
REPLACEMENT.
a.
Hoses
should
not
be
twisted
on
installation.
Pressure
applied
to
a
twisted
hose
may
cause
failure
or loosening
of
the
nut.
b.
Provide
as
large
a
bend
radius
as
possible.
c.
Hoses
should
have
a
minimum
of
one-half
inch
clearance
from
other
lines.
ducts.
hoses
or
surrounding
objects,
or
be
butterfly
clamped
to
same.
or
tied
together with
S-
1693-3
sta-strap
as
required
to
prevent
chafing..
d.
Rubber
hoses
will
take
a
permanent
set
during
extended use
in
service.
Straighten-
ing
a
hose
with
a
bend
having
a
permanent
set will
result
in
hose
cracking.
Care
should
be
taken
during
removal
so
that
hose
is not
bent
excessively.
and
during
reinstallation
to
assure
hose
is
returned
to
its
original
position.
e.
Refer
to
AC
43.13-1.
Chapter
10,
for
additional
installation
procedures
for
flexible
fluid hose
assemblies.
11-20.
STATIC
RUN-UP
PROCEDURES.
In
a
case
of
suspected
low
engine
power.
a
static
RPM
run-up
should
be
conducted
as
follows:
a.
Run-up
engine,
using
takeoff
power and
mixture
settings,
with
the
aircraft
facing
90
°
right
and
then
left
to
the
wind
direction.
b.
Record
the
RPM
obtained
in
each
run-up
position.
NOTE
Daily changes
in
atmospheric
pressure,
temperature
and
humidity
will have
a
slight
effect
on
static
run-up.
c.
Average
the
RPM
values
obtained
in
step
b.
The
resulting
RPM
figure
should
be
within
60
RPM
of
2340
RPM.
d.
If
the
resulting
average
RPM
figure
is
lower
than
stated
above,
the
following
checks
are recommended
to
determine
a
possible
deficiency.
1.
Check
carburetor
heat
control
for
proper
rigging.
If
partially
open
it
would
cause
a
slight
power
loss.
2.
Check
magneto
timing,
spark
plugs
and
ignition
harness
for
settings
and
conditions.
3.
Check
condition
of
induction
air
filter.
Clean
if
necessary.
4.
Perform
an
engine
compression
check.
(Refer
to
engine
manufacturer's
manual.)
11-14
MODEL
172
SERIES
SERVICE
MANUAL
11-21.
ENGINE
BAFFLES.
11-22.
DESCRIPTION.
The
sheet metal
baffles
installed
on
the engine
direct
the
flow
of
air
around
the
cylinders
and
other
engine
components
to
provide
optimum
cooling.
These
baf-
fles
incorporate
rubber-asbestos
composition
seals
at
points
of
contact
with the
engine
cowling
and
other
engine
components
to
help
confine
and
direct
the
flow
to
the
desired
ar-
ea.
It
is
very
important
to
engine
cooling
that
the
baffles
and seals
are in
good
condition
and
installed
correctly.
The
vertical
seals
must
fold
forward
and
the
side
seals
must
fold
upward.
Removal
and
installation
of
the
various
baffle
segments
is
possible
with
the
cowl-
ing
removed.
Be
sure
that
any
new baffle
seals
properly.
Beginning
with
Serials
17270188
and
F17201730,
two
access
holes
have
been added to
the engine
baffling
to
facilitate
the
ac-
cessibility
of
spark
plugs
on
number
3
and
4
cylinders.
Earlier
1977
and
1978
models
(Se-
rials
17267585
thru
17270187
and
F17201515
thru
F17201729)
can
be
modified
by
the
instructions
contained
in
Service
Letter
SE78-22.
11-23.
CLEANING
AND
INSPECTION. The
engine
baffles
should
be
cleaned
with
a
suitable
sol-
vent
to
remove
oil
and
dirt.
NOTE
The
rubber-asbestos
seals
are
oil
and grease
resistant but
should
not
be
soaked
in
sol-
vent
for
long
periods.
Inspect
baffles
for
cracks
in
the
metal
and
for
loose
and/or
torn
seals.
Repair
or
replace
any
defective
parts.
11-24.
REMOVAL
AND INSTALLATION. Removal
and
installation
of
the
various
baffle
seg-
ments
is
possible
with
the
cowling removed.
Be
sure
that
any
replaced
baffles
and
seals
are
installed
correctly
and
that
they
seal
to direct
the
airflow
in
the
correct
direction.
Various
lines,
hoses,
wires
and
controls
are
routed
through
some
baffles.
Make
sure
that
these
parts
are
reinstalled
correctly
after
installation
of
baffles.
11-25.
REPAIR.
Repair
of
an
individual
segment
of
engine
baffle
is
generally
impractical since,
due
to
the
small
size
and
formed
shape
of
the
part,
replacement
is
usually
more
economical.
However,
small
cracks may
be
stop-drilled
and
a
reinforcing
doubler
installed.
Other
re-
pairs
may
be
made
as
long as
strength
and
cooling
requirements
are
met.
Replace
sealing
strips
if
they
do
not
seal
properly.
11-26.
ENGINE
MOUNT.
(See
figure
11-2.)
11-27.
DESCRIPTION.
The
engine
mount
is
composed
of
sections
of
steel
tubing
welded
together
and reinforced
with
gussets.
The
mount
is
fastened
to
the
fuselage
at
four
points.
The
en-
gine
is
attached
to
the
engine mount
with
shock-mount
assemblies
which
absorb
engine
vi-
brations.
11-28.
REMOVAL
AND
INSTALLATION.
Removal
of
the
engine
mount
is
accomplished
by
re-
moving
the
engine
as
outlined
in
paragraph
11-11,
then
removing
the engine
mount
from
the
firewall.
On
reinstallation,
torque the
mount-to-fuselage
bolts
to
160-190
lb-in.
Torque
the
engine-to-mount
bolts
to
450-500
lb-in.
Temporary
Revision
4
-
Feb
16/96
Revision
3
11-15
MODEL
172
SERIES
SERVICE
MANUAL
11-29.
REPAIR.
Repair
of
the engine
mount
shall
be
performed
carefully
as
outlined
in
Section
18.
Refer
to
Section
19
for
mount
painting.
11-30.
ENGINE
SHOCK
MOUNT
PADS.
(See
figure
11-2.)
The
bonded
rubber and
metal
shock
mounts
are
designed
to
reduce
transmission
of
engine
vibrations
to
the
airframe.
The
rub-
ber
pads
should
be
wiped
clean
with
a
clean,
dry
cloth.
NOTE
Do
not clean
the rubber
pads
and dampener assembly
with
any
type
of
cleaning
solvent.
Inspect
the
metal
parts
for
cracks
and
excessive
wear
due
to
aging
and
deterioration.
In-
spect
the
rubber
pads
for
separation
between the
pad
and
metal
backing,
swelling,
crack-
ing
or
a
pronounced
set
of
the
pad.
Install
new
parts
for
all
parts
that
show
evidence
of
wear
or
damage.
11-31.
ENGINE
OIL
SYSTEM.
11-32.
DESCRIPTION.
The
lubricating
system
is
of
the
full
pressure,
wet
sump
type.
Refer
to
ap-
plicable
engine
manufacturers
overhaul
manual
for
specific
details
and
descriptions.
WARNING
The
U.S.
Environmental
Protection
Agency
advises
that
me-
chanics
and
other
workers
who
handle
engine
oil
are
advised
to
minimize
skin
contact
with
used
oil
and
promptly
remove
used
oil
from
the
skin. In
a
laboratory
study,
mice
developed
skin
cancer
after
skin
was
exposed
to used
engine
oil
twice
a
week
without
being
washed
off, for
most
of
their
life
span.
Sub-
stances
found to
cause
cancer
in
laboratory
animals
may
also
cause
cancer
in
humans.
11-33.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
NO
OIL
PRESSURE.
No
oil
in
sump.
Check
with
dipstick.
Fill
sump
with
proper grade
and
quantity
of
oil.
Refer
to
Section
2.
Oil
pressure
line
broken,
Inspect
pressure
lines.
disconnected
or
pinched.
Replace
or
connect
lines
as
required.
Oil
pump
defective.
Remove
and
inspect.
Ex-
amine engine.
Metal
par-
ticles
from
damaged
pump
may
have
entered
engine
oil
passage.
Defective
oil
pressure
Check
with
a
known
gage.
good
gage.
If
second
reading
is
normal,
re-
place
gage.
11-16
MODEL
172
SERIES
SERVICE
MANUAL
11-33.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
NO
OIL
PRESSURE
Oil
congealed
in
gage
line.
Disconnect
line
at engine
(Cont).
and
gage;
flush
with
kero-
sene.
Pre-fill with
kerosene
and
install.
Relief
valve
defective.
Remove
and
check
for
dirty
or
defective
parts.
Clean
and
install:
replace
valve
if
defective.
LOW
OIL
PRESSURE.
Low
oil
supply.
Check
with
dipstick. Fill
sump
with
proper
grade
and
quantity
of
oil.
Refer
to
Section
2.
Low
viscosity
oil.
Drain
sump
and
refill
with
proper
grade
and
quantity
of
oil.
Oil
pressure
relief
valve
Remove
and
inspect spring.
spring
weak
or
broken.
Replace
weak
or
broken
spring.
Defective
oil
pump.
Check
oil
temperature
and
oil level.
If
temperature
is
higher
than
normal
and
oil
level
is
correct,
internal
failure
is
evident.
Remove
and
inspect.
Examine
engine.
Metal
particles
from
dam-
aged
pump
may
have
entered
oil
passages.
Secondary
result
of
high
Observe
oil
temperature
oil
temperature.
gage
for
high
indication.
Determine
and
correct
reason
for
high
oil
temperature.
Leak
in
pressure or
Inspect
gasket
between
suction
line.
accessory housing
and
crank-
case.
Repair
engine
as
required.
Dirty
oil
screens.
Remove
and
clean
oil
screens.
HIGH
OIL
PRESSURE.
High
viscosity
oil.
Drain
sump
and
refill with
proper
grade and
quantity
of
oil.
Relief
valve
defective.
Remove
and
check for
dirty
or defective
parts.
Clean
and
install:
replace
valve
if
defective.
11-17
MODEL
172
SERIES
SERVICE
MANUAL
11-33.
TROUBLE
SHOOTING (Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
HIGH
OIL
PRESSURE Defective
oil
pressure
gage.
Check
with
a
known
good
Cont).
gage.
If
second
reading
is
normal.
replace
gage.
LOW
OIL
TEMPERATURE.
Defective
oil
temperature
Check
with
a
known
good
gage
or
temperature
bulb. gage.
If
second
reading
is
normal,
replace
gage.
If
read-
ing
is
similar.
the
temperature
bulb
is
defective.
Replace
bulb.
Oil
cooler
thermostatic
Remove
valve
and
check
for
valve/bypass
valve
defec-
proper
operation.
Replace
tive
or
stuck.
valve
if
defective.
HIGH
OIL
TEMPERATURE. Oil
cooler
air
passages
Inspect
cooler
core.
clogged.
Clean
air
passages.
Oil
cooler oil
passages
Attempt
to
drain
cooler.
In-
clogged.
spect
for sediment.
Remove
cooler
and
flush
thoroughly.
Thermostatic
valve
or
by-
Feel
front
of
cooler
core
pass
valve
damaged
or
held
with
hand.
If
core
is
cold.
open
by
solid
matter.
oil
is
bypassing
cooler.
Remove
and
clean
valve
and
seat.
If
still
inoperative,
replace.
Low
oil
supply.
Check
with
dipstick.
Fill
sump
with
proper
grade
and
quantity
of
oil.
Refer
to
Section
2.
Oil
viscosity
too
high.
Drain
sump
and
refill
with
proper
grade
and
quantity
of
oil.
Prolonged
high
speed
oper-
Hold
ground
running
above
ation
on
the
ground.
1500
RPM
to a
minimum.
Defective
oil
temperature
Check
with
a
known
good
gage.
gage.
If
second
reading
is
normal.
replace
gage.
11-18
MODEL
172
SERIES
SERVICE
MANUAL
11-33.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
HIGH
OIL
TEMPERATURE
Defective
oil
temperature
Check
for
correct
oil
pres-
(Cont.)
bulb.
sure,
oil
level
and
cylinder
head
temperature.
If
they
are
correct,
check
oil
temperature
gage
for
being defective:
if
similar
reading
is
observed.
bulb
is
defective.
Replace
bulb.
Oil
congealed
in
cooler.
This
condition
can
occur
only
in
extremely
cold
tem-
peratures.
If
congealing
is
sus-
pected,
use
an
external
heater
or
a
heated
hangar
to
warm
the
congealed
oil.
OIL
LEAK
AT
FRONT
OF
Damaged
crankshaft
seal.
Replace.
ENGINE
OIL
LEAK
AT
PUSH
ROD
Damaged
push
rod
housing
Replace.
HOUSING.
oil
seal.
11-34.
FULL-FLOW
OIL
FILTER.
11-35.
DESCRIPTION.
An
external
full-flow
oil
filter
may
be
installed
on
the
engine.
If
the
filter
should
become
clogged,
a
bypass
valve
allows
engine
oil
to
flow
directly
to
the engine
oil
passages.
11-36.
REMOVAL
AND
INSTALLATION.
NOTE
Replacement
filters
are
available
from
the
Cessna
Supply
Division.
a.
Remove
engine
cowling
in
accordance
with
paragraph
11-3.
b.
Remove
safety
wire
from
filter.
c.
Unscrew
filter
from
adapter.
d.
Lightly
lubricate
gasket
with
engine oil,
(or
DC
4
DOW
CORNING
on
CHAMPION
spin-on filters)
prior
to
installation.
e.
Install
spin-on
filter
on
the
stud
and
torque
to
18-20
lb-ft
or
3/4
to
1
full
turn
after
gasket
makes
contact.
f.
Safety
wire
filter
to
adapter.
g.
After
first
engine
run
check for oil
leaks.
11-37.
OIL
COOLER.
11-19
MODEL
172
SERIES
SERVICE
MANUAL
11-38.
DESCRIPTION.
Beginning
with
Serials
17271954
&
on.
and
F17201910
&
on.
the
external
oil
cooler
is
mounted
on
the
aft
side
of
the
right
aft
vertical
baffle.
Flexible
fire
sleeved
hoses
carry
the
oil
to
and
from
the
cooler.
Cooling
air
for
the
cooler
enters
through
a
hole
in the
baffle
assembly.
Exhaust
air
from
the
cooler
is
discharged
into
the
engine
compartment.
A
bypass
valve
causes
oil
to
bypass
the
cooler
in
the
event
of
congealed
oil
or
an
obstruction
in
the
cooler. At
each
engine oil
change,
drain
the
oil
cooler.
11-39.
ENGINE FUEL
SYSTEM.
11-40.
DESCRIPION.
A
single
barrel,
float-type
up-draft
carburetor
is
installed
on
the
engine.
The
carburetor
is
equipped
with
a
manual mixture
control
and
an
idle
cut-off.
For
repair
and
overhaul
of
the
carburetor
refer
to
the
manufacturer's overhaul
and
repair
manual.
11-41.
CARBURETOR.
11-42.
REMOVAL
AND
INSTALLATION.
a.
Place
fuel
selector
valve
in
the
OFF
position.
b.
Remove
engine
cowling
in
accordance with
paragraph
11-3.
c.
Drain
fuel
from
strainer
and
lines
with
strainer
drain
control.
d.
Disconnect
throttle
and
mixture
controls
at
the
carburetor.
Note
EXACT
position.
size
and
number
of
washers
and
spacers
for reference
on
reinstallation.
e.
Disconnect and
cap
or
plug
fuel
lines
at
carburetor.
f.
Remove
induction
airbox.
g.
Remove
nuts
and
washers
attaching
carburetor
to
intake
manifold
and
remove
carburetor.
h.
Reverse
the preceding steps
for
reinstallation.
Use
new
gasket
between
carburetor
and
intake
manifold.
Check
carburetor
throttle
arm
to
idle
stop
arm attachment
for
security.
proper
torque
and
cotter
pin
installation
at
each
normal
engine inspection
in
accordance
with figure
11-4.
11-43.
IDLE
SPEED
AND MIXTURE
ADJUSTMENTS.
Since
idle
RPM
may
be
affected
by
idle
mixture
adjustment.
it
may
be
necessary
to
readjust
idle
RPM
after
setting
the
idle
mixture.
a.
Start
and
run
engine
until
the
oil
temperature
and
oil
pressure
are
in
the
normal
operating
range.
b.
Check the
magnetos
for
proper
operation
in
accordance
with
paragraph
11-56.
c.
Clear
the
engine
by
advancing
the
RPM to
approximately
1000.
then
retard
the
throttle
to
the
idle
position.
The
engine
RPM
should
stabilize
at
600
-
25.
If
not.
adjust
the
idle
speed
screw
IN
to
increase
and
OUT
to
decrease
RPM.
NOTE
An
engine
should
idle
smoothly, without excessive
vibrations.
The
idle
speed
should
be
high
enough
to
maintain
idling
oil
pressure
and
to
preclude
any
possibil-
ity
of
engine
stoppage
in
flight
when the
throttle
is
closed.
d.
After
the
idle speed
has
stabilized
(600
±
25
RPM)..
move
the
mixture
control slowly
toward
the
IDLE
CUT-OFF
position
and
observe
the
tachometer
for
any
minute
change
during
this
manual leaning
procedure.
11-20
MODEL
172
SERIES SERVICE
MANUAL
e.
Quickly
return
the
mixture control
to
the
FULL
RICH
position
before
the
engine
stops.
f.
A
momentary increase
of
approximately
25
RPM
while
slowly,
manually
leaning
the
mixture
is
most
desirable.
An
increase
of
more
than
25
RPM
indicates
a
rich
idle
mixture,
and
an
immediate
decrease
in
RPM
(if
not
preceded
by
a
momentary
increase),
indicates
a
lean
idle
mixture.
g.
If
the
idle
mixture
is
too
rich,
turn
the idle
mixture adjustment
center
screw
one
or
two
notches
in a
clockwise
direction as
viewed
from
the
aft
end
of
the
unit,
then
repeat
steps
"d"
through
"f".
NOTE
After
each
adjustment
to
the
idle
mixture,
run
engine
up
to
approximately
1800
RPM
to
clear
the
engine
of
excess
fuel
and
obtain
a
correct
idle
speed.
h.
If
the
idle
mixture
is
too
lean,
turn
the
idle
mixture
adjustment
center
screw
one
or
two
notches
in
a
counterclockwise direction
as
viewed
from
the
aft
end
of
the
unit.
then
repeat
steps
"d"
thru
"f".
.This
method
of
adjustment
will
give
the
desired
idle
RPM. If
the
adjustments
do
not
remain
stable,
check
the
throttle
and
mixture linkage
for
evidence
of
wear
and
improper
rigging.
Any
looseness
of
the
throttle
and
mixture
linkage
will
cause
erratic
idling.
In
all
cases,
allowance
should
be
made
for
the
effect
of
weather
condition
upon
idling
adjustment.
The
relation
of
the
aircraft
to
the
prevailing
wind
direction
will
have
an
effect
on
the
propeller
load
and
engine
RPM.
It is
advisable
to
make
idle
adjustments
with the
aircraft
crosswind.
.
11-44.
INDUCTION
AIR
SYSTEM.
11-45.
DESCRIPTION.
Ram
air
to
the
engine enters
the
induction
airbox
through
the
induction
filter
located
in
the
forward
part
of
the lower
engine
cowling.
From
the
induction
airbox
the
air
is
directed
to
the
inlet
of
the
carburetor,
mounted
on
the lower
side
of
the
engine
oil
sump
through
the
carburetor
to
the
center
zone
induction
system.
which
is
an
integral
part
of
the
oil
sump.
From
the
center
zone
system,
the
fuel-air
mixture
is
distributed
to
each
cylinder
by
separate
intake
pipes.
The
intake
pipes
are
attached
to
the
center
zone
risers
with
hoses
and
clamps
and
to
the
cylinder
with
a
two-bolt
flange. which
is
sealed
with
a
gasket.
The
induction
airbox
contains
a
valve,
operated
by
the
carburetor
heat control
in
the
cabin.
which
permits
air
from
an
exhaust
heated
source
to
be
selected
in
the
event
carburetor
icing
or
filter
icing
should
be
encountered.
11-46.
REMOVAL
AND
INSTALLATION.
a.
Remove
and
install
air
filter
as
follows:
1.
Thru
Serials
17273579
and
F17202029.
remove
4
machine
screws
from
metal
trim
around
air
filter
and
remove
trim.
Beginning
with
Serials
17273580
&
On.
and
F17202030
&
On,
4
machine
screws are
replaced
by
4
quick-release
fasteners
2.
Release
4
quick-release
fasteners securing filter
element
to cowl
and
remove
element for
cleaning
or
replacement.
Refer
to
Section
2
for
servicing.
3.
Reverse the
preceding
steps
for
reinstallation.
b.
Remove
and
install
induction airbox
as
follows:
1.
Remove
cowling
as
required
for
access
in
accordance
with
paragraph
11-3.
2.
Mark
the
intake
pipes
as
they are
removed
from
the
engine
so
they may
be
reassembled
in
the
same
location
from
which
they
were
removed.
3.
Loosen
hose
clamps
and
slide
hose
connections
from
sump.
Remove
any
clamps
attaching
wires
or
lines
to
the
intake
pipes.
11-21
MODEL
172
SERIES
SERVICE
MANUAL
4.
Remove
the
nuts. washers
and lock
washers
at
cylinder.
5.
Remove
intake
pipe
and
clean
gasket
from
cylinder
mounting
pad and
intake
pipe flange.
6.
Reverse
the
preceding
steps
for
reinstallation.
Use
new
gaskets
and
install
intake
pipes
in
the
same location
from
which
they
were
removed.
11-47.
IGNITION
SYSTEM.
11-48.
DESCRIPTION.
The
ignition system
is
comprised
of
dual
magnetos,
two
spark
plugs
in
each
cylinder,
an
ignition wiring
harness,
an
ignition
switch
mounted
on
the
instrument
panel
and
required
wiring
between
the
ignition
switch
and
magnetos.
11-49.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
WILL
NOT
START.
Defective
ignition
switch.
Check
switch
continuity.
Replace
if
defective.
Spark
plugs
defective.
Clean.
regap
and
test
plugs.
improperly
gapped
or
Replace
if
defective.
fouled
by
moisture
or
deposits.
Defective
ignition
harness.
If
no
defects are
found
by
a
visual
inspection.
check
with
a
harness
tester.
Replace defective
parts.
Magneto
"P"
lead
Check
continuity.
"P"lead
grounded.
should
not
be
grounded
in
the
ON
position,
but
should
be
grounded
in
OFF
posi-
tion.
Repair
or
replace
"P"
lead.
Failure
of
impulse
coup-
Impulse coupling
pawls
ling.
should
engage
at
cranking
speeds.
Listen
for
loud
clicks
as
impulse couplings
operate.
Remove
magnetos
and determine
cause.
Re-
place
defective
magnetos.
Defective
magneto.
Refer
to
paragraph
11-55.
Broken
drive
gear.
Remove
magneto
and
check
magneto
and
engine
gears.
Replace
defective
parts.
Make
sure
no
pieces
of
damaged
parts
remain
in
engine
or
engine disassembly
will
be
required
11-22
MODEL
172
SERIES
SERVICE
MANUAL
11-49.
TROUBLE
SHOOTING.
(Cont).
TROUBLE
PROBABLE
CAUSE REMEDY
ENGINE
WILL
NOT
Spark plugs
defective,
Clean
regap
and
test
plugs.
IDLE
OR
RUN
PROP-
improperly
gapped
or
Replace
if
defective.
ERLY.
fouled
by
moisture
or
deposits.
Defective
ignition
harness
If
no
defects
are
found
by
a
visual
inspection.
check
with
a
harness
tester.
Re-
place
defective
parts.
Defective
magneto.
Refer
to
paragraph
11-55.
Impulse
coupling
pawls
Listen
for
loud
clicks
as
remain
engaged.
impulse
coupling
operates.
Remove
magneto
and
deter-
mine
cause.
Replace
defec-
tive
magneto.
Spark
plugs
loose.
Check
and
install
properly.
11-50.
MAGNETOS.
11-51.
DESCRIPTION.
The
Bendix
D-2000
series
magneto
consists
of
two
electrically
independent
ignition
circuits
in
one
housing.
A
single
four
pole
rotor
provides
the
magnetic
energy
for
both
circuits.
The
magneto
uses
an
impulse
coupling
to
provide
reliable
ignition
at engine
cranking
speed.
Suppression
of
breaker
contact
point
arcing
is
accomplished
by
feed-thru
type
capacitors
mounted
in
the
magneto
cover
which
forms
a
part
of
the
magneto
harness
assembly.
11-52.
REMOVAL
AND
INSTALLATION.
WARNING
The
magneto
is in a
SWITCH ON
condition
when
the
switch
wire
is
disconnected.
Therefore,
ground
the
breaker
contact
points
or
disconnect
the
high-tension
wires
from
the magneto or
the
spark
plugs.
a.
Remove
engine
cowling
in
accordance
with
paragraph
11-3.
b.
Remove
the
eight
screws
securing
the
high-tension
outlet
cover
to
the
magneto.
The
"P"
leads
may
be
disconnected
for
additional
clearance
if
necessary.
11-23
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
It
is
a
good
practice
to
position
No.
1
cylinder
at
its
approximate
advance
firing
position
before
removing
the
magneto.
c.
Remove
nuts.
washers
and
clamps
attaching
the
magneto
to
the
engine
accessory
housing.
Note
the
approximate
angular
position
at
which
the
magneto
is
installed.
then
remove
the
magneto.
d.
Reverse
the
preceding
steps
for
reinstallation
and
time
magneto-to-engine
in
accordance
with
paragraph
11-54.
11-53.
INTERNAL
TIMING.
(MAGNETO
REMOVED FROM
ENGINE.)
NOTE
A
magneto.
correctly
timed
internally.
will
have
the
red
painted
tooth
of
the
large
distributor
gears
approxi-
mately
centered
in
the
timing
windows.
the
R
"E"
gap
mark
on
the
rotor
shaft
in
alignment
with
the
pointer
and
both
sets
of
breaker contacts
opening,
all
at
the
same
time.
a.
Remove
breaker
contact
point
assembly
cover.
if
installed.
by
removing
the
cover
screws,
pulling
cover
directly
aft
away
from
housing
and
disconnecting
both
capacitor
leads
from
breaker
contact
assemblies.
b.
Remove
timing
inspection
hole
plugs
from
magneto.
c.
Slowly
turn
the
rotor
shaft
until
the
red
painted
tooth
of
the
large
distributor
gear
for
each
side
is
approximately
centered
in
the
inspection
windows
with
the
R
("E"
gap)
mark
on
the
rotor
aligned
with
the
pointer.
Lock
the
rotor
in
this
EXACT
position
using
Bendix
Holding
Tool.
Part
No.
11-8465
or
equivalent.
NOTE
Position
the
11-8465
Rotor Holding
Tool
on
drive
end
of
rotor
shaft
in
the
4
o'clock
position
so
that
any
shaft
deflection
caused
by
clamping
action
will
be
in
a
plane
parallel
to
the
breaker
contacts.
d.
Connect
the
timing
light
(Bendix
Part
No.
11-9110
or
equivalent)
black
lead
to
any
unpainted
surface
of
the
magneto.
Connect
the red
lead
to
the
left
breaker
contact
terminal
and
the
green
lead
to
the
right
breaker contact terminal.
e.
Carefully
adjust
the
LEFT
breaker
contacts
to
just
begin
to
open
(light
will
go
out)
with
the
timing
pointer within
the width
of
the
R
("E"
gap)
mark.
f.
Repeat
step
"e"
for the
RIGHT
breaker
contacts.
g.
Loosen
the
rotor
holding
tool
and
turn
rotor shaft
in
normal
direction
of
rotation
until
cam
followers
of
contact assemblies
are
on
the
high
point
of
cam
lobes.
Contact
point
clearance
should
be
0.016
±
0.002
inch
and
0.016
± 0.004
inch
on
LEFT
and
RIGHT
contacts
respectively.
If
dimensions
do
not
fall within
limits, readjust
contact
points
and
recheck
to
be
sure
the
points
just
begin
to
open
when
the
timing
pointer
is
within
the
width
of
the
R
("E"
gap)
mark.
11-24
MODEL
172
SERIES
SERVICE
MANUAL
NOTES
Wire
feeler
gages
are
recommended
when
checking
contact
point
clearance.
No
attempt
should
be
made
to
stone
or
dress
contact
points.
If
the
above
conditions
are
met
and
within
tolerance,
the
magneto
is
timed
internally
and ready
for
installation
If
the
above
conditions
are
not
within
tolerance,
proceed
to
step
"h".
h.
While
holding
the
rotor
shaft,
loosen the screw
securing
breaker contact
cam
to
rotor
shaft
and
back screw
out
approximately
half
way.
Place
the
end
of
a
broad
bladed
screw
driver
between the
bottom
of
the
cam
and
housing.
Strike
the
screw
driver
handle
with
a
sharp
downward
blow
to
"pop"
the
cam loose
from
taper
of
shaft.
i.
Rotate
cam
until
breaker-contact
cam
followers
are
on
the
high
point
of
cam
lobes.
Adjust
breaker
points
to
obtain
a
clearance
of
0.016
±0.002
inch
and
0.016
±0.004
inch
on
LEFT
and
RIGHT
contacts
respectively.
Tighten
breaker
contact
securing
screws
to
20-25
lb-in.
j.
Repeat
step
c.
k.
While
holding
rotor shaft
in
this
EXACT
position.
rotate
the breaker
contact
cam
in
the
opposite
direction
of
rotation
a
few
degrees
BEYOND
where
the
breaker
contacts
close,
then
rotate
cam
in
the
normal
direction
of
rotation
until
the
breaker
contacts
just
begin
to
open.
Point
opening
should
be
determined
by
the
use
of
a
timing
light.
(Bendix
Part
No.
11-9110
or
equivalent.)
1.
While
holding
cam
in
this
EXACT
position,
push
cam
on
rotor
shaft
as
far
as
possible
with
the
fingers. Tighten
cam
securing
screw
thereby drawing
the
cam
down
evenly
and
tightly.
Torque cam
securing
screw
to
16-20
lb-in.
NOTE
Extreme
care
must
be
exercised
in
this
operation.
If
cam
adjustment
is
changed
in
the
slightest
degree.
the
timing
of
the
magneto will
be
thrown
off.
Do
not
drive
cam
on
rotor
shaft
with
a
mallet
or
other
instrument.
m.
Recheck
timing
to
make
sure
both
sets
of
breaker
contact
begin
to
open
within
the
width
of
the
R
("E"
gap)
mark
and
that
the
contact
point
clearance
is in
accordance
with
dimensions
in
step
"g".
NOTE
When
reinstalling
the
inspection
hole
plugs,
make
sure
the
ventilated
plugs
are
installed
in
the
ends
of
the
magneto.
Torque
plugs
to
12-15
lb-in.
11-25
MODEL
172
SERIES
SERVICE
MANUAL
11-54.
MAGNETO-TO-ENGINE
TIMING.
The
magneto
must
be
installed
with
its
timing
marks
carefully
aligned.
with
number
one
cylinder
on
its compression stroke
and
with
the
number
one
piston
at
its
advanced
firing position.
Refer
to
paragraph
11-8
for
the
advanced
firing
position
of
number
one
piston.
To
locate
the
compression
stroke
of
the
number
one
cylinder.
remove
the
lower
spark
plug
from
number
2.3
and
4
cylinders.
Remove the
upper
spark
plug
from
number
1
cylinder.
Place the
thumb
of
one
hand
over
the
spark
plug
hole
of
number
one
cylinder
and
rotate
crankshaft
in
the
direction
of
normal
rotation
until
the
compression
stroke
is
indicated
by
positive
pressure
inside
the
cylinder
lifting
the
thumb
off
the
spark
plug
hole.
After the
compression
stroke
is
attained,
locate the
number
one
piston
at
its
advanced
firing
position.
Locating
the
advanced
firing
position
of
the
number
one
piston
may
be
obtained
by
rotating
the
crankshaft
opposite
to
its
normal direction
of
rotation
until
it
is
approximately
30
degrees
before
top
dead
center
(BTC)
on
the
compression stroke
of
number
one
cylinder.
Rotate
crankshaft
in a
normal
direction
to
align
the
timing
mark
on
the
front
face
of
the
starter
ring
gear
support
with
the
drilled
hole
in
the
starter,
making
sure
the
final
motion
of
the
ring
gear
is in
the
direction
of
normal
rotation.
NOTE
An
accurate
top
center
indicator
which
screws
into
a
spark plug
mounting
hole,
and
a
pendulum
pointer
mounted
on
a
360-degree
timing
disc
may
also
be
used
to
locate the advanced
firing
position.
The
timing
disc
should
be
adapted
to
fit
over
the end
of
the
propeller
spinner
in
such
a
manner that
it
may
be
rotated
as
necessary.
In
all
cases,
it
must
be
definitely
determined
that
the
number
one
cylinder
is
at
the
correct
firing
position
and
on
the
compression
stroke,
when the
engine
is
turned
in
its
normal
direction
of
rotation.
After
the
engine
has
been
placed
in
the
correct
firing
position,
install
the
magneto
to
the
engine
in
the
following
manner:
a.
Remove
the
timing
window
plug
from
the
most
convenient
side
of
the
magneto
housing.
b.
Remove
the
rotor
viewing
location
plug
from
the
top
center
of
the
housing.
c.
Turn
the
rotating
magnet
drive
shaft
in
the
normal direction
of
magneto
rotation
until
the
red
painted
tooth
of
the
large
distributor
gear
is
centered
in
the
timing
hole
(hole
at
each
side
of
magneto).
d.
Also
observe
at
this
time
that
the
built
in
pointer
just
ahead
of
the
rotor viewing
window
aligns
with
the
R
("E"
gap)
mark
on
the
rotor.
e.
Install
the
magneto-to-engine
gasket
on
the
magneto
flange.
WARNING
Do
not
attach harness
spark
plug
leads
to
the
spark
plugs
until
all
magneto-to-engine
timing
procedures are
com-
pleted
and the
switch
leads
("P"
leads)
are
connected.
f.
Remove
the
engine-to-magneto
drive
gear
train
backlash
by
turning
magneto
drive
opposite
to
normal
rotation
as
far
as
possible.
g.
With
the
No.
1
cylinder
at
its
correct
firing
position
as
close
to
its
No.
1
firing
position
as
possible
red
tooth
in
center
of
window
and
pointer
over
R
("E"
gap)
mark
on
rotor
and
install
magneto
to
the
engine.
Loosely
tighten
magneto
in
position.
11-26
MODEL
172
SERIES SERVICE
MANUAL
NOTE
To
facilitate
connection
of
a
timing
light
to
the switch
lead
("P"
lead)
terminals,
short
adapter
leads
may
be
fabricated.
These
can
be
made
by
using
two
switch lead
terminals
and
two
short
pieces
of
insulated
wire.
Install
the
fabricated
adapter
leads
in
the
switch
lead
outlet
terminals
of
the
cover.
h.
Attach
the red
lead
of
the
timing
light
(Bendix
Part
No.
11-9110
or
equivalent)
to
the
left
switch
lead
adapter,
the
green lead
of
the
timing
light
to
the
right
switch
lead
adapter
and
the
black
lead
of
the
timing light
to the
magneto
housing
(common
ground).
NOTE
An
internal
timing
tolerance
is
allowed
when
adjusting
the
two
main breakers.
Therefore,
one
of
the
main
break-
ers
may
open
slightly
before
the
other.
Magneto-to-
engine
timing
should
be
accomplished
using
the
first
main
breaker
to
open
as
the
reference
point
when
the
engine
is in
the
firing
position
for
No.
1
cylinder.
This
will
ensure
that
ignition
created
by
either
spark
plug
will
not
occur
prior
to
the
desired
engine
firing
point.
i.
Turn
the
entire
magneto
in
direction
of
rotor
rotation until
the
timing
lights
are
on.
j.
Turn
magneto
in
direction
of
rotor
rotation,
right-hand rotation
to
right
and
left-hand
rotation
to
left,
until
one
of
the
timing lights
just
goes
off.
Then
tighten
the
magneto
mounting
clamps
evenly
in
this
position.
k.
Back
the
engine
up
approximately
10
°
and
then
carefully
"bump"
the
engine
forward
while
observing
the
timing
lights.
1.
At
the
No.
1
cylinder
firing
position,
one
of
the
timing
lights
should
go
off.
Continue
turning
the
engine
in
its normal
direction
of
rotation until
the
other
timing
light
goes
off.
This
should
be
not
more
than
3
engine
degrees
later
than
the
first
light.
If
not.
repeat
steps
"i"
thru
"k"
until
these
conditions
are
obtained.
m.
Make
sure
the
magneto
clamps
are
tightened
securely,
recheck
timing
once
more
and
remove
timing
equipment.
n.
Reinstall
inspection
plugs
and
torque
plugs
to
12-15
lb-in.
11-55.
MAINTENANCE. At
the
first
25-hour
inspection,
first
50-hour
inspection.
first
200-hour
inspection
and
thereafter
at
each
100-hour
inspection,
the
contact
breaker point
compart-
ment
and
magneto-to-engine
timing
should
be
inspected
and
checked.
If
magneto-to-engine
timing
is
correct
within
plus
zero
and
minus
two
degrees,
internal
timing
need
not
be
checked.
If
timing
is
out
of
tolerance,
remove
magneto
and
set
internal
timing
(paragraph
11-53),
then
install
and
time
to
the
engine.
NOTE
If
engine
operating
troubles
develop
which
appear
to
be
caused
by
the
ignition
system,
it is
advisable
to
check
the
spark
plugs
and
ignition harness
first
before
working
on
the
magnetos.
If
the
trouble
appears
definitely associated
with
a
magneto,
the
following
may
be
used
to
help
disclose
the
source
of
trouble
without
overhauling
the
magneto.
11-27
MODEL
172
SERIES SERVICE
MANUAL
a.
Moisture check.
1.
Remove
contact
breaker point
assembly
cover
and
inspect
cover.
cables
and
capacitor
for
moisture
in
the
area.
2.
Inspect
distributor
block
high
tension
outlets
for
moisture.
3.
If
any
moisture
is
evident,
lightly
wipe
with
a
soft.
dry.
clean. lint-free
cloth.
CAUTION
Do
not
use
gasoline
or
any other solvent,
as
these
will
remove
the
wax
coating
on some
parts
and
cause
an
electrical
leak.
b.
Breaker contact
compartment
check.
1.
Check
all
parts
of
the
contact
breaker
assembly
for
security.
Check
distributor
block
high-tension
outlet
springs
for
evidence
of
spark
erosion
and
proper
height.
The
end
of
spring
should
not
be
more
than
0.422
inch from
top
of
tower.
2.
Check
breaker
contact
assembly points
for
excessive
wear,
burning,
deep
pits
and
carbon deposits. Breaker
points
may
be
cleaned
with
a
hard
finish
paper.
If
breaker
points
are
found
defective,
install
a
new
assembly.
Make
no
attempts
to
stone
or
dress
breaker
points.
Clean
new
breaker
points
with
clean
unleaded
gasoline
and hard
finish
paper
before
installing.
3.
Check
condition
of
the
cam
follower
felt.
Squeeze felt
between
thumb
and
finger.
If
fingers are
not
moistened with
oil,
re-oil
using
2
or
3
drops
of
lubricant
(Bendix
Part
No.
10-86527
or
equivalent).
Allow
approximately
30
minutes
for
felt
to
absorb
the
lubricant.
Blot
off
excess
lubricant
with
a
clean.
lint-free
cloth.
Too
much
lubricant
could
foul
breaker points
and
cause
excessive
burning.
4.
Check
capacitors
for
looseness
in
the
magneto
cover
of
the
harness
assembly
and
for
any
physical
damage.
If
equipment
is
available,
check
the
capacitors
for
leakage,
series resistance
and
capacitance.
The
capacitance
should
be
0.34
to
0.41
microfarads.
NOTE
Spring
in
capacitor
outlet
may
cause
an
indication
of
a
short
to
ground
if
an adapter
lead
is
not
used.
c.
If
the
trouble
has
not
been
corrected
after
accomplishing
the
moisture
and
breaker
contact compartment
check,
check
magneto-to-engine
timing
in
accordance
with
paragraph
11-54.
If
timing
is
incorrect.
remove
magneto
and
adjust
internal
timing
in
accordance
with
paragraph
11-53.
d.
Reinstall
magneto
and
time
to
engine
in
accordance
with
paragraph
11-54.
e.
If
the
trouble
has
not
been
corrected, magneto
overhaul
or
replacement
is
indicated.
11-56.
MAGNETO
CHECK.
a.
Start
and
run
engine
until
the
oil
and
cylinder
head
temperatures
are
in
the
normal
operating
ranges.
b.
Advance
engine
speed
to
1700
RPM.
c.
Turn
the
ignition
switch
to
the
"R"
position
and
note
the
RPM
drop.
then
return
the
switch
to
the
"BOTH"
position
to
clear
the
opposite
set
of
plugs.
d.
Turn
the
switch
to
the
"L"
position
and note the
RPM
drop,
then
return
the
switch
to
the
"BOTH"
position.
11-28
MODEL
172
SERIES
SERVICE
MANUAL
e.
The
RPM
drop
should
not
exceed
150
RPM
on
either
magneto
setting
or
show
greater
than
50
RPM
differential
between
magneto
settings.
A
smooth
RPM
drop-off
past
normal
is
usually
a
sign
of
a
too
lean
or
too
rich
mixture.
A
sharp
RPM
drop-off
past
normal
is
usually
a
sign
of
a
fouled
plug,
a
defective
harness
lead
or
a
magneto
out
of
time.
If
there
is
doubt
concerning
operation
of
the
ignition
system.
RPM
checks
at
a
leaner
mixture
setting
or
a
higher
engine
speeds will
usually
confirm
whether
a
deficiency
exists.
NOTE
An
absence
of
RPM
drop
may
be
an indication
of
faulty
grounding
of
one
side
of
the
ignition system,
a
discon-
nected
ground
lead
at
magneto
or
possibly
the
magneto
timing
is
set
too
far
in
advance.
11-57.
SPARK
PLUGS.
Two
18-mm
spark
plugs
are
installed
in
each
cylinder
and
screw
into
helicoil
type
thread
inserts.
The
spark
plugs
are shielded
to
prevent spark plug
noise
in
the
radios
and
have an
internal
resistor
to
provide
longer
terminal
life.
Spark
plug
life
will
vary
with
operating
conditions.
A
spark
plug
that
is
kept clean
and
properly
gapped will
give
better
and
longer service
than
one
that
is
allowed
to
collect
lead
deposits and
is
improperly
gapped.
NOTE
Refer
to
Section
2
for
inspection
interval.
Remove,
clean.
inspect
and
regap
all
spark
plugs
at
each
inspection.
Install
lower
spark
plugs
in
upper
portion
of
cylinders
and
install
upper
spark
plugs
in
lower
portion
of
cylin-
ders.
Since
deterioration
of
lower
spark
plugs
is
usually
more
rapid
than
that
of
the
upper
spark
plugs,
rotating
helps
prolong
spark
plug
life.
11-58
ENGINE
CONTROLS.
11-59
DESCRIPTION.
The
throttle.
mixture,
propeller,
and
carburetor
heat
controls
are
of
the
push-pull
type.
The
mixture
control
is
equipped
to
lock
in
any
position desired.
To
move
the
control.
the
spring-loaded button,
located
in
the
end
of
the
control
knob.
must
be
depressed.
When
the
button
is
released,
the
control
is
locked. The
mixture
control
also
has
a
vernier
adjustment.
Turning
the
knob
in
eitherdirectionwillchange
the
control
setting.
The
vernier
is
primarily
for
precision control setting.
The
throttle
control
has
neither
a
locking
button
nor
a
vernier
adjustment,
but
contains
a
knurled
friction
knob
which
is
rotated
for
more
or
less
friction
as
desired.
The
friction
knob
prevents
vibration
induced
"creeping"
of
the
control.
The
carburetor heat
control
has
no
locking
device.
Prior
to
1979
Models
the
ball
bearing-type
rod
ends
on
the
throttle,
mixture,
and
propeller
control
cable
ends
are
secured
to
the
engine with
AN
bolt,
washers,
and
self-locking
nut
Beginning
with
1979
Models,
the
bolt
is
replaced
with
a
pre-drilled
AN
bolt,
and
the
self-locking
nut
is
replaced
with
a
castellated
nut
and
cotter
pin.
(See
figure
11-3.)
NOTE
Steel
AN
bolts
with
an
undrilled
shank
are identified
with
an
"A"
suffix
(AN3-6A).
A
steel
bolt
of
the
same
size,
with
the
shank
drilled
for
castellated nut
and
cotter
pin,
is
identified
as
AN3-6.
Aluminum
AN
bolts
are
not
to
be
used
in
this
application.
11-29
MODEL
172
SERIES
SERVICE
MANUAL
2
3
1.
Bolt
2.
Washer
3.
Nut
6
4.
Lock
Nut
5.
Washer
8
6.
Cotter
Pin
7.
Castellated
Nut
8.
Rod
End
Figure
11-3.
Control
Cable
End
(Typical)
11-60.
RIGGING.
When
adjusting
any
engine
control,
it
is
important
to
check
that
the
control
slides
smoothly
throughout
its
full
range
of
travel, that
it
locks
securely
if
equipped
with
a
locking
device
and
the
arm
or
lever
it
operates
moves
through
its
full
arc
of
travel.
CAUTION
Whenever
engine
controls
are being
disconnected, pay
particular
attention
to
the
EXACT
position,
size
and
number
of
attaching
washers
and
spacers.
Be
sure
to
install
attaching
parts
as
noted when
connecting
con-
trols.
11-61.
THROTTLE
CONTROL.
(See
figure
11-4.)
NOTE
Before
rigging
throttle
control,
check
that
clamping
sleeve
(13)
is
secure.
If
any
indication
of
looeness
(total
linear
movement exceeds
.050
in.)
or
breakage
is
appar-
ent,
replace
throttle
control.
a.
Screw
friction lock
nut
(2)
into
threads
of
barrel
(7).
b.
Ensure
washer
(5)
is
installed,
and
nut
(6)
on
forward
side
of
panel
is
secured
against
washer.
c.
Push
knob
assembly
(1)
full
in
against
friction
lock
nut
(2),
then
pull
knob
assembly
out
approximately
118-inch
to
obtain
"cushion."
11-30
MODEL
172
SERIES
SERVICE
MANUAL
d.
Tighten
friction
lock
nut
(2)
against
barrel
(7).
e.
At
the
carburetor,
position throttle
lever
to
the
full forward
power
stop
position
against
throttle
stop
screw.
NOTE
Ensure
palnut
(17)
is
on
threads
of
plunger
(18)
before
installing
rod
end
(16).
f.
See
figure
11-3.
Place
larger washer
(2)
on
bolt
(1).
g.
Insert
bolt
(1)
through
hole
in
throttle
lever
from
the
INBOARD
SIDE
of
throttle
lever.
h.
Screw
rod
end
(16)
on
threads
of
plunger
(18).
until
hole
in
rod
end
bearing
is
aligned
with
end
of
bolt
(1).
NOTE
Ensure
that
rod
end
(16)
is
threaded
on
to
plunger
(18)
so
that
.020-inch
safety
wire
cannot
be
installed
through
drilled
hole
in
rod
end.
i.
Connect rod
end
to
bolt
(1)
in
throttle
lever.
j.
Place
washer
(5)
on
bolt
and
secure
with
castellated
nut
(7)
and
cotter
pin
(6).
k.
Check
clamping
sleeve
(13)
in
bracket
(12)
and
clamp
(15).
1.
Loosen
friction
lock
nut
(2).
m.
Pull
knob
assembly
full
out
and
check
that
idle
stop
on
carburetor
is
contacted.
n.
Push
knob
assembly
full
in
and
check
that
full
power stop
on
carburetor
is
contacted.
o.
Check
that
throttle has
maintained
the
approximate
1/8-inch
"cushion"
set
in
step
"c".
p.
Work
throttle control
in
and
out
several
times
to
check for
binding.
NOTE
Refer
to
the
inspection
chart
in
Section
2
for
inspection.
lubrication.
and/
or
replacement
interval
for
the
throttle
control.
11-62.
MIXTURE CONTROL.
a.
Push
mixture control
full
in,
then
pull
it
out
approximately
1/8
inch for
cushion.
b.
Loosen
clamp
securing
the
control
to
the
engine.
c.
Shift
control
housing
in
the
clamp
so
that
the
mixture
arm
on
the
carburetor
is in
the
full
open
position
(RICH).
Tighten the
clamp
in
this
position.
d.
Unlock and
pull
mixture
control
full
out.
Check
that
idle
mixture
arm
on
carburetor
is
full
closed
(IDLE
CUT-OFF).
e.
Check
that
the
bolt
and
nut
at
the
mixture
arm
on
carburetor
secures
the
control
wire
and
that
the
bolt
will
swivel
in
the
arm.
f.
Bend
the
wire
tip
90
degrees
to
prevent
it
from
being
withdrawn
if
the
attaching
nut
should
become
loose.
g.
When
installing
a
new
control,
it
may
be
necessary
to
shorten
the
wire and/
or control
housing.
h.
The
mixture
arm
on
the
carburetor
must
contact
the
stops
in
each
direction,
and
the
control should
have
approximately
1/8
inch
cushion
when
pushed
in.
11-31
MODEL
172
SERIES
SERVICE
MANUAL
12
13
14
16
19
20
1.
Knob
Assembly
2.
Friction
Lock
Nut
3.
Locking
Collet
4.
Instrument Panel
-
5.
Washer
6.
Nut
NOTE
SERRATED FACES
OF
7.
Barrel
THROTTLE
ARM
AND
STOP
8.
Core
9.
Casing
10.
Clamping
Sleeve
82-43
COTTER
11.
Firewall
81-311 NUT
12.
Bracket
TIGHTEN
TO
13.
Clamping
Sleeve
25/60
LB. IN.
14.
Packing
TORQUE
15.
Clamp
16.
Rod
End
17.
Palnut
18.
Plunger
19.
Plunger
Seal
20.
Plunger
Guide
Figure
11-4.
Throttle
Control
11-32
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Refer
to
the
inspection
chart
in
Section
2
for
inspection
and/or
replacment
interval
for
the
mixture
control.
11-63.
CARBURETOR
HEAT
CONTROL
a.
Loosen
clamp
securing
the
control
to
the
bracket
on
engine.
b.
Push
control
full
in.
then
pull
it
out
approximately
1/8
inch
from
panel
for
cushion.
c.
Shift
control
housing
in
its
clamp
so
that
the
valve
in
the
airbox
is
seated
in
the
full
open
position. Tighten
clamp
in
this
position.
d.
Pull
out
on
the
control
and
check
that
the
air
valve
inside
the
airbox
seats
in
the
opposite
direction.
e.
Check
that
bolt
and
nut
on
the
air
valve
lever
secures
the
control
wire
and
that
the
bolt
will swivel
in
the
lever.
f.
Bend
the
wire
tip
90
degrees
to
prevent
it
from
being
withdrawn
if
the
attaching
nut
should
become
loose.
NOTE
Refer
to
the
inspection
chart
in Section
2
for
inspection.
lubrication,
and/ or replacement
interval
for
the
carbure-
tor
heat
control.
11-64.
STARTING
SYSTEM.
11-65.
DESCRIPTION.
The
starting
system employs
an
electrical
starter
motor
mounted
at
the
front
(propeller
end)
lower
left
side
of
the
engine.
A
starter
solenoid
is
activated
by
the
ignition
key
on
the
instrument
panel.
When
the
solenoid
is
activated,
its
contacts
close
and
electrical
current
energizes
the
starter
motor.
Initial
rotation
of
the
starter
armature
shaft.
engaged
with
the
reduction gear. drives
the
Bendix
shaft
and
pinion.
When
the
armature
turns
the
reduction
gear. the
Bendix
drive
pinion
meshes
with the
crankshaft
ring
gear
assembly
by
inertia
and
action
of
the
screw
threads
within
the
Bendix
sleeve.
A
detent
pin
engages
in
a
notch
in
the screw
threads
which
prevents demeshing
if
the
engine
fails
to
start
when the
starting
circuit
is
de-energized.
When
the
engine reaches
a
predetermined
speed.
centrifugal
action
forces
the
detent
pin
out
of
the
notch
in the
screw
shaft
and
allows the
pinion
to
demesh
from
the
ring
gear.
CAUTION
Never
operate
the
starter
motor
more
than
12
seconds
at
a
time. Allow
starter
motor
to
cool
between
cranking
periods
to
avoid
overheating.
Longer
cranking
periods
without
cooling
time
will shorten
the
life
of
the
starter
motor.
11-33
MODEL
172
SERIES
SERVICE
MANUAL
1-66.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
STARTER
WILL
NOT
Defective
master
switch
or
Check
continuity
of
master
OPERATE.
circuit.
switch
and
circuit.
Install
new
switch
or wires.
Defective
starter
switch
or
Check
continuity
of
switch
switch
circuit.
and
circuit. Install
new
switch
or
wires.
Defective
starter
motor.
Check
voltage
to
starter.
If
voltage
is
present.
Re-
move.
repair
or
install
new
starter
motor.
STARTER
MOTOR
RUNS.
Defective Bendix
drive.
Remove
starter
and
inspect
BUT
DOES
NOT
TURN
Bendix
drive.
Replace
defec-
CRANKSHAFT.
tive
parts.
Damaged
starter
pinion
Inspect
starter
pinion
gear
gear
or
ring
gear. and
ring
gear.
Replace
defective
parts.
STARTER
MOTOR
DRAGS. Low
battery.
Check
battery.
Charge
or
install
new
battery.
Starter
switch
or
relay
con-
Install
servicable
unit.
tacts
burned
or
dirty.
Defective
starter
motor
Inspect
cable.
Install
new
power
cable.
cable.
Loose
or
dirty
connections.
Inspect
connections.
Remove
clean
and
tighten
all
term-
inal
connections.
Defective
starter
motor.
Check
starter
motor
brushes.
brush
spring
tension.
thrown
solder
on
brush
cover.
Re-
pair
or install
new
starter
motor.
Dirty
or
worn
commutator.
Inspect
commutator.
Clean
and
turn
commutator.
STARTER
EXCESSIVELY
Worn
starter
pinion
gear
Inspect
starter
pinion
gear
NOISY.
or
broken
teeth
on
ring
and
ring
gear.
Replace
defec-
gear.
tive
parts.
11-34
MODEL
172
SERIES SERVICE
MANUAL
11-67.
PRIMARY
MAINTENANCE.
The
starting
circuit
should
be
inspected
at
regular intervals.
the frequency
of
which
should
be
determined
by
the
service
and
conditions
under
which
the
equipment
is
operated.
Inspect
the
battery
and
wiring.
Check
battery for
fully
charged
condition,
proper
electrolyte
level
with
approved
water
and
terminals
for
cleanliness.
Inspect
wiring
to
be
sure
that
all
connections
are
clean
and
tight
and
that
the
wiring
insulation
is
sound.
Check
that
the
brushes
slide
freely
in
their
holders and
make
full
contact
on
the
commutator.
When
brushes
are
worn
to
one-half
of
their
original length.
install
new
brushes
(compare
brushes
with
new
ones).
Check
the
commutator
for
uneven
wear,
excessive
glazing
or
evidence
of
excessive
arcing.
If
the
commutator
is
only
slightly
dirty,
glazed
or
discolored,
it
may
be
cleaned
with
a
strip
of No.
00
or
No.
000
sandpaper.
If
the
commutator
is
rough
or
worn,
it
should
be
turned
in
a
lathe and
the
mica
undercut.
Inspect
the
armature shaft
for
rough
bearing
surfaces.
New
brushes
should
be
properly
seated
when
installing
by
wrapping
a
strip
of
No.
00
sandpaper
around
the
commutator
(with
sanding
side
out)
1-1/4 to 1-1/2
times
maximum.
Drop
brushes
on
sandpaper
covered
commutator
and
turn
armature
slowly
in
the
direction
of
normal
rotation. Clean
sanding
dust
from
motor
after
sanding.
11-68.
STARTER
MOTOR.
11-69.
REMOVAL
AND
INSTALLATION.
a.
Remove
engine
cowling
in
accordance with
paragraph
11-3.
CAUTION
When
disconnecting
or
connecting
the
starter
cable,
do
not
permit
starter
terminal
bolt
to
rotate.
Rotation
of
the
bolt could
break
the
conductor
between
terminal
and
field
coils
causing
the
starter
to
be
inoperative.
b.
Disconnect
electrical
cable
at
starter
motor.
Insulate
the
disconnected cable
terminal
as
a
safety
precaution.
c.
Remove
three
nuts
and
washers
and
one
bolt
securing
starter
to
crankcase.
Work
starter
from
engine.
d.
To
install
starter,
position
starter
on
mounting
pad,
aligning
dowel
pins
in
starter
mounting
pad
with
holes
in
mounting
pad
on
engine.
e.
Secure
starter
with
washer,
lockwasher
and
nut
in
three
places
and
install
bolt
and
washers.
f.
Tighten
nuts
and
bolt evenly
to
a
torque
value
of
150
lb-in.
g.
Connect
electrical
cable
to
starter
terminal
and
install
engine cowling.
11-70.
EXHAUST
SYSTEM.
(See
figure
11-5.)
11-71.
DESCRIPTION.
The
exhaust
system
consists
of
an
exhaust pipe
from
each
cylinder
to
the
muffler
located
beneath
the
engine.
The
muffler
assembly
is
enclosed
in a
shroud
which
captures exhaust
heat
that
is
used
to
heat
the
aircraft
cabin.
A
shroud
on
number three
exhaust
pipe
is
used
to
capture
carburetor heat
for the
engine
intake
system.
The
tailpipe
welded
to
the
muffler
routes
the
exhaust
gasses
overboard.
11-72.
REMOVAL
AND
INSTALLATION.
a.
Remove
engine cowling
in
accordance with
paragraph
11-3.
b.
Disconnect flexible
ducts
from
shrouds
on
muffler
assembly
and
exhaust
pipe.
c.
Remove
EGT
probe (optional)
if
installed.
d.
Remove
nuts,
bolts,
washers
and
clamps attaching
exhaust
pipes
to
muffler
assem-
bly.
11-35
MODEL
172
SERIES
SERVICE
MANUAL
e.
Loosen
nuts
attaching
exhaust
pipes
to the
cylinders
and
remove muffler
assembly
f.
Remove
nuts
and
washers
attaching
exhaust
pipes
to
the
cylinders
and
remove pipes
and
gaskets.
g.
Reverse
the
preceding
steps
for
reinstallation. Install
a
new
copper-asbestos
gasket
between
each
exhaust
pipe
and
its mounting
pad.
When
installing
the
attaching
nuts,
install
a
plain
washer,
an
internal
tooth
washer
and
nut.
Make
sure
all
clamps
attaching
muffler
to
exhaust
pipes
are
tight
and
all
air
ducts
are
installed.
11-73.
INSPECTION.
WARNING
Any
time
exhaust
fumes
are
detected
in the
cabin,
an
immediate
inspection
must
be
performed.
The
exhaust
system
must
be
thoroughly
inspected,
especially
the
heat
exchange
section
of
the
muffler.
An
inspection
of
the
exhaust
system must
be
performed
every
50
hours
of
operating
time.
All components
that
show
cracks
and
general
deterioration
must
be
replaced
with
new
parts.
Using
a
flashlight
and
mirror
inspect
diffuser
tubes
through
the
tailpipe.
Replace
muffler
if
defective.
a.
Remove
engine cowling in
accordance
with
paragraph
11-3.
b.
Loosen
or
remove
shrouds
so
that
ALL
surfaces
of
the
exhaust
system
are
visible.
c.
Check
for holes,
cracks
and
burned
spots.
Especially
check the
areas
adjacent
to
welds.
Look
for
exhaust
gas
deposits
in
surrounding
areas
which indicate an
exhaust
leak.
d.
Where
a
surface
is
not
accessible
for
visual
inspection
or
for
a
positive
test,
proceed
as
follows;
1.
Remove
exhaust
pipes
and
muffler.
2.
Remove
shrouds.
3.
Seal
openings
with
expansion
rubber
plugs.
4.
Using
a
manometer
or
gage.apply
approximately
3±1/2
psi
(6
inches
of
mercury)
air
pressure
while the
unit
is
submerged
in
water.
Any
leaks
will
appear
as
bubbles
and
can
be
readily
detected.
5.
It
is
recommended
that
any
components
found
defective
be
replaced
with
new
parts
before
the
next
flight.
6.
If
no
defects
are
found,
remove
plugs
and dry
components
with
compressed
air.
e.
Install
the
exhaust
system
and
engine
cowling.
11-74.
EXTREME
WEATHER
MAINTENANCE.
11-75.
COLD
WEATHER. Cold
weather
starting
is
made
easier
by
the
installation
of
the
manually-
operated
engine
primer
system.
Fuel
is
supplied
by
a
line
from
the
fuel
strainer
to
the
plunger
type
primer. Operating
the
primer
forces
fuel
to
the
intake
valve
port
of
the
cylinder.
Primer
lines
should
be
replaced
when
crushed or
broken
and
should
be
properly
clamped
to
prevent
vibration
and
chafing.
The
following
may also
be
used
to
assist
engine
starting
in
extreme
cold
weather.
After the
last
flight
of
the
day,
drain
the
engine
oil
into
a
clean
container
so
the
oil
can
be
preheated.
Cover
the engine
to
prevent
ice
or
snow
from
collecting inside the
cowling.
When
preparing
the
aircraft
for
flight
or
engine
run-up
after
these conditions
have
been
followed,
preheat
the drained
oil.
11-36
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
TAILPIPE
11-37
11-37
MODEL
172
SERIES
SERVICE
MANUAL
WARNING
Do
not
heat
the
oil
above
121
°
C
(250°F).
A
flash
fire
may
result.
Before
pulling
the
propeller
through.
ascertain
that
the
magneto
switch
is
in
the
OFF
position
to
prevent
accidental
firing
of
the
engine.
After
preheating
the
oil,
fuel
may
be
mixed
with
the
heated
oil
in
a
ratio
of
1
part
fuel
to
12
parts
oil
before
pouring
into
the
engine
oil
sump.
If
the
free
air
temperature
is
below
-29°C
(-
20°F).
the
engine
compartment
should
be
preheated
by
a
ground
heater.
Pre-heating
the
engine
compartment
is
accomplished
by
inducing
heated
air
up
through
opening
in
lower
cowl
assembly:
thus
heating
up
both
the
cylinders
and
oil.
After
the engine
compartment
has
been
preheated,
inspect all
engine
drain
and
vent
lines
for
presence
of
ice.
After this
procedure
has
been
complied
with,
pull
the
propeller
through several
revolutions
by
hand
before
starting
engine.
CAUTION
Due
to
the
desludging
effect
of
the
diluted
oil.
engine
operation
should
be
observed
closely
during
the
initial
warm-up
of
the
engine. Engines
that
have
considerable
amount
of
operational
hours
accumulated
since
their
last
dilution
period
may
be
seriously
affected
by
the
dilution
process.
This
will
be
caused
by
the
diluted
oil
dislodging
sludge
and
carbon
deposits within
the
engine.
This
residue
will
collect
in
the
oil
sump
and
possibly
clog
the
screened
inlet
to
the oil pump.
Small deposits
may
actually enter
the
oil
pump
and
be
trapped
by
the
main
oil
filter
screen.
Partial
or
complete
loss
of
engine
lubrica-
tion
may
result
from
either
condition.
If
these
conditions
are
anticipated
after
oil
dilution.
the
engine should
be
run
for
several
minutes
at
normal
operating
temperatures
and
then
stopped
and
inspected
for
evidence
of
sludge
and
carbon
deposits
in
the
oil
sump
and
oil
filter
screen.
Future
occurrence
of
this
condition
can
be
prevented
by
diluting
the oil
prior
to
each oil
change.
This
will
prevent
the
accumulation
of
the
sludge
and carbon
deposits.
11-76.
DUSTY
CONDITIONS.
Dust
inducted
into
the
intake
system
of
the
engine
is
probably
the
greatest
single
cause
of
early
engine
wear.
When
operating
under
high
dust
conditions.
service
the induction
air
filter
daily
as outlined
in
Section
2.
Also.
change
engine
oil and
lubricate the
airframe
more often
than
specified.
11-77.
SEACOAST
AND
HUMID
AREAS.
In
salt
water
areas,
special
care
should
be
taken
to
keep
the
engine
and
accessories
clean
to
prevent
oxidation.
In
humid
areas,
fuel
and
oil
should
be
checked
frequently
and
drained
of
condensed
moisture.
11-38
MODEL
172
SERIES SERVICE
MANUAL
SECTION
11A
ENGINE
(MODEL
O-320-D2J
AND
MODEL
O-360-A4N)
WARNING
When
performing
any
inspection
or
maintenance that
requires
turning
on
the
master
switch,
installing
a
battery,
or
pulling
the
propeller through
by
hand, treat
the
propeller
as
if
the
ignition
switch
were
ON.
Do
not
stand,
nor
allow
anyone else
to
stand, within
the
arc
of
the
propeller,
since
a
loose or
broken wire,
or
a
component
malfunction,
could
cause
the
propeller
to
rotate.
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
ENGINE
COWLING
.........
2D4/11A-2
Trouble
Shooting
.........
2D11/11A-9
Description
...............
2D4,'11A-2
Full-Flow
Oil
Filter
........
2D16/11A-14
Removal
and
Installation
.....
2D4/11A-2
Description
..........
2D16/11A-14
Cleaning
and
Inspection
.....
2D4/11A-2
Removal
and
Installation
. .
2D16/11A-14
Repair
...................
2D4/11A-2
Oil
Cooler
...............
2D16/11A-14
ENGINE
...................
2D4/11A-2
Description
............
2D16/11A-14
Description
..............
2D4/11A-2
Fuel
System
..............
2D16/11A-14
Engine
Data
..............
2D4/11A-2
Description
.............
2D16/11A-14
ENGINE
(Model
172Q
Only)
....
2D5/11A-3
Carburetor
...............
2D16/11A-14
Description
...............
2D5/11A-3
Removal
and
Installation
...
2D16/11A-14
Engine
Data
..............
2D5/11A-3 Idle
Speed
and
Mixture
Time
Between
Overhaul
(TBO)
.
2D6/11A-4
Adjustments
............
2D16/11A-14
Overspeed
Limitations
.......
2D7/11A-5
Induction
Air
System
........
2D16/11A-14
Trouble
Shooting
..........
2D7/11A-5
Description
.............
2D16/11A-14
Removal
.................
2D10/1A-8
Removal
and
Installation
..
2D16
11A-14
Cleaning
................
2D10/11A-8
Ignition
System
............
2D16
11A-14
Accessories
Removal
........
2D10/11A-8
Description
.............
2D16
11A-14
Inspection
................
2D10/11A-8
Trouble
Shooting
.........
2D16
11A-14
Build-Up
.................
2D10/11A-8
Magnetos
...............
2D18 11A-16
Installation
.....
.........
2D10/11A-8
Description
............
2D18
11A-16
Flexible
Fluid
Hoses
........
2D10/11A-8
Removal
and Installation
.
2D18
11A-16
Leak
Test
...............
2D10/11A-8
Internal
Timing
.........
2D18
11A-16
Replacement
.............
2D10/11A-8
Magneto-to
Engine
Timing
..
2D18
11A-16
Static
Run-up
Procedures
....
2D10/11A-8
Maintenance
.............
2D19
11A-17
Baffles
..................
2D10/11A-8
Magneto
Check
...........
2D20
11A-18
Description
..............
2D10/11A-8
Spark
Plugs
.............
2D20
11A-18
Cleaning and
Inspection
.....
2D10/11A-8
Controls
.................
2D20 11A-18
Removal
and
Installation
.....
2D10/11A-8
Description
.............
2D20
11A-18
Repair
...................
2D10/11A-8
Rigging
................
2D20
11A-18
Mount
...................
2D10/11A-8
Throttle
Control
........
2D20
11A-18
Description
............
2D10/11A-8
Mixture
Control
........
2D20
11A-18
Removal
and
Installation
...
2D11/11A-9
Carburetor
Heat
Control
.
.2D20
11A-18
Repair
.................
2D11/11A-9
Starting
System
...........
2D20
11A-18
Shock-Mount
Pads
..........
2D11/11A-9
Description
.............
2D20
11A-18
Oil
System
..............
2D11/11A-9 Trouble
Shooting
.........
2D20
11A-18
Description
.............
2D11/11A-9
Primary
Maintenance
......
2D21
11A-19
Revision
1
11A-1
MODEL
172
SERIES SERVICE
MANUAL
Starter
Motor
............
2D21/11A-19
Inspection
..............
2D21
11A-19
Removal
and Installation
. .
2D21/11A-19
Extreme
Weather
Maintenance
.
2D21
11A-19
Exhaust
System
...........
2D21/11A-19
Cold
Weather
............
2D21
A-19
Description
.............
2D21/11A-19
Dusty
Conditions
.........
2D21
11A-19
Removal
and
Installation
. ..
2D21/11A-19
Seacoast
and
Humid
Areas
.
2D21
11A-19
11A-1.
ENGINE
COWLING.
Refer
to
paragraph
11-.
11A-2.
DESCRIPTION.
Refer
to
paragraph
11-2.
11A-3.
REMOVAL AND
INSTALLATION.
Refer
to
paragraph
11-3.
11A-4.
CLEANING
AND
INSPECTION.
Refer
to
paragraph
11-4.
11A-5.
REPAIR.
Refer
to
paragraph
11-5.
11A-6.
ENGINE.
11A-7.
DESCRIPTION.
Beginning
with
1981
Models
an
air-cooled,
wet-sump,
four-cylinder, hori-
zontally-opposed,
direct-drive,
carbureted
Lycoming
Model
O-320-D2J
engine
is
used
to
power
the
airplane.
The
cylinders,
numbered
from
front
to
rear,
are
staggered
to
permit
a
separate
throw on
the
crankshaft
for
each
connecting
rod.
The
right
front
cylinder
is
number
one,
and
cylinders
on
right
side
are identified
by
odd
numbers
one
and
three.
The
left
front
cylinder
is
number
two
and the
cylinders
on
the
left
side
are
identified
as
numbers
two
and
four.
Refer
to
Paragraph
11A-8
for
engine data.
For
repair
and
overhaul
of
the
en-
gine,
accessories
and
propeller,
refer
to
the appropriate
publications
issued
by
their
man-
ufacturers.
These
publications
are
available
from
the
Cessna
Supply
Division.
11A-8.
ENGINE
DATA.
(O-320-D2J.)
MODEL
(Lycoming)
O-320-D2J
BHP
at
RPM
160
at
2700
RPM
Number
of
Cylinders
4
Horizontally-Opposed
Displacement
319.8
Cubic
Inches
Bore
5.125
Inches
Stroke
3.875
Inches
Compression
Ratio
8.50:1
Magnetos
(Dual)
Slick
4251
(Impulse
coupling)*
Right
Magneto
Fires
25
°
BTC
1-3
Lower
and
2-4
Upper
Left
Magneto
Fires
25°
BTC
1-3
Upper
and
2-4
Lower
Firing
Order
1-3-2-4
Spark
Plugs
18mm
(Refer
to
Avco
Lycoming
Service
Instruction
No.
1042
for
factory
approved
spark
plugs
and
required
gap.)
Torque
Value
390±30
LB-IN.
11A-2
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
11A-8.
ENGINE
DATA
(Cont).
Carburetor
(Marvel-Schebler)
MA-4SPA
Oil
Sump
Capacity
7
U.S.
Quarts
With
Filter
Change
8
U.S.
Quarts
Tachometer
Mechanical
Approximate
Dry Weight
275
Lbs.
(Weight
is
Approximate
and
will
With
Standard
Accessories
vary
with optional equipment
installed.)
Oil
Pressure
Minimum
Idling
25 PSI
*20
PSI
Normal
60-90
PSI
50-90
PSI
Maximum
115
PSI
115
PSI
Oil
Temperature
Normal
Operation Within
Green
Arc
Maximum
Permissible
Red
Line
(245°P)
Cylinder
Head
Temperature
500°F
Maximum (Not Indicated)
*The
direction
of
rotation
of
the
magneto
shafts,
viewed
from anti-propeller end
of
the
engine
is
clockwise.
**1984
and
On,
and
all
aircraft
equipped
with
0509087
modification
kit.
11A-8A.
ENGINE.
(172Q
Models
Only.)
11A-8B.
DESCRIPTION.
The
Model
172Q
airplane
is
powered
by
a
four-cylinder,
horizontally-op-
posed,
air-cooled,
direct-drive,
wet-sump.
carbureted
Lycoming
Model
O-360-A4N
engine.
The
cylinders,
numbered
from
front
to
rear,
are
staggered
to
provide
each
cylinder
connect-
ing
rod
its
own
crankthrow.
Cylinders
are
numbered
one
through
four
with
number
one
cy-
linder
on
the
right
front
and
number
three
cylinder
on
the
right
rear.
Cylinders
two
and
four
are
on
the
left
front
and
left
rear,
respectively.
Refer
to
Paragraph
114-8C
for
engine
data.
For
repair
and
overhaul
of
the
enigne
accessories
and
propeller,
refer
to
the
appropri-
ate
publications issued
by
their
manufacturers.
These
publications
are available
from
the
Cessna
Supply
Division.
11A-8C.
ENGINE
DATA.
(O-360-A4N.)
MODEL
(Lycoming)
O-360-A4N
BHP
at
RPM
180
BHP
at
2700
RPM
Number
of
Cylinders
4
Horizontally-Opposed
Displacement
361.0
Cubic
Inches
Bore
5.125
Inches
Stroke
4.375
Inches
Compression
Ratio
9.0:1
11A-3
MODEL
172
SERIES
SERVICE
MANUAL
11A-8C.
ENGINE
DATA
(Cont).
Magnetos (Dual)
Slick 4251
Right
Magneto
Fires
25
°BTC
1-3
Lower
and
2-4
Upper
Left
Magneto
Fires
25
°
BTC
1-3
Upper
and
2-4
Lower
Firing
Order
1-3-2-4
Spark
Plugs
18mm
(Refer to
Avco
Lycoming
Service
Instruction
No.
1042
for
factory
approved
spark
plugs
and
required
gap.)
Torque
Value
390
30
LB-IN.
Carburetor
Marvel-Schebler
MA4-5
Oil
Sump
Capacity
7
U.S.
Quarts
With
Filter
Change
8
U.S.
Quarts
Tachometer
Mechanical
Approximate
Dry
Weight
291
Lbs.
(Weight is
Approximate
and
will
With
Standard
Accessories
vary
with
optional
equipment
installed.)
Oil
Presure
Minimum
Idling
25
PSI
*20
PSI
Normal
60-90
PSI
50-90
PSI
Maximum
115
PSI
115
PSI
Oil
Temperature
-
Normal
Operation
Within
Green
Arc
Maximum
Permissible
Red
Line
(245°F)
Fuel
Pressure
Red
Line
0.5
PSI
Normal
0.5-8.0
PSI
Red
Line
8.0
PSI
1984
and
On,
and
all
aircraft
equipped
with 0509087
modification
kit.
11A-9.
TIME
BETWEN
OVERHAUL (TBO).
Refer
to
the
latest
Revision
of
Avco
Lycoming
Service
Instruction
No.
1009,
and
all
applicable
Service
Letters
or
Service
Bulletins,
for
recommen-
dations
applicable
to
O-320-D
and
O-360-A4N
Series
engines.
At
the
time
of
overhaul,
engine
accessories
should
be
overhauled.
11A-4
MODEL
172
SERIES
SERVICE
MANUAL
11A-9A.
OVERSPEED
LIMITATIONS.
The
engine
must
not
be
operated
above
specified
maximum
continuous
RPM.
However,
should
inadvertent
overspeed
occur, refer
to
the
latest
issue
of
Avco
Lycoming
Service
Bulletin
369,
and
all
applicable
Service
Letters
and
Service
Instruc-
tions
for
obligatory recommendations.
11A-10.
TROBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
WILL
NOT
START.
Improper
use
of
starting
Review
starting
procedure.
procedure.
Fuel
tanks
or
bays Visually
inspect
tanks
or
empty.
bays.
Fill
with
proper grade
and
quantity
of
gasoline.
Mixture
control
in
the
Move
control
to
the
full
IDLE
CUT-OFF
position.
RICH
position.
Fuel
selector
valve
in
Place
selector
valve
in
the
OFF
position.
ON
position
to
a
tank
known to
contain gasoline.
Defective
carburetor.
Repair
or
replace
carburetor.
Carburetor
screen
or
fuel
Remove
carburetor and
clean
strainer
plugged.
carburetor
screen
or
fuel
strainer
thoroughly.
Vaporized
fuel.
(Most
Refer
to
Pilot's
Operating
likely
to
occur
in
hot
Handbook.
weather
with
a
hot
engine.)
Engine
flooded.
Refer
to
Pilot's
Operating
Handbook.
Water
in
fuel
system.
Open
fuel
strainer
drain
and check
for
water.
If
water
is
present,
drain
fuel
tank
sumps,
lines,
strainer
and
carburetor.
Defective
magneto
switch
Check
continuity.
Repair
or
grounded
magneto
leads. or replace
switch
or
leads.
Spark
plugs
fouled.
Remove, clean
and
regap
plugs.
Test
harness
cables
to
persistently
fouled
plugs.
Replace
if
defective.
ENGINE
STARTS BUT
Idle
stop
screw
or
idle
mix-
Refer
to
paragraph
11-43.
DIES,
OR WILL
NOT
IDLE.
ture
incorrectly
adjusted.
Carburetor
idling
jet
Clean
carburetor
plugged.
idling jet.
Spark
plugs
fouled
or
im-
Remove,
clean
and regap
properly
gapped.
plugs.
Replace
if
defective.
Water
in
fuel
system.
Open
fuel
strainer drain
and
check
for
water.
If
water
is
present,
drain
fuel
tank
sumps,
lines,
strainer
and
carburetor.
11A-5
MODEL
172
SERIES
SERVICE
MANUAL
11A-10.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
STARTS
BUT
Defective
ignition
system.
Refer
to
paragraph
11A-55.
DIES.
OR
WILL
NOT
IDLE
(Cont).
Vaporized
fuel.
(Most
Refer
to
Pilot's
Operating
likely
to
occur
in
hot
Handbook-
weather
with
a
hot
engine.)
Induction
air
leaks.
Check
visually.
Correct
the cause
of
leaks.
Manual
primer
leaking.
Disconnect
primer
outlet
line.
If
fuel
leaks
through
primer.
repair
or replace
primer.
Leaking
float
valve
or
Perform an
idle
mixture
float
level
set
too
high.
check.
Attempt
to
remove
any rich
indication
with
the
idle
mixture adjustment.
If
the
rich
indication
cannot
be
re-
moved.
the
float
valve
is
leaking
or
the
float
level
is
set
too
high.
Replace
defec-
tive
parts.
reset
float
level.
Defective
carburetor.
If
engine
will
start
when
primed
but
stops
when
priming
is
discontinued.
with
mixture
control
in
full
RICH
position. the carburetor
is
defective.
Repair
or
replace
carburetor.
Defective
engine.
Check
compression.
Listen
for
unusual
engine
noises.
Engine
repair
is
required.
ENGINE
RUNS
ROUGHLY
Restriction
in
aircraft
fuel Refer
to
Section
12.
OR
WILL
NOT
ACCEL-
system.
ERATE PROPERLY.
Worn
or improperly
rigged
Check
visually.
Replace
throttle
or
mixture
control. worn
linkage.
Rig
properly.
Spark
plugs
fouled
or
im-
Remove,
clean
and
regap
properly
gapped.
plugs.
Replace
if
defective.
Defective
ignition
system.
Refer
to
paragraph
11A-55.
11A-6
MODEL
172
SERIES SERVICE
MANUAL
11A-10.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
RUNS
ROUGHLY
Defective
or badly
adjusted
Check
setting
of
accelerator
OR
WILL
NOT
ACCEL-
accelerator
pump
in
carbu- pump
linkage
and
adjust
as
ERATE
PROPERLY.
(Cont).
retor.
necessary.
Float
level
set
too
low.
Check
and
reset
float
level.
Defective
carburetor.
If
engine
will
start
when
primed
but
stops
when
priming
is
discontinued.
with
mixture
control
in
full
RICH
position,
the
carbu-
retor
is
defective.
Repair
or
replace
carburetor.
Defective
engine.
Check
compression.
Listen
for
unusual
engine
noises.
Engine
repair
is
required.
Restricted
carburetor
air
Check
visually.
Clean
in
filter.
accordance with
Section
2.
Cracked
engine
mount.
Inspect
and
repair
or
re-
place
mount as required.
Defective
mounting
bushings.
Inspect
and
install
new
bushings
as
required.
POOR
IDLE
CUT-OFF.
Worn
or improperly rigged
Check
that
idle
cut-off
stop
mixture
control.
on
carburetor
is
contacted.
Replace
worn
linkage.
Rig
properly.
Manual
primer
leaking.
Disconnect
primer
outlet
line.
If
fuel
leaks
through
primer,
it is
defective.
Repair
or
replace
primer.
Defective
carburetor.
Repair
or
replace
carburetor.
Fuel
contamination.
Check
all
screens
in
fuel
system.
Drain
all
fuel
and
flush
out
system.
Clean all
screens,
lines,
strainer
and
carburetor.
11A-7
MODEL
172
SERIES SERVICE
MANUAL
11A-11
REMOVAL.
Refer
to
paragraph
11-11.
11A-12.
CLEANING.
Refer
to
Section
2.
11A-13.
ACCESSORIES
REMOVAL.
Refer
to
paragraph
11-13.
11A-14.
INSPECTION. Refer
to
paragraph
11-14.
11A-15.
BUILD-UP.
Refer
to
paragraph
11-15.
11A-16.
INSTALLATION.
Refer
to
paragraph
11-16.
11A-17.
FLEXIBLE
FLUID
HOSES.
Refer
to
paragraph
11-17.
11A-18.
LEAK
TEST.
Refer
to
paragraph
11-18.
11A-19.
REPLACEMENT.
Refer
to
paragraph
11-19.
11A-20.
STATIC
RUN-UP
PROCEDURES.
In
a
case
of
suspected
low
engine
power.
a
static
RPM
run-up
should
be
conducted
as
follows:
a.
Run-up
engine,
using
takeoff power
and
mixture
settings.
with
the
aircraft
facing
90
°
right
and then
left
to
the
wind
direction.
b.
Record
the
RPM
obtained
in
each
run-up position.
NOTE
Daily
changes
in
atmospheric
pressure,
temperature
and
humidity
will
have
a
slight
effect
on
static
run-up.
c.
Average
the
RPM
values
obtained
in
step
b.
The
resulting
RPM
figure
should
be
2300
to
2420
for
O-320-D2J
engine
or
2350
to
2450
RPM
for
O-360-A4N
engine.
d.
If
the
resulting
average
RPM
figure
is
lower
than
stated
above,
the following checks
are
recommended
to
determine
a
possible
deficiency.
1.
Check
carburetor heat
control
for
proper
rigging.
If
partially
open
it
would
cause
a
slight
power
loss.
2.
Check
magneto
timing,
spark
plugs
and
ignition
harness
for
settings
and
conditions.
3.
Check
condition
of
induction
air
filter.
Clean
if
necessary.
4.
Perform
an
engine
compression
check.
(Refer
to
engine
manufacturer's
manual.
11A-21.
ENGINE
BAFFLES.
Refer
to
paragraph
11-21.
11A-22.
DESCRIPTION.
Refer
to
paragraph
11-22.
11A-23.
CLEANING
AND
INSPECTION.
Refer
to
paragraph
11-23.
11A-24.
REMOVAL
AND
INSTALLATION.
Refer
to
paragraph
11-24.
11A-25.
REPAIR.
Refer to
paragraph
11-25.
11A-26.
ENGINE
MOUNT.
Refer
to
paragraph
11-26.
11A-27.
DESCRIPTION. Refer
to
paragraph
11-27.
11A-8
MODEL
172
SERIES SERVICE
MANUAL
11A-28.
REMOVAL
AND
INSTALLATION.
Refer
to
paragraph
11-28.
11A-29.
REPAIR.
Refer to
paragraph
11-29.
11A-30.
ENGINE
SHOCK
MOUNT
PADS.
Refer
to
paragraph
11-30.
See
Figure
11A-1.
11A-31.
ENGINE
OIL
SYSTEM.
Refer
to
paragraph
11-31.
11A-32.
DESCRIPTION.
Refer
to
paragraph
11-32.
11A-33.
TROUBLE
SHOOTING.
TROUBLE PROBABLE
CAUSE REMEDY
NO
OIL
PRESSURE.
No
oil
in
sump.
Check
with
dipstick.
Fill
sump
with
proper
grade
and
quantity
of
oil.
Refer
to
Section
2.
Oil
pressure
line
broken.
Inspect
pressure
lines.
disconnected
or pinched.
Replace
or
connect
lines
as
required.
Oil
pump
defective.
Remove
and
inspect.
Exam-
ine
engine.
Metal
particles
from
damaged
pump
may
have
entered
engine
oil
passages.
Defective
oil
pressure
Check
with
a
known
good
gage.
gage.
If
second
reading
is
normal,
replace
gage.
Oil
congealed
in
gage
line.
Disconnect line
at
engine
and
gage;
flush
with
kero-
sene. Pre-fill
with
kerosene
and
install.
Relief
valve
defective.
Remove
and
check
for
dirty
or
defective
parts.
Clean
and
install:
replace
valve
if
defective.
LOW
OIL
PRESSURE.
Low
oil
supply.
Check
with dipstick.
Fill
sump with
proper
grade
and
quantity
of
oil.
Refer
to
Section
2.
Low
viscosity
oil.
Drain
sump
and
refill
with
proper
grade
and
quantity
of
oil.
11A-9
MODEL
172
SERIES
SERVICE
MANUAL
11A-33.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
LOW
OIL
PRESSURE
Oil
pressure
relief valve
Remove and
inspect
spring.
(Cont).
spring
weak
or
broken.
Replace
weak
or
broken spring.
Defective
oil pump.
Check
oil
temperature
and
oil
level.
If
temperature
is
higher
than
normal
and
oil
level
is
correct,
internal
failure
is
evident.
Remove
and
inspect.
Examine
engine.
Metal
particles
from
dam-
aged
pump
may
have
entered
oil
passages.
Secondary
result
of
high
Observe
oil
temperature
oil
temperature.
gage
for
high
indication.
Determine
and
correct
reason
for
high
oil
temperature.
Leak
in
pressure
or
Inspect gasket
between
suction
line.
accessory
housing
and
crank-
case.
Repair
engine as
required.
Dirty
oil
filter.
Remove
and
install
new
filter.
HIGH
OIL
PRESSURE.
High
viscosity
oil.
Drain
sump
and
refill
with
proper
grade
and
quantity
of
oil.
Relief
valve
defective.
Remove
and
check for
dirty
or
defective
parts.
Clean
and
install:
replace valve
if
defective.
Defective
oil
pressure
gage.
Check
with
a
known
good
gage.
If
second
reading
is
normal,
replace
gage.
LOW
OIL TEMPERATURE.
Defective
oil
temperature
Check
with
a
known
good
gage
or
temperature
bulb.
gage.
If
second
reading
is
normal,
replace
gage.
If
read-
ing
is
similar,
the
temperature
bulb
is
defective.
Replace
bulb.
Oil
cooler
thermostatic
Remove
valve
and
check
for
valve/bypass
valve
defec-
proper operation.
Replace
tive
or
stuck.
valve
if
defective.
11A-10
MODEL
172
SERIES SERVICE
MANUAL
11A-33.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
HIGH
OIL
TEMPERATURE.
Oil
cooler
air
passages
Inspect
cooler
core.
clogged.
Clean
air
passages.
Oil
cooler
oil
passages
Attempt
to
drain
cooler.
In-
clogged.
spect
for
sediment.
Remove
cooler
and
flush
thoroughly.
Thermostatic
valve
or
by-
Feel
front
of
cooler
core
pass
valve
damaged or
held
with
hand.
If
core
is
cold.
open
by
solid
matter.
oil
is
bypassing
cooler.
Remove
and
clean
valve
and
seat.
If
still
inoperative.
replace.
Low
oil
supply.
Check
with
dipstick.
Fill
sump
with
proper
grade
and
quantity
of
oil.
Refer
to
Section
2.
Oil
viscosity
too
high.
Drain
sump and refill
with
proper
grade
and
quantity
of
oil.
Prolonged
high
speed
oper-
Hold
ground
running
above
ation
on
the ground.
1500
RPM
to
a
minimum.
Defective oil
temperature
Check
with
a
known
good
gage.
gage.
If
second
reading
is
normal,
replace
gage.
Defective
oil
temperature
Check for
correct
oil
pres-
bulb.
sure.
oil
level
and
cylinder
head
temperature.
If
they
are
correct,
check
oil
temperature
gage
for
being
defective:
if
similar
reading
is
observed.
bulb
is
defective.
Replace bulb.
Oil
congealed
in
cooler. This
condition
can
occur
only
in
extremely
cold
tem-
peratures.
If
congealing
is
sus-
pected.
use
an
external
heater
or
a
heated
hangar
to
warm the
congealed
oil.
OIL
LEAK
AT
FRONT
OF
Damaged
crankshaft
seal.
Replace.
Also
refer
to
Service
News
ENGINE. Letter,
SNL85-8,
Feb.
15,
1985.
OIL
LEAK
AT
PUSH
ROD
Damaged
push
rod
housing
Replace.
HOUSING.
oil
seal.
11A-11
MODEL
172
SERIES
SERVICE
MANUAL
UPPER
RIGHT
HAND
SHOCK
MOUNT
C299501-0106
LOWER
RIGHT
HAND SHOCK
MOUNT
C299501-0101
1.
Bolt
2.
Washer
3.
Mounting
4.
Spacer
3
,5.
Engine
Mount
6.
Damper
2
,
7.
Nut
MODEL
172Q
2
7
Figure
11A-1.
Shock
Mount
Details
(Sheet
1
of 2)
11A-12
MODEL
172
SERIES
SERVICE
MANUAL
6
5
2
LOWER
LEFT
HAND
SHOCK
MOUNT
C299501-0106
Figure
11A-1.
Shock Mount
Details
(Sheet
2
of
2)
11A-13
MODEL
172
SERIES
SERVICE
MANUAL
11A-34.
FULL-FLOW
OIL
FILTER.
IA-35.
DESCRIPTION.
An
external
full-flow.
spin-on
oil
filter
is
installed
on
the
engine.
If
the
filter
should
become
clogged.
a
bypass
valve
allows
engine
oil
to
flow
directly
to
the
engine
oil
passages.
11A-36.
REMOVAL
AND
INSTALLATION.
Refer
to
paragraph
11-36.
11A-37.
OIL
COOLER.
Refer
to
paragraph
11-37.
11A-38.
DESCRIPTION.
Refer
to
paragraph
11-38.
11A-39.
ENGINE
FUEL SYSTEM.
Refer
to
paragraph
11-39.
11A-40.
DESCRIPTION.
Refer
to
paragraph
11-40.
11A-41.
CARBURETOR.
Refer
to
paragraph
11-41.
11A-42.
REMOVAL
AND
INSTALLATION.
Refer
to
paragraph
11-42.
11A-43.
IDLE
SPEED
AND
MIXTURE
ADJUSTMENTS.
Refer
to
paragraph
11-43.
11A-44.
INDUCTION
AIR
SYSTEM.
Refer
to
paragraph
11-44.
The
Model
172Q
airplanes
incorporate
an
induction
air
filter
assembly
featuring
a
replacement
filter
element.
11A-45.
DESCRIPTION.
Refer
to
paragraph
11-45.
11A-46.
REMOVAL AND
INSTALLATION.
Refer
to
paragraph
11A-46.
11A-47.
IGNITION
SYSTEM.
11A-48.
DESCRIPTION.
The
ignition
system
is
comprised
of
dual
Slick
4251
magnetos.
two
spark
plugs
in
each
cylinder,
an
ignition wiring
harness,
an
ignition
switch mounted
on
the
instrument
panel
and
required
wiring
between
the
ignition
switch
and
the
magnetos.
11A-49.
TROUBLE SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
WILL
NOT
START.
Defective
ignition
switch.
Check
switch
continuity
Replace
if
defective.
Spark
plugs
defective, Clean.
regap
and
test
plugs.
improperly
gapped
or
Replace
if
defective.
fouled
by
moisture
or
deposit.
Defective
ignition
harness.
If
no
defects
are
found
by
a
visual
inspection.
check
with
a
harness
tester.
Replace
defective
parts.
MODEL
172
SERIES SERVICE
MANUAL
11A-49.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ENGINE
WILL
NOT
START
Magneto
"P"
lead
Check
continuity.
"P"lead
(Cont).
grounded.
should
not
be
grounded
in
the
ON
position
but
should
be
grounded
in
OFF
posi-
tion.
Repair
or
replace
"P"
lead
Failure
of
impulse
coup-
Impulse coupling
pawls
ling.
should
engage
at
cranking
speeds.
Listen
for
loud
clicks
as
impulse
couplings
operate.
Remove
magnetos
and
determine
cause.
Re-
place defective
magnetos.
Defective
magneto.
Refer
to
paragraph
11A-55.
Broken
drive
gear.
Remove
magneto
and
check
magneto
and
engine
gears.
Replace defective
parts.
Make
sure
no
pieces
of
damaged
parts
remain
in
engine
or
engine
disassembly
will
be
required.
ENGINE
WILL
NOT
Spark plugs
defective,
Clean.
regap
and
test
plugs.
IDLE
OR
RUN
PROP-
improperly
gapped
or
Replace
if
defective.
ERLY.
fouled
by
moisture
or
deposits.
Defective
ignition
harness
If
no
defects
are
found
by
a
visual
inspection.
check
with
a
harness tester.
Re-
place defective
parts.
Defective
magneto.
Refer
to
paragraph
11A-55.
Impulse
coupling
pawls
Listen
for
loud
clicks
as
remain
engaged. impulse
coupling
operates.
Remove
magneto
and
deter-
mine
cause.
Replace
defec-
tive
magneto.
Spark
plugs
loose. Check
and
install
properly.
11A-15
MODEL
172
SERIES
SERVICE
MANUAL
11A-50.
MAGNETOS.
11A-51.
DESCRIPTION.
The
engine
is
equipped with
dual
Slick
4251
(impulse
coupling)
magnetos.
The
magnetos incorporate an
integral
feed-thru
capacitor
and
require
no
external
noise
filter
in
the
ground
lead. The
direction
of
rotation
of
the
magneto shafts,
viewed from
the
anti-propeller
end
of
the
engine,
is
clockwise.
Refer
to
Slick
4200/6200
Series
Aircraft
Magnetos Maintenance
and
Overhaul
Instructions
Bulletin,
and
all
revisions
and
supple-
ments thereto,
for
a
detailed
description,
disassembly
and
reassembly
of
the
magneto.
11A-52.
REMOVAL
AND
INSTALLATION.
WARNING
The
magneto
is in a
SWITCH
ON
condition
when
the
switch
wire
is
disconnected.
Therefore,
ground
the
breaker
contact
points
or
disconnect
the
high-tension
wires
from
the
magneto
or
the
spark
plugs.
a.
Remove
engine
cowling
in
accordance
with
paragraph
11-3.
b.
Remove
screws
securing
the
high-tension
outlet
cover
to
the
magneto.
The
"P"
leads
may
be
disconnected
for
additional
clearance
if
necessary.
NOTE
It is a
good
practice
to
position
No.
1
cylinder
at
its
approximate
advance
firing position
before
removing
the
magneto.
c.
Remove
nuts, washers
and
clamps
attaching
the
magneto
to
the
engine accessory
housing.
Note
the
approximate
angular
position
at
which
the
magneto
is
installed,
then
remove
the
magneto.
d.
Reverse
the
preceding
steps
for
reinstallation
and
time
magneto-to-engine
in
accordance
with
paragraph
11A-54.
NOTE
Magneto
(primary)
lead
nut
torque
range
is
11-13
in.-lbs.
Exceeding
this
torque
range
could
result
in
possible
con-
denser
damage.
11A-53.
INTERNAL
TIMING. (MAGNETO REMOVED FROM
ENGINE.)
Refer
to
Slick
4200/6200
Series
Aircraft
Magnetos
Maintenance and
Overhaul
Instructions
Bulletin,
and
all
revi-
sions
and
supplements
thereto,
for
internal
timing
instructions.
11A-54.
MAGNETO-TO-ENGINE
TIMING.
After
100
hours
of
operation
and
every
100
hours
thereafter,
or
at
annual
inspection, whichever
comes
first,
the magneto-to-engine
timing
should
be
checked.
This
is
accomplished
in
the following
manner
WARNING
Be
sure
switch
is in
"OFF"
position
and
the
"P"
lead
is
grounded.
11A-16
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
a.
Turn
the
engine
crankshaft
in
the
normal
direction
of
rotation
until
the
No.
1
cylinder
is in
the
full-advance
firing
position,
following
the engine
manufacturer's
procedure
for
timing
of
magnetos.
b.
Loosen
the
magneto
mounting
bolts,
and
connect
a
standard
timing
light
between
engine
ground
and
the
magneto
condenser
terminal.
NOTE
Switch
must
be
"ON".
c.
Rotate
the
complete
magneto
opposite
normal rotation
of
the
mageto
on
the
engine
mounting,
until
the
timing
light
indicates
the contact
breaker
points
are
just
opening.
Secure
the
magneto
in
this
position.
WARNING
During
all
magneto
maintenance, always
take
proper
precautions
to
make
sure
the
engine
can
not
fire
or
start
when
the
propeller
is
moved.
TURN
SWITCH
"OFF".
11A-55.
MAINTENANCE.
Refer
to
Slick
4200/6200
Series
Aircraft
Magnetos
Maintenance
and
Overhaul
Instructions
Bulletin,
and
all
revisions
and
supplements
thereto,
for
disassembly.
cleaning, inspection,
and
reassembly instructions.
At
500-hour
intervals,
the
contact
assemblies
should
be
checked
for
burning
or
wear.
If
the
points
are
not
discolored
and
have
a
white
frosty
surface
around
the
edges, the
points
are functioning
properly
and
should
not
be
touched
Apply
M-1827
cam
grease
sparingly
to
each
lobe
of
the
cam
before
reassembly.
If
the
points
are
blue
(indicating
excessive
arcing)
or
pitted,
they
should
be
discarded.
Replace
both
condenser
and
damaged
points.
At
500-hour
inspections,
it is
necessary
to
check
the
carbon
brush
in
the
distributor
gear
for
wear,
cracks
and
chipping.
Measure carbon
brush
length
from
distributor
gear
shaft
to
end
of
brush.
Minimum
acceptable
length
is
1/32
inch.
If
worn.
cracked
or
chipped,
the
distributor
gear
must
be
replaced.
Put
a
drop
of
SAE
#20
non-
detergent
machine
oil
in
each
oilite
bearing
in
the
distributor
block
and
bearingbar.
Inspect
the
high
tension
lead
from
the
coil
to
make
sure
it
makes
contact
with the
carbon
brush
on
the
distributor
gear shaft.
At
500-hour
inspection,
visually
inspect
the
impulse
coupling
shell
and
hub for
cracks,
loose
rivets
or
rounded
pawls
that
may
slip
when
latching
up
on
the
pin.
If
any
of
these
conditions
are
evident,
the
coupling
should
be
replaced.
NOTE
If
the
engine
operating
troubles
develop
which
appear
to
be
caused
by
the
ignition
system,
it is
advisable
to
check
the
spark
plugs
and
ignition
harness
first
before
working
on
the magnetos.
If
the
trouble
appears
definitely
asso-
ciated with
a
magneto,
perform
moisture
check
and
breaker
contact
compartment
check
in
accordance with
procedures
outlined
in
paragraph
11-55,
steps
"a"
thru
"b". If
trouble
has
not
been
corrected
after
accomplishing
the
moisture
and
breaker
contact
compartment
checks.
check
magneto-to-engine
timing
in
accordance
with
paragraph
11A-54.
If
timing
is
incorrect,
remove
mag-
neto
and
adjust
internal
timing
in
accordance
with
paragraph
11A-53.
Reinstall
magneto
and
time
to
engine
in
accordance
with
paragraph
11A-54.
If
the
trouble
has
not
been
corrected,
magneto
overhaul
or
replacement
is
indicated.
Revision
1
11A-17
MODEL
172
SERIES
SERVICE
MANUAL
1A-56.
MAGNETO
CHECK.
Refer
to
paragraph
11-56.
11A-57.
SPARK
PLUGS.
Refer
to
paragraph
11-57.
11A-58.
ENGINE
CONTROLS.
Refer
to
paragraph
11-58.
11A-59.
DESCRIPTION. Refer
to
paragraph
11-59.
11A-60.
RIGGING.
Refer
to
paragraph
11-60.
11A-61.
THROTTLE
CONTROL.
Refer
to
paragraph
11-61.
1A-62.
MIXTURE CONTROL.
Refer
to
paragraph
11-62.
11A-63.
CARBURETOR
HEAT
CONTROL.
Refer
to
paragraph
11-63.
11A-64.
STARTING
SYSTEM.
Refer
to
paragraph
11-64.
11A-65.
DESCRIPTION.
Refer
to
paragraph
11-65.
11A-66. TROUBLE
SHOOTING.
TROUBLE
PROBABLE CAUSE
REMEDY
STARTER
WILL
NOT
Defective
master
switch
or
Check
continuity
of
master
OPERATE.
circuit.
switch
and
circuit.
Install
new
switch
or
wires.
Defective
starter
switch
or
Check
continuity
of
switch
switch circuit.
and
circuit.
Install
new
switch
or
wires.
Defective
starter
motor.
Check
voltage
to
starter.
If
voltage
is
present.
Re-
move.
repair
or
install
new
starter
motor.
STARTER
MOTOR
RUNS.
Defective
Bendix
drive.
Remove
starter
and
inspect
BUT
DOES
NOT
TURN
Bendix
drive. Replace
defec-
CRANKSHAFT.
tive
parts.
Damaged
starter
pinion
Inspect
starter
pinion
gear
gear
or
ring
gear.
and
ring
gear.
Replace
defective
parts.
STARTER
MOTOR
DRAGS.
Low
battery.
Check
battery.
Charge
or
install
new
battery.
Starter
switch
or
relay
con-
Install
servicable
unit.
tacts
burned
or
dirty.
Defective
starter
motor
Inspect
cable.
Install
new
power cable.
cable.
11A-18
MODEL
172
SERIES
SERVICE
MANUAL
11A-66.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
STARTER
MOTOR
DRAGS.
Loose
or
dirty
connections.
Inspect
connections. Remove
(Cont.)
clean
and
tighten
all
term-
inal
connections.
Defective
starter
motor.
Check
starter
motor
brushes.
brush
spring
tension thrown
solder
on
brush
cover.
Re-
pair
or
install
new
starter
motor.
Dirty
or
worn
commutator. Inspect
commutator.
Clean
and
turn
commutator.
STARTER
EXCESSIVELY
Worn
starter
pinion gear
Inspect
starter
pinion
gear
NOISY.
or broken teeth
on
ring
and
ring
gear.
Replace
defec-
gear.
tive
parts.
11A-67.
PRIMARY
MAINTENANCE.
Refer
to
paragraph
11-67.
11A-68.
STARTER
MOTOR.
Refer
to
paragraph
11-68.
11A-69.
REMOVAL
AND
INSTALLATION.
Refer
to
paragraph
11-69.
11A-70.
EXHAUST
SYSTEM.
Refer
to
paragraph
11-70.
11A-71.
DESCRIPTION. Refer
to
paragraph
11-71.
11A-72.
REMOVAL
AND
INSTALLATION.
Refer
to
paragraph
11-72.
11A-73.
INSPECTION.
Refer
to
paragraph
11-73.
11A-74.
EXTREME
WEATHER
MAINTENANCE.
Refer
to
paragraph
11-74.
11A-75.
COLD
WEATHER.
Refer
to
paragraph
11-75.
11A-76.
DUSTY
CONDITIONS.
Refer
to
paragrah
11-76.
11A-77.
SEACOAST
AND
HUMID
AREAS.
Refer
to
paragraph
11-77.
11A-19/(11A-20
blank)
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
12
FUEL
SYSTEM
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
FUEL
SYSTEM
............
2E3/12-1
Priming
System
...........
2E17/12-13
Description
...............
2E3/12-1
Description
........... .
2E17
12-13
Precautions
...............
2E4/12-2 Removal
................
2E17/12-13
Trouble
Shooting
......... .
2E4/12-2
Inspection
..............
2E19/12-15
Tanks
...................
2E5/12-3
Installation
.............
2E20
12-16
Description
.............
2E5/12-3
INTEGRAL
FUEL BAYS
.......
2E21
12-17
RemovalInstallation
.......
2E5/12-3
Description
...............
2E21
12-17
Quantity
Transmitters
.......
2E5/12-3
Classification
of
Fuel
Leaks
. . .
2E21/12-17
Vents
...................
2E5/12-3
Fuel
Bay
Purging
..........
2E21/12-17
Description
.............
2E11/12-7
Integral
Fuel
Bay
Sealant
....
2F7
12-27
Checking
...............
2E11/12-7
Mixing
Sealant
...........
2F8/12-28
Selector
Valve
.............
2E1412-10
Sealing
During
and
After
Description
.............
2E14/12-10
Structural
Repair
........
2F8
12-28
Removal'Installation
.......
2E14
12-10
Sealing
Fuel Leaks
........
2F11
12-31
Disassembly
.............
2E14/12-10
Curing
Time
.............
2F12/12-32
Cleaning.
Inspection
and
Testing
................
2F12
12-32
Repair
...............
2E14/12-10
Fuel
Quantity
Transmitters
. ..
2F12
12-32
Reassembly
.............
2E16/12-12
Vented
Fuel
Filler
Cap
.......
2F13
12-33
Strainer
................
2E1612-12
Description
.............
2F13
12-33
Description
.............
2E16
12-12
Inspection,
Cleaning
and
Removal
Installation
.......
2E17
12-13
Repair
................
2F13
12-33
Disassembly
Assembly
.....
2E17/12-13
12-1.
FUEL
SYSTEM.
12-2.
DESCRIPTION
The
172
and
172Q
Series
airplanes
are
equipped
with
either
a
standard
fuel
system,
an
optional
long-range
fuel
system,
or
beginning
with Serials
17274010.
F17202070,
and
17275869
(172Q),
an
optional extended
range
"wet
wing"
system.
The
stan-
dard
and
long-range
systems
are
essentially
the
same,
differing
mainly
in
fuel
tank
capac-
ity.
The
extended
range
system
consists
of
an
integral
fuel
bay
in
the
inboard
end
of
each
wing. Fuel
flows
by
gravity
from
two
aluminum
tanks
(one
per
wing)
in
the
standard
and
long-range
systems,
and
from
an
integral
fuel
bay
area
in
each
wing
in
the extended
range
system,
to
a
four-position
selector
valve,
through
an
electric
auxiliary
fuel
pump
(172Q)
through
a
firewall-mounted
fuel
strainer
to
the
carburetor and
engine
primer.
Depending
upon
selector
valve
handle
position,
fuel
is
directed
from
either
or
both
tanks
or
bays
to
the
engine,
or
flow
can
be
shut
off
completely.
An
important
aspect
of
the
gravity
type
fuel
sys-
tem
is
positive
venting
of
all
tanks
or
bays.
Venting
is
accomplished
in
all
three
systems
by
an
overboard
vent
line
equipped
with
a
vent
check
valve,
incorporated
in
the
left fuel
tank
or
bay.
The
vent
line
protrudes
through
the
bottom of
the
left
wing
into
the
airstream.
In
addi-
tion,
a
vent
crossover
line
connects
the
airspace
in
the
left
tank
to
the
airspace
in
the
right
tank
where
a
vented
fuel
tank
cap is
installed.
An
electric
fuel
quantity
indicating
system
consisting
of
two
float
type
transmitters
(one
per
tank
or
bay) and
two
indicators mounted
on
the
instrument
panel
display approximate
fuel
quantity
to
the
pilot.
The
pilot
primes
the
engine
for
starting
using
a
manual
primer
which
takes
fuel from
the
fuel
strainer
and
di-
rects
it
to
number four
cylinder
(172),
or
three
cylinders
(172Q).
Revision
1
12-1
MODEL
172
SERIES
SERVICE
MANUAL
12-3.
PRECAUTIONS.
Observe
the
following
general precautions and
rules
during
fueling,
defuel-
ing,
tank
or
integral
fuel
bay
purging,
repairing,
assembly or
disassembly
of
system
compo-
nents,
and
electrical
system checks
and
repairs
on
the
airplane
fuel
system:
WARNING
During
all
fueling
procedures,
fire
fighting
equipment
must
be
available.
Attach
a
ground
wire
from
approved
ground
stakes
to
the
mooring
eyebolt
on
LH
and
RH
wing
struts
or
mooring
ring
on
LH
and
RH
wings.
Ground
fuel
nozzle
to
airplane
during
fueling
operations.
a.
Plugs
or
caps
should
be
placed on
all
disconnected
hoses,
lines
and
fittings
to
pre-
vent
residual
fuel
drainage,
thread
damage,
or
entry
of
dirt
or
foreign
material
into
fuel
system.
12-4.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
NO
FUEL
TO
CARBURETOR.
Fuel
selector
valve
not
Turn
valve
on.
turned
on.
Fuel
tanks
or
bays
empty.
Service with
proper
grade
and
amount
of
fuel.
Plugged
fuel
strainer.
Remove
and
clean
strainer
and
screen.
Fuel
line
plugged.
Clean
out
or
replace
fuel
line.
Fuel
tank
or
bay
outlet
Remove and clean
strainers
strainers
plugged.
and
flush
out
fuel
tanks
or
bays.
Inlet
elbow
or
inlet
screen
Clean
and/or
replace.
in
carburetor
plugged.
Fuel line
disconnected
or
Connect
or
repair
fuel
lines.
broken.
Defective
fuel
selector
valve.
Repair
or
replace
selec-
tor
valve.
FUEL
STARVATION
AFTER
Partial
fuel
flow
from
the
Use
the
preceding
remedies.
STARTING.
preceding
causes.
Plugged
fuel
vent.
See
paragraph
12-11.
12-2
MODEL
172
SERIES
SERVICE
MANUAL
12-4.
TROUBLE
SHOOTING
(CONT).
TROUBLE PROBABLE
CAUSE
REMEDY
FUEL
STARVATION
AFTER
Water
in
fuel.
Drain
fuel
tank
or
bay sumps,
STARTING
(CONT).
fuel
lines
and
fuel
strainer.
NO
FUEL
QUANTITY
Fuel
tanks
or
fuel
Service
with
proper
grade
and
INDICATION.
bays
empty.
amount
of
fuel.
Open
circuit
breaker.
Reset
circuit
breaker.
Refer
to
Section
15.
Loose
connections
or
Tighten
connections;
repair
or
open
circuit.
replace
wiring.
Refer
to
Section
20.
Defective
fuel
quantity
Refer
to
Section
15.
indicator
or
transmitter.
PRESSURIZED
FUEL
TANK
Plugged
bleed
hole
in
fuel
Check
per
paragraph
12-11.
OR
BAY.
vent.
12-5.
FUEL
TANKS.
12-6.
DESCRIPTION.
A
rigid
metal
tank
is
installed
in
the
inboard
panel
of
each
wing.
Sump
drain
valves,
one
in
each
tank,
are
provided
for
draining
trapped
water
and
sediment.
Air-
planes
17261445, 17267585
and
On
and
F17201515
and
On
incorporating
SK172-116
have
one
additional
quick
drain
valve
installed
in
the
lower
outboard
corner of
the tank
for
draining
trapped
water
and
sediments.
Airplanes
incorporating
SK172-135
have
four
addi-
tional
quick
drain
valves
in
each
tank
for
draining
trapped
water and
sediment.
12-7.
REMOVAL
AND
INSTALLATION.
a.
Remove
sump
drain
valve
and
drain
fuel
from
applicable
tank.
(Observe
precautions
in
paragraph
12-3.)
b.
Remove
fuel
tank
cover
by
removing
attaching
screws.
c.
Remove
wing
root
fairings.
d.
Disconnect
and
plug
or
cap
all
fuel
and
vent
lines
from
tank.
Remove
fittings as
neces-
sary
for
clearance
when
removing
tank.
e.
Disconnect
electrical
lead
and
ground
strap
from
fuel
quantity
transmitter.
f.
Disconnect
straps
securing
fuel
tank
and remove
tank.
Use
care
to
avoid
damage
to
protruding
fittings
and
hose
connections when
removing
the
tank.
g.
To
install
tank,
reverse
the
preceding
steps.
Be
sure
grounding
is
secure
in
ac-
cordance
with
figure
12-3.
12-8.
FUEL
QUANTITY
TRANSMITTERS.
Fuel
quantity
transmitters
are
installed
in
the
top
of
fuel
tanks.
A
complete
description, along
with
procedures
for
removal.
installation
and
adjustment
are
contained
in
Section
15.
12-9.
FUEL
VENTS.
Revision
3
12.3
MODEL
172
SERIES
SERVICE
MANUAL
FUEL
QUANTITY
INDICATORS
FUEL
FUEL
QUANTITY QUANTITY
TRANSMITTER
VENTED
TRANSMITTER
FILLER
CAP
.
FILLER
CAP
SELECTOR
VENT
VALVE
CHECK
LEFT
FUEL
TANK
RIGHT
FUEL
TANK
VALVE)
DRAIN
DRAIN
VALVE
VALVE
SELECTOR
VALVE
DRAIN
PLUG
FUEL
STRAINER
FUEL
TO
ENGINE
- -
-
-
STRAINER
DRAIN
CONTROL
ENGINE
PRIMER
CONDITION:
SYSTEM SHOWN
WITH
FUEL
SELECTOR VALVE
IN
BOTH
POSITION.
CONTROL
CODE
THROTTLE
CARBURETOR
FUEL
SUPPLY
MIXTURE
VENT
CONTROL
TO
ENGINE
TO
ENSURE
MAXIMUM
FUEL
CAPACITY
WHEN
REFUELING
AND
MINIMIZE
CROSS-FEEDING
WHEN
PARKED
ON
A
SLOPING
ELECTRICAL
SURFACE.
PLACE
THE
FUEL
CONNECTION SELECTOR
VALVE
IN
EITHER
LEFT
OR
RIGHT POSITION.
Figure
12-1.
172
Fuel
System
Schematic
(Sheet
1
of
2)
12-4
MODEL
172
SERIES SERVICE
MANUAL
FUEL
QUANTITY INDICATORS
FUEL
FUEL
QUANTITY
QUANTITY
TRANSMITTER
TRANSMITTER
VENTED
FILLER
CAP
FILLER
CAP
SELECTOR
VENT
SCREEN
VALVE
SCREEN
IWITH
CHECK
LEFT
FUEL
TANK
RIGHT
FUEL
TANK
VALVE)
DRAIN
DRAIN
VALVE
VALVE
FUEL
SELECTOR
DRAIN
VALVE
CONDITION:
SYSTEM
SHOWN
WITH
FUEL
SELECTOR
VALVE
TO
ENSURE
MAXIMUM
FUEL
IN
BOTH
POSITION
CAPACITY
WHEN
REFUELING
AND
MINIMIZE
CROSS-FEEDING
WHEN
PARKED
ON
A
SLOPING
AUXILIARY
SURFACE.
PLACE THE
FUEL
FUEL
PUMP
SELECTOR
VALVE
IN
EITHER
LEFT
OR
RIGHT
POSITION.
AUXILIARY
FUEL
PUMP
SWITCH
ENGINE
FUEL
PRIMER
STRAINER
ENGINE-DRIVEN
FUEL
PUMP
TO
ENGINE
VALVE
DRAIN CONTROL
CODE
CODE
FUEL
PRESSURE
GAGE FUEL
SUPPLY
CARBURETOR
VENT
THROTTLE
--
VENT
MECHANICAL
-
LINKAGE
MIXTURE ELECTRICAL
CONTROL
TO
ENGINE
CONNECTION
MODEL
172Q
SERIES
AIRPLANES
Figure
12-1.
172
Fuel
System
Schematic
(Sheet
2
of
2)
12-4A/(12-4B
blank)
MODEL
172
SERIES
SERVICE
MANUAL.
1.
Right
Fuel
Tank
3.
Tank
Vent
Interconnect
Line
16
4.
Fuel
Supply
Line
5.
Left
Fuel
Tank
6.
Overboard
Vent
Line
7.
Primer
8.
Strainer
Drain Control
Detail B
9.
Primer
Supply
Line
10.
Primer
Delivery
Line
,,
-
11.
Selector
Valve
Handle
17267585
THRU
17275034
12.
Shaft
F17201515
THRU
F17202134
13.
Bracket
15.
Selector
Valve
15
16.
Placard
17.
O-Ring
18.
Nipple
19.
Angle
18
SEE
20.
Lower
Wing
Skin
FIGURE
12-5
Detail
A
Figure
12-2.
Fuel System
(Sheet
1
of
2)
12-5
MODEL
172
SERIES SERVICE
MANUAL
SEE
4
FIGURE
12-3
10
SEE
FIGURE
12-6
SEE
FIGURE
12-8
1.
Right
Fuel
Tank
2.
Vent
Crossover
Line
3.
Vent
Tank
Interconnect
Line
4.
Fuel
Supply
Line
5.
Left
Fuel
Tank
6.
Overboard
Vent
Line
7.
Primer
8.
Strainer
Drain
Control
9.
Primer
Supply
Line
10.
Primer
Delivery
Line
BEGINNING WITH
17275035
AND
F17202135
IN
CLEAR
VIEW
OF
THE
PILOT
Figure
12-2.
Fuel
System
(Sheet
2
of
2)
12-6
Revision
2
MODEL
172
SERIES
SERVICE
MANUAL
12-10.
DESCRIPTION.
A
vent
line
is
installed
in
the outboard
end
of
the
left
fuel
tank
and
extends
overboard
down
through
the
lower
wing
skin
The
inboard end
of
the
vent line
extends
into
the
fuel
tank
then
forward and
slightly
upward.
A
vent
valve
is
installed
on
the
inboard
end
of
the
vent
line
inside
of
the
fuel
tank
A
crossover
line
connects
the
two
tanks
together.
A
tee
is
installed
on each
end
of
the crossover line.
A
separate
vent
line
is
attached
to
the tees.
connecting the
crossover
line
to
each
of
the
aft
fuel
supply
lines
from
each
fuel
tank.
See
figure
12-2.
In
addition,
the
right-hand
fuel
tank
cap
includes
a
small
vent
safety
valve
to
ensure positive
fuel
tank
venting.
12-11.
CHECKING.
If
stoppage
of
either
the
fuel
vent or
vent
bleed
hole
occurs.
with
the
engine
running,
it
can
lose power.
and
eventually
stop
due
to fuel
starvation
which
can
lead
to
collapsing
of
fuel
tank
If
the
above
stoppage
occurs
during
a
non-run
period,
fuel
expansion
can
pressurize
the
fuel
tanks
causing
fuel spillage,
or
can
even
rupture the
tank
a.
Attach
a
rubber
tube
to
the end
of
vent
line beneath
the
wing.
b.
Blow
into tube
to
slightly
pressurize
tank
Ifair
can
be blown
into
tank,
vent
line
is
open.
c.
After
tank
is
slightly
pressurized,
insert
end
of
rubber
tube
into
a
container
of
water
and
watch
for
a
continuous
stream
of
bubbles,
which
indicates
the
bleed
hole
in
valve
assembly
is
open
and
relieving
pressure..
d.
After
completion
of
step
"c",
blow
into
tube
againto
slightly
pressurize
the
tank
and
loosen
but
do
not
remove
filler
cap
on
opposite
wing
to
check
tank
crossover
line.
If
pressure
escapes
from
filler
cap,
crossover
line
is
open.
NOTE
Remember
that
a
plugged
vent
line
or
bleed
hole
can
cause
either
fuel
starvation
and
collapsing
of
fuel
tanks
or
the
pressurization
of
tanks
by
fuel
expansion.
e.
Any
fuel
vent
found
plugged or
restricted
must
be
corrected
prior
to
returning
aircraft
to
service.
WARNING
The
fuel
vent
line
protruding
beneath
the wing
near
the
wing
strut
must
be
correctly
aligned
to
avoid
possible
icing
of
the
vent
tube.
Dimensions
are
shown
in
figure
12-
4.
12-7
MODEL
172
SERIES
SERVICE
MANUAL
TRANSMITTER
GROUNDING
NOTES
Long
range
tank
is
shown:
standard
range
tank
is
similar
except
for
capacity
Hinge
for
vent valve
(22)
must
be
at
top
Remove
shims
(16)
when
required
to
increase tension
of leaf
spring
(17)
Airplanes
17261445.
17267585
and
On
and
F17201515
and
On
incorporating
Airplanes
incorporating
SK172-135
have
Detail
A
four additional
drain
valves.
6
2.
Washer
3.
Drain
Valve
4.
Fuel
Sampler
Cup
18
10
5.
Fuel
Quantity
Transmitter
6.
Gasket
7.
Top
Wing
Skin
8.
Ground
Strap
6
11.
Cap(LH)
6
12.
Plate
13.
Washer
14.
Gasket
15.
Spacer
16.
Shim
18.
Chain
19.
Vented
Cap
(RH)
20.
Overboard
Vent
Line
21.
Vent
Valve Tube
22.
Vent
Valve
23.
Quick
Drain
Valve
(typical)*
Figure
12-3.
Fuel
Tank
12-8
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
3.75"
LOOKING
FORWARD
3
LOOKING
4 /
1.
Wing
4.
Fairing
2.
Vent
5.
Wing
Strut
3.
Grommet
6.
Tie-Down
Ring
Figure
12-4.
Fuel
Vent Location
12-9
MODEL
172
SERIES
SERVICE
MANUAL
12-12.
FUEL SELECTOR
VALVE.
(See
figure
12-5.)
12-13.
DESCRIPTION.
A
four
position
fuel
selector
valve
is
located
beneath
the
floorboard
just
aft
and
slightly
to
the
left
of
the
pedestal
structure.
A
shaft
links
the
valve
to
a
handle
mounted
on
the
pedestal
structure.
The
positions
of
the
handle
are
labelled
"OFF.
LEFT.
BOTH
ON
and
RIGHT".
Beginning with
17275035
and
F17202135.
a
drain
valve assembly
is located
in
the bottom
of
the
selector
valve
body
for
sampling
and
draining
of
fuel.
Valve
repair
is
limited
to
replacement
of
component
parts
only.
12-14.
REMOVAL
AND
INSTALLATION.
(See
figure
12-2.)
a.
Drain
all
fuel from
wing
tanks,
fuel
strainer,
lines
and
selector
valve,
observing
precautions
outlined
in
paragraph
12-3.
b.
Remove
selector valve
handle
(11)
and
pedestal
cover.
c.
Peel
back
carpet
as
required
to
gain
access
to
inspection
plates
aft
of
pedestal
structure.
d.
Disconnect
lower
universal
joint
(14)
at
valve
shaft.
e.
Disconnect
and
cap
inlet
and
outlet
fuel
lines
to
valve.
f.
Remove
screws
(21)
attaching
valve
to
mounting
bracket
(13)
and
withdraw
valve.
g.
Reverse
preceding
steps
for
installation.
Service
aircraft
in
accordance
with
Section
2.
turn
fuel
selector
valve
to
ON
position
and
check
for
leaks.
h.
Replace
items removed
for access.
12-15.
DISASSEMBLY.
(See
figure
12-5.)
a.
Remove
fuel
selector
valve
in
accordance
with
paragraph
12-14.
b.
Remove
screws
(1)
securing
cover
(2)
to
valve
body
(7)
and
carefully
remove
cover.
Discard
O-rings
(15)
and
(6),
but
retain
ball
(3)
and
spring
(4)
for
reinstallation.
c.
Slowly
withdraw
rotor
(5)
from
valve
body.
NOTE
Removal
of
rotor
(5)
will
allow
seal
(8).
O-ring
(9),
washer
(10)
and
spring
(11)
(one
each
installed
in
both
inlet
ports)
to
pop
free.
d.
Remove
washer
(16),
plug
(13)
and
O-ring
(12).
12-16.
CLEANING,
INSPECTION AND
REPAIR. (See
figure
12-5.)
NOTE
Repair
of
damaged
or
worn
parts
of
the
selector
valve
assembly
is
NOT
authorized
and
therefore,
is
limited
to
replacement
of
component
parts
only.
a.
Clean
disassembled
parts
by
washing
in
Stoddard
solvent
or equivalent.
Blow
parts
dry
using
clean
compressed
air.
12-10
MODEL
172
SERIES
SERVICE
MANUAL
2
6
15
*
17267585
THRU
17275034
Inlet
Ports
F17201515
THRU
F17202134
Beginning
with
17275035
Wrap
with
tape
NOTES
Fabricate
two
spring
compressors
(14)
from
1/16
inch
diameter #1
OX-WELD
AC
welding
rod
(or
equivalent)
accord-
ing
to
dimensions
shown.
All
dimensions
in
inches.
1.
Screw
9.
O-Ring
2.
Cover
10.
Washer
5.
Rotor
13.
Plug
6.
O-Ring
14.
Spring
Compressor
7.
Body
15.
O-Ring
8.
Seal
16.
Washer
17.
Drain
Valve
Assembly
Figure
12-5.
Fuel
Selector
Valve
and
Spring
Compressor
12-11
MODEL
172
SERIES
SERVICE
MANUAL
b.
Inspect
all
parts
for
obvious
wear
or
damage
as follows:
1.
Check
detent
holes
in
cover
(2)
for
excessive
wear
and
examine
bearing
surfaces
with
rotor
(5).
2.
Inspect
shaft
and
bearing
surfaces
of
rotor
(5)
for
removal
of
black
anodized
finish
indicating
wear.
Check for
internal
corrosion
of
drilled
passages.
3.
Examine
valve
body
(7)
for
wear.
cracks,
distortion
and
internal
corrosion.
Any
damage
to
thread
surfaces at inlet
and
outlet
ports
or
cover
attach
screw
holes
is
cause
for
rejection.
12-17.
REASSEMBLY.
(See
figure
12-5.)
NOTE
Reassembly
of
selector
valve
is
facilitated
by
mounting
in a
bench
vise or
equivalent
bench
support.
making
sure
valve
body
(7)
is
protected
from
damage.
Fabrication
of
spring
compressors
(14)
(two
required)
is
recommended
before
reassembly.
Replace
O-rings
(6.
9
and
15)
whe-
never
rotor
is
removed
from
valve
body.
a.
Insure
all
component
parts
are
clean, then
coat
sparingly
with
lightweight
engine
oil.
b.
Insert
washer
(16)
and
springs
(11)
into
body
(7).
c.
With
spring
compressors
(14)
in
place
as
shown
in
Section
A-A.
compress
springs
(11)
and
install
washers
(10),
new
O-rings
(9)
and
seals
(8)
into
inlet
ports.
ports.
d.
Holding
springs
compressed.
carefully
insert
rotor
(5)
into
valve
body
(7).
Release
spring
compressors
and
check
for
proper
seating
of
seals
to
rotor.
e.
Insert
new
O-ring
(6)
into
recess
at
top
of
valve
body
(7).
f.
Place
new
O-ring
(15)
over
shaft
of
rotor.
g.
Lubricate
spring
(4)
and
ball
(3)
with
lubricant
conforming
to
Military Specification
VV-P-236
(USP
Petrolatum
or
equivalent),
insert
spring
into
hole
in
top
of
rotor.
h.
Place
ball on
spring
and
turn
rotor
as
required
to
index
one
of
the
detent
holes
in
cover
(2).
i.
Attach
cover
(2)
and
test
rotation
of
rotor
shaft
for
ease
of
operation
and
positive
detent
engagement
j.
Replace
plug
(13)
using
new
O-ring
(12).
k.
Reinstall selector valve
in
accordance
with
paragraph
12-14.
12-18.
FUEL
STRAINER.
(See
figure
12-6.)
12-19.
DESCRIPTION.
The
fuel
strainer
is
mounted
at
the
firewall
in
the
lower
engine
compart-
ment.
The
strainer
is
equipped
with
a
quick-drain
valve
which
provides
a
means
of
draining
trapped
water
and
sediment
from the
fuel
system.
The
quick-drain control
is
located
adjacent
to
the
oil
dipstick
and
is
accessible
through
the
oil
dipstick
door
in
the
upper
engine
cowl.
NOTE
The
fuel
strainer
can
be
disassembled,
cleaned and
reassembled
without removing
the
assembly
from
the
aircraft
(Refer
to
paragraph
12-21.)
12-12
MODEL
172
SERIES
SERVICE
MANUAL
12-20.
REMOVAL
AND
INSTALLATION.
(See
figure
12-6.)
a.
Remove
cowling
as
necessary
to
gain
access
to
strainer.
b.
With
selector
valve
in
"OFF"
position.
drain
fuel from
strainer
and
lines
with
strainer
quick-drain
control.
c.
Disconnect
and
cap
or
plug
all
fuel
lines
and
controls
from
strainer.
(Observe
precautions
in
paragraph
12-3.)
d.
Remove
bolts
attaching
assembly
to
firewall
and remove
strainer.
e.
Reverse
the
preceding steps for
installation.
With
selector
valve
in
"ON"
position
check
for
leaks
and
proper operation
of
quick-drain
valve.
12-21.
DISASSEMBLY
AND
ASSEMBLY.
(See
figure
12-6.)
a.
With
selector valve
in
"OFF"
position.
drain
fuel
from
bowl
and
lines
with
quick-
drain
control.
b.
Remove
drain
tube,
safety
wire,
nut
and
washer
at
bottom
of
filter
bowl
and
remove
bowl.
c.
Carefully
unscrew
standpipe
and
remove.
d.
Remove
filter
screen
and
gasket.
Wash
filter
screen
and
bowl
with
solvent
(Federal
Specification
P-S-661,
or equivalent)
and dry
with
compressed
air.
e.
Using
a
new
gasket
between
filter
screen and
top
assembly,
install
screen
and
standpipe.
Tighten
standpipe
only
finger
tight.
f.
Using
all
new
O-rings,
install
bowl.
Note
that
step-washer at
bottom
of
bowl
is
installed
so
that
step
seats
against
O-ring.
Connect
drain
tube.
g.
With
selector
valve
in
"ON"
position,
check
for
leaks
and
proper
operation
of
quick-
drain
valve.
h.
Safety
wire
bottom
nut
to
top
assembly.
Wire
must
have right-hand
wrap,
at
least
45
degrees.
12-22. PRIMING
SYSTEM.
12-23.
DESCRIPTION.
The
Model
172-Series
airplanes
employ
a
standard
manually-operated
prim-
ing
system
which
primes
one
cylinder.
Fuel
is
supplied
by
a
line
from
the
strainer
to
the
plunger-type
primer.
Operating
the
primer
delivers
fuel
to
the
intake
port
of
the
cylinder.
A
three-cylinder
priming
system
is
available
as
optional
equipment. Operating the
primer
on
this
optional
system
delivers
fuel
to
the
intake
port
of
each individual
cylinder
except
No.
3.
12-24.
REMOVAL.
(See
figure
12-7.)
NOTE
Removal
of
primer
from
instrument
panel
requires
disassembly
of
primer.
a.
Place
fuel
shutoff
valve
in
the
OFF
position.
b.
Spread
drip
cloth
under
left-hand
instrument
panel.
c.
Disconnect
and
cap
or
plug
primer
lines
at
primer.
d.
Unlock
primer
knob
and
pull
aft
to
clear packing
nut
(5).
e.
Unscrew
packing
nut
(5).
f.
Withdraw
primer
knob
and
piston
rod
from
instrument
panel.
g.
The
primer
barrel
assembly
can
now
be
worked
free
from
the
instrument
panel
on
the
firewall
side
of
the
panel.
12-13
MODEL
172
SERIES SERVICE
MANUAL
6
7
5 8
9
10
12
5
.
6
13
3
NOTE
Torque
nut
(22)
to
25-30
lb in.
15
17
27
NOTE
Afte
inserting
drain
control
(6)
wire
through
24
clamp
(3)
bend
wire
tip
90°
(degrees)
to prevent
it
from
being
with
drawn
if
the
attaching
clamp
(3)
should
come
loose.
21
SAFETY
WIRE
HOLE
22
Detail
A
1.
Drain
Tube
10.
Grommet
19.
Bowl
2.
Fuel
Strainer
11.
Elbow
20.
O-Ring
3.
Clamp
12.
Fuel
Line
21.
Step
Washer
4.
Bracket
13.
Plate
22.
Nut
5.
Bracket
14.
O-Ring
23.
Standpipe
6.
Strainer
Drain
Control
15.
Top
Assembly
24.
Collar
7.
Spring
Nut
16.
Gasket
25.
Plunger
8.
Shield
17.
Filter
26.
Washer
9.
Firewall
18.
O-Ring
27.
Spring
Figure
12-6.
Fuel
Strainer
12-14
MODEL
172
SERIES SERVICE
MANUAL
4
3
6
1.
Fitting
4.
Washer
7.
Piston
Rod
2.
Locknut
5.
Packing
Nut
8.
Barrel
3.
O-Ring
6.
Knob
Figure
12-7.
Primer
Assembly
12-25.
INSPECTION.
(See
figure
12-7.)
Visually inspect
the
primer lines
for
crushed.
kinked,
or
broken
condition.
Ensure proper
clamping
to
prevent fatigue
due
to
vibration
or
chafing.
Ensure barrel assembly
(8)
cylinderwall-is
free
of
signs
of
pitting.
corrosion,
or
scoring
and
that
O-rings
(3)
are
in
good
condition.
NOTE
To
remove O-rings
(3)
from
piston
rod
(7).
squeeze
0-
rings
in
grooves
of
piston
rod
with
thumb
and
index
finger.
Work
O-rings
over
end of
piston
rod.
O-rings
can
be
refitted
to
their
grooves
on
piston
rod
(8)
in a
similar
manner.
CAUTION
Do
not
damage
O-rings
(3).
12-15
MODEL
172
SERIES
SERVICE
MANUAL
12-26.
INSTALLATION.
(See
figure
12-7.)
a.
From
the
firewall
side
of
the
instrument
panel.
insert
barrel
assembly
(8)
through
hole
in
panel.
Ensure
that
washer
(4)
is
installed
on
barrel
between
locknut
(2)
and
firewall
side
of
panel.
CAUTION
Do
not
damage
O-rings
(3)
during
step
"b".
b.
While
holding
barrel
assembly
(8)
firmly
in
place.
insert
piston
rod
assembly
(7)
into
barrel.
c.
The
distance
the
barrel
protrudes
through
hole
in
panel
can
be
adjusted
by
turning
locknut
(2).
d.
Tighten
packing
nut
(5)
against
panel.
e.
Unplug
or
uncap
fittings
on
primer
lines
and
attach
to
primer fittings
(1).
f.
Turn
fuel
shutoff
valve
to
the
ON
position.
g.
Check
primer
for
proper
pumping
action
and
positive
fuel
shutoff
in
the
locked
position.
12-26A.
AUXILIARY
ELECTRIC
FUEL
PUMP.
(MODEL
172Q).
12-26B.
DESCRIPTION.
The electric
fuel
pump
is
located
under
the
floorboards
on
the
RH
side
of
the
cabin.
It
is
plumbed
into
the
fuel
system
parallel
with the
engine-driven
fuel
pump.
The
aux-
iliary
electric
fuel
pump may
be
uses
as
a
standby
in
case
of
engine-driven
fuel
pump
fail-
ure.
The
pump
is
controlled
by
a
rocker-switch
located
on
the
switch
and
control
panel
adja-
cent
to
the
master
switch.
12-26C.
REMOVAL
AND
INSTALLATION.
(See
figure
12-8.)
a.
Place fuel
selector
valve
in
OFF
position.
b.
Turn
the
master
switches
and
auxiliary
fuel
pump
switch
OFF.
.
Disconnect
fuel
lines
(16)
and
drain
line
(14)
from
pump
(11).
OBSERVE
precautions
outlined
in
paragraph
12-3.
d.
Disonnect
electrical wires
from
pump
(11).
e.
Loosen
clamp
(13)
and
remove fuel
pump
(11)
from
bracket
(12).
f.
Reverse
preceding
steps
for
installation
of
pump.
g.
Check
for
proper
operation
and
fuel
leaks
after
installing
pump.
12-16
MODEL
172
SERIES
SERVICE
MANUAL
12-27.
INTEGRAL
FUEL
BAYS.
12-28.
DESCRIPTION.
Beginning
with
Serials
17274010
and
F17202070,
an
extended
range
fuel
system
is
available.
The
extended
range
system
is
a
wet
wing
configuration
that
consists
of
integral
fuel
bays
in
the
inboard
end
of
each
wing,
vented
fuel
cap
for
right
wing
fuel
bay,
non-vented
fuel
cap
for
left
wing
fuel
bay,
fuel
quantity
transmitters,
mounted
on
the
side
of
the
left
and
right
wing
root
rib assemblies,
fuel
vent
valve
assembly
mounted
on
the
in-
board
side
of
the
left
outboard
fuel bay
rib,
fuel
sump
drain
valves
in
the
bottom
inboard
end
of
each
fuel bay,
fuel
screens
over
the
end
of
each
fuel
supply
line,
and
baffles
mounted
on
the
bottom
inboard
surface
of
each fuel
bay. In
addition, airplanes
incorporating
SK182-
100
have four
quick
drain
fuel
sump
valves
installed
in each
fuel
bay.
12-29.
CLASSIFICATION
OF
FUEL
LEAKS.
Fuel
leaks
which
do
not
constitute
a
flight
hazard
are
stains,
seeps
and heavy
seeps
NOT
in
an
enclosed
area.
However,
they
should
be
re-
paired
when
the
aircraft
is
grounded
for
other
maintenance.
Fuel
leaks
which
constitute
a
flight
hazard are
running
leaks
in
any
area,
seeps,
heavy
seeps,
or
stains
in
an
enclosed
ar-
ea,
such
as
the
wing
leading
edge,
the
sections
of
wing
inboard
and
outboard
of
the
fuel
bay
and the area
between
the
rear
fuel
spar
and the main
spar.
These
leaks
must
be
repaired
before
that
bay
is
used
for
another
flight.
The
wet
or
stained
spot
on
the
wing
in
the area
of
the
bay is
an
indication
of
the
intensity
of
the
leak.
Fuel
leak
classifications
are
shown
in
figure
12-9.
NOTE
Stains
and
seeps
that
are
not
considered a
flight
hazard
must
be
inspected
after
each
flight
to
ensure
that
they
have
not
grown
in
intensity
to
the
point
of
causing
a
flight
hazard.
If
a
leak
causing
a
flight
hazard
should
occur
at
a
place
where
there
are
no
facilities avail-
able
to
make
an
acceptable repair,
it
is
recommended
that
the
leaking bay
be
drained
and
some
suitable
material
placed
over
the
leak,
if
it
is
within
an
enclosed
area
of
the
wing,
to
eliminate
escaping
fumes.
By
switching
the
fuel
selector valve
to
the
other
bay,
the
air-
craft
can
then
be
flown
to
a
base
where
the
fuel
leak
can
be
repaired.
12-30.
FUEL
BAY
PURGING.
WARNING
Purge
fuel
bays
with
an
inert
gas
prior
to
repairing
fuel
leaks,
to
preclude
the
possibility
of
explosions.
The
following
procedure
may
be
used
to
purge
the
bay
with argon
or
carbon
dioxide.
a.
Ground
the
aircraft
to
a
suitable
ground
stake.
b.
Remove
safety
wire
from
shutoff
valve
control
knob
and
pull
control
to
"OFF"
posi-
tion.
(Resafety
control
knob
after
completion
of
repair.)
c.
Drain
all
fuel
from
bay
being
repaired.
(Observe
the
precautions
in
paragraph
12-3.)
d.
Remove
access door
and
insert
hose
into
bay.
e.
Allow
inert
gas
to
flow
into
bay
for
several
minutes
(time
dependent
upon
hose
size,
rate
of
flow,
etc.)
to
remove
all
fuel
vapors.
Since
argon and carbon
dioxide
are heavier
than air,
these
gases
will
remain
in
the
bay
during
the
repair.
The
repair
shall
be
made
using non-sparking
tools
(air
motors,
plastic
scrapers,
etc.).
Revision
3
12-17
MODEL
172
SERIES
SERVICE
MANUAL
17274010
&
ON
MAXIMUM
TORQUE
F17202070 &
ON
8-
10
LB-INCHES
6
(4
-
Places)
A
2
12-8
12-2
12-6 4
12-2
1.
Right
Integral
Fuel
Bay
7.
Left
Integral
Fuel
Bay
2.
Vent
Crossover
Line
8.
Overboard
Vent
Line
3.
Tank
Vent
Interconnect
Line
9.
Primer
4.
Fuel
Supply
Line
10.
Primer
Supply
Line
5.
Hose
11.Strainer
Drain
Control
6.
Clamp
12.
Primer
Delivery
Line
Figure
128.
Integral
Bay
Fuel
System
(Sheet
1
of
5)
12-18
MODEL
172
SERIES SERVICE
MANUAL
SEE
FIGURE
12-6
17275035
AND
ON
F17202040
THRU
F17202233
172
SERIES
AIRPLANES
1.
Right
Integral
Fuel
Bay
6.
Overboard
Vent
Line
2.
Vent
Crossover
Line
7.
Primer
3.
Vent
Interconnect
Line
8.
Primer
Supply Line
4.
Fuel
Supply
Line
9.
Primer
Delivery
Line
5.
Left
Integral
Fuel
Bay
Figure
12-8.
Integral
Bay
Fuel
System
(Sheet
2
of
5)
12-19
MODEL
172
SERIES
SERVICE
MANUAL
SEE
FIGURE
12-9
7
17275869
AND
ON
1.
Right
Integral
Fuel
Bay
2.
Vent
Crossover Line
3.
Vent
Interconnect
Line
4.
Fuel
Supply
Line
5.
Left
Integral
Fuel
Bay
6.
Overboard
Vent
Line
12
7.
Primer
8.
Primer
Supply
Line
9.
Primer
Delivery
Line
14
10.
Fuel
Pressure
Gage
11.
Fuel
Pump
12.
Puel
Pump
Braket
15
13.
Clamp
14.,
Drain
Line
16
13.
Grommet
16.
Puel
Lines
Detail
D
Figure
12-8.
Integral
Bay
Fuel
Sytem
(Sheet 3
of
5)
12-20
MODEL
172
SERIES
SERVICE
MANUAL
Deail
B
17275035
THRU
17276259
F17202135
THRU
F17202233
1.
Fuel
Selector
Valve
Handle
2.
Placard
3.
Bracket
4.
Shaft
5.
Bolt
6.
Selector
Valve
7.
O-Ring
8.
Nipple
Figure
12-8.
Integral
Bay
Fuel
System
(Sheet
4 of
5)
12-21
MODEL
172
SERIES
SERVICE
MANUAL
1.
Fuel
Selector
Valve
Handle
2.
Placard
3.
Bracket
4.
Roll
Pin
5.
Shaft
4
6.
Spring
7.
Selector
Valve
8.
O-Ring
9.
Nipple
SEE
FIGURE
12-5
9
Detail
C
17276260
AND
ON
NOTE
Roll
pin
(4)
must
be
bonded
to
shaft
(5)
with
EA9316,
EA9309
or
EA9314.
The
products
may
be
purchased
from Hystol
Div.
Dexter
Corp.,
Willow
Pass
Rd;
Pittburg,
CA
94565.
Equivalent
product,
EC2216,
may
be
purchased
from
3M
Co.,
St.
Paul
MN.
55119.
Clean
roll
pin
(4)
and
shaft
(5)
with
MEK,
and
thoroughly
dry
parts
before
applying
bonding
agent.
At
75°F,
bond
cures
to
80%
ultimate
tensile
strength
within
24
hours.
Accel-
erated
cure
times
are
as
follows:
(a)
Five
minutes
at
250°F.
(b)
Ten
minutes
at
200°F.
Figure
12-8.
Integral
Bay
Fuel
System
(Sheet
5
of
5)
12-22
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
After
performing
maintenance
inside
the
fuel
bay
areas,
seal
according
to
para-
graph
12-33.
NOTE
NOTE
*
Airplanes
17274010
and
On
and
F17202070
and
On
incorporating
SK182-100.
5
6
LEFT
HAND
FUEL
BAY
SHOWN
1.
Inspection
Cover
16
10
12
13
11
14
1.
Inspection
Cover
14
16
2.
Upper
Trailing
Edge
Skin
3.
Gusset
8.
Baffle 12.
Fuel
Drain
Valve
4. Screen
9.
Fuel
Spar
13.
Lower
Forward
Skin
5.
Stiffener
10.
Rib
14.
Hat
Section
Stiffener
6.
Flap
Track Rib
11.
Trailing
Edge
15.
Doubler,
Inspection
Port
7.
LH
Channel
Skin Stiffener
16.
Quick
Drain
Valve
Figure
12-9.
Integral
Fuel
Bay
Installation
(Sheet
1
of
4)
Revision
3
12-23
MODEL
172
SERIES
SERVICE
MANUAL
1
2
3
4
5
DetailA
7
1.
Fuel
Vent
Valve
2.
Tube
3.
Inner
Gasket
4.
Rib
5.
Outer
Gasket
9
6.
Washer
7.
Nut
8.
Fuel
Cap
10
9.
Upper
Wing
Skin
10.
Fuel
Filler
Neck
11.
Filler
Collar
Detail
B
NOTES
Hinge
for
vent
valve
(1)
must
be
at
top.
Install
tube
(2)
with
bend
down.
LH
fuel
cap
is
non-vented,
RH
fuel
cap
is
vented
type
(See
figure
12-2).
Figure
12-9.
Integral
Fuel
Bay
Installation
(Sheet
2
of
4)
12-24
MODEL
172
SERIES
SERVICE
MANUAL
1.
Nutring
1
2.
Root
Rib
Gasket
3.
Root
Rib
2
4.
Transmitter
Gasket
3
5.
Fuel
Quantity Transmitter
4
6.
Washer
7.
Screw
Beginning
with
Serial
17267585
thru
17276330.
17276331,
nutring
(1)
is
bonded
to
root
rib
(2).
Order
sealant
kits
SK210-56,
or
SK210-101
from
Cessna
Supply
Division.
17276331
AND
ON
Detail
C
NOTE
After
installing
washers
(6)
and
screws
(7)
torque
screws
to
20
in/lbs
(once
only).
using
a
cross-pattern
sequence.
Figure
12-9.
Integral
Fuel
Bay
Installation
(Sheet
3
of
4)
12-25
MODEL
172
SERIES
SERVICE
MANUAL
FUEL
100LL,
100
MIN.
GRADE AVIATION
GASOLINE
CAP.
21.5
U.S.
GAL.
Fuel
Quantity
Placard
-
Standard
Tanks
FUEL
100LL/100
MIN.
GRADE
AVIATION GASOLINE
CAP.
27
U.S.
GAL.
Fuel
Quantity
Placard
-
Long
Range
Tanks
FUEL
100LL/100
MIN.
GRADE AVIATION GASOLINE
CAP.
34
U.S.
GAL.
CAP.
24.0
U.S.
GAL.
TO
BOTTOM
OF
FILLER
COLLAR
Fuel
Quantity
Placard
-
Integral
Tank
AVGAS
ONLY
Fuel
Grade
Placard
1.
Fuel
Cap
(See
figure
12-12)
2.
Fuel
Fller
Collar
2
Figure
12-9.
Integral
Fuel
Bay
Installation
(Sheet
4
of 4)
12-26
MODEL
172
SERIES
SERVICE
MANUAL
3/4"
Max.
STAIN
with location
RUNNING
and
intensity.
LEAK
3/4"
to
11/2"
SEEP
Fuel
will
usually
flow
in
this
area
along
skin
con-
tour
after
it
is
wiped
dry.
1
1/2"
to
4"
HEAVY
SEEP
Fuel
usually
drips
WARNING
at
this
point.
REFER
TO
PARAGRAPH
12-13
FOR FUEL
BAY
PURGING
WHICH
SHOULD
BE
ACCOMPLISHED
BEFORE
REPAIRING
FUEL
BAYS.
Figure
12-10. Classification
of
Fuel
Leaks
NOTE
Portable
vapor
detectors
are
available
to
determine
presence
of
explosive
mixtures
and
are
calibrated
for
leaded
fuel.
These
detectors
can
be
used
to
determine
when
it
is
safe
to
make
repairs.
12-31.
INTEGRAL
FUEL
BAY
SEALANT.
Two
kinds
of
sealants are
used,
one
to
seal
the
fuel
bay
and
the
other
to
seal
the
access
doors
and
fuel
quantity
transmitter
adapter.
The
access
door
sealant
is
more
pliable
and
will
not
adhere
to metal
as firmly as
the
bay
sealant
does.
This
permits the
access
doors
and
fuel
quantity
transmitter
adapter
to
be
removed
without
dam-
age
to
them.
Service
Kits
SK210-56
(6
ounce
tube)
and
SK210-101
(2.5
ounce
tube)
.
avail-
able
from
the
Cessna
Supply
Division,
contain
these
sealants
with
the
proper
quantity
of
ac-
celerator
for
each
sealant.
The
sealants
can
be
identified
by
color.
The
bay
sealant
is
white
and
its
accelerator
is
a
black
paste.
The
access door
sealant
is
gray
and
its
accelerator
is
a
clear
liquid.
WARNING
The
accelerator,
EC-1608B
contains
cumene
hydroperox-
ide.
Keep
away
from
heat
and
flame.
Use
only
in a
well
ventilated
area.
Avoid
skin
and
eye
contact.
WEAR
EYE
SHIELDS.
In
case
of
eye
contact,
flush
with
water
and
get
prompt
medical
attention.
12-27
MODEL
172
SERIES
SERVICE
MANUAL
12-32
MIXING
SEALANT.
Use
all
the
accelerator
and
sealant
in
the
container
when
mixing,
to
ensure
the
proper
ratio
of
accelerator
to
sealant.
Stir
the
accelerator
to
absorb
all
floating
liquid
before
it
is
mixed
with
the
sealant.
The
accelerator
can
then
be
poured
into
the
container
of
sealant
for
mixing:
otherwise,
a
wax-free
container
must
be
used.
Stir
accelerator
and
sealant
until
it
becomes
a
uniform
mixture.
Do
not
allow
air
bubbles
to
mix
in.
If
this
occurs, work
air
bubbles
out.
12-33.
SEALING DURING
AND
AFTER STRUCTURAL
REPAIR.
CAUTION
Protect
drain
holes
and
fuel
outlet
screens
when
applying
sealants.
DO
NOT
plug
drain
channels
between
stiffeners
(4)
at
inboard
end
of
stringers
(5)
on
lower
skin
(6).
See
figure
12-12
(typical
lower
skin
section).
Any
repair
that
breaks
the
fuel
bay
seal
will
necessitate
resealing
of
that
area
of
the
bay.
Repair
parts that
need
sealing
must
be
installed
and riveted
during
the
sealing
operation.
All
joints
within
the
boundary
of
the
bay,
but which
do
not
provide
a
direct
fuel
path
out
of
the
bay.
such
as
stringers
and rib
flanges within
the
bay,
must
be
fay
surface
sealed
only.
Joints
which
provide
a
direct
fuel
path
out
of
the
bay
area,
such
as
fuel
spar
flanges
and
inboard
and
outboard
rib
flanges,
must
be
fay
surface sealed
and
fillet
sealed
on
the
fuel
side.
Fay
surface
sealing
is
applying
sealant
to
one
mating
part
before
assembly.
Enough
sealant
must
be
applied
so
it
will
squeeze
out completely
around
the
joint
when
the
parts
are
riveted
or
fastened
together.
The
fillet
seal
is
applied
after
the
joint
is
fay
surface
sealed
and
riveted
or
fastened
together.
Fillet
sealing
is
applying
sealant
to
the edge
of
all
riveted
joints,
joggles.
bend
reliefs,
voids,
rivets
or
fasteners
through
the
boundary
of
the
bay
and
any
place
that
could
produce
a
fuel
leak.
The
fay
sealant
need
not
be
cured
before
the
fillet
seal
is
applied.
but
the
squeezed
out
sealant,
to
which
the
fillet
sealant
is
applied,
must
be
free
of
dirt
and
contamination.
Fillets
laid
on
intersecting
joints
shall
be
joined
together
to
produce
a
continuous
fillet.
Filler
sealant
must
be
pressed
into
the
joint,
working
out
all
entrapped
air.
The
best method
of
applying
sealant
is
with an
extrusion
gun.
Then
work
the
sealant
into
the
joint
with
a
small
paddle.
being
careful
to
eliminate
all
air
bubbles.
NOTE
During
structural
repair,
parts
must
be
predrilled.
coun-
tersunk
or
dimpled
and cleaned
before
being
sealed
and
positioned
for
final
installation.
a.
Remove
all
existing
sealant
from
area
to
be
sealed,
leaving
a
taper
on
the
remaining
sealant.
The
taper
will
allow
a
scarf
bond
and a
continuous
seal
when
the
new
sealant
is
applied.
NOTE
The
best
method of removing
sealant
is
with
a
chisel-type
tool
made
of hard
fiber.
Remaining
sealant
may
then
be
removed
with
aluminum
wool.
Steel
wool
or
sandpaper
must
not
be
used.
b.
Vacuum
thoroughly
to
remove
all
chips,
filings,
dirt.
etc..
from
the
bay
area.
12-28
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Refer
to
paragraph
12-33.
TYPICAL
INSPECTION
PLATE
TYPICAL
RIB
SECTION
1.
Faying
2.
Fillet
Seal
3.
Rivet and
Fastener
Seal
Figure
12-11.
Typical
Fuel
Bay
Sealing
(Sheet
1
of
2)
12-29
MODEL
172
SERIES
SERVICE
MANUAL
TYPICAL
FASTENER
Fastener
3
.25"
TYPICAL
FUEL
BAY
SPAR
Fillet
TYPICAL
END
SECTION
4
1.
Fuel
Side
2.
Nutplate
3.
Fillet
Seal
4.
Stiffener
5.
Stringer
6.
Lower
Skin
TYPICAL
LOWER
SKIN
SECTION
Figure
12-11.
Typical
Fuel
Bay
Sealing
(Sheet
2 of
2)
12-30
MODEL
172
SERIES
SERVICE
MANUAL
c.
All
surfaces
and
areas
to
be
sealed
shall
be
thoroughly
cleaned
by
wiping
with
a
clean
cloth
dampened
with
Methyl
Ethyl
Ketone
(MEK).
acetone
or
similar
solvent
and dried
with
a
clean cloth
before
the
solvent
evaporates.
Always
pour
the
solvent
on
the
cloth.
Never
use
contaminated
solvent.
The
cloth
shall
not
be
so
saturated
that
dripping
occurs.
NOTE
Allowable
work
life
of
EC-1675B/
A
sealant
is
four
hours
from
the
starting
time
of
mixing.
Allowable
work
life
of
EC-1608B/
A
sealant
is
one
hour.
These
apply
to
standard
conditions
of
77°
Fahrenheit
and
50%
relative
humidity.
An
increase
in
temperature
or
a
decrease
in
humidity
will
shorten
the
work
life
of
the
sealant
d.
Apply
fay
surface
sealant
to one
mating
part
and
install
rivets or
fasteners
while
sealant
is
still
within
its allowable
work
life.
NOTE
During
the
sealing
operation,
sealant must
be
checked
at
various
times
to
determine
that
it
has not
exceeded
its
allowable work
life. Use
a
small
wood
paddle,
such
as
a
tongue
depressor,
to
gather
some
sealant
Touch
the
sealant
to a
piece
of
clean
sheet
metal.
If
the
sealant
adheres
to
the
sheet metal,
it
is
still
within
its
allowable
work
life.
If
the
sealant
does
not
adhere
to
the
sheet
metal.
it
is
beyond
its
allowable
work
life
and
must
not
be
used.
e.
Apply
a
fillet seal
to
the
repaired
area
on
the inside
of
the
bay.
f.
Apply
fay
surface
door
sealant
to
access
doors and
fuel
quantity
transmitter
adapter.
if
removed.
and
install
the
doors and adapter.
g.
Allow the
sealant
to
cure.
Refer
to
paragraph
12-34
for
curing time.
h.
Clean
stains
from
outside
of
bay
area.
i.
Test
fuel
bay
for
leaks
as
described
in
paragraph
12-35.
12-34
SEALING
FUEL
LEAKS.
First
determine
the
source
of
the
fuel leaks.
Fuel
can
flow
along
a
seam or
the
structure
of
the
wing
for
several
inches,
making
the
leak
source
difficult
to
find.
A
stained
area
is
an
indication
of
the
leak source.
Fuel
leaks
can
be
found
by
testing
the
complete
bay
as
described
in
paragraph
12-35.
Another
method
of
detecting the
source
of
a
fuel
leak
is
to
remove
access
doors
and
blow
with
an
air
nozzle
from
the
inside
of
the
bay
in
the
area
of
the
leak
while
a
soap
bubble
solution
is
applied
to
the
outside
of
the
bay.
After
the
leak
source
has
been found,
proceed
as
follows:
a.
Remove
existing
sealant
in
the
area
of
the
leak
as described
in
paragraph
12-32.
step
"a".
b.
Clean
the
area
and
apply
a
fillet
seal.
Press
sealant
into leaking
area
with
a
small
paddle,
being sure
to
work
out
all
entrapped
air.
c.
If
a
leak
occurs around
a
rivet
or bolt,
restrike
the
rivet
or
torque
the
bolt
to
the
maximum
allowable
torque,
and
repair
any
damaged
sealant.
d.
Apply fay
surface
door
sealant
to
access
doors or
fuel
quantity
transmitter
adapter,
if
removed, and
install
the
doors
and
adapter.
e.
Test
fuel
bay
for
leaks
as
described
in
paragraph
12-35.
12-31
MODEL
172
SERIES SERVICE
MANUAL
12-35.
CURING TIME.
Service
Kits
SK210-56
and
SK210-101
contain
SP654890B2
Fuel
Tank
Area
Sealant
Kit and
SP654706B2
Access Door
Sealant
Kit.
Normal
curing
time
for SP264706B2
Sealant
Kit
is
24
hours.
These
values
are
based
on
a
Standard
condition
of
77°
Fahrenheit
and
50%
humidity.
Curing
time
may
be
accelerated as
shown
in
the following
chart.
Temperature
of
Sealant
°F
Time
in
Hours
160
3
140 4
120
7
NOTE
Temperature
shall
not
exceed
160°F.
Bay
must
be
vented
to
relieve
pressure
during
accelerated
curing.
WARNING
Access
door
sealant
must
not
be
heated
above
90
°
until
sealant
is
cured
for
24
hours
based
on a
standard
condi-
tion
of
77
°
Fahrenheit
and
50%
relative
humidity.
Harm-
ful
vapors
are released
if
sealant
is
heated above
90°F.
12-36
TESTING
INTEGRAL FUEL
BAY.
a.
Remove
vent
line
from
vent
fitting
and
cap
the
fitting.
b.
Remove forward and aft fuel
lines-from
bay.
c.
To
one
of
the
bay
fittings,
attach
a
water
manometer
capable
of
measuring
20
inches
of
water.
d.
To
the
other
bay
fitting.
connect
a
well-regulated
supply
of
air
(1/2
PSI
MAXIMUM
or
13.8
INCHES
OF
WATER).
Nitrogen
may
be
used where
the
bay
might
be
exposed
to
temperature
changes
while
testing.
e.
Make
sure filler
cap
is
installed
and
sealed.
CAUTION
Do
not
attempt
to
apply
pressure
to
the
bay
without
a
good
regulator
and
a
positive
shutoff
in
the
supply
line.
Do
not
inflate
the fuel
bay
to
more
than
1/2
psi
or
damage
may
occur.
f.
Apply
pressure
slowly
until
1/2
psi
is
obtained.
g.
Apply
soap
solution
as
required.
h.
Allow
15
to
30
minutes
for
pressure
to
stabilize.
i.
If
bay holds
for
15
minutes,
without
pressure
loss,
bay
is
acceptable.
j.
Reseal
and
retest
if
any leaks
are
found.
12-37.
,
FUEL
QUANTITY
TRANSMITTERS.
One
float-actuated,
variable-resistive
transmitter
is
located
in
each fuel
bay.
They
are
connected
electrically
to
separate
galvanometric
gages,
one
for
each
bay,
thereby
indicating
fuel
level
in
each
bay.
A
complete
description
of
the
transmitters,
operation,
and
maintenance
procedures
is
contained
in
Section
15.
12-32
MODEL
172
SERIES
SERVICE
MANUAL
12-38.
VENTED FUEL
FILLER
CAP.
(See
figure
12-11.)
.
12-39.
DESCRIPTION. The
RIGHT-HAND
fuel
filler
cap
incorporates
a
vent
and
safety
valve
that
provides
both
vacuum
and
positive
pressure
relief.
12-40.
INSPECTION,
CLEANING
AND
REPAIR.
a.
Remove
RIGHT-HAND
fuel
filler
cap
from
the
adapter
assembly.
b.
Disconnect
the
safety
chain
from
the
cap
and
cover
or plug
the
tank
opening
to keep
out foreign
matter.
c.
Check
condition
of
gasket
and
frictionless washer,
replace
as
required.
d.
Using
cotton
swabs
and
Stoddard
solvent
or
equivalent,
gently
lift
edges
of
rubber
umbrella
and
clean
seat
and
umbrella
removing
all
contaminates.
Using
a
second
swab wipe
seat
and
umbrella
thoroughly,
removing
all
cotton
fibers. Repeat
until
swabs
show
no
discoloration.
e.
If
the
umbrella
continues
to
leak
or
is
deteriorated, remove
and
replace.
To
remove
the
umbrella, lubricate
the
umbrella
stem
with
(MIL-H-5606)
hydraulic
fluid
to
prevent
tearing
the
stem.
When
installing
the
new
umbrella,
lubricate
the
stem
with
(MIL-H-5606)
hydraulic
fluid
and
use
a
small
blunt
tool to
insert
the
retaining
knob
on
the
umbrella,
into
the
check
valve
body.
f.
Connect
fuel
cap
to
safety
chain
and
reinstall
cap
in
the
adapter
assembly.
NOTE
Check valve
(2)
shall
open
at
or
before
4.0
inches
of
water
vacuum
pressure,
and
be
able
to
withstand
.5
PSI
positive
pressure
without
leakage.
1.
Umbrella
2.
Check
Valve
(Vent)
2
3.
Gasket
4.
Frictionless
Washer
5.
Fuel
Cap
Body
6.
Cover
7.
Screw
Figure
12-12.
Vented
Fuel
Filler
Cap
12-33/(12-34
blank)
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
13
PROPELLER
WARNING
When
performing
any
inspection
or
maintenance
that
requires
turning
on
the
master
switch,
installing
a
battery,
or
pulling
the
propeller
through
by
hand,
treat
the
propeller
as
if
the
ignition
switch
were
ON.
Do
not
stand,
nor
allow
anyone
else
to
stand,
within
the
arc
of
the
propeller,
since
a
loose
or
broken
wire,
or
a
component
malfunction,
could
cause
the
propeller
to
rotate.
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
PROPELLER
..............
2F19/13-1
Description
...............
2F19/13-1
Repair
...................
2F19/13-1
Removal
.................
2F19/13-1
Installation
...............
2F21/13-3
Time
Between
Overhaul
(TBO)
.
2F21/13-3
13-1.
PROPELLER.
(See
figure
13-1.)
13-2.
DESCRIPTION.
An
all-metal,
fixed-pitch
propeller,
equipped
with
a
spinner,
is
used
on
the
aircraft.
13-3.
REPAIR.
Repair
of
a
metal
propeller
first
involves
evaluating the
damage
and
determining
whether
the
repair
is
to
be
a
major
or
minor
one.
Federal
Aviation
Regulations,
Part
43
(FAR
43).
and
Federal
Aviation
Agency
Advisory
Circular
No.
43.13
(FAA
AC
No.
43.13),
define
major
and
minor
repairs,
alterations
and
who
may
accomplish
them.
When
making
alterations
or
repairs
to
a
propeller,
FAR
43,
FAA
AC
No.
43.13
and
the
propeller
manufacturer's
instructions
must
be
observed.
The
propeller
manufacturer's
Service
Manual
may
be
obtained
from the
Cessna
Service
Parts
Center.
NOTE
For
information
not
covered
in
this
section,
refer
to
the
applicable
McCauley Service
Manual
and supplements
thereto.
13-4.
REMOVAL.
(See
figure
13-1.)
WARNING
Be
sure
magneto
switch
is in
OFF
position
before
turning
propeller.
Revision
1
13-1
MODEL
172
SERIES SERVICE
MANUAL
NOTE
4
TORQUE
PROPELLER
MOUNTING
BOLTS
TO
540
-
560
LB-IN
OR
45
-
46.5
LB-FT
AND
SAFETY
WIRE.
-
NOTE
Propeller
(4)
and
spacer
(8)
are
balanced
as
a
set.
The
spacer
is
stamped
with
a
matching
propeller
serial
number.
9
When
installing the
propeller
and
spac-
er,
the
serial
number
on
the
spacer
must
be
toward
the
number
one
blade
of
the
propeller.
10
1.
Spinner
6.
Crankshaft
Bushing
2.
Mounting
Bolt
7.
Ring
Gear
Support
Assembly
3.
Forward
Bulkhead
8.
Spacer
4.
Propeller
9.
Aft
Bulkhead
5. Engine
Crankshaft
10.
Dowel
Pin
13-1.
Propeller
Installation
13-2
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
a.
Remove
spinner
(1).
b.
Remove
safety
wire
from
mounting
bolts.
c.
Remove
mounting
bolts
(2)
and
remove forward
spinner
bulkhead
(3).
propeller
(4).
rear
spinner
bulkhead
(9)
and
spacer
(8).
NOTE
Propeller
mounting
bolts
should
be
magnafluxed
whe-
never
propeller
is
removed
from
the
engine
for
recondi-
tioning
or
repair.
d.
If
removal
of
the
ring
gear
support
assembly
(7)
is
necessary,
loosen
the
alternator
adjusting
arm
and
disengage
the
drive pulley
belt
from
pulley
on
the
aft
face
of
the
starter
ring
gear
support
assembly.
13-5.
INSTALLATION.
(See
figure
13-1.)
WARNING
Be
sure
magneto
switch
is
in OFF
position
before
turning
propeller.
a.
If
the
starter
ring
gear
support
assembly
(7)
was removed,
clean
the
mating
surface
of
support
assembly
and
engine
crankshaft
b.
Place
alternator
drive
belt in
the
pulley
groove
of
the
starter ring
gear support.
Fit
support
assembly
over
propeller
flange
bushing
of
the
crankshaft.
NOTE
Make
sure
the
bushing
hole
in the
ring gear
support
that
bears
the
identification
"O".
is
assembled
at the
"O"
identified
crankshaft
flange
bushing.
This
bushing
is
marked
"O"
by
an
etching
on
the
crankshaft
flange
next
to
the
bushing.
The
starter
ring
gear
must
be
located
correctly
to
assure
proper
alignment
of
the
timing
marks
on
the
ring
gear.
c.
Clean
mating
surfaces
of
the
propeller,
bulkheads
and
spacer
and
assemble
as
illustrated
in
figure
13-1.
d.
Find
the
top
center
(TC)
mark
on
the
aft
face
of
the
starter
ring
gear
support.
Locate
one
of
the
propeller
blades
over
the
TC
mark,
rotate
the
propeller
clockwise
(as
viewed
from
front
of
engine)
to
the
first
bushing
and
install
propeller.
e.
Tighten
propeller
mounting
bolts evenly,
torque
bolts
to
45
lb-ft,
and
safety
wire.
NOTE
The
propeller
mounting
bolt
torque
should
be
checked
at
least
once
per
year.
f.
Install
spinner.
g.
Adjust
alternator
drive
belt
tension
as
outlined
in
Section
16.
13-6
TIME
BETWEEN OVERHAUL
(TBO).
There
is
no
recommended
overhaul
period
for fixed-
pitch
propellers.
These
shall
be
reconditioned
or
repaired
as
required
for
blade
surface
conditions.
13-3/(13-4
blank)
MODEL
172
SERIES SERVICE
MANUAL
SECTION
14
UTILITY
SYSTEMS
Page
No.
TABLE
OF
CONTENTS Aerofiche/
Manual
UTILITY
SYSTEMS
...........
2G3/14-1
Ventilating
System
........
2G6 14-4
Heating
System
...........
2G3/14-1
Description
.............
2G6
14-4
Description
............
2G3/14-1
Operation
..............
2G6
14-4
Operation
...............
2G3/14-1
Trouble
Shooting
........
2G7/14-5
Trouble
Shooting
.........
2G3/14-1
Removal,
Repair
and
Removal,
Repair
and
Installation
............
2G7
14-5
Installation
.............
23/14-1
Air
Circulation
Fan
Defroster System
...........
2G6/14-4
System
.................
2G7/14-5
Description
.............
2G6/14-4
Description
............
2G7/14-5
Operation
...............
2G6/14-4
Removal
................
2G7/14-5
Trouble
Shooting
.........
2G6/14-4 Inspection/Repair
.......
2G7/14-5
Removal,
Repair
and
Installation
............
2G7/14-5
Installation
.............
2G6/14-4
14-1.
UTILITY
SYSTEMS.
14-2.
HEATING
SYSTEM.
(See
figure
14-1.)
14-3.
DESCRIPTION.
The
heating
system
is
comprised
of
the
heat
exchange section
of
the
exhaust
muffler.
a
shut-off
valve,
mounted
on
the
right
forward
side
of
the
firewall,
a
push-
pull
control
on
the
instrument
panel,
outlets
and
flexible
ducting
connecting
the
system.
14-4.
SYSTEM
OPERATION.
Ram
air
is
ducted
through
an
engine
baffle
inlet
and
heat
exchange
section
of
the
exhaust
muffler,
to
the
shut-off
valve
at
the
firewall.
The
heated
air
flows
from
the
shut-off
valve
into
a
duct
across
the
aft
side
of
the
firewall,
where
it is
distributed
into
the
cabin.
The
shut-off
valve,
operated
by
a
push-pull
control
marked
"CABIN
HT,"
located
on
the
instrument
panel,
regulates
the
volume
of
heated
air
entering
the
system.
Pulling
the
control
full
out
supplies
maximum
flow,
and
pushing
control
in
gradually
decreases
flow.
shutting
off
flow
completely
when
the
control
is
pushed full-in.
14-5.
TROUBLE
SHOOTING.
Most
of
the
operational
troubles
in
the
heating, defrosting
and
ventilating
systems
are
caused
by
sticking
or
binding
air
valves
and
their
controls.
damaged
air
ducting
or
defects
in
the
exhaust
muffler.
In
most
cases,
valves
or
controls
can
be
freed
by
proper
lubrication.
(Refer
to
Section
2
of
this
manual
for
lubrication
informa-
tion.)
Damaged
or broken
parts
must
be
repaired
or
replaced.
When
checking controls.
ensure
that
valves
respond freely
to
control
movement,
that
they
move
in
the correct
direction,
and
that
they
move
through
their
full
range
of
travel
and
seal
properly.
Check
that
hoses
are
properly
secured,
and
replace
hoses
that
are
burned,
frayed
or
crushed.
If
fumes
are
detected
in
the
cabin,
a
thorough
inspection
of
the
exhaust
system
should
be
accomp-
lished.
Refer
to
applicable
paragraph
in
Section
11
of
this
manual
for
this
inspectin.
Since
any
holes
or
cracks
may
permit
exhaust
fumes
to
enter
the
cabin,
replacement
of
defective
parts
is
imperative,
because fumes
constitute
an
extreme danger.
Seal
any
gaps
in
shutoff
valves
at
the
firewall
with
Pro-Seal
#700
(Coast
Pro-Seal
Co..
Los
Angeles,
California)
compound,
or
equivalent
compound.
14-6.
REMOVAL,
REPAIR
AND
INSTALLATION.
The
heating
and
defrosting
systems are
illustrated
in
figure
14-1.
The
figure
may
be
used
as
a
guide
for
removal,
repair
or
Revision
1
14-1
MODEL
172
SERIES
SERVICE
MANUAL
B
B
A
THRU
1979
MODELS
BEGINNING
WITH
1980
MODELS
10
*10
Refer
to
Section
2
for
hinge
point
lubrication
iformation.
2
*3
1.
Heater
Hose
2.
Clamp
3.
Vave
Body
4.
Shim
17267585
thru
17275034
5.
Valve
Plate
F17201515
thru
F17202134
6.
Clamp
Bolt
7.
Control
Arm
8.
Cabin
Heat
Control
9.
Valve
Spring
12
10.
Valve
Seat
17275035
&
On
11.
Knob
F17202135
&
On
12.
Vale
13.
Valve
Guide
14.
Nozzle
15.
Clamp
16.
Defroster
Hose
16
17.
Screw
Detail
B
Figure
14-1.
Heating
and
Defrosting
Systems
14-2
MODEL
172
SERIES
SERVICE
MANUAL
C
Detail
D
10
Detail
B
Refer
to
Section
2
for
2
hinge
point
lubrication
information.
1.
Hose
29
Detail
C
2.
Clamp
3.
Inlet
.
29
4.
Seal
5.
Clamp
Bolt
19.
Washer
7.
Fuselage
Skin
21.
Nut
8.
Air
Vent
Silencer
22.
Felt
Washer
9.
Escutcheon
23.
Tube
Assembly
12.
Spring
26. Nutplate
Insert
(15)
is
cemented
to
knob
(10)
with
EC1300L.
14.
Knob
28.
Element
(3M
Co.,
St.
Paul.
Minn. 55101)
Beginning
with
15.
nsert
29.
Adapter
17275991
and
F17202215 thru
F17202233,
insert
16.
Outlet
Assembly
30.
Bracket
(15)
is
retained
by
screw
(11).
17.
Bullet
Catch
31.
Cap
18.
Seal
32.
O-Ring
Figure
14-2.
Ventilating
Systems
14-3
MODEL
172
SERIES SERVICE
MANUAL
installation
of
system
components.
Burned.
frayed
or
crushed
hose
may
be
replaced
with
new hose.
cut
to
correct
length
and
installed
in
the
original
routing.
Trim hose
windings
shorter
than
complete
hose
length
to
allow
clamps
to
be
installed.
Defective
air
valves
should
be
repaired
or replaced.
Check
for
correct
operation
of
valves
and
their
controls
after
repair
and/or
installation.
14-7
DEFROSTER
SYSTEM.
(See
figure
14-1.)
14-8.
DESCRIPTION.
The
defrosting
system
is
comprised
of
a
duct
across
the
aft side
of
the
firewall,
defroster
outlets,
mounted
on
the cowl deck,
immediately
aft
of
the
windshield,
and
flexible
ducting
connecting
the
system.
14-9.
SYSTEM
OPERATION.
Air
from
the
duct
across
the
aft
side
of
the
firewall
flows
through
the
flexible
ducting
to
the
defroster
outlet.
Temperature
and
volume
of
this
air
is
controlled
by
settings
of
the
heater system
control.
14-10.
TROUBLE
SHOOTING.
Since
the
defrosting system
depends
on
proper
operation
of
the
heating system,
trouble
shooting
procedures
outlined
in
paragraph
14-5
should
be
followed
for
checking the
defroster
system.
14-11.
REMOVAL.
REPAIR
AND
INSTALLATION.
The
defroster
system
is
illustrated
in
figure
14-1
in
conjunction
with
the
heating
system.
The
figure
may
be
used
as
a
guide
for
removal.
repair
or installation
of
system
components.
Burned,
frayed
or
crushed
hose
must
be
replaced
with
new
hose,
cut
to
correct
length
and
installed
in the
original
routing.
Trim
hose
windings
shorter
than
complete
hose
length
to
allow
clamps
to
be
installed.
A
defective
defroster
outlet should
be
repaired
or
replaced.
Check
for
correct
operation
of
control
after
repair
and/or
installation.
14-12.
VENTILATING
SYSTEMS.
(See
figure
14-2.)
14-13.
DESCRIPTION.
Three
separate
systems
are
installed
for
cabin
ventilation.
One
system
is
comprised
of
an
airscoop,
located
in
each
wing
root
fillet,
with
flexible
ducting
connecting
each
airscoop
to
an adjustable
air
vent
silencer
unit,
located
on
each
side
of
the
rear
cabin
area.
Another
system
is
comprised
of
an
airscoop.
located
in
the
leading
edge
of
each wing.
just
outboard
of
the airscoop
in
the
wing
root
fillets.
These
airscoops
are
connected
to
cabin
outlets,
installed
on
each
side
of
the
cabin,
near
the
upper corners
of
the windshield.
These
outlets
are manually-adjustable
with
knobs
on
the
outlet
assemblies.
A
third
system
is
comprised
of
a
fresh
airscoop
door
on
the
right
side
of
the
fuselage,
just
forward
of
the
copilot seat. Flexible
ducting
connects
this
airscoop
to
the
duct
across
the
aft
side
of
the
firewall.
This
system
is
controlled
by
a
push-pull
control
on
the
instrument
panel.
14-14.
SYSTEMS
OPERATION.
Heating,
defrosting
and
ventilating
systems
work
together
to
pro-
vide
the conditions
desired
by
the
pilot.
When
the
heating
system,
defrosting
system
and
one ventilating
control
is
pushed
in,
no
heated
air
can
enter
the
firewall
duct;
therefore,
if
the
"CABIN
AIR"
control
(to
the
scoop
door
on
the
right
forward fuselage) is
pulled
out,
only
fresh
air
from
the
scoop
will
flow
through
the
duct
into the
cabin.
As
the
"CABIN
HT"
control
is
gradually
pulled
out,
more
and
more
heated
air
will
blend
with
the
fresh
air
from
the
scoop,
and be
distributed into
the
cabin.
Either
one,
or both
of
the
controls
may
be
set
at
any
position
from
full open
to
full
closed.
Rear
seat
ventilation
is
provided
by
air
vent
si-
lencer
assemblies,
mounted
in
the
left
and
right
rear
cabin
wing root
areas.
These
units
re-
ceive
ram
air
from
the
airsoops
in
the
wing
root
fillets. Each
silencer
assembly
is
equipped
with
a
valve
which meters
incoming
cabin
ventilating
air,
which
greatly
reduces
inlet
air
noise.
The
outlet assemblies,
installed
near the
upper
corners
of
the
windshield
are
manu-
ally
operated,
increasing
or
decreasing
flow
of
ram
air
into
the
cabin.
14-4
MODEL
172
SERIES SERVICE
MANUAL
NOTE
Beginning
with 17276260
CABIN
HT and
CABIN
AIR
controls
are
replaced
with
locking
type
controls.
To
oper-
ate
a
locking
type
control,
push
in
and
hold
the
center
button
before
moving
knob
in
either
diretion-
14-15.
TROUBLE
SHOOTING.
Most
of
the
operational
troubles in
the
ventilating
systems
are
caused
by
sticking or
binding
of
the
inlet
scoop
door
or
its
control.
Check
airscoop
filter
elements
in
the
wing leading
edges for
obstructions.
The
elements
may
be
removed
and
cleaned or
replaced.
Since
air
passing
through
the
filters
is
emitted
into
the
cabin,
do
not
use
a
cleaning solution
which
would
contaminate
the
air.
The
filters
may
be
removed
to
increase
air
flow.
However,
their
removal
will
cause
a
slight
increase
in
noise
level.
14-16.
REMOVAL,
REPAIR
AND
INSTALLATION. The
ventilating
system
is
illustrated
in
figure
14-2.
The
figure
may
be
used
as
a
guide
for
removal,
repair
or
installation
of
system
components.
A
defective
ventilator
or
scoop
must
be
repaired
or
replaced.
Check
for
proper
operation
of
controls
after
repair
and/or
installation.
14-17.
AIR
CIRCULATION
FAN
SYSTEM.
(See
figure
14-3.)
14-18.
DESCRIPTION.
An
optional
cabin
ventilating
fan
may
be
located
above
the
extended
baggage
compartment.
The
system
consists
of
a high-speed
blower
and
overhead
ductwork.
similar
to
that
offered
with
the
air
conditioning
option.
This
fan
only
circulates
air
and
no
cooling
components
are
attached.
The
blower
is
controlled
by
a
four-position switch, located
on
the
pilot's
console.
The
four
switch
positions
are
labeled
HI.
MED.
LOW
and OFF.
14-19.
REMOVAL.
(See
figure
14-3.)
Access
to
the
blower
assembly
and
ducting
is
gained
through
the
baggage
door.
a.
Remove
baggage
compartment
panel.
b.
Disconnect
forward
and
aft
ends
of
hoses
(8)
by
removing
hose
clamps.
c.
Remove
8
screws
attaching
blower
assembly
(5)
and
duct
assembly
(9)
to
supports
(3)
and
(6).
d.
Remove
lower
support
(6).
e.
Disconnect
electrical
connections.
f.
Remove
blower
assembly.
14-20.
INSPECTION
AND
REPAIR. Hoses
should
be
checked
for
security.
and
replaced
if
frayed
or
crushed.
Check
that
hose
clamps
are
properly
tightened:
check
electrical
connections.
and
check
that
blower
rotates
freely.
14-21.
INSTALLATION.
(See
figure
14-3.)
a.
Install
blower
unit
(5)
and
duct
assembly
(9)
to
upper
support
(3).
b.
Connect
electrical
connections.
c.
Install
lower
support
(6).
and
attach
blower
assembly
and
duct
(9).
d.
Install
hoses
and
hose
clamps.
e.
Install
baggage
compartment
panel.
14-5
MODEL
172
SERIES
SERVICE
MANUAL
--------------------.......
1.
Switch
6
2.
Circuit
Breaker
3.
Support
4.
Bulkhead
S.
Blower
Assembly
6.
Support
7.
Clamp
8.
Duct
9.
Duct
Assembly
Figure
14-3.
Circulating
Fan
Installation
14-6
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
15
INSTRUMENTS AND INSTRUMENT
SYSTEMS
Page
No.
TABLE
OF
CONTENTS Aerofiche/
Manual
INSTRUMENTS
AND
INSTRU-
Trouble
Shooting
.........
2H11/15-20C
MENT
SYSTEMS
.............
2G14/15-2
Removal
.................
2H11/15-20C
General
.....................
2G14/15-2
Installation
..............
2H12/15-20D
Instrument
Panel
............
2G14/15-2
Engine
Indicators
...........
2H12/15-20D
Description
...............
2G14/15-2
Tachometer
..............
2H12/15-20D
Removal/Installation
......
2G14/15-2
Description
............
2H12/15-20D
Shock-Mounts
............
2G14/15-2
Oil
Pressure
Gage
........
2H13/15-21
Instruments
............
2G14/15-2
Description
............
2H13/15-21
Removal
.
............
2G14/15-2
Trouble Shooting
......
2H13/15-21
Installation
...........
2G16/15-4
Oil
Temperature
Gage
....
2H14/15-22
Pitot
and
Static
Systems
......
2G16/15-4
Description
............
2H14/15-22
Description
............
2G16/15-4
Cylinder
Head
Temperature
Maintenance
...........
2G16/15-4
Gage
.................
2H14/15-22
Static
System Inspection/
Description
............
2H1415-22
Leakage Test
........
2G16/15-4
Carburetor
Air
Temperature
Pitot
System Inspection/
Gage
................
2H14/15-22
Leakage
Test
...........
2G17/15-5
Description
............
2H14/15-22
Blowing
Out
Lines
........
2G17/15-5
Trouble Shooting
......
2H14/15-22
Removal/Installation
Of
Economy
Mixture
Indicator
2H15/15-23
Components
............
2G18/15-6
Description
............
2H15/15-23
Encoding
Altimeter
.......
2G18/15-6
Calibration
............
2H15/15-23
Description
..........
2G18/15-6
Removal/Installation
...
2H17/15-25
Removal/Installation
....
2G18/15-6
Trouble
Shooting
......
2H17/15-25
Trouble
Shooting
.........
2G18/15-6
Fuel
Quantity
Indicating
True
Airspeed
Indicator
....
2G21/15-9
System
...............
2H17/15-25
Description
...........
2G21/15-9
Description
............
2H17/15-25
Removal/Installation
....
2G21/15-9
Removal/Installation
...
2H17/15-25
Trouble
Shooting
.......
2G21/15-9
Trouble Shooting
......
2H18/15-26
Trouble
Shooting-Altimeter
2G23/15-11
Transmitter
Calibration
2H19/15-26A
Trouble
Shooting-Vertical
Hourmeter
..............
2H21/15-27
Speed
Indicator
.........
2G24/15-12
Description
............
2H21/15-27
Vacuum
System
.............
2H115-13
Magnetic
Compass
.......
2H21/15-27
Description
...............
2H1/15-13
Description
............
2H21/15-27
Trouble
Shooting
..........
2H1/15-13
Removal/Installation
...
2H23/15-29
Trouble
Shooting-Gyros
....
2H2/15-14
Stall Warning
............
2H23/15-29
Trouble
Shooting-Pump
....
2H3/15-15
Description
............
2H23/15-29
Maintenance
Practices
.....
2H6/15-18
Removal/Installation
...
2H23/15-29
Removal
of
Vacuum
Turn
Coordinator
........
2H23/15-29
Pump
..................
2H6/15-18
Description
............
2H23/15-29
Mounting
Pad Inspection
...
2H6/15-18
Trouble Shooting
......
2H23/15-29
Installation
of
Vacuum
Turn-and-Slip
Indicator
...
2H24/15-30
Pump
.
............
2H7/15-19
Description
............
2H24/15-30
Cleaning
.................
2H8/15-20
Trouble
Shooting
......
2H24/15-30
Low-Vacuum
System
......
2H8/15-20
Outside
Air
Temperature
Vacuum
Relief
Valve
Gage
.................
2H25/15-31
Adjustment
............
2H8/15-20
Standby
Vacuum
System
..
2H8/15-20
Description
.............
2H8/15-20
Revision
3
15-1
MODEL
172
SERIES
SERVICE
MANUAL
15-1.
INSTRUMENTS
AND INSTRUMENT SYSTEMS.
15-2.
GENERAL.
This
section
describes
typical
instrument
installations
and
their
respective
operating
systems. Emphasis
is
placed
on
trouble
shooting
and
corrective
measures
only.
It
does
NOT
deal with
specific
instrument
repairs
since
this
usually
requires
special
equipment
and
data
and
should
be
handled
by
instrument
specialists.
Federal
Aviation
Regulations
require malfunctioning
instruments
to
be
sent
to
an
approved
instrument
overhaul
and
repair
station
or
returned
to
manufacturer
for
servicing.
Our
concern
here
is
with
preventive maintenance
and
correction
of
system
faults
which
result
in instrument
malfunctions.
The
descriptive
material.
maintenance
and
trouble
shooting
information
in
this
section
is
intended
to
help
the
mechanic
determine
malfunctions
and
correct
them.
up
to
the
defective
instrument itself
at
which
point
an
instrument
technican
should
be
called
in.
Some
instruments,
such
as
fuel
quantity
and
oil
pressure
gages,
are
so
simple
and
inexpensive,
repairs usually
will
be
more
costly
than
a
new
instrument.
On
the
other
hand.
aneroid
and
gyro
instruments usually
are
well
worth
repairing.
The
words
"replace
instrument"
in
the
text,
therefore,
should
be
taken
only
in
the sense
of
physical
replacement
in
the
aircraft.
Whether
replacement
is
to
be
with
a
new
instrument,
an
exchange
one,
or
original
instrument
is
to
be
repaired
must
be
decided
on
basis
of
individual
circumstances.
15-3.
INSTRUMENT
PANEL.
15-4.
DESCRIPTION.
The
instrument
panel
assembly
consists
of
a
stationary
(right
side)
and
shock-mounted
(left
side)
panel.
Beginning
with
1983
models,
the
left
side
also
contains
a
stationary
panel.
The
stationary
panel contains
engine,
radio and
flight
hour
recording
in-
struments.
The
shock-mounted panel
contains
major
flight-instruments
such
as
horizontal
and
directional
gyros.
Most
of
the
instruments
are
screw-mounted
on
the
panel
backs.
15-5.
REMOVAL
AND
INSTALLATION.
(See
figure
15-1.)
The
stationary
panel
is
secured
to
engine
mount
stingers
and
a
forward
fuselage
bulkhead
and
ordinarily
is
not considered
removable.
The
shock-mounted
panel
is
secured
to
the
stationary
panel
with
rubber
shock-
mounted
assemblies.
To
remove
shock-mounted
panel
proceed
as
follows:
a.
Unscrew
threaded
buttons
securing
decorative
cover
and
remove
cover.
b.
Remove
nuts
and
washers
from
shock-mounts.
c.
Tag
and
disconnect
instrument
wiring.
d.
Disconnect
plumbing
and
cap
all
open
fittings
and
lines.
e.
Pull.panel
straight
back
to
remove.
f.
For installation
reverse
the
preceding
procedure.
Ensure
ground
strap
is
properly
installed.
15-6.
SHOCK
MOUNTS.
Service
life
of
instruments
is
directly
related
to
adequate shock-
mounting
of
panel
If
removal
of
panel
is
necessary,
check
mounts
for
deterioration.
15-7.
INSTRUMENTS.
15-8.
REMOVAL.
(See
figure
15-.)
Most
instruments
are
secured
to
panel
with
screws
inserted
through
panel
face.
To
remove
an
instrument,
remove
decorative
cover,
disconnect
wiring
or
plumbing
to
the
instrument,
remove
mounting
screws
and
take
instrument
out from
behind,
or
in
some
cases,
from
front
of
panel Instrument
clusters
are
installed
as
units
and
are
secured by
a
screw
at
each
end.
A
cluster
must
be
removed
from
panel
to
replace
an
individual
gage.
In
all cases
when
an
instrument
is
removed, disconnected
lines
or
wires
should
be
protected.
Cap
open
lines
and
cover
pressure
connections
on
instrument
to
prevent thread
damage
and
entrance
of
foreign
matter.
Wire
terminals
should
be
insulated
or
tied
up
to
prevent
accidental
grounding
or
short-circuiting.
15-2
MODEL
172
SERIES SERVICE
MANUAL
3
4
9
10
NOTE
POSITION
OF
GROUND
STRAP
AND
SEQUENCE
OF
ATTACHING
PARTS
WHEN
REMOVING OR
INSTALLING
11
SHOCK
PANEL.
Detail
A
12
Detail
B
1.
Shock-Mounted
Panel
5.
Switch
and
Circuit
Breaker
Panel
9.
Stud
2.
Radio
Panel
6.
Engine
Instruments
10.
Instrument
Panel
3.
Heating
and
Ventilating
Controls
7.
Shock-Mount
11.
Decorative
Cover
4.
Engine
Controls
8.
Ground
Strap
12.
Threaded
Button
Figure
15-1.
Typical
Instrument
Panel
15-3
MODEL
172
SERIES
SERVICE
MANUAL
15-9.
INSTALLATION.
Generally,
installation
procedure
is
the
reverse
of
removal
procedure.
Ensure
mounting
screw
nuts
are tightened
firmly,
but
do
not
over-tighten.
particularly
on
instruments
having
plastic
cases.
The
same
rule
applies
to
connecting
plumbing
and
wiring.
NOTE
All
instruments
(gages
and
indicators),
requiring
a
thread
seal
or
lubricant,
shall
be
installed
using
teflon
tape
on
male
fittings
only.
This
tape
is
available
through
Cessna
Supply
Division.
When
replacing
an
electrical
gage
in
an instrument
cluster
assembly.
avoid
bending pointer
or
dial
plate.
Distortion
of
dial
or
back plate
could
change
calibration
of
gages.
15-10.
PITOT
AND
STATIC
SYSTEMS.
(See
figure
15-2.)
15-11.
DESCRIPTION.
The
pitot
system
conveys
ram
air
pressure
to
the
airspeed
indicator.
The
static
system
vents
vertical
speed
indicator, altimeter
and
airspeed
indicator
to
atmos-
pheric
pressure
through
plastic
tubing
connected
to
a
static
port.
A
static
line sump
is
installed
at
source
button
to
collect
condensation
in
static
system.
A
pitot
tube
heater may
be
installed.
The
hating
element
is
controlled
by
a
switch
at
instrument
panel
and
powered
by
the
electrical
system.
An
alternate
static
source
valve
may
be
installed
in
the
static system
for
use
when
the
external
static
source
is
malfunctioning.
Refer
to
the
Pilot's
Operating
Handbook for
flight
operation
using
the
alternate static
source.
15-12.
MAINTENANCE.
Proper
maintenance
of
pitot
and
static
system
is
essential
for
proper
operation
of
altimeter,
vertical
speed
and
airspeed
indicators.
Leaks,
moisture
and
obstruc-
tions
in
pitot
system
will
result
in
false
airspeed indications,
while
static
system
malfunc-
tions
will
affect
readings
of
all
three
instruments.
Under
instrument
flight
conditions,
these
instrument errors
could
be
hazardous.
Cleanliness
and
security
are
the
principal
rules
for
system
maintenance.
The
pitot
tube
and
static ports
MUST
be
kept
clean
and
unobstructed.
15-13.
STATIC
PRESSURE
SYSTEM
INSPECTION
AND
LEAKAGE
TEST.
The
following
proce-
dure
outlines
inspection
and
testing
of
static
pressure
system,
assuming
altimeter
has
been
tested
and
inspected
in
accordance
with
current
Federal
Aviation Regulations.
a.
Ensure
static
system
is
free
from
entrapped
moisture
and
restrictions.
b.
Ensure
no
alterations
or
deformations
of
airframe
surface
have
been
made
which
would affect
the
relationship
between
air
pressure
in
static
pressure
system
and
true
ambient
static
air
pressure
for
any
flight
configuration.
c.
Close
static
pressure
alternate
source
control,
if
installed.
d.
Attach
a
source
of
suction
to
static
pressure
source
opening.
Figure
15-3
shows
method
of
obtaining suction.
e.
Slowly
apply
suction
until altimeter
indicates
a
1000-foot
increase
in
altitude.
CAUTION
When
applying
or
releasing
suction,
do
not
exceed
range
of
vertical
speed
indicator
or
airspeed
indicator.
15-4
MODEL
172
SERIES
SERVICE
MANUAL
f.
Cut
off
suction
source
to
maintain
a
"closed"
system
for
one
minute.
Leakage
shall
not
exceed
100
feet
of
altitude loss
as
indicated
on
altimeter.
g.
If
leakage
rate
is
within
tolerance,
slowly
release
suction
source.
NOTE
If
leakage
rate
exceeds
maximum
allowable,
first
tighten
all
connections,
then
repeat
leakage
test.
If
leakage
rate
still
exceeds
maximum
allowable,
use following
proce-
dure.
h.
Disconnect
static
pressure
lines
from
airspeed
indicator
and
vertical
speed
indica-
tor.
Use
suitable
fittings
to
connect
lines
together
so
altimeter
is
the
only
instrument
still
connected
into
static
pressure
system.
i.
Repeat
leakage
test
to
check
whether
static
pressure
system
or
the
bypassed
instruments
are
cause
of
leakage.
If
instruments
are
at
fault,
they
must
be
repaired
by
an
"appropriately
rated
repair
station"
or
replaced.
If
static
pressure
system
is
at
fault,
use
following
procedure
to
locate
leakage.
j.
Attach
a
source
of
positive pressure
to
static
source
opening.
Figure
15-3
shows
one
method
of
obtaining
positive
pressure.
CAUTION
Do
not
apply
positive
pressure
with
airspeed indicator
or
vertical
speed
indicator
connected
to
static pressure
system.
k.
Slowly
apply
positive pressure
until
altimeter indicates
a
500-foot
decrease
in
altitude
and
maintain
this
altimeter
indication
while checking
for
leaks.
Coat
line:
connections
and
static
source flange
with
solution
of
mild
soap and
water,
watching
for
bubbles
to
locate
leaks.
1.
Tighten
leaking
connections.
Repair
or
replace
parts
found
defective.
m.
Reconnect
airspeed
and
vertical
speed
indicators
into
static
pressure
system
and
repeat
leakage
test
per
steps
"c"
thru
"g".
15-14.
PITOT SYSTEM
INSPECTION
AND
LEAKAGE
TEST.
To
check
pitot
system
for
leaks,
place
a
piece
of
tape
over
small
hole
in
lower
aft
end
of
pitot
tube,
fasten
a
piece
of
rubber
or
plastic
tubing
over
pitot
tube,
close
opposite
end of
tubing
and slowly
roll
up
tube
until
airspeed
indicator
registers
in
cruise
range.
Secure
tube
and
after
a
few
minutes
recheck
airspeed
indicator.
Any
leakage
will
have
reduced
the
pressure
in
system,
resulting
in
a
lower
airspeed
indication.
Slowly
unroll
tubing
before
removing
it,
so
pressure
is
reduced
gradually.
Otherwise
instrument
may
be
damaged.
If
test
reveals
leak
in
system,
check
all
connections
for
tightness.
15-15.
BLOWING
OUT
LINES.
Although pitot system
is
designed
to
drain
down
to
pitot
tube
opening,
condensation
may
collect
at other
points
in
system
and
produce
a
partial
obstruction.
To
clear
line,
disconnect
at
airspeed
indicator. Using
low
pressure air.
blow
from
indicator
end
of
line
toward
pitot
tube.
15-5
MODEL
172
SERIES SERVICE
MANUAL
CAUTION
Never
blow
through
pitot
or static
lines
toward
instru-
ments.
Like
pitot lines,
static
pressure
lines
must
be
kept
clear
and
connections tight.
All
models
have
a
static source
sump
which collects
moisture
and keeps
system clear.
However.
when
necessary.
disconnect
static
line
at
first
instrument
to
which
it is
connected,
then
blow
line
clear
with low-pressure
air.
Check
all static pressure
line
connections
for
tightness.
If
hose
or
hose
connections
are
used,
check
for
general
condition
and
clamps
for
security.
Replace
hose
which
cracked, hardened
or
show
other
signs
of
deterioration.
15-16.
REMOVAL
AND
INSTALLATION
OF
COMPONENTS.
(See
figure
15-2.)
To
remove
pitot
mast
remove
four
mounting
screws
on
side
of
connector
(13)
and
pull
mast
out
of
connector
far
enough
to
disconnect
pitot
line
(5).
Electrical
connections
to
heater
assembly
(if
installed)
may
be
disconnected
through
wing
access
opening
just
inboard
of
mast.
Pitot and
static
lines
are
removed
in
the
usual
manner, after
removing
wing
access plates,
lower
wing
fairing
strip
and
upholstery
as
required.
Installation
of
tubing will
be
simpler
if
a
guide
wire
is
drawn
in
as
tubing
is
removed
from
wing.
The
tubing
may
be
removed
from
wing.
The
tubing may
be
removed
intact
by
drawing
it
out
through
cabin
and
right
door.
Tighten
-
connections
firmly
but
avoid
overtightening
and
distorting
fittings.
It
twisting
of
plastic
tubing
is
encountered
when
tightening
fittings,
VV-P-236
(USP
Petrolatum). may
be
applied
sparingly
between
tubing
and
fittings.
15-17.
ENCODING ALTIMETER.
15-18.
DESCRIPTION.
An encoding
altimeter
may
be
installed
which
is
also
connected
to
static
system
pressure.
The
encoding
altimeter supplies
coded
altitude
signals
to
the
aircraft's
transponder
for
transmission
to
ground
based
interrogating
radar.
The
encoding
altimeter
installation
requires
the
use
of
a
fully
operational
secondary
altimeter
as backup.
15-19.
REMOVAL
AND
INSTALLATION.
Figure
15-2,
sheet
2
may
be
used
as
a
guide
for
removal
and
installation
of
the encoding
altimeter.
15-20.
TROUBLE
SHOOTING
--
PITOT STATIC SYSTEM.
TROUBLE
PROBABLE
CAUSE
REMEDY
LOW
OR
SLUGGISH
AIR-
Pitot
tube
obstructed,
leak Test
pitot
tube
and
line
for
SPEED
INDICATION.
(Nor-
or
obstruction
in
pitot
line.
leaks
or
obstructions.
Blow
mal
altimeter
and
vertical
out
tube
and line.
repair
speed.)
or
replace
damaged
line.
INCORRECT
OR
SLUGGISH
Leaks
or
obstruction
in
Test
line
for leaks
and
ob-
RESPONSE.
(All
three
static
line.
structions. Repair
or
replace
instruments.)
line,
blow
out
obstructed
line.
15-6
MODEL
172
SERIES SERVICE
MANUAL
INSTALLATION
Detail
A
16
HEATED
20
22
Detail
E
WITHOUT
ALTERNATE
Detail E
STATIC
SOURCE
WITH
ALTERNATE
STATIC
SOURCE
NOTE
11.
Instrument
Panel
Detail
C
12.
Spacer
Do
not
overtighten
screws
(7)
15
13.
Connector
and
do
not
lubricate
any
parts.
1.
Vertical
Speed
Indicator
14
Mast
Body
15.
Heater Element
Use
spacers
(12)
as
required
3.
Altimeter
3.Shock-Mounted
Panel
16.
Valve
for
adequate
friction
on
ring
4.
Airspeed Indicator
17.
Knob
5.
Pitot
Line
18.
Insert
THRU
17276468
AND
7.
Mounting
Screw
20.
Static
Sump (Plastic) F17202233
8.
Cover
21. Flange
9.
Retainer 22.
Static
Port
*
BEGINNING
WTTH
17276469
10.
True
Airspeed
Ring
31.
Statc
Sump
(Metal)
AND
F17202234
Figure
15-2.
Pitot
Static
Systems
(Sheet
1
of
2)
15-7
MODEL
172
SERIES SERVICE
MANUAL
ENCODING
ALTIMETER
INSTALLATION
27
Detail
F
23.
Backup
Altimeter
24.
Vertical
Speed
Indicator
25.
Encoding
Altimeter
26.
Static
Line
27.
Airspeed
Indicator
28.
Pttot
Line
29.
Static Line
30.
Cable (to
Transponder)
Figure
15-2.
Pttot
Static
Systems
(Sheet
2
of
2)
15-8
MODEL
172
SERIES SERVICE
MANUAL
15-21.
TRUE
AIRSPEED
INDICATOR.
15-22.
DESCRIPTION.
The
true
airspeed indicator
is
equipped
with
a
conversion
ring,
which
may
be
rotated
until
pressure
altitude
is
aligned
with
outside
air
temperature.
then
airspeed
indicated
on
the
instrument
is
read
as
true
airspeed
on
the adjustable
ring.
15-23.
REMOVAL AND
INSTALLATION. (See
figure
15-2.)
Upon
installation,
before
tightening
mounting
screws
(7),
calibrate
instrument as
follows:
Rotate
ring
(10)
until
105
knots
on
the
adjustment
ring
aligns
with
105
knots
on
the
indicator.
Holding
this
setting,
move
retainer
(9)
until
60°F
aligns
with
zero
pressure
altitude,
then
tighten
mounting
screws
(7)
and
replace decorative
cover
(8).
15-24.
TROUBLE
SHOOTING
--
AIRSPEED
INDICATOR.
TROUBLE
PROBABLE
CAUSE
REMEDY
HAND
FAILS
TO
RESPOND.
Pitot
pressure
connection
Test
line
and
connection
for
not properly
connected
to
leaks.
Repair
or
replace
dam-
pressure
line
from
pitot
aged
line,
tighten
connections.
tube.
Pitot
or
static lines
clogged.
Check
line
for
obstructions.
Blow
out
lines.
INCORRECT
INDICATION
Leak
in
pitot
or
static
lines.
Test
lines
and
connections
OR
HAND
OSCILLATES.
for
leaks.
Repair
or
replace
damaged
lines,
tighten
con-
nections.
Defective
mechanism
or
Substitute
known
good
indi-
leaking
diaphragm.
cator
and
check
reading.
Re-
place
instrument.
HAND
VIBRATES.
Excessive
vibration.
Check
panel
shock
mounts.
Replace
defective
shock
mounts.
Excessive
tubing
vibration.
Check
clamps
and
line
con-
nections
for
security.
Tighten
clamps
and
connections.
re-
place
tubing
with
flexible
hose.
15-9
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Air
bulb
with
check
valves
may
be
obtained
locally
from
a
surgical
supply
company.
This
THICK-WALLED
PRESSURE
is
the
type used
in
measuring
blood
pressure.
SURGICAL
HOSE
PRESSURE
BLEED-OFF
SCREW
(CLOSED)
AIR
BULB
WITH
CHECK
VALVES
CLAMP
THICK-WALLED
CLAMP
SURGICAL
HOSE-
CHECK
VALVE
SUCTION
CHECK
VALVE
TO
APPLY
SUCTION:
1.
Squeeze
air
bulb
to
expel
as
much
air
as
possible.
2.
Hold
suction
hose
firmly
against
static
pressure
source
opening.
3.
Slowly
release
air
bulb
to
obtain
desired
suction, then
pinch
hose shut tightly
to
trap
suction
in
system.
4.
After leak
test,
release
suction
slowly
by
intermittently
allowing a
small
amount
of
air
to
enter
static
system.
To
do
this,
tilt
end
of
suction
hose
away
from
opening, then
immediately
tilt
it
back
against
opening.
Wait
until
vertical
speed
indicator approaches
zero,
then
repeat.
Con-
tinue
to
admit
this
small
amount
of
air
intermittently
until
all
suction
is
released,
then
remove
test
equipment.
TO
APPLY
PRESSURE:
CAUTION
Do
not apply
positive
pressure
with
airspeed
indicator
or
vertical
speed
indicator
connected
into
static
system.
1.
Hold
pressure
hose
firmly
against static
pressure
source
opening.
2.
Slowly
squeeze
air
bulb
to
apply
desired
pressure
to
static
system.
Desired
pressure
may
be
maintained
by
repeatedly
squeezing
bulb to
replace
any
air
escaping
through
leaks.
3.
Release
pressure
by
slowly
opening
pressure
bleed-off
screw,
then
remove
test
equipment.
Figure
15-3.
Static
Test
Equipment
15-10
MODEL
172
SERIES
SERVICE
MANUAL
15-25.
TROUBLE
SHOOTING
--
ALTIMETER.
TROUBLE
PROBABLE
CAUSE REMEDY
INSTRUMENT
FAILS
TO
Static
line
plugged.
Check
line
for obstructions.
OPERATE.
Blow out
lines.
Defective
mechanism. Substitute
known-good
alti-
meter
and
check
reading.
Replace
instrument.
INCORRECT
INDICATION.
Hands
not
carefully
set
Reset
hands
with
knob.
Leaking
diaphragm.
Substitute
known-good
alti-
meter
and
check
reading.
Replace
instrument.
Pointers
out
of
calibration.
Compare
reading
with
known-
good
altimeter.
Replace
instrument.
HAND
OSCILLATES.
Static
pressure
irregular.
Check
lines
for
obstruction
or
leaks.
Blow
out
lines.
tighten
connections.
Leak
in
airspeed or
vertical
Check
other
instruments
and
speed
indicator
installations.
system
plumbing
for
leaks.
-
Blow
out
lines,
tighten
con-
nections.
15-11
MODEL
172
SERIES SERVICE
MANUAL
15-26.
TROUBLE
SHOOTING
--
VERTICAL
SPEED
INDICATOR.
TROUBLE
PROBABLE
CAUSE
REMEDY
INSTRUMENT
FAILS
TO
Static line
plugged.
Check
line
for
obstructions.
OPERATE.
Blow
out
lines.
Static
line
broken. Check
line
for
damage.
con-
nections
for
security.
Re-
pair
or
replace
damaged
line.
tighten
connections.
INCORRECT
INDICATION.
Partially
plugged
static
line.
Check
line
for
obstructions.
Blow
out
lines.
Ruptured
diaphragm.
Substitute
known-good
indi-
cator
and
check
reading.
Replace
instrument.
Pointer
off
zero.
Reset
pointer
to
zero.
POINTER
OSCILLATES.
Partially
plugged
static
line.
Check
line for
obstructions.
Blow
out
lines.
Leak
in
static
line.
Test lines
and connections
for leaks.
Repair
or
re-
place
damaged
lines.
tighten
connections.
Leak
in
instrument
case.
Substitute
know-good indi-
cator
and
check
reading.
Replace
instrument.
HAND
VIBRATES.
Excessive
vibration.
Check
shock mounts.
Replace
defective
shock mounts.
Defective
diaphragm.
Substitute
known-good indi-
cator
and
check
for
vibration.
Replace
instrument.
15-27.
Deleted.
15-12
MODEL
172
SERIES SERVICE
MANUAL
15-28.
VACUUM
SYSTEM.
15-29.
DESCRIPTION.
Suction
to
operate
the
gyros
is
provided
by
a
dry-type
engine-driven
vacuum
pump,
gear-driven
through
a
spline-type
coupling.
A
suction
relief
valve,
to
control
system
pressure,
is
connected
between
the
pump
inlet
and
instruments
In
the
cabin.
the
vacuum
line
is
routed
from
gyro
instruments
to
the
relief valve
at
the
firewall.
A
throw
away
type
central
air
filtering unit
is
installed.
The
reading
of
the
suction gage
indicates
net
difference
in
suction
before
and
after
air
passes
through
a
gyro.
This
differential
pressure
will
gradually
decrease
as
the
central
air
filter
becomes
dirty,
causing
a
lower
reading
on
the
suction
gage.
NOTE
Excessive
smoking
will
cause
premature
filter
clogging.
15-30.
TROUBLE
SHOOTING
--
VACUUM
SYSTEM.
TROUBLE
PROBABLE
CAUSE
REMEDY
HIGH
SUCTION
GAGE
Gyros
function
normally-
Check
screen,
then
valve.
READINGS.
relief
valve
screen
clogged,
Compare
gage
readings
with
relief
valve malfunction.
new gage.
Clean
screen.
reset
valve.
Replace
gage.
NORMAL
SUCTION
GAGE
Instrument
air
filters
Check
filter.
Replace
if
READING, SLUGGISH
OR
clogged.
required
ERRATIC
GYRO
RESPONSE.
LOW
SUCTION GAGE
Leaks or
restriction
between Check
lines
for
leaks. dis-
READINGS.
instruments
and
relief valve,
connect
and
test
pump.
relief
valve
out
of
adjust-
Repair
or
replace
lines,
ment,
defective
pump.
adjust
or
replace
relief
valve,
repair
or
replace
pump.
Central
air
filter
dirty.
Check
filter.
Replace
if
required.
SUCTION
GAGE
Defective
gage
or
sticking
Check
suction
with
test
gage.
FLUCTUATES.
relief
valve.
Replace
gage.
Clean
sticking
valve
with
Stoddard
solvent
Blow
dry
and
test.
If
valve
sticks
after
cleaning,
re-
place
valve.
15-13
MODEL
172
SERIES
SERVICE
MANUAL
15-31.
TROUBLE SHOOTING
--
GYROS.
TROUBLE
PROBABLE
CAUSE REMEDY
HORIZON
BAR OSCIL-
Central
filter
dirty.
Check
filter.
Replace
if
LATES
OR
VIBRATES
required.
EXCESSIVELY.
Suction
relief
valve
im-
Adjust
or
replace
relief
properly
adjusted.
valve.
Faulty
suction
gage.
Substitute
known-good
suction
gage
and
check
gyro
indication.
Replace suction
gage.
Defective
mechanism.
Substitute
known-good
gyro
and
check
indication.
Replace
instrument.
Excessive vibration.
Check
panel
shock-mounts.
Replace defective
shock-
mounts.
EXCESSIVE
DRIFT
IN
Central
air
filter
dirty.
Check
filter.
Replace
if
EITHER
DIRECTION.
required
Low
vacuum,
relief
valve
Adjust
or
replace
relief
improperly
adjusted.
valve.
Faulty
suction
gage.
Substitute
known-good
suction
gage and
check gyro
indication.
Replace
suction
gage.
Vacuum
pump
failure.
Check
pump.
Replace
pump.
Vacuum
line
kinked
or
Check
lines
for
damage
and
leaking. leaks.
Repair
or
replace
damaged
lines,
tighten
connections.
DIAL
SPINS
IN
ONE
Operating
limits
have
been
Replace
instrument.
DIRECTION CONTINU- exceeded
OUSLY.
Defective
mechanism.
Substitute
known-good
gyro
and
check
indication.
Re-
place
instrument.
15-14
MODEL
172
SERIES
SERVICE
MANUAL
15-31.
TROUBLE
SHOOTING
--
GYROS.
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
HORIZON
BAR
FAILS
TO
Central
filter
dirty.
Check
filter. Replace
if
RESPOND.
required.
Suction
relief
valve
improp-
Adjust
or
replace
relief
erly
adjusted.
valve.
Faulty
suction
gage.
Substitute
known-good
suction
gage
and
check
gyro
response.
Replace
suction
gage.
Vacuum
pump failure.
Check
pump.
Replace pump.
Vacuum
line
kinked
or
Check
lines for damage
and
leaking.
leaks.
Repair
or
replace
dam-
aged
lines,
tighten
connections.
HORIZON
BAR DOES
NOT
Defective
mechanism. Substitute
known-good
gyro
SETTLE.
and
check
indication.
Replace
instrument.
Insufficient
vacuum.
Adjust or
replace
relief
valve.
Excessive
vibration.
Check
panel
shock-mounts.
Replace
defective
shock-mounts.
15-32.
TROUBLE
SHOOTING
--
VACUUM
PUMP.
TROUBLE
PROBABLE CAUSE
REMEDY
OIL
IN
DISCHARGE.
Damaged
engine
drive seal.
Replace
gasket.
HIGH
SUCTION.
Suction
relief valve filter
Check
filter
for
obstructions.
clogged.
Clean
or
replace
filter.
LOW
SUCTION.
Relief
valve
leaking.
Replace
relief
valve.
Vacuum
pump
failure. Substitute
known-good
pump
and
check
pump
suction.
Replace
vacuum
pump.
LOW
PRESSURE.
Safety
valve
leaking.
Replace
safety
valve.
Vacuum
pump
failure. Substitute
known-good
pump
and check
pump
pressure.
Replace vacuum
pump.
15-15
MODEL
172
SERIES SERVICE
MANUAL
BEGINNING
WITH
5
17267749
3
7
8
*THRU
17267748
9
2.
Overboard
Vent Tube
3.
Firewall
4.
Bracket
5.
Filter
Assembly
6.
Gyro
Horizon
7.
Directional
Gyro
8.
Suction
Gage
9.
Suction
Relief
Valve
THRU 17274199
10.
Firewall
and
F1722039
Figure
15-4.
Vacuum
System
(Sheet
1
of
2)
15-16
MODEL
172
SERIES
SERVICE
MANUAL
3
BEGINNING
WITH
2.
Overboard
Vent
Tube
SERIAL
17274200
AND
ON
3.
Firewall
--
F17202040
AND
ON
5.
Filter
Assembly
6.
Gyro
Horizon
7.
Directional Gyro
8.
Suction
Gage
9.
Suction
Relief
Valve
10.
Firewall
1.
Low
Vacuum
Light
*
SERIAL
17275834
AND
ON
BEGINNING
WITH
12.
Pressure
Switch
F17202195
AND
ON
17276193
13.
Overboard
Vent
Hose
14.
Cover
Figure
15-4.
Vacuum
System
(Sheet 2
of
2).
15-17
MODEL
172
SERIES SERVICE
MANUAL
15-33. MAINTENANCE
PRACTICES.
CAUTION
When
replacing
a
vacuum
system
component,
ensure
all
connections
are
made
correctly
to
avoid
damage
to
gyro
system
When
a
component is
removed.
cap off
and
iden-
tify
all
open
lines,
hoses, and
fittings
to
prevent
dirt
from
entering
system
and
to
ensure
proper
reinstallation.
Upon
component
replacement
check
all
hoses
carefully
to
be
sure
they
are
clean
and
free
of
debris,
oil,
solvent.
collapsed
inner
liners,
and
external
damage.
Replace
old.
hard
cracked,
or
brittle
hoses.
particularly
on
pump
inlet,
to
avoid
possible
pump
damage.
On
vacuum
pump.
where
hose
clearance
is
tight,
making
it
difficult
to
reinstall
hoses,
apply
a
light
film of
petrolatum
to
the
fit-
ting.
Install
hoses
by
pushing
them
straight
on,
and
do
not
wiggle hoses
from
side
to
side
as
this
could
cause
particles
to
be
out
from
inside
of
hose,
allowing
particles
to
enter
system.
CAUTION
Do
not
use
teflon
tape,
pipe
dope,
or
thread lubricants
of
any
type
on
fitting
threads,
and
avoid
over-tightening
of
connections.
All
filters
in
vacuum
system
must
be
changed
when
intalling
a
new
pump.
Failure
to
do
so
will
void
pump
warranty.
DO
NOT
CONNECT
A
PUMP
BACKWARDS.
Since
the
manifold
check
valves
provide
no
pressure
relief,
the
pump
will
be
destroyed
within
a
matter
of
seconds
after
starting
the
engine.
15-33A.
REMOVAL
OF
VACUUM
PUMP.
a.
Remove
upper
engine
cowling
in
accordance
with
procedures
in
Section
11.
b.
Disconnect,
cap
off
and identify
hose
on inlet
side
of
vacuum pump.
c.
Identify
and
disconnect
hose
on
outlet side
of
vacuum
pump.
d.
Remove
nuts,
lockwashers,
and
flat
washers
securing
vacuum
pump
to
engine.
e.
Remove
vacuum
pump
from
mounting studs
on engine.
f.
Remove
elbow
from
pump
and
retain
if it
is
reusable.
NOTE
Discard
any
twisted
fittings
or
nuts
with rounded
cor-
ners.
15-33B.
MOUNTING
PAD INSPECTION.
a.
Check
condition
of
the
AND
20000 pad
seal.
If
the
seal shows
any
signs
of
oil
leak-
age,
replace
the
seal.
MODEL
172
SERIES
SERVICE
MANUAL
15-33C.
INSTALLATION
OF
VACUUM
PUMP.
a.
Before
installing
a
new
vacuum
pump,
purge
all
lines
in
system
to
remove carbon
particles
or
other
pump
components
that
may have
been
deposited
in
lines
by
previ-
ous
pump.
NOTE
Before
installing
vacuum
pump
an
engine,
ensure
that
mating
surfaces are
clean
and
free
of
any
old
gasket
ma-
terial.
b.
Consult
the
applicable
Parts
Catalog,
the
pump
vendor's
application
list,
or
the
PMA
label
on
pump
box
to
verify
that
the
pump
is
the correct
model
for
the
engine
and/or
system.
c.
Position
vacuum
pump
in
a
jaw-protected
vise,
with
drive
coupling
downward.
CAUTION
The
pump
housing
should
never
be
placed
directly
in a
vise,
since
clamping
across
center
housing
will cause
an
internal
failure
of
carbon
rotor.
Protect
pump
mounting
flange
with
soft
metal
or
wood. NEVER
install
a
vacuum
pump
that
has
been
dropped.
d.
Install
elbow
in
pump;
hand-tighten
only.
NOTE
Do
not
use
teflon
tape,
pipe
dope,
or
thread lubricants
of
any
type,
and
avoid
over-tightening
of
connections.
NOTE
Use
only
a
box
wrench
to
tighten
fittings
to
desired
posi-
tion.
Do
not
make
more
than
one
and one
half
(1
1/2)
turns
beyond
hand-tighten
position.
e.
Position
new
mounting
pad
gasket
on
mounting
studs
on
engine.
f.
Position
vacuum
pump
on
mounting studs.
g.
Secure
pump
to
engine
with
flat washers,
new
lockwashers.
and
nuts.
CAUTION
Always
replace
all
lockwashers with
new
ones
when
in-
stalling
a
new
vacuum
pump.
Tighten
all
four mounting
nuts
(4)
to
50
to
70
pound-inches.
h.
Connect
hose
to
inlet
side
of
vacuum
pump.
i.
Install
upper engine
cowling
in
accordance
with
procedures
in
Section
11.
15-19
MODEL
172
SERIES SERVICE
MANUAL
15-34.
CLEANING.
In
general.
low-pressure,
dry
compressed
air
should
be
used
in
cleaning
vac-
uum
system
components.
Suction
relief
valve,
exposed
to
engine
oil
and
dirt, should
be
re-
placed.
Check hose
for
collapsed
inner
liners
as
well
as
external
damage.
CAUTION
Never
apply
compressed
air
to
lines
or
components
instal-
led
in
aircraft.
The
excessive
pressures
will
damage
gyros.
If
an
obstructed
line
is
to
be
blown
out,
disconnect
at
both
ends
and
blow
from
instrument
panel out.
15-34A.
LOW-VACUUM
WARNING LIGHT.
A
red
low-vacuum
light
is
installed
on
the
instrument
panel.
The
light
is
controlled
by
a
vacuum
switch
mounted
on
the
back
of
the
gyro
horizon.
The
switch
contacts
are
normally
closed.
The
light
may
be
checked
by
turning
ON
the
mas-
ter
switch.
With
the
engine
running,
the
light
should illuminate
when
the
vacuum
drops
below
3
± .5
inches
Hg.
15-35.
VACUUM
RELIEF
VALVE
ADJUSTMENT.
A
suction
gage
reading
of
5.3
inches
of
mercury
is
desirable
for
gyro
instruments.
However,
a
range
of
4.5
to
5.4
inches
of
mercury
is
ac-
ceptable.
To
adjust
the
relief
valve,
remove
central
air
filter,
run
engine
to
2200
rpm
on
the
ground
and
adjust
relief
valve
to 5.3
±
.1
inches
of
mercury.
CAUTION
Do
not
exceed
maximum
engine
temperature.
Be
sure
filter
element
is
clean
before
installing.
If
reading
drops
noticeably,
install
new
filter
element.
15-35A.
STANDBY
VACUUM
SYSTEM.
5-35B.
DESCRIPTION.
A
standby
vacuum
system
may
be
installed
in
the
airplane.
The
system
con-
sists
of
an
electric
motor
driven
vacuum
pump
and
associated hoses
mounted
on
the
aft
side
of
the
firewall.
One
hose
is
the
vacuum
pump
vent hose
and
the
other
connects
to
a
manifold
with
the
engine-driven
vacuum
pump,
just
prior
to
the
system
relief
valve.
A
two-position
circuit
breaker
switch, mounted
adjacent
to
the
master
switch
on
the
instrument
panel,
con-
trols
and
protects
the
system.
15-20
MODEL
172
SERIES SERVICE
MANUAL
1.
Circuit
Breaker
Switch
.
2.
Instrument
Panel
Detail
A
2
Figure
15-4A.
Standby
Vacuum
System
(Sheet
1
of
2)
15-20A
MODEL
172
SERIES
SERVICE
MANUAL
4.
Relief
Valve
3.
Hose
(to
Gyro
Horizon)
3.
Hose
(to Directional
Gyro)
9.
Nut
11.
Fittings
12.
Ground
Wire
1
3.Motor
14.
Washer
15.
Bolt
16.
Bracket
17.
Voltage
Input
Wire
18.
Washer
19.
Nut
20.
Vaccuum
Pump
21.
Hose
22.
Manifol
d
23.
Firewall
Figure
15-4A.
Standby
Vacuum
System
(Sheet 2
of
2)
15-20B
MODEL
172
SERIES
SERVICE
MANUAL
15-35C.
TROUBLE
SHOOTING
-
STANDBY
VACUUM
SYSTEM.
TROUBLE
PROBABLE
CAUSE
REMEDY
NO
SUCTION
GAGE
Circuit
breaker
switch
Reset
circuit breaker
switch.
READING.
has
opened. If
switch
reopens, check
wire
from
switch
to
bus
bar
for
short.
Repair
or
replace wire.
Defective
motor.
Check
voltage
input
wire
and
ground
wire.
Repair
or
re-
place
wires.
Defective
pump.
Check
pump
operation.
Replace
pump.
LOW SUCTION
GAGE
Leak
or
restriction
Check
hoses
and
connections
READING.
between
pump
and for
leaks
and
obsuctions.
In-
suction
gage.
stall
new clamps
at
connection.
clear
or
replace
hoses.
Relief
valve
not
Adjust
relief
valve.
properly
adjusted.
Defective
pump.
Check
pump.
Replace
pump.
Central
air
filter
Replace
central
air
filter.
dirty.
15-35D.
REMOVAL.
(See
figure
15-4A.)
a.
Release
clamps
securing
hoses
(7)
and
(8)
to
pump
(20).
b.
Cap
hoses
(7),
(8)
and
pump
fittings
(11)
so
dirt
cannot
enter
system.
c.
Make
sure
circuit breaker
switch
(1)
and
battery
switch
are
off.
d.
Disconnect
motor
voltage
input
wire
(17)
and
ground
wire
(12).
e.
Remove
safety
from
bolts
(15).
f.
Support
pump
and
motor
assembly
and
remove
bolts
(15)
and
washers
(14).
g.
If
pump
is
to
be
removed
from
motor,
remove
nuts
(19)
and washers
(18).
15-20C
MODEL
172
SERIES
SERVICE
MANUAL
15-35E.
INSTALLATION.
(See
figure
15-4A.)
a.
If
removed,
install
pump
(20)
on
motor
(13)
drive
studs
and
install washers
(18)
and
nuts
(19).
b.
Position
pump
and motor
assembly
up
against
bracket
(16)
and
install
washers
(14)
and
bolts
(15).
c.
Safety-wire
bolts
(15).
d.
Connect
motor
voltage
input
wire
(17)
and
ground
wire
(12).
e.
Remove
caps
from
hoses
(7), (8).
and
fittings
(11)
then
install
hoses
and
clamps.
f.
Turn
on
battery
switch
and
circuit breaker
switch
(1)
then
check
suction
gage
to
see
that
system
is
operating
properly.
Then
turn
off
switches.
CAUTION
Check
that
voltage
input
wire
(17)
is
not
pushed
down
into
motor
as
it
could
become
entangled
with the
arma-
ture,
locking
it.
15-36.
ENGINE
INDICATORS.
15-37.
TACHOMETER.
15-38.
DESCRIPTION. The
tachometer
used
on
Cessna single-engine
aircraft
is a
mechanical
indicator
driven
at
half
crankshaft
speed
by
a
flexible
shaft.
Most
tachometer
difficulties
will
be
found
in
the
drive-shaft.
To
function
properly,
shaft
housing
must
be
free
of
kinks,
dents
and
sharp
bends.
There
should
be
no
bend
on
a
radius
shorter
than
six
inches
and
no
bend
within
three
inches
of
either
terminal.
If
a
tachometer
is
noisy
or
pointer
oscillates.
check
cable
housing
for
kinks, sharp
bends
and
damage.
Disconnect
cable
at
tachometer
and
pull
it
out
of
housing.
Check
cable for worn
spots,
breaks
and
kinks.
15-20D
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
NOTE
Before
replacing
a
tachometer
cable
in
housing,
coat
lower
two
thirds
with
AC
Type
ST-640
speedometer
cable
grease
or
Lubriplate
No.
110.
Insert
cable
in
housing
as
far
as
possible,
then slowly
rotate
to
make
sure
it
is
seated
in
engine
fitting.
Insert
cable
in
tachometer,
making
sure
it
is
seated
in
drive
shaft
then
reconnect
housing
and hand
tighten then
torque
1/4
turn
15-39.
OIL
PRESSURE
GAGE.
15-40.
DESCIPTION.
The
Bourdon
tube-type
oil
pressure
gage
is
a
direct-reading
instrument,
op-
erated
by
a pressure
pickup
line
connected
to
the
engine
main
oil
gallery
at
the
rear
of
the
engine
below
the
engine
mount.
The
oil
pressure
line
on
1984
and
On
and
all
aircraft
equipped
with
a
0509087
Modification
Kit,
is
located
at the front
of
the
engine
near
the
upper
right
corner.
The
oil
pressure
line
from
the
instrument
to
the
engine
should
be
filed
with
kerosene,
especially
during
cold
weather
operation
to
attain an
immediate
oil
indica-
tion.
15-41.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
GAGE
DOES
NOT
Pressure
line clogged.
Check
line
for
obstructions.
REGISTER.
Clean
line.
Pressure
line
broken.
Check
line
for
leaks
and
damage.
Repair
or
replace
damaged
line.
Fractured
Bourdon
tube.
Replace
instrument
Gage
pointer
loose on
staff.
Replace
instrument.
Damaged
gage
movement
Replace
instrument
GAGE
POINTER
FAILS
Foreign
matter in
line.
Check
line
for
obstructions.
TO
RETURN
TO
ZERO.
Clean
line.
Foreign
matter
in
Bourdon Replace
instrument
tube.
Bourdon tube
stretched.
Replace
instrument
GAGE
DOES
NOT
REGIS-
Faulty
mechanism.
Replace
instrument
TER
PROPERLY.
15-21
MODEL
172
SERIES
SERVICE
MANUAL
15-41.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
GAGE
HAS
ERRATIC
Worn
or
bent
movement.
Replace
instrument.
OPERATION.
Foreign
matter
in
Bourdon
Replace
instrument.
tube.
Dirty
or
corroded
movement
Replace
instrument.
Pointer
bent
and
rubbing
on
Replace
instrument.
dial, dial
screw
or
glass.
Leak
in
pressure
line.
Check
line
for
leaks
and
damage.
Repair
or
replace
damaged
line.
15-42.
OIL
TEMPERATURE
GAGE.
15-43.
DESCRIPTION.
The
oil
temperature
gage
is
an
electrically
operated
indicator
mounted
in
the
instru-
ment
cluster
with
the
oil
pressure
gage.
One
electrical
lead
is
routed
from
the
indicator
to
the
sending
unit
installed
in
the
engine.
The
other
lead
supplies
power
from
the
bus
bar
to
the
indicator.
Refer
to
Table 1
on
page
15-26A
when
trouble
shooting the
oil
temperature
gage.
15-43A.
CYLINDER
HEAD
TEMPERATURE
GAGE.
15-43B.
DESCRIPTION.
The
temperature
sending
unit
regulates
electrical
power
through
the
cylinder
head
temperature
gage.
The
gage
and
sending
unit
require
little
or no
maintenance
other
than
cleaning,
making
sure
lead
is
properly
supported
and
all
connections
are
clean,
tight
and
properly
insulated.
Rochester
gages
are
connected
the
same
as the
Stewart Warner
gages,
but
the
Rochester
gages
do
not
have the
calibration
pot
and
are
not
adjustable.
Refer
to
Table
2
on
page
15-26B
when
trouble
shoot-
ing
the
cylinder
head
temperature
gage.
15-44.
CARBURETOR AIR
TEMPERATURE
GAGE.
15-45.
DESCRIPTION.
The
carburetor
air
temperature
gage is
a
resistance
bridge
type.
Changes
in
elec-
trical
resistance
of
the
element
are
indicated
by
the
gage,
calibrated
for
temperature.
The
system
re-
quires
power
from
the
airplane
electrical
system
and
operates
only
when
the
master
switch
is
on.
Al-
though
both
instrument
and
sending
unit
are
grounded,
two
leads
are
used
to
avoid
possibility
of
in-
strument
error
induced
by
poor
electrical
bonds
in
the
air
frame
15-46.
TROUBLE SHOOTING
-
CARBURETOR
AIR
TEMPERATURE
GAGE.
TROUBLE
PROBABLE
CAUSE
REMEDY
GAGE
POINTER
STAYS
OFF
Open
circuit breaker.
Reset
breaker..
LOW
END OF
SCALE.
Master
switch
"OFF"
or
Check
switch
"ON".
Replace
switch
defective.
-
defective
switch.
Broken
or
grounded
leads
Repair
or
replace
defective
between
gage
and
sending
wiring.
unit.
15-22
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
15-46.
TROUBLE
SHOOTING
--
CARBURETOR
AIR
TEMPERATURE
GAGE
(Cont).
TROUBLE PROBABLE
CAUSE
REMEDY
GAGE
POINTER
GOES
OFF
Broken
or
grounded lead.
Repair
or
replace
defective
HIGH
END
OF
SCALE.
wiring.
Defective
gage
or sensing
Replace
gage
or
sensing
unit. unit.
GAGE
OPERATES INTER- Defective
master
switch.
Replace
switch,
repair
or
MTTTENTLY.
broken
or
grounded lead.
replace
defective
wiring.
Defective
gage
or
sensing
Replace
gage
or
sensing
unit.
unit.
EXCESSIVE
POINTER
Loose
or
broken
lead.
Repair
or
replace
defective
OSCILLATION.
wiring.
Defective
gage
or
sensing
Replace
gage
or
sensing
unit.
unit.
Excessive panel
vibration.
Tighten
panel
mounting
screws.
OBVIOUSLY
INCORRECT
Defective
gage
or
sensing
Replace
gage
or
sensing
TEMPERATURE READING.
unit.
unit.
POINTER
FAILS
TO
GO
Defective
master
switch.
Replace switch.
OFF
SCALE
WITH
CURRENT
OFF. Defective
gage.
Replace
gage.
15-46A.
ECONOMY
MIXTURE
INDICATOR
(EGT)
(BEGINNING
WITH
1979
MODELS.)
15-46B.
DESCRIPTION.
The
economy
mixture indicator
is
an
exhaust
gas
temperature
(EGT)
sensing
device
which
is
used
to
aid
the
pilot
in
selecting
the
most
desirable
fuel-air
mixture
for
cruising
flight
at
less
than
75%
power.
Exhaust gas
temperature
(EGT)
varies
with
ratio
of
fuel-to-air
mixture
entering
the
engine
cylinders.
Refer
to
the
Pilot's
Operating
Handbook
for
operating
procedure
of
the system.
15-46C.
CALIBRATION.
A
potentiometer
adjustment
screw
is
provided
behind
the
plastic
cap at
the
back
of
the
instrument
for
calibration.
This
adjustment
screw
is
used
to
position
the
pointer
over
the reference
increment
line
(4/5
of
scale)
at
peak
EGT.
Establish
75%
power
in
level
flight,
then
carefully
lean
the
mixture
to
peak
EGT.
After
the
pointer
has
peaked.
using
the
adjustment
screw.
position
pointer
over
reference
increment
line
(4/5
scale).
15-23
MODEL
172
SERIES
SERVICE
MANUAL
A
Detail A
1.
Probe
2.
Panel
Cover
3.
Screw
4.
Instrument
Panel
5.
Indicator
6.
Lockwasher
7.
Nut
15-4A.
Economy
Mixture Indicating
System
E.G.T.
15-24
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
This
setting
will
provide selective
temperature
indica-
tions
for
normal
cruise
power
settings
within
range
of
the
instrument.
Turning
the screw
clockwise
increases
the
meter
reading
and
counterclockwise
decreases
the
meter
reading.
There
is a
stop
in
each
direction
and
damage
can
occur
if
too
much
torque
is
applied
against
stops.
Approximately
600°F
total
adjustment
is
provided.
The
adjustable
yellow
pointer
on
the
face
of
the
instrument
is a
reference
pointer
only.
15-46D.
REMOVAL AND
INSTALLATION.
(See
figure
15-4A.)
a.
Indicator.
1.
Remove
instrument
panel
decorative
cover.
2.
Disconnect
EGT
indicator
leads.
3.
Remove
screws,
nuts
and
washers
securing indicator
and
remove
indicator.
4.
To
install
reverse
the
preceding
steps.
b.
Probe.
1.
Disconnect
probe
leads.
2.
Remove
clamp
and
probe
assembly.
3.
When
installing
probe,
tighten
clamp
to
30-35
lb-in.
4.
Coil
or
fold
excess
lead
and
tie
in a
covenient
out
of
the
way
location.
15-46E.
TROUBLE
SHOOTING.
TROUBLE PROBABLE
CAUSE REMEDY
GAGE
INOPERATIVE
Defective
gage, probe
or
Repair
or
replace
defective
circuit.
part.
INCORRECT
READING
Indicator
needs
calibrating.
Calibrate
indicator
in
accord-
ance
with
paragraph
15-46C.
FLUCTUATING
READING
Loose,
frayed
or
broken
Tighten
connection
and
lead,
permitting
alternate
repair
or
replace
defec-
make
and
break
of
circuit.
tive
leads.
15-47.
FUEL
QUANTITY
INDICATING
SYSTEM.
15-48.
DESCRIPTION.
The
magnetic
type
fuel
quantity indicators are
used in
conjunction
with
a
float-operated
variable-resistance
transmitter
in
each
fuel
tank.
The
full
position
of
float
produces
a
minimum
resistance
through
transmitter. permitting
maximum
current
flow
through
the
fuel
quantity
indicator
and
maximum
pointer
deflection.
As
fuel level
is
lowered,
resistance
in
the
transmitter
is
increased,
producing
a
decreased
current
flow
through
fuel
quantity
indicator
and
a
smaller pointer
deflection.
15-49.
REMOVAL
AND
INSTALLATION
OF
FUEL
QUANTITY
TRANSMITTER.
a.
Drain
fuel
from
tank.
(Observe
precautions
in
Section
12.)
b.
Remove
access
plate
above
fuel
tank
for
access
to
transmitter.
c.
Disconnect
electrical
lead
and
ground
strap
from
transmitter.
d.
Remove
screws
attaching
transmitter
and
carefully
work
transmitter
from
tank.
DO
NOT
BEND
FLOAT
ARM.
15-25
MODEL
172
SERIES
SERVICE
MANUAL
e.
Install
transmitter
by
reversing
preceding
steps,
using
new
gaskets around
opening
in fuel
tank
and
under
screw
heads.
Be
sure
to
righten
screws
evenly.
f.
Service
fuel
tanks.
Check
for
leaks
and
correct
quantity
indication.
NOTE
Ensure
transmitter
is
properly
grounded
in
accordance
with
Section
12.
15-50.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
FAILURE
TO
INDICATE.
No
power
to
indicator
or
Check
fuse
and
inspect
for
transmitter.
(Pointer
stays
open
circuit
Replace
fuse.
below
E.)
repair
or
replace
defective
wire.
Grounded
wire.
(Pointer
Check
for
partial
ground
be-
stays
above
F.)
tween
transmitter
and
gage.
Repair
or
replace
defective
wire.
Low
voltage.
Check
voltage
at
indicator.
Correct
voltage.
Defective
indicator.
Substitute
known-good indi-
cator. Replace
indicator.
OFF
CALIBRATION.
Defective
indicator.
Substitute
known-good
indi-
cator.
Replace
indicator.
Defective
transmitter.
Substitute
known-good
trans-
mitter.
Recalibrate
or
replace.
Low
or
high
voltage.
Check
voltage
at
indicator.
Correct
voltage.
STICKY
OR
SLUGGISH
Defective
indicator.
Substitute
known-good
indi-
INDICATOR
OPERATION.
cator.
Replace
indicator.
Low
voltage.
Check
voltage
at
indicator.
Correct
voltage.
ERRATIC
READINGS.
Loose
or
broken
wiring
on
Inspect
circuit
wiring.
Repair
indicator
or
transmitter.
or replace
defective
wire.
Defective
indicator
or
trans-
Substitute
known-good
com-
mitter.
ponent.
Replace
indicator
or
transmitter.
Defective
master
switch. Replace
switch.
15-26
MODEL
172
SERIES
SERVICE
MANUAL
15-51.
TRANSMITTER
ADJUSTMENT.
WARNING
Using the
following
fuel
transmitter
calibration
procedure
on compo-
nents
other
than
the
originally
installed
(Stewart
Warner)
components
will
result
in
a
faulty
fuel
quantity
reading.
15-51A.
STEWART
WARNER
GAGE
TRANSMITTER
CALIBRATION.
Chances
of
transmitter
calibration
changing
in
normal
service
is
remote;
however,
it
is
possible
that
float
arm
or
float
arm
stops may
be-
come
bent
if
transmitter
is
removed
from
cell.
Transmitter
calibration
is
obtained
by
adjusting
float
travel.
Float
travel
is
limited
by float
arm
stops.
WARNING
Use
extreme
caution
while
working
with
electrical
components
of
the
fuel
system.
The
possibility
of
electrical
sparks
around
an
"empty"
fuel
cell
creates
a
hazardous
situation.
Before
installing
transmitter,
attach
electrical wires and
place
master
switch in
"ON"
position.
Allow
float
arm
to
rest
against
lower
float
arm
stop
and
read
indicator.
The pointer should
be
on
E
(empty)
position.
Adjust
the
float
arm against
lower
stop
so
pointer indicator
is
on
E.
Raise
float
until
arm
is
against
upper
stop
and
adjust upper
stop
to
permit
indicator
pointer
to
be
on
F
(full).
Install transmit-
ter
in accordance
with
paragraph
15-49.
15-51B.
ROCHESTER
GAGE
TRANSMITTER.
Do
not
attempt
to
adjust
float arm
or
stop.
No
adjustment
is
allowed.
Table
1
NOTE
Select
the
oil
temperature
sending
unit
part
number
from
the
left
col-
umn
and
the
temperature
from
the
column
headings.
Read
the
ohms
value
under
the
appropriate
temperature
column.
Part
Number
Type
72°F
120°F 165°F 220°F
250°F
S1630-1
Oil
Temp
46.4
S1630-3
Oil
Temp
620.0
52.4
S1630-4
Oil
Temp
620.0
52.4
S1630-5
Oil
Temp
192.0
S2335-1
Oil
Temp
990.0
34.0
15-26A
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
Table
2
NOTE
Select
the
cylinder
head
temperature
sending
unit
part
number
that
is
used
in
your aircraft
from
the
left
column
and
the
temperature
from
the
column
headings.
Read
the
ohms value
under
the
appropriate
tempera-
ture
column.
Part
Number
Type
200°F
220°F
450°F
475°F
S1372-1
CHT
310.0
34.8
S1372-2
CHT
310.0
34.8
S1372-3
CHT
113.0
S1372-4
CHT
113.0
S2334-3
CHT
745.0
38.0
S2334-4
CHT 745.0
38.0
15-26B
Revision
3
MODEL
172
SERIES
SERVICE
MANUAL
15-51.
TRANSMITTER
ADJUSTMENT.
(Refer
to
page
15-26A.)
15-52.
HOURMETER.
(See
figure
15-5.)
15-53.
DESCRIPTION.
The
hourmeter
is
electrically
operated and
is
actuated
by
a
pressure switch
in
the
oil
pressure
system.
Electrical
power
is
supplied
through
a
one-amp
fuse
from
the
electrical
clock
circuit,
and
therefore,
will
operate
independent
of
the
master
switch.
If
no
clock
is
installed,
a
line direct
from
the
battery
contactor provides
power
independent
of
the
master
switch through
a
one-amp
fuse
located
adjacent
to
the
battery
box.
An
indicator
on
the
dial
face
rotates
when the
meter
is
actuated.
If
the
me-
ter
is
inoperative
and the
clock is
operating,
the meter
or
its
wiring
is
faulty
and
must
be
replaced.
NOTE
When
installing
the
hourmeter,
the
positive
(red) wire
must
be
con-
nected
to
the
white
(+)
terminal.
Connecting
wires
incorrectly
will
damage
the
meter.
15-54.
MAGNETIC
COMPASS.
15-55.
DESCRIPTION.
The
magnetic
compass
is
liquid-filled,
with
expansion
provisions
to
compensate
for
temperature
changes.
It
is
equipped
with
compensating
magnets
adjustable
from
the
front
of
the
case.
The
compass
is
internally
lighted,
controlled
by
the
panel lights
rheostat.
No
maintenance
is
required
on
the
compass
except
for
a
check
on
a
compass
rose
each
200
hours
for
adjustment.
Revision 3
15-27
MODEL
172
SERIES
SERVICE
MANUAL
6
1.
Doorpost
Cover
13.
Pressure
Switch
2.
Horn
Assembly
14.
Positive
Wire
Detail
C
3.
Scoop
15.
Ground
Wire
4.
Adapter
16.
Wire
from
Clock
5.
Felt
Seal
Circuit
..
Adjustable
Plate
17.
O.A.T.
Gage
7.
Screen
18.
Rubber
Washer
NOTE
8.
Compass
19.
Knob
9.
Compass
Card
20.
Air
Vent
Bug
screen
(7)
should
be
inspected
10.
Bracket
21.
Washer
and
cleaned
periodically.
11.
Hourmeter
22.
Plastic
Washer
12.
Adapter
23.
Nut
Figure
15-5.
Miscellaneous
Instruments
and
Stall
Warning System
15-28
MODEL
172
SERIES
SERVICE
MANUAL
15-56.
REMOVAL
AND
INSTALLATION.
See
figure
15-5
for
removal
and
installation.
15-57.
STALL WARNING
SYSTEM.
15-58.
DESCRIPTION.
The
system
is composed
of
an
adjustable plate
on
left
wing
leading
edge,
connected
to
a
reed type
horn
by
means
of
plastic
tubing.
The
horn
is
actuated approxi-
mately
5
to
10
knots
above
stalling
speed
as
a
negative
air
pressure
area
at
wing
leading
edge
causes
a
reverse
flow
of
air through
horn.
By
moving
adjustable plate
(6)
up, actuation
of
horn
will occur
at
a
higher
speed
and
moving
plate
down
causes
actuation
to
occur
at
a
slower
speed.
Center
adjustable
plate
opening
in
wing
leading
edge
upon
installation,
then
flight test
aircraft,
observing
horn
actuation
during
stall.
Readjust
plate
to
obtain desired
results
if
necessary.
Approximatley
3/32
inch
adjustment
of
plate
will
change
speed
at
which horn
actuation
occurs
by
5
knots.
To
test
horn
operation,
cover
opening
in plate
(6)
with
a
clean cloth,
such
as
a
handkerchief
and
apply
a
slight
suction
by
mouth
to
draw
air
through
horn.
15-59.
REMOVAL
AND
INSTALLATION.
Refer
to
figure
15-5
for
removal
and
installation.
15-60.
TURN
COORDINATOR.
15-61.
DESCRIPTION.
The
turn
coordinator
is
an
electrically
operated, gyroscopic,
roll-rate
turn
indicator.
Its
gyro
simultaneously
senses
rate
of
motion
roll
and
yaw axes
which
is
projected on
a
single indicator.
The
gyro
is
a
non-tumbline
type
requiring
no
caging
mechanism
and
Incorporates
an
a.
c.
brushless
spin
motor
with
a
solid
state
inverter.
15-62.
TROUBLE
SHOOTING.
TROUBLE PROBABLE
CAUSE
REMEDY
INDICATOR
DOES
NOT
Friction
cause
by
contam-
Replace
instrument.
RETURN
TO
CENTER.
ination
in
the
indicator
dampening.
Friction
in
gimbal
assembly.
Replace
instrument.
DOES
NOT
INDICATE
A
Low
voltage.
Correct
voltage.
STANDARD
RATE
TURN
(TOO
SLOW).
Inverter
frequency
changed.
Replace
instrument.
NOISY
MOTOR.
Faulty
bearings.
Replace
instrument.
ROTOR
DOES
NOT
START.
Faulty
electrical
connec-
Correct
voltage or
replace
tion.
faulty
wire.
Inverter
malfunctioning.
Replace
instrument.
Motor
shorted.
Replace
instrument.
Bearings
frozen.
Replace
instrument.
15-29
MODEL
172
SERIES
SERVICE
MANUAL
15-62.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
IN
COLD
TEMPERATURES.
Oil
in
indicator
becomes
Replace
instrument.
HAND
FAILS
TO
RESPOND too
thick.
OR
IS
SLUGGISH.
Insufficient
bearing
end
Replace
instrument.
play.
Low
voltage.
Check
voltage
at
instrument.
Correct
voltage.
NOISY
GYRO.
High
voltage.
Check
voltage
to
instrument.
Correct
voltage.
Loose
or
defective
rotor
Replace
instrument
bearings.
15-63.
TURN-AND-SLIP
INDICATOR.
15-64.
DESCRIPTION. The
turn-and-slip indicator
is
an
electrically
operatedinstrument
powered
by
the
aircraft
electrical system,
therefore,
operating
only
when
the
master
switch
is
ON.
15-65.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
INDICATOR
POINTER
FAILS
Internal
fuse
blown.
Check
wiring
for
continuity.
TO
RESPOND.
check
voltage
at
indicator.
Replace
fuse.
if
fuse
still
blows. replace
instrument.
Master
switch
"OFF"
or
Check
switch
"ON."
Re-
switch
defective.
place
defective
switch.
Broken
or
grounded
lead
to
Check
circuit
wiring.
Repair
indicator. or
replace
defective
wiring.
Indicator
not
grounded.
Check
ground wire. Repair
or
replace
defective
wire.
Defective
mechanism.
Replace
instrument.
HAND
SLUGGISH
IN
Defective
mechanism. Replace
instrument.
IN
RETURNING
TO
ZERO.
Low
voltage.
Check
voltage
at
indicator.
Correct
voltage.
POINTER
DOES
NOT
INDI-
Defective
mechanism.
Replace
instrument.
CATE
PROPER
TURN.
15-30
MODEL
172
SERIES SERVICE
MANUAL
15-65.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
HAND DOES
NOT
SIT
Gimbal
and
rotor
out
of
Replace
instrument.
ON ZERO.
balance.
Hand
incorrectly
sits
on
rod. Replace
instrument.
Sensitivity
spring
adjust-
Replace
instrument.
ment
pulls
hand
off
zero.
IN
COLD
TEMPERATURES,
Oil
in
indicator
becomes
too
Replace
instrument.
HAND
FAILS
TO
RESPOND
thick.
OR
IS
SLUGGISH.
Insufficient
bearing
end
play.
Replace
instrument.
Low
voltage.
Check
voltage
at
indicator.
Correct
voltage.
NOISY
GYRO.
High
voltage.
Check
voltage
at
indicator.
Correct
voltage.
Loose
or
defective
rotor
Replace
instrument.
bearings.
15-66.
OUTSIDE
AIR
TEMPERATURE
GAGE
(See
figure
15-5).
15-31/(15-32
blank)
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
16
ELECTRICAL
SYSTEMS
WARNING
When
performing
any
inspection or
maintenance
that
re-
quires
turning
on
the master
switch,
installing
a
battery,
or
pulling
the
propeller
through
by
hand,
treat
the
prop-
eller
as
if
the
ignition
switch
were
ON. Do
not
stand,
nor
allow
anyone
else
to
stand,
within
the
arc
of
the
propel-
ler,
since
a
loose
or
broken
wire,
or
a
component
mal-
function,
could
cause
the
propeller
to
rotate.
Page
No.
TABLE
OF CONTENTS
Aerofiche/
Manual
ELECTRICAL SYSTEMS
.......
2I8/16-2
Ground
Service
Receptacle
....
2J2
16-18
General
..................
2I8/16-2
Description
.............
2J2
16-18
Electrical
Power Supply
Trouble
Shooting
.........
2J5
16-21
System
.................
2I9/16-3
Removal/Installation
.......
2J6
16-22
Description
.............
2I9,16-3
Alternator
Power
System
.....
2J6
16-22
Split
Bus
Bar
............
2I9/16-3
Description
.............
2J6
16-22
Description
............
2I916-3
Alternator
........
.....
2J6
16-22
Master
Switch
...........
2I9/16-3
Description
...........
2J6
16-22
Description
............
2I9/16-3
Trouble
Shooting
the
Ammeter
...............
2I9/16-3
Alternator
System
Description
............
2I9/16-3
(Thru
1977
Models)
......
2J8
16-24
Battery
Power
System
.......
2I9/16-3
Trouble
Shooting
the
Battery
................
2I9/16-3
Alternator
System
Description
............
2I9/16-3 (1978 Models)
..........
2J11
16-27
Trouble
Shooting
........
2I21/16-13
Trouble
Shooting
the
Removal/Installation
....
2I22/16-14
Alternator
System
Cleaning
the
Battery
.....
2I23/16-15
(Beginning
with
Adding Electrolyte
or
1979
Models)
.......... .
2J15
16-31
Water
to
Battery
.......
2I23/16-15
RemovalInstallation
.......
2J19
16-35
Testing
the
Battery
......
2I23/16-15 Over-Voltage
Warning
System
.
2J19
16-35
Charging the
Battery
.....
2I24/16-16
Description
..............
2J19
16-35
Battery
Box
.............
2I24/16-16
Alternator
Voltage
Regulator
..
2J20
16-36
Description
............
2I24/16-16
Description
.............
2J20
16-36
Removal/Installation
.....
2J1/16-17
Alternator
Control
Unit
......
2J20
16-36
Maintenance
of
Battery
Description
............
2J20
16-36
Box
..................
2J1/16-17
Removal
Installation
.......
2K3
16-41
Battery
Contactor
.........
2J1/16-17
Aircraft
Lighting
System
.....
2K3
16-41
Description
............
2J1/16-17
Description
.............
2K3
16-41
Removal/Installation
.....
2J1/116-17
Trouble
Shooting
.........
2K3
16-41
Battery
Contactor
Closing
Landing
Taxi
Light
.........
2K8
16-46
Circuit
..............
2J2/16-18
Description
.............
2K8
16-46
Description
..........
2J2/16-18
Removal
Installation
.......
2K8 16-46
Revision
1
16-1
MODEL
172
SERIES
SERVICE
MANUAL
Adjustment
.............
2K8
16-46
Control
Wheel
Map
Light
.....
2K21
16-57
Landing
Taxi
Lights
(Dual)
...
2K8
16-46
Description
............
2K21
16-57
Description
............
2K8
16-46
Removal
Installation
......
2K21
16-57
Removal
Installation
.......
2K8
16-46
Pitot
Heater
...............
2K21
16-57
Navigation
Lights
..........
2K12
16-50
Description
........... .
2K21
16-57
Description
.............
2K12
16-50
Cigar
Lighter
............
.
2K21
16-57
Removal
Installation
.......
2K12
16-50
Description
.............
2K21
16-57
Anti-Collision
Strobe
Light
....
2K12/16-50
Clock
...................
2L3,16-61
Description
.............
2K12/16-50
Description
.............
2L3/16-61
Removal
Installation
.......
2K12.
16-50
Emergency
Locator
Transmitter
Operational
Requirements
..
2K12/16-50
(Thru
17268576)
..........
2L3
16-61
Flashing
Beacon
...........
2K1216-50
Description
.............
2L3 16-61
Description
.............
2K12,16-50
Operation
...............
2L4,16-62
Removal
Installation
.......
2K12/
16-50
Checkout
Interval
.........
2L4
16-62
Instrument,
Dome
Lights
.....
2K16/16-54
Removal/Installation
of
Description
............
2K16/16-54
Transmitter
............
2L416-62
Removal
Installation
.......
2K16/16-54
Removal/Installation
of
Courtesy
Lights
...........
2K16/16-54
Antenna
................
2L16-64
Description
............
2K16/16-54
Removal/Installation
of
Removal
Installation
.......
2K16/16-54
Lithium Four
Cell
Compass
Radio
Dial
Lighting
..
2K16/16-54
Battery
Pack
...........
2L6/16-64
Description
.............
2K16/16-54
Trouble
Shooting
.........
2L8/16-66
Instrument
Post
Lighting
....
2K16,16-54
Emergency
Locator
Transmitter
Description
.............
2K16,16-54
(Beginning
with
17268577)
..
2L10/16-68
Removal
Installation
.......
2K16,16-54
Description
.............
2L10/1668
Trouble
Shooting
.........
2K17
16-54A
Operation
...............
2L10
16-68
Trouble
Shooting
Transistor
Checkout
Interval
.........
2L11
/16-69
Heat Sink
..............
2K1816-54B
Removal/Installation
of
Transistorized
Light
Dimming
.
2G23
16-54B
Transmitter
............
2L11
16-69
Description
.............
2G23
16-54B
Remova/Installation
of
Removal
Installation
.......
2G23,16-54B
Antenna
...............
2L11
16-69
Trouble
Shooting
.........
2G23/16-54B
Removal/Installation
of
Map
Lighting
.............
2K21
16-57
Battery
Pack
...........
2L15
16-72A
Description
............
2K21/16-57
Trouble
Shooting
.........
2L1816-74
Removal
Installation
.......
2K21/16-57
Electrical
Load
Analysis
Chart
..................
2L19
16-75
16-1.
ELECTRICAL SYSTEMS.
16-2.
GENERAL.
This
section
contains
service
information
necessary
to
maintain
the
Aircraft
Electrical
Power
Supply System.
Aircraft
Lighting
System.
Pitot
Heater.
Cigar
Lighter
and
Electrical
Load
Analysis
Chart.
16-2
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
16-3.
ELECTRICAL
POWER
SUPPLY
SYSTEM.
16-4.
DESCRIPTION.
Electrical
energy
for
the
aircraft
is
supplied
by
a
14-volt.
direct-current.
single
wire, negative
ground
electrical system.
A
single
12-volt
battery
supplies
power
for
starting
and
furnishes
a
reserve
source
of
power
in
the
event
of
alternator
failure
thru
1977
models.
Beginning
with
1978
models
the
electrical
system
is
28-volt
and
a
24-volt
battery
is
utilized
An
engine-driven
alternator
is
the
normal
source
of
power
during
flight
and
maintains
a
battery
charge
controlled
by
a
voltage
regulator.
An
external
power
receptacle
is
offered
as
optional
equipment
to
supplement
the
battery system
for
starting
and
ground
operation.
16-5.
SPLIT
BUS
BAR.
16-6.
DESCRIPTION.
Electrical
power
is
supplied
through
a
split
bus
bar.
One
side
of
the
bus
bar
supplies
power
to
the
electrical
equipment
while
the
other
side
supplies
the
electronic
installations.
When
the
master
switch
is
closed,
the
battery
contactor engages
and
the
battery
power
is
supplied
to
the
electrical
side
of
the
split
bus
bar.
The
electrical
bus
feeds
battery
power
thru
a
relay,
thru
1977
models
and
an
avionics
master
switch
beginning
with
1978
models,
to
the
electronics
bus.
16-7.
MASTER
SWITCH.
16-8.
DESCRIPTION.
The
operation
of
the
battery
and
alternator
systems
is
controlled
by
a
master
switch.
The
switch
is
an
interlocking
split
rocker
with
battery
mode
on
the
right-
hand side
and
alternator
mode
on
the left-hand
side.
This
arrangement
allows
the
battery
to
be
on
the line
without
the
alternator,
however,
operation
of
the
alternator
without
the
battery
on
the
line
is
not
possible.
16-9.
AMMETER.
16-10.
DESCRIPTION.
The
ammeter
is
connected between
the
battery
and
the
aircraft
bus.
The
meter
indicates
the
amount
of
current
flowing
either
to
or
from
the
battery.
With
a
low
battery
and
the
engine
operating
at
cruise,
the
ammeter
will show
the
full
alternator
output.
When
the
battery
is
fully
charged
and
cruise
is
maintained
with
all
electrical
equipment
off.
the
ammeter
will
show
a
minimum
charging
rate.
16-11.
BATTERY
POWER
SYSTEM.
16-12.
BATTERY.
16-13.
DESCRIPTION.
Thru
17269309
and
F17201639
a
12-volt
battery
with
an
approximate
25
ampere-hour
capacity
is
installed.
On
aircraft
serials
17269310
thru
17269605
and
F17201640
thru
F17201729
the
battery
is
24-volt
and
approximately
17
ampere-hour
capacity.
Begin-
ning
with
17269742
and
F17201730
the
battery
is
also
24-volts with
an
approximate
12.75
ampere-hour
capacity
as
standard
and
an
optional
battery
with
an
approximate
15.5
ampere-hour
rating.
The
battery
is
mounted
on
the
forward
left
hand
side
of
the
firewall.
16-3
MODEL
172
SERIES
SERVICE
MANUAL
.-- -.
16-4
THRU
1980
MODELS
8
1.
Screw
6.
Lockwasher
2.
Lockwasher
7.
Nut
3.
Circuit
Breaker
8.
Avionics
Switch
4.
Instrument Panel
9.
Avionics
Bar
5.
Decorative
Cover
10.
Primary
Bus
Figure
16-1.
Circuit
Breaker
and Bus
Bar
Installation
(Sheet
1
of
3)
16-4
MODEL
172
SERIES
SERVICE
MANUAL
3
1.
Screw
3.
Circuit
Breaker
8.
Avionics
Switch
9.
Avionics
Bus
Bar
10.
Primary
Bus
Figure
16-1.
Circuit
Breaker
and
Bus
Bar
Installation
(Sheet
2
of
3)
16-5
MODEL
172
SERIES SERVICE
MANUAL
1.
Screw
3.
Circuit
Breaker
8.
Avionics
Switch
9.
Avionics
Bus
Bar
10.
Primary
Bus
Figure
16-1.
Circuit
Breaker
and
Bus
Bar
Installation
(Sheet
3
of
3)
16-6
MODEL
172
SERIES SERVICE
MANUAL
16
12
or
24
VOLT
INSTALLATION
1.
Battery
Box
Lid
2.
Battery
3.
Battery
Box
4.
Nut.
5.
Lockwasher
7.
Insulating Washer
8.
Bracket
10.
Solder
Terminal
11.
Diode
12.
ire
to
Battery
Contactor
13.
Resistor
14.
Screw
15.
Fuse
-
Battery
Co
n
tactor
Closing
Circuit
16.
Fuse
-Clock
18.
Wire
to Diode
Board
19.
Ground
Service
Receptacle
Contactor
20.
Wire
from
Fuse
to
Battery
Contactor
21.
Wire
to
Clock
22.
Wire
from
Starter
Contactor
to
Battery Contactor
23.
Cover
24.
Starter
Contactor
25.
Wire
to
Ignition
Switch
26.
Wire
to
Starter
27.
Wire
from
Starter
Contactor
to
Battery
Contactor
28.
Positive
Battery
Lead
29.
Diode
Assembly
30.
Wire
to
Master
Switch
31.
Negative Ground
Strap
12
VOLT
INSTALLATION
32.
Battery Contactor
Figure
16-2.
Battery
and
Electrical
Equipment
Installation
(Sheet
1
of
7)
16-6A/(16-6B
blank)
MODEL
172
SERIES
SERVICE
MANUAL
2
3
20
Detail
A
Detail
B
THRU
17269605
AND
F17201729
24
VOLT
INSTALLATION
1.
Battery
6.
Vent
Tube
11.
Nut
16.
Battery Contactor
2.
Battery
Box
Lid
7.
Screw
12.
Lockwasher
17.
Wire
(to
Starter
Contactor,
3.
Positive
Cable
8.
Ground
Strap
13.
Starter
Contactor
18.
Wire (to
Starter)
4.
Firewall
9.
Cover
14.
Wire
(to
Master
Switch)
19.
Wire
(to
Ignition
Switch)
5.
Side
Panel
10.
Sta-Strap
15.
Diode
Assembly
20.
Bolt
Figure
16-2.
Battery
and
Electrical
Equipment
Installation
(Sheet
2
of
7)
16-7
MODEL
172
SERIES SERVICE
MANUAL
2
3
Detail
A
17269606
THRU
17272884
AND
F17201730
THRU
F17201909
Figure
16-2.
Battery
and
Electrical
Equipment
Installation
(Sheet
3
of
7)
16-8
MODEL
172
SERIES SERVICE
MANUAL
2
1.
Washer
2.
Bolt
3.
Cover
4.
Terminal
Cover
5.
Sta-strap
19
6.
Battery
7.
Positive
Cable
8.
Elbow
9.
Drain
Tube
10.
Battery
Contactor
11.
Wire
(to
Master
Switch)
12.
Diode
13
13.
Starter
Contactor
14.
Wire
(to
Ammeter)
15.
Wire
(to
Ignition
Switch)
16.
Wire
(to
Starter)
17.
Wire
(to Diode
Board)
14
18.
Wire
(to
Receptacle)
19.
Ground
Service
Contactor
16
20.
Pan
15
21.
Ground
Strap
22.
Clamp
17272885
THRU
17274009
AND
23.
Cover
(Starter
Contactor)
F17201910
THRU
F17201828
Figure
16-2.
Battery
and
Electrical
Equipment
Installation
(Sheet
4
of
7)
16-9
MODEL
172
SERIES
SERVICE
MANUAL
23
BEGINNING
WITH
17274010
.
AND
F17202070
24.
Cover (Ground Service)
25.
Cover
(Starter
Contactor)
29
26.
Clock
Fuse
27.
Fuse
Battery
Contactor
Closing
Circuit
28.
Diode
29.
Ground
Service
Receptacle
Figure
16-2
Battery
and
Electrical
Equipment
Installation
(Sheet
5
of
7)
16-10
MODEL
172
SERIES SERVICE
MANUAL
*
Used
on
All
Three
Contactors
THRU
17275339
AND
F17202169
Detail
B
BEGINNING
WITH
17274010
AND
F17202070
30.
Wire
(to
Starter
Contactor)
_
31.
Wire
(to
Ground
Service)
32.
Ground
Wire
33.
Wire
(to
Battery
Contactor)
34.
Wire
(to
Diode)
35.
Wire
(to
Starter
Contactor)
36.
Wire
(to
Clock
Fuse)
-37.
Jumper
Wire
38.
Wire
(to
Battery)
Figure
16-2.
Battery
and
Electrical Equipment
Installation
(Sheet
6
of
7)
16-11
MODEL
172
SERIES
SERVICE
MANUAL
Used on
All
Three
Contactors
3
BEGINNING
WITH
17275340
AND
F17202170
41
40
1.W
ashe
r
2.
Bolt
3.
Cover
4.
Terminal
Cover
5.
Sta-strap
8.
Elbow
9.
Drain
Tube
20. Pan
21.
Ground
Strap
22.
Clamp
29.
Ground
Service
Receptacle
39.
Shield
40.
Cooling
Duct
41. Clamp
Figure
16-2.
Battery
and
Electrical
Equipment
Installation
(Sheet
7
of
7)
16-12
MODEL
172
SERIES
SERVICE
MANUAL
16-14.
TROUBLE SHOOTING THE
BATTERY
POWER
SYSTEM.
TROUBLE
PROBABLE
CAUSE REMEDY
BATTERY
WILL
NOT
SUP-
Battery
discharged.
1.
Measure
voltage
at
"BAT"
PLY
POWER
TO
BUS
OR
IS
terminal
of
battery
contactor
INCAPABLE
OF
CRANKING
with
master
switch
and
a
suit-
ENGINE.
able
load
such
as
a
taxi
light
turned
on.
Normal
battery
will
indicate
11.5
volts
or
more
on
a
14
volt system
or
23
volts
or
more
on
a
28
volt
system.
If
voltage
is
low,
proceed
to
Step
2.
If
voltage
is
normal,
proceed
to
Step
3.
Battery
faulty.
2.
Check
fluid
level
in
cells
and
charge
12-volt
battery
at
14
volts
or
24-volt
battery
at
28
volts
for
approximately
30
minutes or
until
the bat-
tery
voltage
rises
to
14
volts
on
12-volt
battery
or
28
volts
on
24-volt
bat-
tery.
If
tester
indicates
a
good
battery,
the
malfunc-
tion
may
be
assumed
to
be
a
discharged
battery.
If
the
tester
indicates
a
faulty
bat-
tery
replace
the
battery.
Faulty
contactor or
wiring
3.
Measure
voltage
at
mas-
between
contactor or
master
ter
switch
terminal
(smallest)
switch.
on
contactor with
master
switch
closed.
Normal
indi-
cation
is
zero
volts.
If
voltage
reads
zero. proceed
to
step
4.
If
a
voltage
reading
is
obtained
check
wiring
between
contactor
and
master
switch.
Also
check
master
switch.
Open
coil
on
contactor.
4.
Check
continuity
between
"BAT"
terminal
and
master
switch
terminal
of
contactor.
Normal
indication
on
14
volt
aircraft
is
16-24
ohms.
Nor-
mal
indication
on
28
volt
aircraft
is
50-70
ohms.
If
ohmmeter
indicates
an
open coil.
replace contactor.
If
ohmmeter
indicates
a
good
coil.
proceed
to
step
5.
16-13
MODEL
172
SERIES
SERVICE
MANUAL
16-14.
TROUBLE
SHOOTING
THE BATTERY
POWER
SYSTEM
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
BATTERY
WILL
NOT
SUP-
Faulty
contactor
contacts.
5.
Check
voltage
on
"BUS"
PLY
POWER
TO
BUS
OR
IS
side
of
contactor with
master
INCAPABLE
OF
CRANKING
switch
closed.
Meter
normally
ENGINE.
(Cont).
indicates battery voltage
If
voltage
is
zero
or
intermit-
tant.
replace
contactor.
If
volt-
age
is
normal,
proceed
to
Step
6.
Faulty
wiring
between
con-
6.
Inspect
wiring
between
tactor
and
bus.
contactor
and
bus.
Repair
or
replace
wiring.
16-15.
REMOVAL AND
INSTALLATION.
(See
figure
16-2.)
CAUTION
When
installing
or
removing
battery
always
observe
the
proper
polarity
with
the
aircraft
electrical
system
(nega-
tive
to
ground),
reverse
the
polarity,
even
momentarily.
may
result
in
failure
of
semiconductor
devices
(alterna-
tor
diodes,
radio
protection
diodes
and
radio
transistors).
Always
remove
the
battery
ground
cable
first
and
replace
it
last
to
prevent
accidental
short
circuits.
a.
THRU
1979
MODELS..
1.
Remove
upper
half
of
cowl.
2.
Remove
battery
box
cover
and
beginning
with
1978
models
also
remove side
panel.
3.
Disconnect
the
ground
cable
from
the
negative
battery terminal.
4.
Disconnect
the
cable
from
the
positive
terminal
of
the
battery.
5.
Lift
the
battery
out
of
the
battery
box
6.
To
replace
the
battery, reverse
this
procedure.
b.
BEGINNING
WITH
1980
MODELS.
1.
Remove
upper
half
of
engine
cowl.
2.
Disconnect
ground
strap
from
negative
battery
terminal.
3.
Cut
sta-strap
and
remove cover
from
positive
battery
terminal.
4.
Disconnect
the
cable
from
the
positive
battery
terminal.
5.
Remove
clamp
and
battery
drain
tube.
6.
Remove
bolts
and
washers
securing battery
and
cover,
then
remove
cover
and
lift
battery
out
of
pan.
16-14
MODEL
172
SERIES SERVICE
MANUAL
16-16.
CLEANING
THE
BATTERY.
For
maximum
efficiency,
the
battery
and
connections
should
be
kept
clean at
all
times.
a.
Remove
the
battery
in
accordance
with
the
preceding
paragraph.
b.
Tighten battery cell
filler
caps
to
prevent
the
cleaning
solution
from
entering
the
cells.
c.
Wipe
the
battery
cable ends,
battery
terminals
and
entire
surface
of
the
battery
with
a
clean
cloth
moistened
with
a
solution
of
bicarbonate
of
soda (baking
soda)
and water.
d.
Rinse
with
clear
water,
wipe
off
excess
water
and
allow
battery
to
dry.
e.
Brighten
up
cable
ends
and
battery terminals
with
emery
cloth
or
a
wire
brush.
f.
Install
the
battery
according
with
the
preceding
paragraph
g.
Coat
the
battery
terminals
with petroleum
jelly
or
an
ignition
spray
product
to
reduce
corosion.
16-17.
ADDING ELECTROLYTE
OR
WATER
TO
THE BATTERY.
A
battery being
charged
and
discharged
with
use
will
decompose
the
water
from
the
electrolyte
by
electrolysis.
When
the
water
is
decomposed,
hydrogen
and
oxygen
gases
are
formed
which
escape
into the
atmosphere through
the
battery
vent
system.
The
acid
in
the
solution
chemically
combines
with
the
plates
of
the
battery
during
discharge
or
is
suspended
in
the
electrolyte
solution
during
charge.
Unless
the
electrolyte
has
been
spilled
from
a
battery,
acid
should
not
be
added
to
the
solution.
The
water,
however,
will
decompose
into
gases
and
should
be
replaced
regularly.
Add
distilled water
as
necessary
to
maintain
the
electrolyte
level
with
the
horizontal
baffle
plate
or
the
split
ring
on
the
filler
neck
inside
the
battery.
When
"dry
charged"
batteries
are
put
into
service,
fill
as
directed
with
electrolyte.
When
the
electrolyte
level
falls
below
normal with
use,
add
only
distilled
water
to
maintain
the
proper
level.
On
Aircraft
Serials
17269310
thru
17269605
and
F1721640
thru
F1721729
refer
to
Cessna
Single-
Engine
Service
Letter,
SE78-6
Dated
February
13,
1978
when
filling
the
battery.
The
battery
electrolyte
contains
approximately
25%
sulphuric
acid
by
volume. Any
change
in
this
volume
will
hamper
the
proper
operation
of
the
battery.
CAUTION
Do
not
add
any
type
of
"battery
rejuvenator"
to the
electrolyte.
When
acid
has
been
spilled
from
a
battery,
the
acid
balance
may
be
adjusted
by
following
instructions
published
by
the
Association
of
American
Battery
Manu-
facturers.
16-18.
TESTING
THE
BATTERY.
The
specific
gravity
of
the
battery
may
be
measured
with
a
hydrometer
to
determine
the
state
of
battery
charge.
If
the
hydrometer
reading
is
low,
slow-
charge
the
battery
and
retest.
Hydrometer
readings
of
the
electrolyte
must
be
compensated
for
the
temperature
of
the
electrolyte.
Some
hydrometers
have
a
built-in
thermometer
and
conversion
chart.
The
following
chart
shows
the
battery
condition
for
various
hydrometer
readings
with
an
electrolyte
temperature
of
80°
Fahrenheit.
16-15
MODEL
172
SERIES
SERVICE
MANUAL
BATTERY
HYDROMETER
READINGS
READINGS
BATTERY
CONDITION
1280
Specific
Gravity
100%
Charged
1250
Specific
Gravity
75%
Charged
1220
Specific
Gravity
50%
Charged
1.190
Specific
Gravity
25%
Charged
1.160
Specific
Gravity
Practically
Dead
NOTE
All
readings
shown
are
for
an
electrolyte temperature
of
80
°
Fahrenheit.
For
higher
temperatures
the
readings
will
be
slightly
lower.
For cooler
temperatures
the
read-
ings
will
be
slightly
higher.
Some
hydrometers
have
a
built-in
temperature
compensation
chart
and
a
ther-
mometer.
If
this
type
tester
is
used,
disregard
this
chart.
16-19.
CHARGING
THE BATTERY.
When
the
battery
is
to
be
charged,
the level
of
electrolyte
should
be
checked
and
adjusted
by
adding
distilled
water
to
cover
the
tops
of
the
internal
battery
plates.
Remove
the
battery
from
the
aircraft
and
place
in a
well
ventilated
area
for
charging.
WARNING
When
a
battery
is
being charged,
hydrogen and
oxygen
gases
are
generated. Accumulation
of
these
gases
can
create
a
hazardous
explosive
condition. Always
keep
sparks
and
open
flame
away
from
the
battery.
Allow
unrestricted
ventilation
of
the
battery
area
during
charging.
The
main
points
of
consideration
during
a
battery
charge
are
excessive
battery
temperature
and
violent
gassing.
Test
the
battery
with
a
hydrometer
to
determine
the
amount
of
charge.
Decrease
the
charging
rate
or
stop
charging
temporarily
if
the
battery
temperature
exceeds
125°F.
16-20.
BATTERY
BOX
(THRU
17272884
AND
F17201909).
16-21.
DESCRIPTION.
The
battery
is
completely
enclosed
in
a
boxwhich
is
painted
with
acid
proof
paint.
The
box
has
a
vent
tube
which
protrudes through
the
bottom
of
the
aircraft
allowing
battery
gases
and
spilled
electrolyte
to
escape.
The
battery
box
is
riveted
to
the
forward
side
of
the
firewall.
16-16
MODEL
172
SERIES SERVICE
MANUAL
16-22.
REMOVAL
AND
INSTALLATION.
(See
figure
16-1A.)
The
battery
box is
riveted
to
mounting
brackets
on
the
firewall.
The
rivets
must
be
drilled
out
to
remove
the
box.
When
a
battery
box
is
installed
and
riveted
into place,
all
rivets
and
scratches
inside
the
box
should
be
painted
with
acid
proof
lacquer
Part
No. CES1054-381.
available
from
the
Cessna
Service
Parts
Center.
16-23.
MAINTENANCE
OF
BATTERY
BOX
The
battery
box
should
be
inspected
and
cleaned
periodically.
The
box
and
cover should
be
cleaned
with
a
strong
solution
of
bicarbonate
of
soda
(baking
soda)
and
water.
Hard
deposits
may
be
removed
with
a
wire
brush.
When
all
corrosive
deposits
have
been removed from
the
box.
flush
it
thoroughly
with
clean
water.
WARNING
Do
not
allow
acid
deposits
to come
in
contact
with
skin
or
clothing. Serious
acid
burns
may
result
unless
the
affected
area
is
washed
immediately
with
soap
and water.
Clothing
will
be
ruined
upon
contact
with
battery
acid.
Inspect
the
cleaned
box
and
cover
for
physical
damage
and
for
areas
lacking proper
acid
proofing.
A
badly
damaged
or
corroded
box
should
be
replaced.
If
the
box
or
lid
require
acid
proofing,
paint
the
area
with
acid
proof
lacquer
Part
No.
CES1054-381.
available
from
the
Cessna
Service
Parts
Center.
16-24.
BATTERY
CONTACTOR.
16-25.
DESCRIPTION. The
battery
contactor
is
bolted
to
the
side
of
the
battery
box
thru
1977
models
and
on
the
firewall
beginning
with
1978
models.
The
contactor
is
a
plunger
type
which
is
actuated
by
turning
the
master
switch
on.
When
the
master
switch
is
off,
the
battery
is
disconnected
from
the
electrical
system.
A
silicon
diode
is
used
to
eliminate
spiking
of
transistorized
radio
equipment.
The
large
terminal
of
the
diode
connects
to
the
battery
terminal
of
the
battery
contactor.
The small
terminal
of
the
diode
and
the
master
switch
wire
connect
to
the
minus
terminal
of
the
contactor
coil.
A
nylon
cover is
installed
over
the
contactor
terminals
to
prevent
accidental
short circuits.
16-26.
REMOVAL AND
INSTALLATION.
(See
figure
16-2.)
a.
THRU
1980
MODELS.
1.
Remove
engine
cowl
per
Section
11.
2.
Thru
1979
models, remove
battery
box
cover
and disconnect
ground
strap
from
negative battery terminal.
3.
Beginning
with
1980
models,
disconnect ground
strap
from
negative battery termi-
nal.
4.
Cut
sta-straps
and
remove
nylon covers
from
contactor
terminals.
5.
Remove
nuts
and
washers
securing
each
side
of
the
battery contactor
and
remove
contactor.
6.
Remove
bolt
and
washer
securing
each
side
of
the
battery
contactor
and
remove
contactor.
7.
To
install
contactor,
reverse
the
preceding
steps:
be
sure
to
install
diode
assembly
if
removed.
Use
new
sta-straps
on
nylon
covers.
16-17
MODEL
172
SERIES SERVICE
MANUAL
b.
BEGINNING
WITH
1981
MODELS.
1.
Remove
engine
cowl
per
Section
11.
2.
Disconnect
ground
strap
from
negative
battery
terminal.
3.
Cut
sta-straps
and
remove
contactor
cover.
4.
Remove
nuts
and
washers,
then
remove
and
tag
wires
for
reinstallation.
5.
Remove
bolt
and
washer securing
each
side
of
the
battery
contactor
and
remove
contactor.
6.
To
install
contactor.
reverse
the
preceding
steps:
be
sure
to
install
diode
assembly
if
removed.
Use
new
sta-straps
on cover.
16-27.
BATTERY CONTACTOR
CLOSING
CIRCUIT.
16-28.
DESCRIPTION.
This
circuit consists
of
a
5
amp
fuse,
a
resistor
and
a
diode
located
on
the
firewall
fuse
bracket
adjacent
to
the
battery.
This
serves
to
shunt
a
small
charge
around
the
battery
contactor
so
that
ground
power
may
be
used
to
close
the
contactor
when
the
battery
is
too
dead
to
energize
the
contactor
by
itself.
16-29.
GROUND
SERVICE
RECEPTACLE.
16-30.
DESCRIPTION.
A
ground
service
receptacle
is
offered
as
optional
equipment
to
permit
use
of
external
power
for
cold
weather
starting
or
when
performing lengthy electrical
mainte-
nance.
A
reverse
polarity
protection
system
is
utilized
whereby
ground
power
must
pass
through
an
external
power
contactor
to
be
connnected
to
the
bus.
A
silicon
junction
diode
is
connected
in
series
with
the
coil
on
the
external
power
contactor
so
that
if
the
ground
power
source
is
inadvertently
connected
with
a
reversed
polarity,
the
external
power
contactor
will
not
close.
This
feature
protects
the
diodes
in
the
alternator,
and
other
semi-conductor
devices
used
in
the
aircraft
from
possible
reverse
polarity
damage.
NOTE
On
Aircraft
Serials
17267585
thru
17269971
refer
to
Cessna
Single-Engine
Service
Letter
SE78-19,
dated
March
27,
1978.
NOTE
Thru
1977
models
application
of
external
power
opened
the
relay
supplying
voltage
to
the
electronics
bus. Begin-
ning
with
1978
models
this
relay
is
replaced
by
an
avionics
master
switch.
The
avionics
master
switch
must
be
OFF when
external
power
is
applied.
NOTE
When
using
ground
power
to
start
the aircraft,
close
the
master
switch
before
removing
the
ground power
plug.
CAUTION
Failure
to
observe
polarity
when
connecting
an
external
power
source
directly
to
the
battery or
directly
to
the
battery
side
of
the
battery
contactor,
will
damage
the
diodes
in
the
alternator
and
other
semiconductor
devices
in
the
aircraft.
16-18
MODEL
172
SERIES
SERVICE
MANUAL
..-
THRU
1980
MODELS
1.
Diode
Board
2.
Cable
(To
Contactor)
3.
Nut
4.
Ground
Strap
5. Washer
6.
Brace
7.
Bracket Assembly
8.
Firewall
9.
Receptacle
13.
Rubber
Nipple
Figure
16-3.
Ground
Service
Receptacle Installation
(Sheet
1
of
2)
16-19
THRU
1980
MODELS
1.
Diode
Board
2.
Cable
(To
Contactor)
3.
Nut
4.
Ground
Strap
5.
Washer
6.
Brace
7.
Bracket
Assembly
8.
Firewall
9.
Receptacle
10.
Doubler
11.
Door
12.
Cowl
Skin
13.
Rubber
Nipple
Figure
16-3.
Ground
Service
Receptacle
Installation
(Sheet
1
of
2)
16-19
MODEL
172
SERIES SERVICE
MANUAL
10
11
13
Detail
A
BEGINNING
WITH
1981
MODELS
Figure
16-3.
Ground
Service
Receptacle
Installation
(Sheet
2
of
2)
18-20
MODEL
172
SERIES SERVICE
MANUAL
16-31.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
STARTER
ENGAGES
WHEN
Shorted
or
reversed
diode
Check
wiring
to.
and condi-
GROUND
POWER
IS
CON-
in
split
bus-bar
system. tion
of
diode
mounted
on
the
NECTED.
(THRU
1977
split
bus
relay
bracket
adja-
MODELS)
cent
to
the magneto
switch.
Correct
wiring.
Replace
diode
board
assembly.
GROUND POWER
WILL
Ground
service
connector
1.
Check
for
voltage
at all
NOT
CRANK
ENGINE.
wired incorrectly. three
terminals
of
external
power contactor
with
ground
power
connected
and
master
switch
off.
If
voltage
is
pre-
sent
on
input
and
coil
termi-
nals
but
not on
the output
terminal
proceed
to
step
4.
If
voltage
is
present
on
the
input
terminal
but
not
on
the
coil
terminal,
proceed
to
step
2.
If
voltage
is
present
on
all
three
terminals,
check
wiring
between
contactor
and
bus.
2.
Check for
voltage
at
small
terminal
of
ground
ser-
vice
receptacle.
If
voltage
is
not
present,
check
ground
service plug
wiring.
If
volt-
age
is
present,
proceed
to
step
3.
Open
or
mis-wired
diode
3.
Check
polarity
and
conti-
on
ground
service
diode
uity
of
diode
board
at
board
assembly.
rear
of
ground
service
recept-
acle.
If
diode
is
open
or
im-
properly
wired.
replace
diode
board
assembly.
Faulty
external
power
con-
4.
Check
resistance
from
tactor.
small
(coil)
terminal
of
exter-
nal
power
contactor
to
ground (master switch
off
and
ground
power unplugged.
Normal indication
is
16-24
ohms
on
the
12
volt
and
50-
70
on
the
24
volt.
If
re-
sistance
indicates
an
open
coil.
replace
contactor.
If
resistance
is
normal.
pro-
ceed
to step
5.
16-21
MODEL
172
SERIES
SERVICE
MANUAL
16-31.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
GROUND
POWER
WILL
Faulty
contacts
in
exter-
5.
With
master
switch
off
NOT
CRANK
ENGINE
nal
power
contactor. and
ground
power
applied.
(Cont.)
check
for
voltage
drop
be-
tween
two
large terminals
of
external
power
(turn
on
taxi
light
for
a
load).
Normal
in-
dication
is
zero
volts
If
voltage
is
intermittently
present
or
present
all
the
time,
replace
contactor.
16-32.
REMOVAL
AND
INSTALLATION.
(See
figure
16-2.)
a.
Open
battery
box
and
disconnect
the
ground
cable
from
the
negative
terminal
of
the
battery
and
pull
the
cable
from
the
battery
box.
b.
Remove
the
nuts, washers,
ground
strap
and
diode
board
from
the
studs
of
the
receptacle
and
remove
the
battery
cable.
c.
Remove
the
screws
and
nuts
holding the
receptacle.
The
receptacle
will
then
be
free
from the
bracket.
d.
To
install
a
ground
service
receptacle,
reverse
this
procedure.
Be
sure
to
place
the
ground
strap
on
the
negative stud
of
the
receptacle.
16-33.
ALTERNATOR
POWER
SYSTEM.
16-34.
DESCRIPTION.
The
alternator
system
consists
of
a
belt-driven
alternator,
a
voltage
regulator/
alternator
control
unit,
mounted
on
the
left
hand
side
of
the
firewall
and
a
circuit
breaker
located
on the
instrument
panel.
The
system
is
controlled
by
the
left
hand
portion
of
the
split
rocker,
master
switch
labeled
"ALT".
Thru
1978
models
an
over-voltage
sensor
switch
and
red
warning
light
labeled
"HIGH
VOLTAGE"
are
incorporated
to
protect
the
system. Beginning with
1979
models,
over-voltage
and
under-voltage
switches
are
con-
tained
within
the
alternator
control
unit.
A
red
warning
light
labeled
"LOW
VOLTAGE"
is
installed
on
the
instrument
panel.
The
aircraft
battery
supplies
the
source
of
power
for
excitation
of
the
alternator.
16-35.
ALTERNATOR.
16-36.
DESCRIPTION.
The
60-ampere
alternator
is
three phase,
delta
connected
with
integral
silicon
diode
rectifiers.
The
alternator
is
belt
driven
and
is
rated
at
14
volts
at
60
amperes
continuous
output
thru
1977
models
and
28
volts
at
60
amperes
beginning
with
1978
models.
18-22
MODEL
172
SERIES
SERVICE
MANUAL
THRU
17273938
AND
F17202033
BEGINNING
WITH
17273934
AND
F17202040
2.
Washer
Detail
B
8*
3.
Lower
Adjustment
Bracket
4.
Safety
Wire
5.
Upper
Adjustment
Bolt
6.
Nut
7.
Mounting
Bracket
8.
Bracket
9.
Bolt
10.
Alternator
Mounting
Bolt
11.
Alternator
Figure
16-4.
Belt-Driven
Alternator
Installation
16-23
MODEL
172
SERIES
SERVICE
MANUAL
16-37.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(THRU
1977
MODELS)
TROUBLE
PROBABLE
CAUSE
REMEDY
AMMETER
INDICATES
Shorted
radio
noise
filter
1.
Remove
cable
from out-
HEAVY
DISCHARGE
WITH
or
shorted
wire.
put
terminal
of
alternator.
ENGINE
NOT
RUNNING
OR
Check
resistance
from
end
ALTERNATOR CIRCUIT of
cable
to
ground
(MASTER
BREAKER
OPENS
WHEN
SWITCH
MUST
BE
OFF).
MASTER
SWITCH
IS
If
resistance
does
not
indi-
TURNED
ON.
cate
a
direct
short,
pro-
ceed
to
step
4.
If
resist-
ance
indicates
a
direct
short.
proceed
to
step
2.
2.
Remove
cable
connections
from
radio
noise
filter.
Check
resistance
from
the
filter
input terminal
to
ground. Normal indication
is
infinite
resistance.
If
read-
ing
indicates
a
direct
short.
replace
filter.
If
no
short
is
evident,
proceed
to
step
3.
3.
Check
resistance
from
ground
to
the
free
ends
of
the
wires
which
were
con-
nected
to
the
radio
noise
filter
(or
alternator
if
no
noise
filter
is
installed).
Normal indication
does
not
show
a
direct
short.
If
a
short exists
in
wires,
re-
pair
or
replace
wiring.
Shorted
diodes
in
alternator.
4.
Check
resistance
from
output terminal
of
alter-
nator
to
alternator
case.
Reverse
leads and
check
again.
Resistance
reading
may
show
continuity
in
one
direction
but
should
show
an
infinite reading
in
the
other
direction.
If
an
in-
finite
reading
is
not
ob-
tained
in
at
least
one
direc-
tion.
repair
or
replace
alter-
nator.
16-24
MODEL
172
SERIES
SERVICE
MANUAL
16-37.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(THRU
1977
MODEL)
(Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
ALTERNATOR
SYSTEM
Regulator faulty
or
improp-
1.
Start
engine
and
adjust
for
WILL
NOT
KEEP
BAT-
erly adjusted.
1500
RPM.
Ammeter
should
TERY
CHARGED.
indicate
a
heavy
charge
rate with all
electrical
equipment
turned
off.
Rate
should
taper
off
in
1-3
min-
utes.
A
voltage
check
at
the
bus
should
indicate
a
reading
consistant
with
the
voltage
vs
temperature
chart
in
the
Cessna Alternator
Charging
System
Service/
Parts
Manual.
If
charge
rate
tapers
off
very
quickly
and
voltage
is
normal,
check bat-
tery
for
malfunction.
If
ammeter
shows
a
low
charge
rate
or
any
discharge rate,
and
voltage
is
low,
proceed
to
step
2.
2.
Stop
engine,
remove
cowl,
and
remove
cover
from
volt-
age
regulator. Turn
master
switch
ON/OFF
several
times
and
observe
field
relay
in
regulator.
Relay
should
open
and
close
with
master
switch
and
small arc
should
be
seen
as
contacts
open.
If
relay
is
inoperative.
proceed
to
step
3.
If
relay
operates,
proceed
to
step
4.
3.
Check
voltage
at
"S"
ter-
minal
of
regulator
with master
switch
closed. Meter
should
indi-
cate
bus voltage.
If
voltage
is
present.
replace
regula-
tor.
If
voltage
is
not
present.
check
wiring
between
regu-
lator
and bus.
16-25
MODEL
172
SERIES SERVICE
MANUAL
16-37.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(THRU
1977
MODEL)
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
CAUTION
Before
performing
step
4.
remove
radios
from
the
panel.
ALTERNATOR
SYSTEM
Regulator
faulty or
improp-
4.
Remove
plug
from
regu-
WILL
NOT
KEEP
BAT-
erly
adjusted.
(Cont.)
lator
and
start
engine.
Mo-
TERY
CHARGED.
(Cont.)
mentarily
jumper
the
"A+"
and
"F"
terminals
together
on
the
plug. Ship's
ammeter
should
show
heavy
rate
of
charge.
If
heavy
charge
rate
is
observed, replace
regula-
tor.
If
heavy
charge
rate
is
not
observed.
proceed
to
step
5.
5.
Check
resistance
from
"F"
terminal
of
regulator
to
"F"
terminal
of
alternator.
Normal
indication
is
a
very
low
resistance.
If
reading
indicates
no
or
poor
conti-
uity,
repair
or
replace
wir-
ing
from
regulator
to
alter-
nator.
6.
Check
resistance
from
"F"
terminal
of
alterntor
to
alternator
case.
Normal
in-
dication
is
6-7
ohms.
If
re-
sistance
is
high or
low.
re-
pair
or
replace
alternator.
7.
Check
resistance
from
case
of
alternator
to
air-
frame
ground.
Normal
indica-
tion
is
very
low
resistance.
If
reading
indicates
no. or
poor
continuity,
repair
or
re-
place
alternator
ground
wiring.
ALTERNATOR OVERCHAR-
Regulator
faulty
or
improp-
Check
bus
voltage
with
en-
GES BATTERY
-
BATTERY
erly
adjusted.
gine
running.
Normal
indica-
USES
EXCESSIVE
WATER.
tion
agrees
with the
Cessna
Alternator
Charging
System
Service/Parts
Manual.
Ob-
serve
ship's
ammeter,
am-
meter
should
indicate
near
zero
after
a
few
minutes
of
engine
operation.
Replace
regulator.
16-26
MODEL
172
SERIES
SERVICE
MANUAL
16-37.
TROUBLE
SHOOTING
THE ALTERNATOR
SYSTEM
(THRU
1977
MODEL)
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
OVER-VOLTAGE
WARN-
Regulator
faulty
or
improp-
1.
With
engine
running
turn
ING
LIGHT
ON.
erly
adjusted.
Faulty
sensor
off
and
on
battery portion
switch,
of
the master
switch.
If
the
light
stays
on
shut
down
engine
then
turn
on
the
"BAT"
and
"ALT"
portion
the
master
switch.
Check
for
voltage
at
the
"S"
terminal
of
the
volt-
age
regulator.
If
voltage
is
present
adjust or
replace
reg-
ulator.
If
voltage
is
not
pre-
sent
check
master
switch and
wiring
for
short
or
open
cond-
ition.
If
wiring
and
switch
are
normal
replace
sensor.
16-37A.
TROUBLE
SHOOTING THE
ALTERNATOR
SYSTEM.
(1978
MODELS)
a.
ENGINE
NOT
RUNNING.
TROUBLE
PROBABLE CAUSE
REMEDY
AMMETER
INDICATES
Shorted
diode
in
alternator.
Turn
off
Battery
Switch
and
HEAVY
DISCHARGE
OR
remove
"B"
Lead
from
alter-
ALTERNATOR
CIRCUIT
nator.
Check
resistance
from
BREAKER
OPENS.
(Bat-
"B"
Terminal
to
alternator
tery
Switch
ON,
Alter-
case.
Reverse leads
and
nator
Switch
OFF,
all
check again.
Resistance
other
electrical switches
reading
may
show
continuity
OFF.)
in
one
direction
but
should
show
an
infinite
reading
in
the
other
direction.
If
an
infinite
reading
is
not obtained
in
at
least
one
direction,
repair
or
replace
alternator.
ALTERNATOR
REGULATOR
Short
in
Over-Voltage
Disconnect
Over-Voltage
CIRCUIT
BREAKER
OPENS
sensor.
Sensor
plug
and
recheck.
WHEN
BATTERY
AND
If
circuit
breaker
stays
in
ALTERNATOR
SWITCHES
replace
Over-Voltage
Sensor.
ARE
TURNED
ON.
Short
in
alternator
voltage
Disconnect
regulator
plug
regulator.
and
recheck.
If
circuit
breaker
stays
in.
replace
regulator.
Short
in
alternator
field.
Disconnect
"F"
terminal
wire
and
recheck.
If
circuit
breaker
stays
in.
replace
alternator.
16-27
MODEL
172
SERIES
SERVICE
MANUAL
16-37A.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM.
(Cont.)
b.
ENGINE
RUNNING
(Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
ALTERNATOR
CIRCUIT
Defective
circuit
breaker.
Replace
circuit
breaker.
BREAKER
OPENS
WHEN
BATTERY
AND
ALTER-
NATOR
SWITCHES
ARE
TURNED
ON,
OVER-
VOLTAGE
LIGHT
DOES
NOT
COME
ON.
ALTERNATOR REGULATOR
Shorted
field
in
alternator.
Check
resistance
from
"F"
CIRCUIT
BREAKER OPENS
terminal
of
alternator
to
WHEN
BATTERY
AND
alternator
case.
if
resistance
ALTERNATOR SWITCHES
is
less
than
5
ohms
repair/
ARE
TURNED
ON.
OVER-
replace.
VOLTAGE
LIGHT
DOES
NOT
COME
ON.
CAUTION
This malfunction frequently causes
a
shorted
regulator
which
will
result
in
an
over-voltage
condition
when
system
is
again
operated.
ALTERNATOR
MAKES
Shorted
diode
in
alternator.
Turn
off
Battery
Switch and
ABNORMAL
WHINING
remove
"B"
Lead from
NOISE.
alternator.
Check
resistance
from
"B"
Terminal
of
alter-
nator
to
alternator
case.
Reverse leads
and
check
again.
Resistance
reading
may
show
continuity
in
one
direction
but
should
show
an
infinite reading
in
the
other
direction.
If
an
infin-
ite
reading
is
not
obtained
in
at
least
one
direction.
repair
or
replace
alternator.
OVER-VOLTAGE
LIGHT
Shorted
regulator.
Replace
regulator.
DOES
NOT
GO
OUT
WHEN
ALTERNATOR
AND
BAT-
TERY
SWITCHES
ARE
TURNED
ON.
Defective
over-voltage
Replace
sensor.
sensor.
16-28
MODEL
172
SERIES
SERVICE
MANUAL
16-37A.
TROUBLE
SHOOTING THE
ALTERNATOR (Cont).
b.
ENGINE
RUNNING.
TROUBLE
PROBABLE CAUSE
REMEDY
AFTER
ENGINE
START
Regulator
faulty or
high
With
engine
not
running
turn
WITH
ALL
ELECTRICAL
resistance
in
field
circuit.
off
all
electrical loads and
EQUIPMENT TURNED
OFF
turn
on
battery
and
alternator
CHARGE
RATE
DOES
NOT
switches.
Measure
bus volt-
TAPER OFF
IN
1-3
MIN-
age to ground,
then
measure
UTES.
voltage
from
terminal
of
alter-
nator
to
ground.
If
there
is
more
than
2
volts
difference
check
field
circuit
wiring
shown
on
alternator
system
wiring
diagram
in
Section
20.
Clean
all
contacts.
Replace
components
until
there
is
less
than
2
volts
difference
between
bus
voltage
and
field
voltage.
NOTE
Also
refer
to
battery
power
system trouble
shooting
chart.
ALTERNATOR
SYSTEM
Alternator
output
voltage
1.
Connect
voltmeter
be-
WILL NOT
KEEP
BAT-
insufficient.
tween
D.C.
Bus
and
ground.
TERY
CHARGED.
Turn
off
all
electrical
loads.
Turn
on
Battery
Switch,
start
engine
and
adjust
for
1500
RPM.
voltage
should
read
ap-
proximately
24
volts.
Turn
on
alternator
switch,
voltage
should
read
between
27.4
and
28.0
volts.
Ammeter
should
indicate
a
heavy
charge
rate
which
should
taper
off
in 1-3
minutes.
If
charge
rate
tapers
off
very
quickly
and
voltage
is
normal,
check
battery
for
malfunction.
If
ammeter
shows
a
low
charge
rate
or
any
discharge rate,
and
voltage
does
not
rise
when
alternator
switch
is
turned
on
proceed
to
Step
2.
16-29
MODEL
172
SERIES
SERVICE
MANUAL
16-37A.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(Cont).
b.
ENGINE
RUNNING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ALTERNATOR
SYSTEM
Alternator
output voltage
2.
Stop
engine.
turn
off
all
WILL
NOT
KEEP
BAT-
insufficient
(Cont.)
switches.
Connect
voltmeter
TERY
CHARGED.
(Cont.)
between
"F"
terminal
of
alternator
and
ground.
Do
NOT
start
engine.
Turn
on
battery
switch
and
alternator
switch.
Battery
voltage
should
be
present
at
"F"
terminal.
less
1
volt
drop
thru
regulator,
if
not
refer
to
Step
3.
3.
Starting
at
"F"
terminal
of
alternator
trace circuit
to
voltage
regulator.
at
"B"
terminal
of
regulator
trace
circuit
to
over-voltage
sen-
sor.
to
master
switch,
to
Bus
Bar.
Replace
component
which
does
not
have voltage
present
at
output.
Refer
to
alternator
system wiring
diagram
in
Section
20.
Alternator
field
winding
1.
If
voltage
is
present
turn
open.
off
alternator
and
battery
switches.
Check
resistance
from
"F"
terminal
of
alterna-
tor
to
alternator
case.
turn-
ing
alternator
shaft
during
measurement.
Normal
indica-
tion
is
12-20
ohms.
If
resist-
ance
is
high
or
low.
repair
or
replace
alternator.
If
ok
refer
to
step
2.
2.
Check
resistance
from
case
of
alternator
to
airframe
ground.
Normal indication
is
very
low
resistance.
If
read-
ing
indicates
no.
or
poor
con-
tinuity.
repair
or
replace
alternator
ground
wiring.
MODEL
172
SERIES SERVICE
MANUAL
16-37B.
TROUBLE
SHOOTING
--
ALTERNATOR
SYSTEM
(BEGINNING
1979
MODELS).
a.
ENGINE
NOT
RUNNING.
TROUBLE
PROBABLE
CAUSE REMEDY
AMMETER
INDICATES
Shorted
diode
in
alternator.
Turn
off
Battery
Switch
and
HEAVY
DISCHARGE
OR
remove
"B"
Lead
from
alter-
ALTERNATOR
CIRCUIT
nator.
Check
resistance
from
BREAKER OPENS.
"B"
Terminal
of
alternator
to
(Battery
Switch
ON,
Alter-
alternator
case.
Reverse
nator
Switch
OFF,
all
leads
and
check
again.
Re-
other
electrical
switches
sistance
reading
may
show
OFF.)
continuity
in
one
direction
but
should show
an
infinite
reading
in
the
other
direction.
If
an
infinite
reading
is
not
ob-
tained
in
at
least
one
direction.
repair
or
replace
alternator.
ALTERNATOR REGULA-
Short
in
alternator
control Disconnect
Over-Voltage
TOR CIRCUIT
BREAKER
unit.
Sensor
plug
and
recheck.
If
OPENS
WHEN
BATTERY
circuit
breaker
stays
in
re-
AND ALTERNATOR
place
Over-Voltage
Sensor.
SWITCHES
ARE
TURNED
ON.
Disconnect
control
unit
plug
and
recheck.
If
circuit
breaker
stays
in,
replace
alternator
con-
trol
unit.
Short
in
alternator
field.
Disconnect
"F"
terminal
wire
and
recheck.
If
circuit
break-
er
stays
in.
replace
alternator.
b.
ENGINE
RUNNING.
ALTERNATOR
CIRCUIT
Defective
circuit
breaker.
Replace
circuit breaker.
BREAKER
OPENS
WHEN
BATTERY
AND
ALTER-
NATOR
SWITCHES
ARE
TURNED
ON,
LOW-VOLT-
AGE
LIGHT
DOES
NOT
COME
ON.
16-31
MODEL
172
SERIES SERVICE
MANUAL
16-37B.
TROUBLE
SHOOTING
--
ALTERNATOR
SYSTEM
(Cont).
b.
ENGINE RUNNING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ALTERNATOR
REGULA-
Shorted
field
in
alternator.
Check
resistance
from
"F"
TOR
CIRCUIT
BREAKER
terminal
of
alternator
to
OPENS
WHEN
BATTERY
alternator
case.
if
resis-
AND
ALTERNATOR
tance
is
less
than
5
ohms
SWITCHES
ARE
TURNED
repair/replace.
ON.
LOW-VOLTAGE
LIGHT
MAY
OR MAY
NOT
COME
ON.
CAUTION
This
malfunction
may
cause
a
shorted
alternator
control
unit
which will
result
in
an
over-voltage
condition
when
system
is
again
operated.
ALTERNATOR MAKES
Shorted
diode
in
alternator.
Turn
off
Battery
Switch
and
ABNORMAL
WHINING
remove
"B"
Lead
from
al-
NOISE.
ternator.
Check
resistance
from
"B"
Terminal
of
alter-
nator
to
alternator
case.
Re-
verse
leads
and
check
again
Resistance reading
may
show
continuity
in
one
direction
but
should
show
an infinite
reading
in
the other direction.
If
an
in-
finite
reading
is
not
obtained
in
one
direction,
repair
or
re-
place
alternator.
LOW-VOLTAGE
LIGHT
Shorted
alternator
control
Replace
alternator
control
DOES
NOT
GO
OUT
WHEN
unit.
unit.
ALTERNATOR
AND BAT-
TERY
SWITCHES ARE
Defective low-voltage Replace
alternator
control
TURNED
ON.
sensor.
unit.
16-32
MODEL
172
SERIES
SERVICE
MANUAL
16-37B.
TROUBLE SHOOTING
--
ALTERNATOR
SYSTEM
(Cont).
b.
ENGINE
RUNNING
(Cont).
TROUBLE PROBABLE
CAUSE REMEDY
AFTER
ENGINE
START
Alternator
control
unit
With
engine
not
running
turn
WITH
ALL
ELECTRICAL
faulty
or
high
resist-
off
all
electrical
loads and
EQUIPMENT
TURNED
OFF
ance
in
field
circuit.
turn
on
battery
and
alternator
CHARGE
RATE
DOES NOT
switches.
Measure
bus
voltage
TAPER
OFF
IN
1-3
to
ground,
then measure
volt-
MINUTES.
age
from
terminal
of
alterna-
tor
to ground.
If
there
is
more
than
2
volts
difference
check
field
circuit
wiring
shown
on
alternator
system
wiring
diagram
in
Section
20.
Clean
all
contacts.
Replace
components
until
there
is
less
than
2
volts difference
be-
tween bus
voltage
and field
voltage.
NOTE
Also
refer
to
battery
power
system trouble
shooting
chart.
ALTERNATOR
SYSTEM
Alternator
output
voltage
1.
Connect
voltmeter
between
WILL
NOT
KEEP
BAT-
insufficient.
D.C.
Bus
and
ground.
Turn
TERY
CHARGED.
off
all
electrical
loads. Turn
on
Battery
Switch,
start
engine
and
adjust
for
1500
RPM.
voltage
should
read
approximately
24
volts.
Turn
on
alternator
switch,
voltage
should
read
between
28.4
and
28.9
volts.
Ammeter
should
indicate
a
heavy charge
rate
which
should
taper
off
in
1-3
minutes.
If
charge
rate
tapers
off
very quickly
and
voltage
is
normal,
check
battery
for
malfunction.
If
ammeter
shows
a
low
charge
rate
or
any
discharge
rate.
and
voltage
does
not
rise
when
alternator
switch
is
turned
on
proceed
to
Step
2.
16-33
MODEL
172
SERIES SERVICE
MANUAL
16-37B.
TROUBLE
SHOOTING
--
ALTERNATOR
SYSTEM
(Cont).
b.
ENGINE
RUNNING
(Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
ALTERNATOR
SYSTEM
Alternator
output
voltage
2.
Stop
engine,
turn
off
all
WILL
NOT
KEEP
BAT-
insufficient
(Cont.)
switches.
Connect
voltmeter
TERY
CHARGED.
(Cont.)
between
"F"
terminal
of
alternator
and
ground.
Do
NOT
start
engine.
Turn
on
battery
switch
and
alternator
switch-
Battery voltage
should
be
present
at
"F"
terminal, less
1
volt
drop
thru
regulator.
if
not
refer
to
Step
3.
3.
Starting
at
"F"
terminal
of
alternator.
trace
circuit
to
alternator
control
unit
at
Pin
1
(Blue
Wire).
Trace
cir-
cuit
from
Pin
3
(Red
Wire)
to
master
switch,
to
Bus
Bar.
Trace
circuit
from
alternator
control
unit
Pin
2
(Orange
Wire)
to
alternator
"BAT"
terminal
Check
connections
and
replace
component
which
does
not
have voltage
present
at
output.
Refer
to
alternator
system.
wiring
diagram
in
Sec-
tion
20.
Alternator
field
winding
1.
If
voltage
is
present turn
open.
off
alternator
and
battery
switches.
Check
resistance
from
"F"
terminal
of
alter-
nator
to
alternator
case.
turning
alternator
shaft
dur-
ing
measurement. Normal
indication
is
12-20
ohms.
If
resistance
is
high
or
low.
repair
or
replace
alternator.
If
ok refer
to
Step
2.
2.
Check
resistance
from
case
of
alternator
to
air-
frame
ground.
Normal
indi-
cation
is
very
low
resistance.
If
reading
indicates
no,
or
poor
continuity.
repair
or
replace
alternator
ground
wiring.
16-34
MODEL
172
SERIES
SERVICE
MANUAL
16-38.
REMOVAL AND
INSTALLATION. (See
figure
16-4.)
a.
Ensure
that
the
master
switch
is
off
and
the
negative
lead
is
disconnected
from
the
battery.
b.
Remove
wiring
from
the
alternator
and label.
c.
Remove
safety
wire
from
the
upper
adjusting
bolt
and
loosen
bolt.
d.
Remove
safety
wire
from
lower
adjusting
bolt
and
remove
bolt.
e.
Remove
the
locknut
from
the
alternator
mounting
bolt.
f.
Remove
the
alternator
drive
belt and the
alternator
mounting
bolt.
the
alternator
will
then
be
free
for
removal
g.
To
replace
the
alternator,
reverse
this
procedure.
h.
Apply
a
torque wrench
to
the
nut
on
alternator
pulley
and adjust
the
belt
tension
so
the
belt
slips
when
the
following
torque
value
is
applied.
TORQUE
VALVES
FOR
CHECKING ALTERNATOR
BELT
TENSION
Used
Belt
New Belt
Slips
At
Slips
At
7
to
9
Ft.
Lb.
11
to
13
Ft.
Lbs.
NOTE
On
new
aircraft
or
whenever
a
new
belt
is
installed,
belt
tension
should
be
checked
within
10
to
25
hours
of
opera-
tion.
i.
Tighten
and
safety
wire
upper
and
lower
adjusting
bolts.
j.
Tighten
alternator
mounting
bolt.
16-39.
OVER-VOLTAGE
WARNING
SYSTEM.
16-40.
DESCRIPTION.
Thru
1978
Models
the
over-voltage
system
consists
of
an
over-voltage
sensor
switch
and
a
red
warning
light
labeled
"HIGH
VOLTAGE".
The
over-voltage
sensor
is
attached
to
the
wire
bundle
behind
the
instrument
panel
thru
1977
models
and
on
a
mounting
bracket
just
forward
of
the
instrument
panel
on
the
left
hand
side
beginning
with
1978
models.
When
an over-voltage
tripoff
occurs
the over-voltage
sensor turns
off
the
alternator
system
and
the
red
warning
light
comes
on.
The
ammeter
will
show
a
discharge.
Turn
off
bolt
sections
of
the
master
switch
to
recycle
the
over-voltage
sensor.
If
the
over-
voltage
condition
was
transient,
the
normal
alternator
charging
will resume
and
no
further
action
is
necessary.
If
the
over-voltage
tripoff
recurs, then
a
generating
system
malfunction
has
occurred
such
that
the
electrical
accessories
must
be
operated
from
the
aircraft
battery
only.
Conservation
of
electrical
energy
must
be
practiced
until
the
flight
can
be
terminated.
The
over-voltage
light
filament
may
be
tested
at
any
time
by
turning
off
the
"Alternator"
portion
of
the
master
switch
and
leaving
the
battery
portion
on.
This
test
does
not
induce
an
over-voltage
condition on
the
electrical
system.
16-35
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
The
over-voltage
sensor
switch
contains
solid
state
devices.
Observe
proper
polarity
before
supplying
power.
Grounding
the
orange
lead
or
interconnecting
orange
and
black leads
will
destroy
the
device.
When
removal
is
required
for
replacement.
identify
(tag)
wir-
ing
and
follow
the
wiring diagram
in
Section
20
for
rewiring.
Beginning
with
1979
Models
the
over-voltage
sensor
is
contained
within
the
alternator
control
unit.
The
unit
also contains
a
low-voltage
sensor.
A
red
warning light
labeled"LOW
VOLTAGE"
is
installed
on
the
instrument
panel.
When
an
over-voltage
condition
occurs
the
over-voltage
sensor
turns
off
the
alternator
and
the
voltage
in
the
system
drops.
When
system
voltage
drops
below
24.5
volts
the
low-voltage
sensor
turns
on
the
low-voltage
light
indicating
a
drain
on
the
battery
and
the
ammeter
will show
a
discharge.
Turn
off
both
sections
of
the
master
switch
to
recycle
the
over-voltage
sensor.
If
the
over-voltage
condition
was
transient.
the
normal alternator
charging
will
resume
and
no
further
action
is
necessary.
If
the
over-voltage
tripoff
recurs,
then
a
generating system
malfunction
has
occurred such
that
the
electrical
accessories
must
be
operated
from
the
aircraft
battery
only.
Conservation
of
electrical
energy must
be
practiced
until
the
flight
can
be
terminated.
The
over-voltage
light
filament
may
be
tested
at
any
time
by
turning
off
the
"Alternator" portion
of
the
master
switch
and
leaving
the
battery
portion
on.
This
test
does
not
induce
an
over-
voltage
condition
on the
electrical
system.
16-41.
ALTERNATOR VOLTAGE REGULATOR.
16-42.
DESCRIPTION.
Thru
1977
Models
the
voltage
regulator
is
semi-solid state.
The
mechanical
relay
in
the
regulator
is
actuated
by
the
aircraft
master
switch
and
connects
the
regualtorto
the
battery.
The
solid
state
portion
is
voltage
sensitive
and
controls
the current
applied
to
the
field
windings
of
the
alternator.
The
regulator
is a
remove
and
replace
item and
not
repairable.
The
regulator
is
adjustable,
but
adjustment
on the
aircraft
is
not
recommended.
A
bench
adjustment
procedure
is
outlined
in
the
Cessna
Alternator
Charging Systems
Service/
Parts
Manual
Thru
1978
Models
the
voltage
regualtor
is
solid-state.
The
regualtor
is
a
remove-and
replace
item
and not
repairable.
The
regulator
is
adjustable.
but
adjustment
on
the
aircraft
is
not
recommended.
A
bench
adjustment
procedure
is
outlined
in
the
Cessna
Alternator Charging
Systems
Service/Parts
Manual
A
Cessna
Alternator Charging
System
Test
Box
Assembly
(PN-9870000-1)
is
available
through
the
Cessna
Service/Parts
Center
for
use
in
isolating
failures
in
the 28-volt
regulator
and
the
28-volt
alternator. Refer
to
paragraph
16-43
for
removal
and
installation.
16-42A.
ALTERNATOR CONTROL
UNIT.
16-42B.
DESCRIPTION.
The
alternator
control
unit
is a
solid
state
voltage
regulator
with
an
over-
voltage
sensor
and
low-voltage
sensor
incorporated
in
the
unit
The
control
unit
is
not
adjustable
and
is a
remove
and
replace
item.
A
Cessna
Alternator Charging
System
Test
Box
Assembly
(PN9870005)
is
available
through
the
Cessna
Service/Parts
Center
for
use
in
isolating
failures
in
the
28-volt
alternator
control
units
(C811005-0101
and
C611005-0102)
and
the
28-volt
alternator.
16-36
MODEL
172
SERIES
SERVICE
MANUAL
2
8
Detail
A
THRU
1977
MODELS
1.
Voltage
Regulator
7.
Wire
to
Overvoltage
Light
2.
Screw
8.
Wire
to
Filter
3.
Housing
9.
Wire
to
Alternator
Ground
4.
Wire
Shields
to
Ground
10.
Filter
-
Radio Noise
5.
Wire to
Alternator
"F"
11.
Wire
to
Master
Switch
6.
Wire
to
Alternator
"A+"
12.
Shield
-
Ground
Figure
16-5.
Voltage
Regulator
Installation
(Sheet
1
of
5)
16-37
MODEL
172
SERIES SERVICE
MANUAL
Detail
A
Detail
B
Rotated
180°
1.
Housing
Plug
2.
Housing
Cap
3.
Ground
Wire
4.
Over-Voltage
Sensor
5.
Mounting
Bracket
6.
Screw
7.
Voltage
Regulator
8.
Firewall
1978
MODELS
Figure
16-5.
Voltage
Regulator
Installation
(Sheet
2
of
5)
16-38
MODEL
172
SERIES
SERVICE
MANUAL
1.
Housing
Plug
2.
Alternator
Control
Unit
3.
Firewall
4.
Ground
Wire
5.
Housing
Cap
6
6.
Bolt
Detail
A
1979
MODELS
Figure
16-5.
Voltage
Regulator
Installation
(Sheet
3
of
5)
16-39
MODEL
172
SERIES SERVICE
MANUAL
BEGINNING
WITH
17271453
AND
F17201795
7
1.
Wire
to
Alternator
6
2.
Wire
to
Alternator
Circuit
Breaker
3.
Terminal
Block
4.
Alternator
Ground
BEGINNING
WITH
1981
MODELS
5.
Alternator
Control
Unit
6.
Housing-Plug
7.
Sta-Strap
8.
Housing
Cap
17276885
THRU
17276199
AND
9.
Ground
Wire
F17201910
THRU
F17202233
10.
Cover
11.
Washer
Figure
16-5.
Voltage
Regulator
Installation
(Sheet
4 of
5)
16-40
MODEL
172
SERIES
SERVICE
MANUAL
3
2
1.
Wire to
Alternator
6
2.
Wire to
Alternator
Circuit
Breaker
3.
Terminal
Block
4.
Alternator
Ground
5.
Alternator
Control
Unit
6.
Housing-Plug
7.
Sta-Strap
8.
Housing
Cap
9.
Ground
Wire
10.
Cover
11.
Spacer
BEGINNING
WITH
17276200
AND
F17202234
Figure
16-5.
Voltage
Regulator
Installation
(Sheet
5
of
5)
16-40A/(16-40B
blank)
MODEL
172
SERIES SERVICE
MANUAL
16-43.
REMOVAL
AND
INSTALLATION.
(See
figure
16-5.)
a.
Remove
upper half
of
engine
cowl.
b.
Place
master
switch
in
the
"OFF"
position.
c.
Disconnect
negative
lead
from
the
battery
and
pull
lead
free
of
the
battery
box.
d.
Disconnect
housing
plug
from
the
regulator/
alternator
control
unit.
e.
Remove
screws
securing
the
regulator/alternator
control
unit
to
the
firewall.
f.
To
install
regulator/alternator
control
unit,
reverse
the
preceding
steps.
Be
sure the
connections
for
grounding
are
clean
and
bright
before
assembly.
Otherwise
faulty
voltage
regulation
and/or
excessive
radio
noise
may
result.
16-44.
AIRCRAFT
LIGHTING
SYSTEM.
16-45.
DESCRIPTION. The
aircraft
lighting
system
consists
of
landing
and
taxi
lights.
navigation
lights,
anti-collision
strobe
lights,
flashing
beacon
light.
dome.
instrument
flood
lights
and
courtesy light,
control
wheel map
light,
compass
and
radio
dial
lights.
16-46.
TROUBLE
SHOOTING.
TROUBLE
PROBABLE
CAUSE REMEDY
LANDING
AND
TAXI
Short
circuit
in
wiring.
1.
Inspect
circuit
breaker.
LIGHT(S)
OUT.
If
open.
proceed
to
Step
2.
If
ok.
proceed
to
Step
3.
Defective
wiring.
2.
Test
each
circuit
sepa-
rately
until
short
is
located.
Repair
or
replace
wiring.
Defective
switch.
3.
Check
voltage
at
lights
with
master
and
landing
and
taxi
light
switches
ON.
Should
read
battery
voltage.
Replace switch.
LANDING
AND/OR
TAXI
Lamp
burned
out.
1.
Test
lamp
with ohmmeter
LIGHT
OUT.
or new lamp.
Replace lamp.
Open
circuit
in
wiring.
2.
Test
wiring
for
continuity.
Repair
or
replace
wiring.
FLASHING
BEACON
DOES
Short
circuit
in
wiring.
1.
Inspect
circuit
breaker.
NOT
LIGHT.
If
open.
proceed
to
Step
2.
If
ok,
proceed
to
Step
3.
Defective
wiring.
2.
Test
circuit until
short
is
located.
Repair
or
replace
wiring.
Lamp
burned
out.
3.
Test
lamp
with
ohmmeter
Replace
lamp.
If
lamp
is
good,
proceed
to
Step
4.
16-41
MODEL
172
SERIES
SERVICE
MANUAL
16-46.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
FLASHING
BEACON
DOES
Open
circuit
in
wiring.
4.
Test
circuit
from
lamp
NOT
LIGHT
(Cont).
to
flasher
for
continuity.
If
no
continuity
is
present.
re-
pair
or
replace
wiring.
If
continuity
is
present.
pro-
ceed
to
Step
5.
Defective
switch.
5.
Check
voltage
at
flasher
with
master
and
beacon
switch
on. Should
read
bat-
tery
voltage.
Replace
switch.
If
voltage
is
present,
pro-
ceed
to
Step
6.
Defective
flasher.
6.
Intall
new
flasher.
FLASHING
BEACON
Defective
flasher.
1.
Install
new
flasher.
CONSTANTLY LIT.
ALL
NAV LIGHTS
OUT.
Short
circuit
in
wiring.
1.
Inspect
circuit
breaker.
If
open. proceed
to
Step
2.
If
ok.
proceed
to
Step
3.
Defective
wiring.
2.
Isolate
and
test
each
nav
light
circuit
until
short
is
located.
Repair
or
replace
wiring.
Defective
switch.
3.
Check
voltage
at
nav
light
with master
and
nav
light
switches
on.
Should
read
bat-
tery
voltage.
Replace
switch.
ONE
NAV
LIGHT
OUT.
Lamp
burned
out.
1.
Inspect lamp.
Replace
lamp.
Open
circuit
in
wiring.
2.
Test
wiring
for
continuity.
Repair
or
replace
wiring.
WARNING
The
anti-collision
system
is a
high voltage
device.
Do
not
remove
or
touch
tube
assembly
while
in
operation.
Wait
at
least
5
minutes after
turning
off
power
before
starting
work.
1642
MODEL
172
SERIES SERVICE
MANUAL
16-46.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
BOTH
ANTI-COLLISION
Open
circuit
breaker.
1.
Check.
if
open
reset.
If
STROBE
LIGHTS
WILL
circuit
breaker
continues
to
NOT LIGHT.
open
proceed
to
Step
2.
2.
Disconnect
red
wire
be-
tween
aircraft
power
supply
(battery/external
power) and
strobe
power
supplies,
one
at
a
time.
If
circuit
breaker
opens on
one
strobe
power
supply,
replace
strobe
power.
If
circuit
breaker
opens
on
both
strobe
power
sup-
plies
proceed
to
Step
3.
If
circuit
breaker
does
not
open
proceed
to
Step
4.
3.
Check
aircraft
wiring.
Repair
or
replace
as
nec-
essary.
4.
Inspect
strobe
power
supply
ground
wire
for
con-
tact
with
wing
structure.
CAUTION
Extreme
care should
be
taken
when
exchanging
flash
tube.
The
tube
is
fragile
and
can
easily
be
cracked
in
a
place
where
it
will
not
be
obvious
visually.
Make
sure
the
tube
is
seated
properly
on
the
base
of
the nav
light
assembly
and
is
centered
in
the
dome.
NOTE
When
checking
defective
power
supply
and
flash
tube,
units
from
opposite
wing
may
be
used.
Be
sure
power
leads are
protected
properly
when
unit
is
removed
to
prevent short
circuit.
16-43
MODEL
172
SERIES
SERVICE
MANUAL
16-46.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
ONE
ANTI-COLLISION
Defective
Strobe
Power
1.
Connect
voltmeter
to
red
STROBE
LIGHT
WILL
Supply.
or
flash
tube.
lead
between
aircraft
power
NOT
LIGHT.
supply
(battery/external
power)
and
strobe power supply.
con-
necting
negative
lead
to
wing
structure.
Check
for
12
volts.
thru
1977
models and
24
volts
beginning
with
1978
models.
If
ok
proceed
to
Step
2
If
not,
check
aircraft
power
supply
(battery/
external
power).
2.
Replace
flash
tube
with
known
good
flash
tube.
If
system
still
does
not
work.
replace strobe
power
supply.
DOME
LIGHT
TROUBLE.
Short
circuit
in
wiring.
1.
Inspect
circuit
breaker.
If
circuit
breaker
is
open.
proceed
to
Step
2.
If
circuit
breaker
is
ok.
proceed
to
Step
3.
Defective
wiring.
2.
Test
circuit
until
short
is
located.
Repair
or
replace
wiring.
3.
Test
for
open
circuit.
Repair
or
replace
wring.
If
no
short
or
open
circuit
is
found.
proceed
to
Step
4.
Lamp
burned
out.
4.
Test lamp with
ohmmeter
if
defective.
Replace
lamp.
Defective
switch.
5.
Check
for
voltage
at
dome
light
with
master
and
dome
light
switch
on. Should
read
battery
voltage.
Replace
switch.
INSTRUMENT
LIGHTS
Short
circuit
in
wiring.
.
Inspect
circuit
breaker.
WILL
NOT
LIGHT.
If
open, proceed
to
Step
2.
If
ok.
proceed
to
Step
3.
Defective
wiring.
2.
Test
circuit
until
short
is
located.
Repair
or
replace
wiring.
16-44
MODEL
172
SERIES
SERVICE
MANUAL
16-46.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
INSTRUMENT LIGHTS
Defective
wiring.
3.
Test
for
open
circuit.
WILL
NOT
LIGHT (Cont).
Repair
or
replace
wiring.
If
no
short
or
open
circuit
is
found,
proceed
to
Step
4.
Faulty
section
in
dim-
4.
Lights
will
work
when
ming
potentiometer.
control
is
placed
in
brighter
position.
Replace
potentiometer.
Faulty light
dimming
5.
Test
both
transistors
transistor. with
new
transistor.
Replace
faulty
transistor.
Faulty
selector
switch.
6.
Inspect. Replace switch.
INSTRUMENT
LIGHTS
Open
resistor
or
wiring
1.
Test
for
continuity.
Re-
WILL
NOT
DIM.
in
minimum
intensity
end
place
resistor
or
repair
of
potentiometer.
wiring.
Shorted
transistor.
2.
Test
transistor
by
substitu-
tion.
Replace
defective
trans-
istor.
CONTROL WHEEL
MAP
Nav
light
switch
turned
off.
1.
Nav light
switch
has
to
LIGHT
WILL
NOT
LIGHT.
be
ON
before
map
light
will
light.
Short
circuit
in
wiring.
2.
Check lamp
fuse
on
ter-
minal
board
located
on
back
of
stationary
panel
with
ohm-
meter.
If
fuse
is
open.
proceed
to
Step
3.
If
fuse
is
ok.
pro-
ceed to
Step
4.
Defective
wiring.
3.
Test
circuit
until
short
is
located.
Repair
or
replace
wiring.
4.
Test
for
open
circuit.
Repair
or
replace
wiring.
If
a
short
or
open
circuit
is
not
found,
proceed
to
Step
5.
Defective
map
light
5.
Check
voltage
at
map
assembly.
light
assembly
with
master
and
nav
switches
on.
If
bat-
tery
voltage
is
present.
re-
place
map
light
assembly
16-45
MODEL
172
SERIES SERVICE
MANUAL
16-47.
LANDING
AND
TAXI
LIGHT.
(THRU
17275034
AND
F17202135.)
16-48.
DESCRIPTION.
The
landing
and
taxi
light
is
mounted
in
the
nose
cap
of
the
lower cowl.
The
lamp
is
controlled
by
a
rocker
type
switch
on
the
instrument
panel.
A
circuit
breaker
on
the
panel
protects
the
system.
16-49.
REMOVAL
AND
INSTALLATION.
(See
figure
16-6.)
a.
Remove
upper
half
of
engine
cowl.
b.
Disconnect
lamp
wires
then
remove
lower
half
of
cowl.
c.
Remove
screws
(7)
and
remove lamp
assembly.
NOTE
Note
position
and
number
of
washers-between
support
(2)
and
bracket
(3).
d.
Remove
screws
(9)
then
remove
gaskets
(5)
and
lamp.
e.
To
install
reverse
the
preceding
steps.
16-50.
ADJUSTMENT
OF
LANDING
AND
TAXI
LIGHT.
(THRU
17275034
AND
F17202134.)
(See
figure
16-6.)
Adjustment
of
the
landing
and
taxi
light
is
pre-set
at
the
factory,
however
changes
to
this
adjustment
may
be
made
as
desired
by
adding
or
subtracting
from
the
number
of
washers
(8).
A
maximum
of two
washers
may
be
used.
16-51.
LANDING
AND
TAXI LIGHTS
(DUAL).
16-52.
DESCRIPTION.
Thru
17275034
and
F17202134
the
landing
and
taxi lights
are
cowl
mounted.
Beginning
with
17275035
and
F17202135,
the
landing
and
taxi
lights
are
wing-mounted. The
left
hand
light
is
used
for
taxi
and the
right
hand
for
landing.
Two
rocker
type
switches
on
the
pilots
switch
panel
control
the
lights.
A
20
amp
circuit
breaker
is
installed
to
protect
the
system.
See
figure
16-6
for
adjustment.
NOTE
On
Aircraft
Serials
17261899
thru
17270181
and
F17201035
thru
F17201675,
refer
to
Cessna
Single-Engine
Service
Letter
SE78-15
dated
March
20.
1978.
16-53.
-
REMOVAL
AND
INSTALLATION.
(See
figure
16-6.)
a.
THRU
17275034
AND
F17202134.
1.
Remove
screws
(1)
and
pull
bracket
assembly
(2)
from
nose
cap
to
gain access
to
electrical
leads.
2.
Disconnect
electrical
leads
from
lamps
making
sure
switches
are
off
and
leads
do
not
short
out.
3.
Remove
screws
(9)
from
plate
(7)
and
remove
lamp
assembly
from
bracket
(2).
If
left
hand
(taxi)
light
is
being
removed,
not
position
of
spacers
(3)
and
(11)
for
reinstallation.
4.
Remove
screws
(10)
from
bracket
(4)
and
remove
gaskets
and
lamp.
5.
Install
new
lamp
reassemble.
b.
BEGINNING
WITH
17275035
AND
F17202135.
1.
Remove
screws
(2)
and
remove
lens
assembly
(1).
2.
Remove
screws
(3)
and remove
brackets
(4)
and
(5).
3.
Pull
lamp
(6)
forward
and
disconnect
electrical
leads.
4.
If
plates
(8)
are
to
be
removed,
remove
screws
(7),
plates
(8),
and
spacers
(9),
(10).
(11),
(12).
(13),
and
(14).
Note
position
of
spacers
for
reinstallation.
5.
To
install,
reverse
the
preceding
procedure.
16-46
MODEL
172
SERIES
SERVICE
MANUAL
A
Park
the
aircraft
3
feet
from
a wall
or
any
suitable
light
reflecting
surface
(distance
is
measured between
landing
light
and
wall).
With
the
nose
gear
shock
strut
extended
2
5
inches,
the
center
of
the
landing
light
beam
on
the
wall
should
be
35
3/4
inches
above
the
floor.
4
Detail
A
1.
Landing
Light
Support
2.
Bracket
Assembly
3.
Plate
4.
Lamp
5.
Gasket
6.
Bracket
7.
Adjustment
Screw
8.
Washer
9.
Screw
Figure
16-6.
Landing
and
Taxi
Light
Installation
(Sheet
1
of
3)
16-47
MODEL
172
SERIES SERVICE
MANUAL
OPTIONAL
A
A
minimum
of
one
gasket
and
a
maximum
of
two
(2)
gaskets
may
be
installed
to
secure
lamp.
the
center
of
the
landing
light
7.
Plate
beam
(right
hand)
on
the
wall
When
landing
or taxi
light
are
8.
Nose
Cap
should be 35 3/4 inches
above
removed
be
sure
to
note
position
9.
ScreW
Park
the
aircraft
3
feet
from
1.
Screw
a
wall
or
any
suitable
light
Detail
A
2.
Bracket
Assembly
reflecting surface
(distanc
e
is
.
Spacer
measured
between landing
light
4.
Bracket
and
wall).
With
the
nose
gear
shock
strut
extended
2
inches,
NOTE
the
center
of
the
landing
light
beam
(right
hand)
on
the
wall
When
landing
or
taxi
light
are
8.
Nose
Cap
should
be
35
3/4
inches
above
removed
be
sure
to
note
position
9.
Screw
the
floor.
The
center
of
the
taxi
of
spacers
for
reinstallation
10.
Screw
light
beam,
(left
hand)
on
the
11.
Washer
wall
should
be
32
1/8
Inches
above
the
floor.
Figure
16-6.
Landing
and
Taxi
Light
Installation
(Sheet
2
of
3)
16-48
MODEL
172
SERIES
SERVICE
MANUAL
Park
the
aircraft
on
a
level
surface
in
front
of
a light
re-
flecting
surface.
Distance
from surface
to
be
three
feet
measured
from
the
front
spar
bottom
rivet
line.
The
aircraft
waterline
shall
be
level.
the
center
of
the
light
beam
above
ground
shall
be;
landing
light
74.41
inches
and
taxi
light
73.29
inches.
Add
AN960-10
washers
between
and
plate
to
obtain
proper
adjustment.
1.
Lens
Assembly
2.
Screw
9.
Spacer
3.
Screw
10.
Spacer
4.
Bracket
11.
Spacer
5.
Bracket
12.
Spacer
6.
Lamp
13.
Spacer
7.
Screw
14.
Spacer
8.
Plate
15.
Nutplate
Figure
16-6.
Landing
and
Taxi
Light
Installation
(Sheet
3
of
3)
16-49
MODEL
172
SERIES SERVICE
MANUAL
16-54.
NAVIGATION
LIGHTS.
16-55.
DESCRIPTION.
The
navigation
lights
are
mounted
on
each
wing
tip
and
the
aft
end
of
the
vertical
fin
tip.
The
lights
are
controlled
by
a
rocker
type
switch
located
on
the
instrument
panel.
A
circuit
breaker
is
installed
on
the
panel
to
protect
the
system.
16-56.
REMOVAL
AND
INSTALLATION.
For
removal
and
installation
of
the
navigation
lights.
see
figure
16-7.
16-57.
ANTI-COLLISION
STROBE
LIGHTS.
16-58.
DESCRIPTION.
A
white
strobe
light
may
be
installed
on
each
wing
tip
with
the
navigation
lights.
Strobe
lights
are
vibration
resistant
and
operate
on
the
principle
of
a
capacitor
discharge
into
a
xenon
tube,
producing
an
extremely
high
intensity
flash.
Energy
is
supplied
to
the
lights
from
individual
power
supplies
mounted
on
each
wing
tip
rib.
16-59.
REMOVAL AND
INSTALLATION.
For
removal
and
installation
of
strobe
light
and
power
supply,
see
to
figure
16-7.
WARNING
This anti-collision
system
is a
high
voltage
device.
Do
not
remove
or touch
tube
assembly
while
in
operation.
Wait
at
least
5
minutes
after
turning
off
power
before
starting
work.
16-60.
OPERATIONAL REQUIREMENTS
(THRU
1977
MODELS).
CAUTION
The
capacitors
in
the
strobe
light
power
supplies
must
be
reformed
if
not
used
for
a
period
of
(6)
months.
The
following procedure
must
be
used.
Connect
the
power
supply,
red
wire
to
plus.
black
to
ground
to
6
volt
DC
source.
Do
not
connect
strobe
tube.
Turn
on
6
volt
supply.
Note
current
draw
after
one
minute.
If
less
than
1
ampere.
continue
operation
for
24
hours.
Turn
off
DC
power
source.
Then
connect
to
proper
voltage.
12
volt.
Connect
tube
to
outputof
strobe
power
supply
and
allow
to
operate.
flashing.
for
15
minutes.
Remove
strobe tube.
Operating
power
supply
at
12
volts,
note
the
current
drain
after
one
minute.
If
less
than
0.5
amperes.
operate
for
6
hours.
If
current
draw
is
greater
than
0.5
amperes,
reject
the
unit.
16-61.
FLASHING
BEACON.
16-62.
DESCRIPTION.
The
flashing
beacon
light
is
attached
to
the
vertical
fin tip.
The lamp
is
iodine-vapor,
electrically
switched
by
a
solid-state
flasher
assembly.
The
flasher
assembly
is
mounted
in
the
aft
section
of
the tailcone.
The
switching
frequency
of
the
flasher
assembly
operates
the
beacon
at
approximately
45
flashes
per
minute.
A
1.5
ohm
resistor
is
installed
thru
1977
models
and
a
6
ohm
resistor
is
installed
to
eliminate
a
pulsing
effect
on
the
cabin
lighting
and
ammeter.
16-63.
REMOVAL AND
INSTALLATION.
For removal
and
installation
of
flashing
beacon,
see
figure
16-8.
16-50
MODEL
172
SERIES SERVICE
MANUAL
1.
Electrical
Leads
10.
Flash
Tube
Assembly
Detail
B
2.
Cap
11.
Screw
THRU
17268211
3.
Washer
12.
Lens
Retainer
4.
Insulated
Washer
13.
Lens
5.
Spring
14.
Bulb
6.
Insulator
15.
Seal
7.
Wing
Tip
16.
Mount
8.
Receptacle
17.
Wing
Tip
Rib
9.
Gasket
18.
Power
Supply
Figure
16-7.
Navigation
and
Anti-Collision
Strobe
Light
Installation
Revision
3
16-51
MODEL
172
SERIES
SERVICE
MANUAL
THRU
17272894
BEGINNING
WITH
17272895
1. Dome
10.
Tip
Assembly
-
Fin
Detail
A
2.
Gasket
11.
Housing-
Plug
3.
Lamp
12.
Housing-
Cap
4.
Screw
13.
Fin
Assembly
5.
Baffle
14.
Flasher
Assembly
6.
Clamp
Assembly
15.
Bulkhead
7.
Plate
-
Mounting
16.
Resistor
8.
Socket
Assembly
17.
Spacer
9.
Nut
Plate
18.
Z
Bracket
Figure
16-8.
Flashing
Beacon
Light
Installation
(Sheet
1
of
2)
16-52
MODEL
172
SERIES
SERVICE
MANUAL
3
NOTE
When
installing
lamp
be
sure
socket.
assembly
is
installed
in
8
mounting plate
so
lamp
may
be
installed
with
filament
perpendicu-
lar
to
the
longitudinal
axis
of
the
aircraft
Detail
C
BEGINNING
WITH
17273742
AND F17202000
Figure
16-8.
Flashing
Beacon
Light
Installation
(Sheet
2
of
2)
16-53
MODEL
172
SERIES SERVICE
MANUAL
16-64.
INSTRUMENT
AND
DOME
LIGHTS.
16-65.
DESCRIPTION.
The
instrument
flood
light
and
dome
light
are
installed
in
the overhead
console.
The
dome
light consists
of
a
frosted
lens
and
a
single
bulb
controlled
by a
switch
mounted
forward
of
the
light.
The
instrument
flood
light
consists
of
a
red
lens
and
a
single
bulb
controlled
by
an
off/on
switch
mounted
aft
of
the
light.
Intensisty
of
the
lamp
is
controlled
by
a
rheostat
switch
located
on
the
instrument
panel.
16-66.
REMOVAL
AND
INSTALLATION.
For
removal
and
installation
of
instrument
and
dome
light,
see
figure
16-9.
16-67.
COURTESY
-LIGHTS.
16-68.
DESCRIPTION.
The
courtesy
lights
are mounted
in
the
underside
of
each
wing,
inboard
of
the
upper
wing
strut
attach.
The
light
consists
of
a
lens
socket
and
a
single
bulb.
The
lights
are controlled
by
the
dome
light
switch.
16-69.
REMOVAL
AND
INSTALLATION.
For
removal
and
installation
of
the courtesy
lights.
see
figure
16-9.
16-70.
COMPASS
AND
RADIO
DIAL
LIGHTING.
16-71.
DESCRIPTION.
The
compass
and radio
dial
lights
are
contained
within
the
individual
units.
The
lights
are controlled
by
the
instrument
flood
light
switch
on
the overhead
console.
Intensity
is
controlled
by
a
rheostat
located
on
the
instrument
panel.
16-72.
INSTRUMENT
POST
LIGHTING.
16-73.
DESCRIPTION.
Individual
post
lighting
may
be
installed
to
provide non-glare
instrument
lighting.
The
post
light
consists
of
a
cap and
a
clean
lamp
assembly
with
a
tinted
lens
bonded
to
the
decorative covers. The
intensity
of
the
post
lights
is
controlled
by
the
radio
light
dimming
rheostat
located
on
the
instrument
panel.
16-74.
REMOVAL
AND
INSTALLATION.
For removal
and
installation
of
post
lamp.
slide
the
cap
and
lens
assembly
from
the
base.
Slide
the
lamp
from
the
socket
and
replace.
NOTE
When
installing
postlight
assemblies,
assemblies
shall
be
coated
with
RTV-102,
General
Electric, Waterford,
New
York.
on
forward
side
of
panel
where
postlight
could
come
in
contact
with
sheet
metal subpanel.
This
coating
shall
insulate postlight
assembly
from
contact with
airplane
structure.
Maximum
coating
thickness
to
be
.03.
16-54
MODEL
172
SERIES
SERVICE
MANUAL
16-74A.
TROUBLE
SHOOTING
-
POSTIGHTING.
TROUBLE
PROBABLE
CAUSE
REMEDY
LAMP
WILL NOT LIGHT.
Defective
lamp.
1.
Test
lamp
with ohmmeter
or
replace
with
a
new
lamp.
If lamp
is
OK,
proceed
to step
2.
Defective
socket
or
open
2.
With
switch
on,
test
socket.
If
circuit.
defective,
replace
socket
or
wiring.
ONE
SECTION
OF
LAMPS
Defective
connector.
1.
Test
for
voltage
on
lamp
side
WILL
NOT
LIGHT.
of
connector.
If
voltage
is not
present,
check
opposite
side
of
connector.
If voltage
is
present.
replace
pins
and
sockets
as
neces-
sary.
If
voltage
is
not
present,
check connections
at terminal
block.
Defective
circuit
in
dimming
2.
Refer
to
paragraph
16-74B.
assembly.
Defective
rheostat.
3.
Check
voltage
at
output
side
of
rheostat
with
battery
switch
on.
Should
read
battery
voltage
with
rheostat
turned
full
clockwise.
Voltage
should
decrease
as
rheo-
stat
is
turned
counterclockwise.
If
no
voltage
is
present
or
voltage
has
a
sudden
drop
before
rheostat
has
been
turned
full
counterclock-
wise
replace
rheostat.
ALL
LAMPS
OUT.
Open
circuit
breaker.
1.
With
battery switch
on,
check
circuit
breaker.
Reset if
open.
If
circuit
breaker
is
set,
check
volt-
age
at
output
side
of
breaker.
If
no
voltage
is
present,
replace
cir-
cuit
breaker.
LAMPS
WILL
NOT
DIM.
Defective
resistor
or
rheostat.
1.
Check
resistor
and
rheostat
for
continuity
and
resistance
value.
Also,
check
transistors
for
partial
short.
Refer to
paragraph
16-74B.
Replace
rheostat
and
transistor.
16-54A
MODEL
172
SERIES
SERVICE
MANUAL
16-74B.
TROUBLE
SHOOTING
-
TRANSISTOR
BEAT
SINK. Remove
heat
sink
from
airplane.
Check
transistors
for opens
and
shorts,
check
transistor
sockets
for
evidence
of
shorting
out
against
heat
sink,
especially
on
the
bottom
side.
Check
that
legs
of
transistor
socket
have
not
been
bent
up
against
heat
sink.
If
this
has
happened. you
may
see
burned
spot
on
the
socket
leg.
If
the
transistor
sockets
and
wiring
appear
to
be
in
good
condition
install
trans-
istor
back
in heat
sink
and
make
a
continuity
check.
Attach
one
lead
of
an ohmmeter
to
the
heat
sink
then
check
every
pin
of
the
pigtail
plug
with
the
other
lead
for continuity.
(These
should
not
be
continuity).
If
continuity
is
found,
this
will
burn
out
transistors
immediately.
16-75.
TRANSISTORIZED
LIGHT
DIMMING.
16-76.
DESCRIPTION.
A
remotely
located,
two-circuit
transistorized
dimming
assembly
is
installed
to
control
instrument
lighting.
One
circuit
controls
the
compass
light.
map
light
and
instrument
flood
lights.
The
other
circuit
controls
radio
lighting.
A
concentric knob
arrangement
on
a
dual
rheostat
assembly
mounted on
the
instrument
panel.
16-77.
REMOVAL AND
INSTALLATION.
For
removal
and
installation
of
transistorized
dimming
assembly,
see
figure
16-10.
16-77A. TROUBLE
SHOOTING
-
HEAT
SINK.
Refer to
paragraph
16-74B.
16-54B
MODEL
172
SERIES SERVICE
MANUAL
Detail
B
1.
Tinnerman
Nut
7.
Machine
Screw
13.
Washer
2.
Tinnerman
Screw
8.
Grommet
14.
Nut
Plate
3.
Reflector
9.
Nut
15.
Socket
4.
Lamp
10.
Support
16.
Switch
5.
Lens
11.
Pin
17.
Seal
6.
Cover
12.
Adjustment
Screw
18.
Plug
Button
19.
Lens
Retainer
Figure
16-9.
Instrument,
Dome
and
Courtesy
Light
Installation
16-55
MODEL
172
SERIES
SERVICE
MANUAL
4.
Knob
(Radio)
5.
Mounting
Bracket
6.
Screw
7.
Insulator
8.
Transistor
*
THRU
17269308
9.
Washer
AND
F17201638
10.
Relay
11.
Diode
Board
12.
Diode
Figure
16-10.
Transistorized
Dimming
16-56
MODEL
172
SERIES SERVICE
MANUAL
16-78.
MAP
LIGHTING.
16-79.
DESCRIPTION.
White
map
lighting
and red
non-glare
instrument
lighting
are
provided
by
an
adjustable
light
mounted
on
the
upper
forward
part
of
the
left
door
post.
The
switch
is a
three
position
type
with
red.
white and
off
positions.
The
map
light contains
a
white
bulb
for
general purpose
lighting
and
a
red
bulb
for
adjustable
instrument
lighting.
The
intensity
of
the red bulb
is
controlled
by
the
center
portion
of
a
concentric
knob
arrangement thru
a
dual
rheostat
assembly
located
on
the
pilot's
switch
panel.
16-80.
REMOVAL
AND INSTALLATION.
(See
figure
16-11.)
a.
For
replacement
of
defective
lamp
slide
the
hood
and
lens
from
the
map
light
assembly
and
remove
the
bayonet
type
bulb.
b.
For
removal
of
the
map
light
assembly,
remove
the
screws
from
the
front
door
post
shield.
Remove
the
washer
and
nut
attaching
the map
light
Remove
the
ground
wire
from
the
map
light
screw. Detach
the
wires
at
the
quick
disconnect
fasteners
and
remove
the map
light
assembly.
16-81.
CONTROL
WHEEL
MAP LIGHT.
16-82.
DESCRIPTION.
The
control
wheel
map
light
is
mounted
on
the
lower
side
of
the
control
wheel.
Light
intensity
is
controlled
by
a
rheostat.
For
dimming
the
rheostat
should
be
turned
clockwise.
16-83.
REMOVAL
AND
INSTALLATION. (See
figure
16-12,
sheet
1
of
2)
(THRU
17275674)
a.
For
easy
access
to
map
light
assembly
rotate
control
wheel
90
° .
b.
Label the
wires
connected
to
the
map light
assembly
(terminal
block)
and
remove
screws
securing
wires
to
the
terminal
block.
c.
The
assembly
is
now
free for
removal,
Remove
the
two
screws
securing
the
map
light
to
the
control
wheel
and
remove
map
light
assembly.
d.
For
reassembly
reverse
this
procedure.
16-83A.
REMOVAL
AND
INSTALLATION.
(See
figure
16-12,
sheet
2
of
2)
BEGINNING
WITH
17275675)
a.
For
easy
access
to
map
light
assembly
rotate
control
wheel
90
° .
b.
To
remove
lamp
press
in and
rotate
counterclockwise.
c.
To
remove
rheostat
remove
screws
securing
bracket
(10).
d.
Disconnect
electrical
leads
from
rheostat
(8).
e.
Eor reassembly
reverse
this
procedure.
16-84.
PITOT
HEATER.
16-85.
DESCRIPTION.
An
electrical
heater
unit
is
installed
in
some
pitot tubes.
The
heater
offsets
the
possibility
of ice
formations
on
the
pitot
tube.
The
heater
is
integrally
mounted
in
the
pitot
tube
and
is
operated
by
a
switch
on
the
instrument
panel.
(See
figure
16-13.)
16-86.
CIGAR
LIGHTER.
16-87.
DESCRIPTION.
Thru
17275035
and
F17202135
the
cigar
lighter
(located
on
the
instrument
panel)
is
equipped
with
a
thermal-actuated
circuit
breaker
16-57
MODEL
172
SERIES
SERVICE
MANUAL
4
6
13 10
1.
Nut
2.
Washer
3.
Grommet
4.
Adjustment
Screw
5.
Maplight
Assembly
6.
Socket
Assembly
7.
Lamp
8.
Red Lamp
9.
Lens
10.
Hood
11.
Screw
12.
Front
Doorpost Shield
13.
Maplight
Switch
14.
Insulator
Figure
16-11.
Map
Light
Installation
16-58
MODEL
172
SERIES
SERVICE
MANUAL
1.
Fuse
2.
Nut
3.
Washer
4.
Control
Wheel
Assembly
9
5.
Spacer
6.
Map
Light
Assembly
7.
Cover
8.
Screw
9.
Clamp
10.
Cable
Assembly Detai
A
11.
Lamp
THRU
17275674
Figure
16-12.
Control
Wheel
Map
Light
Installation
(Sheet
1
of
2)
16-59
MODEL
172
SERIES SERVICE
MANUAL
7
6
5
12
1.
Fuse
2.Nut
BEGINNING
WITH 17275675
3.
Washer
4.
Control
Wheel
Assembly
5.
Insert
6.
Map
Light
Assembly
7.
Pad
8.
Rheostat
9.
Insert
10.
Bracket
11.
Knob
12.
Setscrew
13.
Screw
14.
Clamp
15.
Cable
Figure
16-12.
Control
Wheel
Map
Light
Installation
(Sheet
2
of
2)
16-60
MODEL
172
SERIES
SERVICE
MANUAL
1.
Electrical
Leads
Detail
A
2.
Pitot
Tube
3.
Heating
Element
Figure
16-13.
Heated
Pitot Installation
1.
Decorative
Cover
2.
Screw
3.
Instrument Panel
4.
Clock
Figure
16-14.
Digital
Clock
Installation
16-60A/(16-60B
blank)
MODEL
172
SERIES
SERVICE
MANUAL
which
is
attached
to
the
rear
of
the
cigar lighter.
The
circuit
breaker
will
open
if
the
lighter
becomes
jammed
in
the
socket
or
held
in
position
too long.
The
circuit breaker
may be
reset
by
inserting
a
small
probe
into
the
.078
diameter
hole
in
the
back
of
the
circuit
breaker
and
pushing
lightly
until
a
click
is
heard.
CAUTION
Make
sure
master
switch
is
"OFF"
before
inserting
probe
into
circuit
breaker
on
cigar
lighter
to
reset
1687A.
CLOCK.
16-87B.
DECRIPTION.
Thru
1978
Models
an
electric
clock
may
be
installed
in
the
aircraft.
During
the
1979
Models
a
digital
clock
may
be
installed.
The
digital
clock
has
the
capability
of
date
and
second
rea
out
as
well
as
time. Both clocks
are
installed
in.
the
instrument
panel
in
the
same
manner,
see
figure
16-14.
16-88.
EMERGENCY
LOCATOR
TRANSMITTER.
(THRU
17268576)
16-89.
DESCRIPTION.
The
ELT
is a
self-contained, solid
state
unit,
having
its
own
power
supply.
with
an
externally
mounted
antenna.
The
C589511-0209
transmitter
is
designed
to
transmit
simultaneously
on
dual
emergency
frequencies of
121.5
and
243.0
Megahertz. The
C589510-
0211
transmitter
thru
17265192
and the
C589510-0212
beginning
with
17265193
used
for
Carnadian
registry,
operates
on
121.5
only. The
unit
is
mounted
in
the
tailcon,
aft
of
the
bag-
gage
curtain
on
the
right
hand
side.
The
transmitters
are
designed
to provide
a
broadcast
tone
that
is
audio
modulated
in a
swept
manner
over
the
range
of
1600
to 300
Hz
in a
dis-
tinct,
easily
recognizable
distress
signal
for
reception
by
search
and
rescue
personnel
and
others
monitoring
the
emergency
frequencies.
Power
is
supplied
to
the
transmitter
by
a
bat-
tery-pack
which
has the
service
life of
the
batteries placarded
on
the
batteries
and
also
on
the
outside
end
of
the
transmitter.
ELT's
are
equipped
with
a
battery-pack
containing
alkline
"D"
size
batteris
batteries
(See
figure
16-13).
The
ELT
exhibits
line
of
sight
trans-
misson
characteristics
which
correspond
approximately
to
100
miles
at
a
search
altitude
of
10,000
feet.
When
battery
inspection
and
replacement schedules
are
adhered
to,
the
trans-
mitter
will
broadcast
an
emergency
signal at
rated
power
(75
MW-minimum),
for
a
continu-
ous
period
of
time
as
listed
in
the
following
table.
TRANSMITTER
LIFE
TO
75
MILLIWATTS
OUTPUT
4
Cell
Temperature
Lithium
Battery
Pack
+130°F
115
hrs
+
70°F
115
hrs
-
4°F
95
hrs
-
40°F
23
hrs
Battery-packs
have
a
normal
shelf
life
of
five
to
ten
(5-10)
years
and
must
be
replaced
at
1/2
of
normal
shelf
life
in
accordance
with
TSO-C91.
Cessna
specifies
5
years
replacement
of
lithium
(4-cell)
battery
packs.
16-61
MODEL
172
SERIES
SERVICE
MANUAL
16-90.
OPERATION.
A
three
position
switch
on
the
forward
end
of
the
unit controls
operation.
Placing the switch
in
the
ON
position
will
energize
the
unit
to
start
transmitting
emergency
signals.
In
the
OFF
position,
the
unit
is
inoperative.
Placing
the
switch
in
the
ARM
position
will
set
the
unit
to
start
transmitting
emergency
signals
only
after the
unit
has
received
a
5g
(tolerances
are
-2g and
-0g)
impact
force,
for
a
duration
of
11-16
milliseconds.
NOTE
Transmitter
is
also
attached
to
the
mounting
bracket
by
velcro
strips:
pull
transmitter
to
free
from
mounting
bracket
and
velcro.
CAUTION
Do
not
leave
the
emergncy
locator
transmitter
in
the
ON
position
longer
than
1
second
(3
sweeps
of
the
warble
tone)
or
you may
activate
downed
aircraft
procedures
by
C.A.P.,
D.O.T.
or
F.A.A.
personnel.
16-91.
CHECKOUT
INTERVAL
100
HOURS
OR
THREE
MONTHS,
WHICHEVER
COME
FIRST.
a.
Turn aircraft
master
switch
ON.
b.
Turn
aircraft
transceiver
ON
and
set
frequency
on
receiver
to
121.5
MHz.
c.
Remove
the
ELT's
antenna
cable
from
the
ELT
unit.
d.
Place
the
ELTs
function
selector
switch
in
the
ON
position
for
1
second
or
less.
Im-
mediately
replace
the
ELT
function
selector
switch
in
the
ARM
position
after
testing
ELT.
e.
Test
should
be
conducted
only
within
the
time
period
made
up
of
the
first
five
min-
utes
after
any hour.
CAUTION
Tests
with
the
antenna
connected
should
be
approved
and
confirmed
by
the nearest
control tower.
The
FAA/DOT
al-
lows
free space
transmission
tests
from
the
airplane
any-
time
within
five
minutes
after
each
hour.
The
tst
time
allowed
is
generally three
sweeps
of
the
warble
tone,
or
approximately
one
second.
The
control
tower
should
be
notified
that
a
test
is
about
to
be
performed.
NOTE
After
accumulated
test
or
operation
time
equals
1
hour,
battery-pack
replacement is
required
Do
Not
use
substi-
tute
battery-pack.
f.
Check
calendar
date
for
replacement
of
battery-pack.
This
date
is
supplied
on
a
sticker
attached
to
the
outside
of
the
ELT
case
and
to
each
battery.
16-92
REMOVAL
AND
INSTALLATION
OF
TRANSMITTER
(See
figure
16-15.)
a.
Remove
baggage
curtain
to
gain
access
to
the
transmitter
and
antenna
b.
Disconnect
co-axial
cable
from
end
of
transmitter.
c.
Cut
sta-strap securing
antenna
cable and
unlatch
metal
strap
to remove
transmitter.
16-62
MODEL
172
SERIES
SERVICE
MANUAL
A
B
NOTE
Metal
Strap (4)
must
be
positioned
so
that
latch
is
on
top
of
transmitter as
installed
in
the
aircraft
and
not
across
transmitter
13
cover.
1.
Tailcone
Skin
9.
Connector
2.
Bracket
10.
Arm
Switch
3.
Fabric
Fastener
-
Hook
11.
Co-axial
Cable
4.
Metal
Strap
12.
Sta-strap
5.
Fabric
Fastener
-
Pile
13.
Rubber
Washer
6.
Transmitter
14.
Rubber
Boot
7.
Cover
15.
Antenna
8.
Access
Cover
16.
Doubler
Figure
16-15.
Emergency Locator
Transmitter
Installation
16-63
MODEL
172
SERIES SERVICE
MANUAL
NOTE
To
replace
velcro
strips,
clean surface
thoroughly
with
clean
cloth
saturated
in
one
of
the
following
solvents:
Trichloric
thylene.
Aliphatic
Napthas.
Methyl
Ethyl
Ketone
or Enmar
6094
Lacquer
Thinner.
Cloth
should
be
folded
each time
the
surface
is
wiped
to
present
a
clean
area
and
avoid
redepositing
of
grease.
Wipe
surface
immediately
with
clean dry
cloth,
do
not
allow
solvent
to
dry
on
surface.
Apply
Velcro
#adhesive
to
each surface
in
a
thin
even
coat
and
allow
to
dry
until
quite
tacky. but
no
longer
transfers
to
the
finger
when
touched
(usually
between
5
and
30
minutes).
Porous surfaces
may
require
two
coats.
Place
the
two
surfaces
in
contact
and
press
firmly
together
to
ensure
intimate
contact.
Allow
24
hours
to
complete
cure.
d.
To
reinstall
transmitter,
reverse
preceding steps.
NOTE
An
installation
tool
is
required
to
properly
secure
sta-
strap.
This tool
may
be
purchased
locally
or
ordered
from
the
Panduit
Corporation.
Tinley
Park,
III,
part
number
GS-2B
(Conforms
to
MS90387-1).
CAUTION
Ensure
that
the
direction
of
flight
arrows
(placarded
on
the
transmitter)
are
pointing
towards
the nose
of
the
aircraft.
16-93.
REMOVAL AND
INSTALLATION
OF
ANTENNA.
(See
figure
16-15.)
a.
Disconnect
co-axial
cable
from
base
of
antenna.
b.
Remove
the
nut and
lockwasher
attaching
the
antenna
base
to
the
fuselage
and
the
antenna
will
be
free
for removal.
c.
To
reinstall
the
antenna,
reverse
the
preceding
steps.
NOTE
Upon
reinstallation
of
antenna,
cement
rubber
boot
(14)
using
RTV102.
General Electric
Co.
or
equivalent,
to
antenna
whip
only;
do
not
apply
adhesive
to
fuselage
skin
or
damage
to
paint
may
result.
16-94.
REMOVAL
AND
INSTALLATION
OF
LITHIUM
FOUR
(4)
CELL
BATTERY-PACK.
(See
figure
16-16.)
NOTE
When
existing
battery
fails
or
exceeds
normal
expiration
date,
convert
ELT
System
to
new
D/M
alkaline
powered
ELT
per
Avionics
Service
Letter
AV78-31.
dated
November
10,
1978.
16-64
MODEL
172
SERIES
SERVICE
MANUAL
TRANSMITTER
BATTERY
PACK
C5895100209
C589510-0210
NOTE
A
PVC
spacer
is
installed
in
this
position
on
the
C589510-
0213
battery
pack
used in
the
C589510-0212
transmitter
used
on
Canadian
aircraft
Figure
16-16.
Lithium
4
Cell
Battery
Pack
Installations
16-65
MODEL
172
SERIES SERVICE
MANUAL
NOTE
Transmitters
equipped
with
the
4
cell
battery-pack
can
only
be
replaced
with
another
4
cell
battery-pack.
a.
After the
transmitter
has
been
removed from
aircraft
in
accordance
with
para
16-92.
place
the
transmitter
switch
in
the
OFF
position.
b.
Remove
the
four
screws
attaching
the
cover
to
the
case
and
then
remove
the
cover
to
gain
access
to
the
battery-pack.
NOTE
Retain
the
rubber gasket
and
screws
for
reinstallation.
c.
Disconnect the
battery-pack
electrical
connector
and
remove
battery-pack.
d.
Place
new
battery-pack
in
the
transmitter
with
four
batteries
as
shown
in
the case
in
figure
16-16.
e.
Connect
the
electrical
connector
as
shown
in
figure
16-16.
NOTE
Before
installing
the
new
4
cell
battery-pack,
check
to
ensure
that
its
voltage
is
112
volts
or
greater.
CAUTION
It is
desirable
to
replace
adhesive
material
on
the
4
cell
battery-pack,
use
only
3M
Jet
Melt
Adhesive
#3738.
Do
not
use
other
adhesive
materials
since
other
materials
may
corrode
the
printed
circuit
board
assembly.
f.
Replace
the
transmitter
cover
and
gasket.
g.
Remove
the
old
battery-pack
placard
from
the
end
of
transmitter
and
replace with
new
battery-pack placard
supplied
with
the
new
battery-pack.
CAUTION
Be
sure
to
enter
the
new
battery-pack
expiration
date
in
the
aircraft
records.
It is
also
recommended
this
date
be
placed
in
your
ELT
Owner's Manual
for
quick
reference.
16-95.
TROUBLE
SHOOTING.
Should
your
Emergency Locating
Transmitter
fail
the
100
Hours
performance
checks,
it is
possible
to
a
limited
degree
to
isolate
the
fault
to
a
particular
area
of
the
equipment.
In
performing
the
following trouble
shooting procedures
to
test
peak
effective
radiated
power,
you
will
be
able
to
determine
if
battery replacement
is
necessary
or
if
your
unit
should
be
returned
to
your
dealer
for
repair.
16-66
MODEL
172
SERIES
SERVICE
MANUAL
16-95.
TROUBLE SHOOTING.
TROUBLE
PROBABLE
CAUSE REMEDY
*POWER
LOW
Low
battery
voltage.
1.
Set
toggle
switch
to
off.
2.
Remove
plastic
plug
from
the
remote
jack
and
by
means
of
a
Switchcraft
#750
jack-
plug,
connect
a
Simpson
260
model
voltmeter
and
mea-
sure
voltage.
If
the
battery-
pack
transmitters
is
11.2
volts
or
less,
the
battery-
pack
is
below
specification.
Faulty
transmitter.
3.
If
the battery-pack
volt-
age
meets
the specifications
in
Step
2,
the
battery-pack
is
ok.
If
the
battery
is
ok.
check the
transmitter
as
follows:
a.
Remove
voltmeter.
b.
By
means
of
Switchcraft
#750
jackplug
and
3
inch
maximum
long leads,
connect
a
Simpson
Model
1223
am-
meter
to
the
jack.
c.
Set the
toggle
switch
to
ON
and
observe
the
ammeter
current
drain.
If
the
current
drain
is in
the
85-100
ma
range,
the
transmitter
or
the
co-axial cable
is
faulty.
Faulty
co-axial
4.
Check
co-axial
antenna
antenna
cable.
cable
for
high resistance
joints.
If
this
is
found
to
be
the
case,
the
cable
should
be
replaced.
*This
test
should
be
carried
out
with
the
co-axial
cable
provided
with
your
unit.
16-67
MODEL
172
SERIES
SERVICE
MANUAL
16-96. EMERGENCY
LOCATOR
TRANSMITTER.
(BEGNNING
WITH
17268577)
16-97. DESCRIPTION.
The
ELT
is
a
self-contained,
solid
state
unit,
having its
own
power
supply
with an
externally
mounted
antenna.
The
unit
is
mounted
in
the
tailcone,
aft
of
the baggage
curtain
on
the
right
hand
side.
The
transmitters
are
designed
to provide
a
broadcast
tone
that
is
audio
modulated
in
a
swept
manner
over
the
range
of
1600
to
300
Hz
in a
distinct,
easily
recogniable
distress
signal
for
reception
by
search
and
rescue
personnel
and
others
monitoring
the
emergency
frequencies.
The
ELT
exhibits
line
of
sight
transmission
charac-
teristics
which
correspond
approximately
to
100
miles
at
a
search
altitude
of
10000
feet.
The
C589511-0103
transmitter
on
domestic
aircraft,
and
the
C589511-0104
transmitter
on
aircraft
with
Canadian
registry,
are
used
thru
17271034
and
F17201749.
The
C589511-
0117
transmitter
on
domestic
aircraft,
and
the
C589511-0113
transmitter
on
aircraft
with
Canadian
registry,
are
used
17271035
thru
17275871
and
F17201750
thru
F17202194.
Be
ginning
with
17275915
and
F17202195
the
C589512-0103
transmitter
is
used
on
all
air-
craft.
The
C589511-0104
transmits
on
121.5
MHz
at
25 mw
rated
power
output
for
100
continu-
ous
hours
in
the
temperature
range
of
-40°F
(-40°C
to
+
55°C).
The
C589511-0113
transmits
on
121.5
MHz
at
25
mw
rated
power
output
for
100
continuous
hours
in
the
temperature
range
of
-4°F
to
+
131°F
(-20°C
to
+
55°C).
The
C589511-0103
transmits
on
121.5
and
243.0
MHz
simultaneously at
75
mw
rated
power
output
for
48
continuous
hours
in
the
tempera-
ture
range
of
-40°F
to
+
131°F
(-40°C
to
+
55°C).
The
C589511-0117
and
C58912-0103
transmits
on
121.5
and
343.0
MHz
at
75
mw
rated
power
output
for
48
continuous
hours
in
the
temperature
range
of
-4°F
to
+
131°F
(-20°C
to
55°C).
Power
is
supplied
to
the
transmitter
by
a
battery-pack.
The
C589511-0104
and
C589511-
0103
ELTs
equipped
with
a
lithium
battery-pack
must
be
modified
by
SK185-20
as
outlined
in
Avionics
Service
Letter
AV78-31,
dated
20
November,
to
incorporate
alkaline
battery-
packs.
The
C589511-0114
alkaline
battery-packs
have
the
service
life
of
the
battery-pack
stamped
on
the
battery-pack,
on
the
end
of
the
transmitter
below
the
switch
and
on
top
of
the
transmitter.
The
C589512-0107
alkaline battery-packs
have
the
replacement
date and
date
of
installation
on
the
battery-pack
and
the
replacement
date
on
the
top of
the
transmit-
ter.
16-98.
OPERATION.
A
three
position
switch
on
the
forward
end
of
the
unit
controls operation.
Placing
the
switch
in
the
ON
position
will
energize
the
unitto
starttransmittingemergency
signals.
In
the
OFF
position,
the
unit
is
inoperative.
Placing
the
switch
in
the
ARM
position
will
set
the
unit
to
start transmitting
emergency
signals
only
aftertheunithas
received
a5g
(tolerances
are
-2g
and
-0g)
impact
force,
for
a
duration
of
11-16
milliseconds.
CAUTION
Do
not
leave
the
emergency
locator
transmitter
in
the
ON
position
longer
than
1
second
(3
sweeps
of
the
warble
tone)
or
you may activate
downed
aircraft
procedures
by
C.A.P.,
D.O.T.
or
F.A.A.
personnel.
MODEL
172
SERIES SERVICE
MANUAL
16-99.
CHECKOUT
INTERVAL:
100
HOURS,
OR
THREE
MONTHS.
WHICHEVER
COMES
FIRST.
a.
Turn
aircraft
master
switch
ON.
b.
Turn
aircraft
transceiver
ON
and
set frequency
on receiver
to
121.5
MHz.
c.
Remove
the
ELT's
antenna
cable
from
the
ELT
unit.
d
Place
the
ELT's
function
selector
switch
in
the
ON
position
for
1
second
or
less.
Im-
mediately
replace
the
ELT
function
selector
switch
in
the
ARM
position
after
testing
ELT.
e.
Test
should
be
conducted
only
within
the
time
period
made
up
of
the
first
five
min-
utes
after
any
hour.
CAUTION
Tests
with
the
antenna
connected
should
be
approved
and
confirmed
by
the
nearest
control
tower.
The
FAA/DOT
al-
lows
free
space
transmision
tests
from
the
airplane
any-
time
within
five
minutes
after
each
hour.
The
test
time
allowed
is
generally
three
sweeps
of
the
warble
tone,
or
approxiamtely
one
second
The
control
tower
should
be
notified
that
a
test
is
about
to
be
performed.
NOTE
After accumulated
test
or
operation
time
equals
1
hour,
battery-pack
replacement is
required.
Do
Not
use
substi-
tute
battery
pack.
f.
Check
calendar date
for
replacement
of
battery-pack. This date
is
supplied
on
a
sticker
attached
to
the
outside
of
the
ELT
case
and
to
each
battery.
16-100.
REMOVAL
AND
INSTALLATION
OF
TRANSMITTER.
(See
figure
16-17.)
a.
Remove
baggage
curtain
to
gain
access
to
the
transmitter
and
antenna.
b.
Disconnect
co-axial
cable
from end
of
transmitter.
c.
Remove
the
two
#10
screws
from
the
baseplate
of
the
ELT
and
remove
ELT
d.
To
reinstall
transmitter,
reverse
preceding
steps.
CAUTION
Ensure
that
the
direction
of
flight
arrows
(placarded
on
the
transmitter)
are
pointing
towards
the
nose
of
the
aircraft
16-101.
REMOVAL
AND
INSTALLATION
OF
ANTENNA.
(See
figure
16-17.)
a.
Disconnect
co-axial
cable
from
base
of
antenna.
b.
Remove
the
nut
and
lockwasher
attaching
the
antenna
base
to
the
fuselage
and
the
antenna will
be
free
for
removal.
d.
To
reinstall
the
antenna,
reverse
the
preceding
steps.
CAUTION
The
C589511-0111
and
C589511-0119
co-axial
cable
must
be
installed
as
indicated
on
the
cable
sleeve.
Cable
end
marked
"TO
ANT"
must
be
connected
to
the
ELT
antenna,
and
the
end
marked
"TO
ELT"
must
be
connected
to
the
C589511-0113/ -0117
and
C589511-0103/-0104
transmitters.
16-69
MODEL
172
SERIES SERVICE
MANUAL
12
Detail
A
THRU
17271034
AND
F17201749
1.
Cabin
Skin
7.
Arm
Switch
2.
Bracket
8.
Co-axial
Cable
3.
Transmitter
9.
Rubber
washer
4.
Cover
10.
Rubber
Boot
5.
Screw
11.
Antenna
6.
Battery
Pack
12.
Doubler
Detail
C
13.
Access Cover
ROTATED
180°
Figure
16-17.
Emergency
Locator
Transmitter
Installation
(Sheet
1
of
3)
16-70
MODEL
172
SERIES
SERVICE
MANUAL
PLACARD
Detail
B
ROTATED
180°
Figure
16-17.
Emergency
Locator
Transmitter
Installation
(Sheet
2
of
3)
16-71
MODEL
172
SERIES
SERVICE
MANUAL
PLACARD
11
Detail
A
BEGINNING
WITH
17275872
AND
F17202195
ELT
IS
LOCATED
BEHIND
THIS
SURFACE
PLACARD
LOCATED
ON
RIGHT
HAND
SIDE
OF
TAILCONE
ADJACENT
TO
ELT.
ON CANADIAN
AIRCRAFT.
Detail
C
ROTATED
180°
Figure
16-17.
Emergency
Locator
Transmitter
Installation
(Sheet
3
of
3)
16-72
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
Upon
reinstallation
of
antenna,
cement
rubber
boot
(14)
using
RTV102.
General
Electric
Co.
or
equivalent,
to
antenna
whip
only;
do
not
apply
adhesive
to
fuselage
skin
or
damage
to
paint
may
result.
16-102.
REMOVAL
AND
INSTALLATION
OF
BATTERY
PACK. (See
figure
16-18.)
NOTE
Transmitters
equipped
with
the
C589511-0105
or
C589511-
0106
battery-packs
can
only
be
replaced with
a
C589511-
0114
after
modification
by
SK185-20
has
been
completed.
CAUTION
Lithium
battery-pack
must
be
replaced
with
alkaline
battery-packs
per
SK185-20.
CAUTION
Replacement
battery-packs
other
than
Dorne
and
Margo-
lin
(C589511-0114
or
C589512-0107)
battery-packs
may
seriously
degrade
operating
life,
signal
strength
and.
in
come
cases,
the
mechanical configuration
of
the
ELT.
a.
After
the
transmitter
has
been
removed
from
aircraft
in
accordance
with
para.
16-100.
place
the
transmitter
switch
in
the
OFF
position.
b.
Remove
the
four
screws
attaching
the cover
to
the
case
and
then remove the cover
to
gain
access
to
the
battery-pack.
c.
Disconnect the
battery-pack
electrical
connector
and
remove
battery-pack.
d.
Place
new
battery-pack
in
the
transmitter
with
four
batteries
as
shown
in
the
case
in
figure
16-18.
e.
Connect
the
electrical
connector
as
shown
in
figure
16-18.
NOTE
Before
installing
the
battery-pack,
check
to
ensure
that
its
voltage
is
7.5
volts
or
greater.
f.
Replace
the
transmitter
baseplate
on
the
unit
and
pressing
the
baseplate
and
unit
together attach
baseplate
with four
nylok
patch screws.
g.
Stamp
the
new
replacement
date
on
the
outside
of
the
ELT.
The
date
should
be
noted
on
the
switching nameplate
on
the
side
of
the
unit
as
well
as
on
the
instruction
nameplate
on
top
of
the
unit.
WARNING
The
battery-pack has
pressurized
contents.
Do
not
recharge,
short
circuit
or
dispose
of
in
fire.
CAUTION
Be
sure
to
enter
the new
battery-pack
expiration
date
in
the
aircraft
records.
It
is
also
recommended
this
date
be
placed
in
your
ELT
Owner's
Manual
for
quick
reference.
16-72A/(16-72B
blank)
MODEL
172
SERIES SERVICE
MANUAL
C589511-0103
TRANSMITTER
C589511-0104
TRANSMITTER
(CANADIAN)
C589511-0105
BATTERY
PACK
C589511-0106
BATTERY
PACK
(CANADIAN)
C589511-0117
TRANSMITTER
C589511-0113
TRANSMITTER (CANADIAN
C589511-0114
DOMESTIC
&
CANADIAN
Figure
16-18.
Battery
Pack
Installation
16-73
MODEL
172
SERIES SERVICE
MANUAL
16-103.
TROUBLE
SHOOTING.
Should
your
Emergency
Locating
Transmitter
fail the
100
Hours
performance checks,
it
is
possible
to
a
limited
degree
to
isolate
the
fault
to
a
particular
area
of
the
equipment.
In
performing
the
following
trouble
shooting
procedures
to
test
peak
effective
radiated
power. you
will
be
able
to
determine
if
battery
replacement
is
necessary
or
if
your
unit should
be
returned
to
your
dealer
for
repair.
TROUBLE
PROBABLE
CAUSE
REMEDY
*POWER
LOW
Low
battery
voltage.
1.
Set
toggle
switch
to off.
2.
Disconnect the
battery-
pack
from
the
transmitter
and
connect
a
Simpson
260
model
voltmeter
and
mea-
sure
voltage.
If
the
battery-
pack
transmitter
is
7.5
volts
or
less,
the
battery-
pack
is
below
specification
Faulty
transmitter.
3.
If
the
battery-pack
volt-
age
meets
the
specifications
in
Step
2.
the
battery-pack
is
ok.
If
the
battery
is
ok,
check
the
transmitter
as
follows:
a.
Reconnect
battery
pack
to
the
transmitter.
b. By
means
of
E.F.
John-
son
105-0303-001
jackplugs
and
3
inch
maximum
long
leads,
connect
a
Simpson
Model
1223
ammeter
to
the
jack.
c.
Set
the
toggle
switch
to
AUTO
and
observe
the
ammeter
current
drain
If
the
current
drain
is in
the
15-25
ma
range.
the transmitter
or
the co-axial
cable
is
faulty.
Faulty
co-axial
4.
Check
co-axial
antenna
antenna
cable.
cable
for
high
resistance
joints.
If
this
is
found
to
be
the
case.
the
cable
should
be
replaced.
*This
test
should
be
carried
out
with
the
co-axial
cable
provided
with
your
unit.
16-74
MODEL
172
SERIES
SERVICE
MANUAL
ELECTRICAL
LOAD
ANALYSIS
CHART
STANDARD EQUIPMENT
(Running
Load)
AMPS
REQD
1977 1978
1979
1980
1981
1982
Battery
Contactor
............................
0.6
0.45
0.5
0.5
0.5
0.5
Fuel
Indicators
.........
...............
.
0.4
0.11
0.1
0.1
0.1
0.1
Flashing
Beacon
Light
.......................
7.0 6.0
6.0
6.0
Instrument Lights
...........................
1.3
0.67
0.7
0.7
0.7
0.7
Position
Lights
..............................
5.6
2.5
2.5
2.5
2.5
2.5
Turn
Coordinator
............................
0.8
0.28
0.3
0.3
0.3
0.3
OPTIONAL
EQUIPMENT
(Running
Load)
Altitude
Blind
Encoder
......................
0.1 0.1
0.1
0.1
0.1
Strobe
Lights
................................
3.0 3.0
3.0
3.0
3.0
Cessna
300
ADF
(Type
R-546E)
.............. 1.0 1.0
1.0
1.0
1.0
1.0
Cessna
300
Nav/Com
(100
Channel)
(Type
RT-308C)
................... .........
1.5
Cessna
300
Nav/Com
(Type
RT-385A)
.......
1.0
1.0
1.0
.
1.0
1.0.
2.25 2.25
2.25
2.25 2.25
Cessna
300
HF
Transceiver
(PT10-A)
........
1.5
1.0- 1.0-
1.0-
9.0- 9.0
9.0
9.0-
Cessna
300
Transceiver
(Type
RT-524A)
.....
32
Cessna
300
Transponder
(Type
RT-359A)
....
1.0
2.0
2.0
2.0
2.0
2.0
Cessna
400
Glide
Slope (Type
R-443B)
(40
Channel)
...............................
0.4 0.5
0.5
0.5
0.5
Cessna
400
Glide
Slope (Type
R-446B)
0.5
Cessna
400
Marker
Beacon
(Type
R-402A/B).
0.3
0.1
0.1
0.1
Sunair
SS
Bank
HF
Transceiver
(Type
ASB-125)
............................
5.0
2.5
2.5-
2.5-
2.5-
2.5
7.5
7.5
7.5
7.5
7.5
Cessna
300
A
Navomatic
(Type
AF-395A)
...
2.0 2.5
2.5
2.5
2.5
2.5
Cessna
200
Navomatic
(Type
AF-295B)
......
2.0
2.5 2.5
2.5
2.5
2.5
Cessna
EA-401A
Encoding
Altimeter
........
0.1 0.1
0.1
0.1
0.1
0.1
Cessna
400
Transponder
(RT-459A)
..........
2.0 2.0
2.0
2.0
Cessna
300
Nav/Com
(720
Channel
RT-328T)
1.5
1.5-
Narco
190
DME
..............................
2.9
2.9
2.9
2.9
2.9
DM
E-451
..................................... 12
Cessna
400
XPDR
(ARC
Type
RT-459A)
.....
2.0
2.0 2.0
2.0
2.0
Bendix
GM-247A
Marker
Beacon
............
0.1
1.0
Pitot
Heat
....................................
2.9 2.9
2.9
2.9
2.9
Post
Lights
................................. .
0.6 0.6
0.6
0.6
0.6
RNAV
511....................................
1.0
1.0
1.0
RNAV AN5-351
..............................
0.65
Interphone
System
........................... t
Avionics
Fan
................................
1.0
1.0
ITEMS
NOT CONSIDERED
AS
PART
OF
RUNNING
LOAD
Cigarette
Lighter
............................
10.0
7.0
7.0
7.0
7.0
Clock
................... ..................... t t t t t
Control
Wheel
Map
Light
....................
0.33
0.1 0.1
0.1
0.1
0.1
Courtesy
&
Dome
Lights
......................
2.5
1.2 1.2
1.2
1.2
1.2
Flap
M
otor
................................. .
15.0 8.5 8.5
8.5
8.5
8.5
Landing
and
Taxi
Lights
(Single)............
20.0
8.9 8.9
8.9
8.9
Landing
and
Taxi
Lights
(Dual)
.............
15.6
3.6
ea
3.6
ea
3.6
ea
3.6
ea
Landing
and
Taxi
Lights
.....................
9.0
ea
Map
Light
(Door
Post)
.......................
0.33
0.2
0.2
0.2
0.2
0.2
Air
Conditioner (High
Blower)
..............
6.7
6.7
6.7
6.7
Ventilation
System
Blower
(High
Speed)
....
5.0
5.0
5.0
5.0
t
Negligible
2.25
Transmitting
9.00
Transmitting
Receiving
*
Export
Only
7.50
Transmitting
*
6.00
Transmitting
16-75
MODEL
172
SERIES
SERVICE
MANUAL
ELECTRICAL
LOAD
ANALYSIS
CHART
ALL
MODELS
STANDARD
EQUIPMENT
(Running
Load)
AMPS
REQD
1983
1984
1985
1986
Battery
Contactor
.................................................
......
0.5 0.5
0.5
0.5
Fuel
Indicators
............................................................
0.1
0.1
0.1
0.1
Flashing
Beacon
Light
.................................................
6.0
6.0 7.0
7.0
Instrum ent
Lights
.......................................................
0.7 0.7
0.7
0.7
Position
Lights
............................................................
2.5
2.5
2.5
2.5
Turn
Coordinator
........................................................
0.3 0.3
0.3
0.3
OPTIONAL
EQUIPMENT
(Running
Load)
Altitude
Blind
Encoder
................................................
.
1
0.1
0.1
0.1
Strobe
Lights
..............................................................
3.0
3.0 2.0
2.0
Cessna
300
ADF
(Type
R-546E)
....................................
1.0 1.0
1.0
1.0
Cessna
300
Nav/Com
(RT-385A)
....................................
1.0
1.0
1..0
1.0-
2.25*
2.25*
2.25*
2.25*
Cessna 300
Transponder
(Type
RT-359A)
.....................
2.0 2.0
2.0
2.0
Cessna
400
Glide
Slope
(Type
R-443B)
(40-Channel)
......
0.5 0.5
0.5
0.5
Cessna
400
Marker
Beacon (Type
R-402A
or
R-402B)
...
0.1 0.1 0.1
0.1
Sunair
SS
Bank
HF
Transceiver
(Type
ASB-125)
.....................................................
2.5-
2.5
2.5
2.5
7.5*
7.5*
7.5*
7.5*
Cessna
300A
Navomatic
(Type
AF-395A)
......................
2.5
2.5
2.5
2.5
Cessna
200
Navomatic
(Type
AF-295B)
.........................
2.5
2.5 2.5
2.5
Cessna
EA-401A
Encoding
Altimeter
.........................
0.1
0.1
0.1
0.1
Cessna
400
Transponder
(Type RT-459A)
.....................
2.0
2.0 2.0
2.0
DME-451
...................................................
1.2
1.2
Pitot
H
eat
....................................................................
2.9
2.9
2.9 2.9
Post
Lights
................................................................
0.6
0.6
0.6
0.6
RNAV
AN5-351
...........................................................
0.65 0.65
Interphone
System
......................................................
Avionics
Fan
.. . ..............................................
0.6
0.6
1.0
1.0
ITEMS
NOT
CONSIDERED
PART
OF
RUNNING
LOAD
C
lock
......................................................................
Control
Wheel Map
Light
.............................................
0.1
0.1
0.1
0.1
Courtesy
&
Dome
Lights
..............................................
1.2
1.2
1.2
1.2
Flap
M
otor
..................................................................
8.5
8.5
1.8
1.8
Landing
and
Taxi
Lights
.............................................
9.0
ea
9.0
ea
9.0
ea
9.0
ea
Map
Light
(Door
Post)
..................
...............................
0.2
0.2
0.2
Air
Conditioner
(High
Blower)
.....................................
6.7
6.7
6.7
6.7
Ventilation
System
Blower
(High
Speed)
.......................
5.0
5.0
5.0
5.0
Standby
Vacuum
System
............................................
13.0
13.0
Sperry
RT-377A
DME
.................................................
0.3
0.3
Negligible
Receiving
Transmitting
16-76
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
SECTION
18
STRUCTURAL
REPAIR
Page
No.
TABLE OF CONTENTS
Aerofiche/
Manual
STRUCTURAL
REPAIR
........
3A4/18-2
Damage
Necessitating
Repair
Criteria
............
3A4/18-2
Replacement
of
Parts
....
3A7
18-5
Equipment
and
Tools
........
3A4/18-2
Wing
Leading
Edge
.......
3A7
18-5
Support
Stands
...........
3A4/18-2
Negligible
Damage
......
3A7
18-5
Fuselage
Repair
Jigs
......
3A4/18-2
Repairable
Damage
......
3A8
18-6
Wing
Jigs
..............
3A4/18-2
Damage
Necessitating
Wing
Twist
and
Stabilizer Replacement
of
Parts
....
3A8
18-6
Angle-of-Incidence
.........
3A4/18-2
Elevators
and
Rudders
.......
3A8
18-6
Repair
Materials
...........
3A4/18-2
Negligible
Damage
........
3A8
18-6
Wing
...................
3A5/18-3
Repairable
Damage
.......
3A8
18-6
Description
.............
3A5/18-3
Damage
Necessitating
Wing
Skin
..............
3A5/18-3
Replacement
of
Parts
.....
3A8
18-6
Negligible
Damage
......
3A5/18-3
Fin
and
Stabilizer
.........
3A8
18-6
Repairable
Damage
......
3A5/18-3
Negligible Damage
........
3A8
18-6
Damage
Necessitating
Repairable
Damage
........
3A8
18-6
Replacement
of
Parts
....
3A6/18-4
Damage
Necessitating
Wing
Stringers
.........
3A6/18-4
Replacement
of
Parts
.....
3A8
18-6
Negligible
Damage
......
3A6/18-4
Fuselage
................
3A8
18-6
Repairable
Damage
......
3A6/18-4
Description
............
3A9
18-7
Damage
Necessitating
Negligible Damage
........
3A9
18-7
Replacement
of
Parts
....
3A6/18-4
Repairable
Damage
........
3A9
18-7
Wing
Auxiliary
Spars
......
3A6/18-4
Damage
Necessitating
Negligible
Damage
......
3A6/18-4
Replacement
of
Parts
. ...
3A9
18-7
Repairable Damage
......
3A6/18-4
Bonded
Doors
.............
3A9
18-7
Damage
Necessitating
Repairable Damage
.......
3A9
18-7
Replacement of
Parts
....
3A6,18-4
Bulkheads
................
3A9
18-7
Wing Ribs
..............
3A6/18-4
Landing
Gear
Bulkheads
...
3A9
18-7
Negligible
Damage
......
3A6/18-4
Repair
After
Hard
Repairable
Damage
......
3A6/18-4
Landing
.........
3A10
18-8
Damage
Necessitating
Firewall Damage
..
.....
3A10
18-8
Replacement
of
Parts
....
3A6/18-4
Fasteners
............
3A10
18-8
Wing
Spars
.............
3A7/18-5
Rivets
..... ...
.....
3A10
18-8
Negligible Damage
......
3A7/18-5
Replacement
of
Hi-Shear
Repairable
Damage
......
3A7/18-5
Rivets
. ...........
3A10
18-8
Damage
Necessitating
Substitution
of
Rivets
.....
3A10
18-9
Replacement
of
Parts
....
3A7/18-5
Engine
Mount
.............
3A15
18-13
Ailerons
.................
3A7/18-5
Description
.............
3A15
18-13
Negligible
Damage
......
3A7/18-5
General
Considerations
.. ..
3A15
18-13
Repairable
Damage
......
3A7/18-5
Engine
Mount
Radial
Damage
Necessitating
Support
Damage
.........
3A15
18-13
Replacement
of
Parts
....
3A7/18-5
Damage
Involving
Engine
Balancing
..... ....
3A7/18-5
Mounting Lugs
and
Engine
Wing
Flaps
.............
3A7/18-5
Mount-to-Fuselage
Attach-
Negligible Damage
......
3A7/18-5
Fittings
............ ..
3A15
18-13
Repairable
Damage
......
3A7/18-5
Baffles
.................
3A15
18-13
Revision
1
18-1
MODEL
172
SERIES
SERVICE
MANUAL
I
Engine
Cowling
............
3A15
18-13
Repair
of
Glass-Fiber
Skin
Repair
.............
3A15
18-13
Constructed
Components
....
3A15
18-13
Reinforcement
Angle
Corrosion
and
Corrosion
Repair
..............
3A15
18-13
Control
..............
3A15
18-13
18-1
STRUCTURAL
REPAIR.
18-2
REPAIR CRITERIA.
Although
this
section
outlines
repair
permissible
on
structure
of
the
aircraft,
the
decision
of
whether
to
repair or
replace
a
major
unit
of
structure
will
be
influenced
by
such
factors as
time
and
labor
available,
and
by
a
comparison
of
labor
costs
with
the
price
of
replacement
assemblies.
Past
experience
indicates that-replacement,
in
many
cases,
is
less
costly
than
major
repair.
Certainly,
when the
aircraftmustbe
restoredto
its
airworthy
condition
in
a
limited
length
of
time,
replacement
is
preferable.
Restoration
of
a
damaged
aircraft
to
its
original
design
strength,
shape,
and
alignment involves
careful
evaluation
of
the
damage,
followed
by
exacting
workmanship
in
performing
the
repairs.
This
section
suggests
the
extent
of
structural
repair
practicable
on
the
aircraft,
and
supplements
Federal
Aviation
Regulation,
Part
43.
Consult
the
factory
when
in
doubt
about
a
repair
not
specifically
mentioned
here.
18-3.
EQUIPMENT
AND
TOOLS.
18-4.
SUPPORT
STANDS.
Padded,
reinforced
sawhorse
or
tripod
type
support
stands,
sturdy
enough
to
support
any
assembly
placed upon
them,
must
be
used
to
store
a
removed
wing
or
tailcone.
Plans
for
local
fabrication
of
support
stands
are
contained
in
figure
18-1.
The
fuselage
assembly,
from
the
tailcone
to
the
firewall,
must
NOT
be
supported
from
the
underside.
since
the
skin
bulkheads
are
not designed
for
this
purpose.
Adapt
support
stands
to
fasten
to
the
wing
attach
points
or
landing gear
attach
points
when
supporting
a
fuselage.
18-5
FUSELAGE
REPAIR
JIGS.
Whenever
a
repair
is
to
be
made
which
could
affect
structural
alignment,
suitable
jigs
must
be
used
to
assure
correct
alignment
of
major
attach points,
such
as
fuselage,
firewall,
wing
and
landing
gear.
These
fuselage
repair
jigs
are
obtainable
from
the
factory.
18-6
WING
JIGS.
These
jigs
serve
as
a
holding
fixture
during
extensive
repair
of
a
damaged
wing,
and
locates
the
root
rib,
leading
edge
and
tip
rib
of
the
wing.
These
jigs
are
also
obtainable
from
the
factory.
18-7
WING
TWIST
AND
STABILIZER
ANGLE-OF-INCIDENCE.
18-8.
Wing
twist
(washout)
and
horizontal
stabilizer
angle
of
incidence
are
shown
below.
Stabilizers
do
not
have
twist.
Wings
have
no
twist
from
the
root
to
the
lift
strut
station.
All
twist
in
the
wing
panel
occurs
between
this
station
and
the
tip
rib.
See
figure
18-2
for
wing
twist
measurement.
WING
Twist
(Washout)
3°
00'
STABILIZER
Angle
of
Incidence
-3°
30'
18-9.
REPAIR
MATERIALS.
Thickness
of
a
material
on
which
a
repair
is
to
be
made
can
easily
be
18-2
Revision
1
MODEL
172
SERIES
SERVICE
MANUAL
determined
by
measuring
with
a
micrometer.
In
general.
material
used
in
Cessna
aircraft
covered
in
this
manual
is
made
from
2024
aluminum
alloy, heat
treated
to a
-T3. -T4.
or
-T42
condition.
If
the
type
of
material
cannot
readily
be
determined.
2024-T3
may
be
used
in
making
repairs.
since
the
strength
of
-T3
is
greater
than
-T4
or
-T42
(-T4
and
-T42
may
be
used
interchangeably,
but
they
may
not
be
substituted
for
-T3).
When
necessary
to
form
a
part
with
a
smaller
bend
radius
than
the
standard
cold
bending
radius
for
2024-T4.
use
2024-0
and
heat
treat
to
2024-T42
after
forming.
The
repair
material
used
in
making
a
repair must
equal
the
gauge
of
the
material
being
replaced
unless
otherwise
noted.
It
is
often
practical
to
cut
repair
pieces from
service
parts
listed
in
the
Parts
Catalog.
A
few
components
(empennage
tips,
for
example)
are fabricated
from
thermo-formed
plastic
or
glass-fiber
constructed
material.
18-10.
WING.
18-11.
DESCRIPTION.
The
standard
wing
assemblies
are
a
semicantilever
type.
employing
semimonocoque
type
of
structure.
Basically,
the
internal
structure
consists
of
built-up
front
and
rear
spar
assemblies,
a
formed
auxiliary
spar
assembly
and
formed
sheet
metal
nose
intermediate,
and
trailing
edge
ribs.
Stressed
skin. riveted
to
the
rib
and
spar
structures.
completes the
rigid
structure.
Access
openings
(hand holes
with
removable cover
plates)
are
located
in
the
underside
of
the
wing
between the
wing
root
and
tip
section.
These
openings
afford
access
to
aileron
bellcranks,
flap
bellcranks.
electrical
wiring,
strut
attach
fittings,
control
cables
and
pulleys,
and
control disconnect points.
Beginning
with
1981
Models, an
optional
fuel
system
installation
employs
a
different wing
assembly
These
wings
are
sheet metal constructed,
with
a
single main
spar.
two
fuel
spars.
formed
ribs
and
stringers.
The
front
fuel
spar
also
serves
as
an
auxiliary
spar
and
is
the
forward
wing
attaching
point.
An
inboard
section forward
of
the
main
spar
is
sealed
to
form an
integral
fuel
bay
area.
The
main
spar consists
of
milled
spar
caps
attaching
fittings
joined
by
a
web
section.
The
aft
fuel
spar
is
a
formed
channel.
The
front
fuel
spar
is
a
built-up
assembly
consisting
of
a
formed
channel, doubler,
attach
strap
and
support
angle.
Stressed
skin.
riveted
to
the
ribs.
spars
and
stringers,
completes
the wing
structure.
Access
openings
(hand
holes
with
removable
cover
plates)
are
located
in
the
underside
of
the
wing
between
the
wing
root
and
tip
section.
These
openings
afford
access
to
the
flap
and
aileron
bellcranks.
flap
drive
pulleys.
flap
actuator
in
left
wing, flap
and
aileron
control
cable
disconnect
points,
fuel
adapter
plate,
air
scoop
connectors
and
electrical
wiring.
18-12.
WING
SKIN.
18-13.
NEGLIGIBLE
DAMAGE.
Any
smooth
dents
in
the
wing skin
that
are
free
from
cracks
abrasions
and
sharp
corners,
which are
not
stress
wrinkles
and
do
not
interfere
with
any
internal
structure
or mechanism,
may
be
considered
as
negligible
damage
in
any
area
of
the
wing.
On
the
optional
fuel
bay
wing,
outboard
of
wing
station
65.125
in
areas
of
low
stress
intensity, cracks,
deep
scratches
or
sharp
dents,
which
after
trimming
or
stop-drilling
can
be
enclosed
by
a
two-inch
circle,
can
be
considered
negligible
if
the
damaged
area
is
at
least
one
diameter
of
the
enclosing
circle
away
from
all
existing
rivet
lines
and
material
edges.
The
area
on
the
lower
surface
of
the
wing
between
the
two
stringers
adjacent
to
the
main
spar
is
not considered
low
stress
intensity.
Stop-drilling
is
considered
a
temporary
repair
and
a
permanent
repair
must
be
made
as
soon
as
practicable.
18-14.
REPAIRABLE
DAMAGE.
On
a
standard
wing.
Figure
18-4
outlines
typical
repair
to
be
employed
in
patching
skin.
Before
installing
a
patch.
trim
the
damaged
area
to
form
a
retangular pattern.
leaving
at
least
one-half
inch
radius
at
each
corner,
and
de-burr.
The
sides
of
the
hole
should
lie
span-wise
or
chord-wise.
A
circular
patch
may
also
be
used.
If
the
18-3
MODEL
172
SERIES
SERVICE
MANUAL
patch
is
in
an
area
where flush
rivets
are
used.
make
a
flush
patch
type
of
repair
if
in
an
area
where
flush
rivets
are
not
used.
make
an
overlapping
type
of
repair.
Where
optimum
appearance
and
airflow
are
desired.
the
flush
patch
may
be
used.
Careful
workmanship
will
eliminate
gaps
at
butt-joints: however.
an
epoxy
type
filler may
be
used at
such
joints.
On
the
optional
fuel
bay
wing.
repairs
must
not
be
made
to
the
upper
or
lower
wing
skin
inboard
of
station
65.125
without
factory
approval.
However,
an
entire
skin
may
be
replaced
without
factory
approval.
Refer
to
Section
1
for
wing
station
locations.
Figure
18-4
outlines
typical
repairs
to
be
employed
in
patching
skin.
Before
installing
a
patch.
trim
the
damaged
area
to
form
a
rectangular pattern.
leaving
at
least
one-half
inch
radius
at
each
corner
and
de-burr.
The
sides
of
the
hole
should
lie
span-wise
or
chord-wise.
A
circular
patch
may
also
be
used.
If
the
patch
is
in
a
area
where
flush
rivets
are used.
make
a
flush
patch
type
of
repair,
if
in
an
area where
flush
rivets
are
not
used,
make
an
overlapping
type
of
repair.
Where
optimum
appearance
and
airflow
are
desired,
the
flush
patch
may
be
used.
Careful
workmanship
will
eliminate
gaps
at
butt-joints:
however. an
opoxy
type
filler
may
be
used at
such
joints.
18-15.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
If
a
skin
is
badly
damaged.
repair
must
be
made
by
replacing
an
entire
skin
panel. from
one
structural
member
to
the
next.
Repair
seams
must
be
made
to
lie
along
structural
members
and
each
seam
must
be
made
exactly
the
same
in
regard
to
rivet
size,
spacing,
and
pattern
as
the
manufactured
seams
at
the
edges
of
the
original
sheet.
If
the
manufactured seams
are
different, the
stronger
must
be
copied.
If
the
repair
ends
at
a
structural
member where
no
seam
is
used,
enough
repair
panel
must
be
used
to
allow
an
extra
row
of
staggered
rivets,
with
sufficient
edge
margin.
to be
installed.
18-16.
WING
STRINGERS.
18-17
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
18-18.
REPAIRABLE
DAMAGE.
Figure
18-5
outlines
a
typical
wing
stringer
repair.
Two
such
repairs
may
be
used
to
splice
a
new
section
of
stringer
material
in
position.
without
the
filler
material.
18-19
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
If
a
stringer
is
so badly
damaged
that
more
than
one
section
must
be
spliced.
replacement
is
recommended.
18-20.
WING
AUXILIARY
SPARS.
18-21.
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
18-22.
REPAIRABLE
DAMAGE.
Figure
18-8
illustrates
a
typical
auxiliary
spar
repair.
18-23.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
If
damage
to
an
auxiliary
spar
would
require
a
repair
which
could
not
be
made
between
adjacent
ribs,
the
auxiliary
spar
must
be
replaced.
18-24.
WING
RIBS.
18-25.
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
18-26.
REPAIRABLE
DAMAGE.
Figure
18-6
illustrates
a
typical
wing
rib
repair.
18-27.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
Leading
and
trailing
edge
ribs
that
are
extensively
damaged
can
be
replaced.
However.
due
to
the
necessity
of
unfastening
an
excessive
amount
of
skin
in
order
to
replace
the
rib,
they
should
be
repaired
if
practicable.
18-4
MODEL
172
SERIES SERVICE
MANUAL
Center
ribs,
between
the
front
and
rear
spar
should always
be
repaired
if
practicable.
18-28.
WING
SPARS.
18-29.
NEGLIGIBLE
DAMAGE.
Due
to
the
stress
which
wing
spars
encounter.
very
little damage
can
be
considered
negligible.
All
cracks,
stress
wrinkles,
deep
scratches.
and
sharp
dents
must
be
repaired.
Smooth
dents,
light
scratches
and
abrasions
may
be
considered
negligible.
18-30.
REPAIRABLE
DAMAGE.
Figure
18-7
illustrates
typical
spar
repairs.
It
is
often
practical
to
cut
repair
pieces
from
service
parts
listed
in
the
Parts
Catalog.
Service
Kits
are
available
for
certain
types
of
spar
repairs.
18-31.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
Damage
so
extensive that
repair
is
not
practicable
require replacement
of
a
complete
wing
spar.
Also
refer
to
paragraph
18-2.
18-32.
AILERONS.
18-33.
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
18-34.
REPAIRABLE
DAMAGE.
The
repair
shown
in
figure
18-9
may
be
used
to
repair
damage
to
aileron
leading
edge
skins.
Figure
18-4
may
be
used
to
repair
damage
to
flat
surfaces
between
corrugations;
when
damage
area
includes
corrugations.
see
figure
18-3A.
It
is
recommended
that
material
used for
repair
be
cut
from
spare
parts
of
the
same
gauge
and
corrugation spacing.
Following
repair
the
aileron
must
be
balanced.
Refer
to
paragraph
18-
36
and
figure
18-3
for
balancing
the
aileron.
If
damage
would
require
a
repair
which
could
not
be
made
between
adjacent
ribs,
see
the
following
paragraph.
18-35.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
If
the
damage would
require
a
repair
which
could
not
be
made
between
adjacent
ribs.
complete
skin
panels
must
be
replaced.
Ribs
and spars
may
be
repaired,
but
replacement
is
generally preferable.
Where
extensive
damage has
occurred,
replacement
of
the
aileron
assembly
is
recommended.
After
repair
and/or
replacement,
balance
aileron
in
accordance
with
paragraph
18-36
and
figure
18-3.
18-36.
AILERON
BALANCING.
Following
repair,
replacement
or
painting,
the
aileron
must
be
ba-
lanced.
A
flight
control
surface
balancing
fixture
kit
is
available
(P/N
5180002-1).
See
figure
18-3
for
procedures
pertaining
to
the
use
of
this
kit.
18-37.
WING
FLAPS.
18-38.
NEGLIGIBLE DAMAGE.Refer
to
paragraph
18-13.
18-39.
REPAIRABLE
DAMAGE.Flap
repairs
should
be
similar
to
aileron
repairs
discussed
in
paragraph
18-34.
A
flap leading
edge
repair
is
shown
in
figure
18-10.
If
an
overlapping
patch
is
to
be
used,
be
sure
it
will
not
interfere
with
the
wing during
flap
operation.
18-40.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
Flap
repairs
which
require
replacement
of
parts
should
be
similar
to
aileron
repairs
discussed
in
paragraph
18-35.
Since
the
flap
is
not
considered
a
moveable
control
surface.
no
balancing
is
required.
18-41.
WING
LEADING
EDGE.
18-42.
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
18-5
MODEL
172
SERIES SERVICE
MANUAL
18-43.
REPAIRABLE
DAMAGE.
A
typical
leading
edge
skin
repair
is
shown
in
figure
18-9.
An
epoxy-type
filler
may
be
used
to
fill
gaps at
butt-joints.
To
facilitate
repair.
extra
access
holes
may
be
installed
in
the
locations
noted
in
figure
18-11.
If
the
damage
would
require
a
repair
which
could
not
be
made between
adjacent
ribs.
refer
to
the
following
paragraph.
18-44.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
For
extensive
damage.
com-
plete
leading
edge
skin
panels
must
be
replaced.
To
facilitate
replacement.
extra
access
holes
may
be
installed
in
the
locations
noted
in
figure
18-11.
18-45.
ELEVATORS
AND
RUDDER.
18-46.
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
The
exception
to
negligible
damage
on
the
elevator surfaces
is
the
front
spar,
where
a
crack
appearing
in
the
web
at
the
hinge
fittings or
in
the
structure
which
supports
the
overhanging
balance
weight
is
not
considered
negligible. Cracks
in
the
overhanging
tip
rib.
in
the
area
at
the
front
spar
intersection
with
the
web
of
the
rib.
also
cannot
be
considered
negligible.
18-47
REPAIRABLE
DAMAGE.
Skin
patches
illustrated
in
figure
18-4
may
be
used
to
repair
skin
damage between
corrugations.
For
skin
damage
which
includes
corrugations,
see figure
18-
3A.
Following
repair,
the
elevator/
rudder
must
be
balanced.
See
figure
18-3
for
balancing.
If
damage
would
require
a
repair
which
could
not
be
made
between
adjacent
ribs.
see
the
following
paragraph.
18-48.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
If
the
damaged
area
would
require
a
repair
which
could
not
be
made
between
adjacent
ribs,
complete
skin
panels
must
be
replaced.
Ribs
and
spars
may
be
repaired,
but
replacement
is
generally
preferable.
Where
extensive
damage
has
occurred,
replacement
of
the
entire
assembly
is
recommended.
After
repair
and/
or replacement, balance
elevators
and
rudder
in
accordance
with
paragraph
18-
49
and
figure
18-3.
18-49.
ELEVATOR
AND
RUDDER
BALANCING.
Following
repair,
replacement
or
painting,
the
elevators
and
rudder
must
be
balanced.
A
flight
control
surface balancing
fixture
kit
is
available
(P/N
5180002-1).
See
figure
18-3
for
procedures
pertaining
to
the
use
of
this kit.
18-50
FIN
AND
STABILIZER.
18-51
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
18-52
REPAIRABLE
DAMAGE.
Skin
patches
illustrated
in
figure
18-4
may
be
used
to
repair
skin
damage.
Access
to
the
dorsal
area
of
the
fin
may
be
gained
by
removing
the
horizontal
closing
rib
at
the
bottom
of
the
fin.
Access
to
the
internal
fin
structure
is
best
gained
by
removing skin
attaching
rivets
on one
side
of
the
rear
spar
and
ribs.
and
springing
back
the
skin.
Access
to
the
stabilizer
structure
may
be
gained
by
removing
skin
attaching
rivets
on
one
side
of
the
rear
spar
and
ribs,
and
springing
back
the
skin
If
the damaged
area
would
require
a
repair
which
could
not
be
made
between
adjacent
ribs.
or
a
repairwould
be
located
in
an
area
with
compound
curves,
see
the
following
paragraph.
18-53.
DAMAGE
NECESSITATING
REPLACEMENT
OF
PARTS.
If
the
damaged
area
would
require
a
repair
which
could
not
be
made
between
adjacent
ribs,
or
the
repair
would
be
located
in
an
area
with
compound
curves,
complete
skin panels
must
be
replaced.
Ribs
and
spars
may
be
repaired,
but
replacement
is
generally
preferable.
Where
damage
is
extensive.
replacement
of
the
entire
assembly
is
recommended.
18-54.
FUSELAGE.
18-6
18-33A.
CRACKS
IN
CORRUGATED
AILERON SKINS
(Continued
from page
18-5)
1. It
is
permissible
to
stop
drill
crack(s)
that originate
at
the
trailing
edge
of
the
control
surface
provided
the
crack
is
not
more
than
2
inches
in
length.
2.
Stop
drill
crack
using
a
#30
(.128
inch)
drill.
3. A
crack
may only
be
stop
drilled
once.
NOTE:
A
crack
that
passes
through
a
trailing
edge
rivet
and
does not
extend
to
the
trailing
edge
of
the
skin
may
be
stop
drilled
at
both ends
of
the
crack.
4.
Any
control
surface that
has
a
crack that progresses past
a
stop
drilled
hole
shall
be
repaired.
Refer
to
-
paragraphs
18-33, -34,
and
-35
as
applicable
for
repair
information.
5. A
control
surface
that
has any
of
the
following
conditions
shall
have
a
repair
made
as
soon
as
practicable
A. A
crack
that
is
longer
than
2
inches.
B.
A
crack that
does
not
originate
from the
trailing
edge
or
a
trailing
edge
rivet.
C.
Cracks
in
more
than
six
trailing
edge
rivet
locations
per
skin.
Refer
to
paragraphs
18-33,
-34,
and
-35
as
applicable for
repair
information.
6.
Affected
control
surfaces
with
corrugated
skins
and
having
a
stop drilled crack
that
does
not
extend
past
the
stop
drilled
hole,
may
remain
in
service
without
additional
repair.
18-38A.
CRACKS
IN
CORRUGATED
FLAP
SKINS
(Continued from
page
18-5)
1.
It
is
permissible to
stop
drill
crack(s) that originate
at
the
trailing
edge
of
the
control
surface
provided
the
crack
is
not more
than
2
inches
in
length.
2.
Stop drill
crack
using
a
#30
(.128 inch)
drill.
3.
A
crack may
only
be
stop
drilled
once.
NOTE:
A
crack
that passes
through
a
trailing edge
rivet
and
does
not
extend
to
the
trailing
edge
of
the
skin
may
be
stop
drilled
at
both
ends
of
the
crack.
4.
Any
control
surface
that
has
a
crack
that progresses
past
a
stop drilled
hole
shall
be
repaired.
Refer
to
paragraphs 18-38,
-39, and
-40
as
applicable
for
repair
information.
5.
A
control
surface
that
has
any
of
the
following conditions shall
have
a
repair made as
soon
as
practicable:
A.
A
crack
that
is
longer
than
2
inches.
B.
A
crack
that
does
not
originate
from the
trailing
edge
or
a
trailing
edge
rivet.
C.
Cracks
in
more
than six
trailing
edge
rivet
locations
per
skin.
Refer
to
paragraphs
18-38,
-39,
and
-40
as
applicable
for
repair
information.
6.
Affected
control
surfaces
with
corrugated
skins
and
having
a
stop
drilled crack
that
does
not
extend
past
the
stop
drilled
hole,
may
remain
in
service
without
additional
repair.
Temporary
Revision
Number
5
18-6A
7
January
2000
MODEL
172
SERIES
SERVICE
MANUAL
18-46A.
CRACKS
IN
CORRUGATED ELEVATOR
SKINS (Continued
from
page
18-6)
1. It
is
permissible
to
stop
drill
crack(s)
that
originate
at
the trailing edge
of
the
control
surface
provided
the
crack
is
not
more
than
2
inches
in
length.
2.
Stop drill
crack
using
a
#30
(.128 inch)
drill.
3.
A
crack
may only
be
stop
drilled
once.
NOTE: A
crack
that passes
through
a
trailing
edge
rivet
and
does not
extend
to
the
trailing
edge
of the
skin
may
be
stop
drilled
at
both
ends
of
the
crack.
4.
Any
control
surface that
has
a
crack
that
progresses
past
a
stop
drilled hole
shall
be
repaired.
Refer
to
paragraphs
18-46,
-47,
and
-48 as
applicable
for
repair information.
5.
A
control surface
that
has
any
of
the following
conditions
shall
have
a
repair
made as
soon
as
practicable:
A.
A
crack that
is
longer
than
2
inches.
B.
A
crack
that
does not
originate
from the
trailing
edge
or
a
trailing
edge
rivet.
C.
Cracks
in
more
than
six
trailing
edge rivet locations
per
skin.
Refer to
paragraphs
18-46,
-47,
and
-48 as
applicable
for
repair
information.
6.
Affected
control
surfaces
with
corrugated skins
and having
a
stop
drilled crack
that
does not
extend
past
the
stop
drilled
hole, may remain
in
service
without additional
repair.
18-6B
Temporary
Revision
Number
5
7
January
2000
MODEL
172
SERIES SERVICE
MANUAL
18-55.
DESCRIPTION.
The
fuselage
is
of
semimonocoque construction.
consisting
of
formed
bulkheads,
longitudinal
stringers,
reinforcing
channels.
and
skin
panels.
18-56.
NEGLIGIBLE
DAMAGE.
Refer
to
paragraph
18-13.
Mild
corrosion
appearing
upon
alclad
surfaces
does
not
necessarily
indicate
incipient
failure
of
the
base
metal.
However.
corrosion
of
all
types
must
be
carefully
considered,
and
approved
remedial action
taken.
Small
cans
appear
in
the
skin
structure
of
all
metal aircraft.
It is
strongly
recommended.
however,
that
wrinkles
which appear
to
have
originated
from
other
sources.
or
which
do
not
follow
the
general
appearance
of
the
remainder
of
the
skin
panels,
be
thoroughly
investig-
aged.
Except
in
the
landing
gear
bulkhead areas.
wrinkles
occurring
over
stringers
which
disappear
when the
rivet
pattern
is
removed.
may
be
considered
negligible.
However,
the
stringer
rivet
holes may
not align perfectly
with
the
skin
holes
because
of
a
permanent
"
set"
in
the
stringer.
If
this
is
apparent,
replacement
of
the
stringer
will
usually
restore
the
original
strength
characteristics
of
the
area.
NOTE
Wrinkles
occurring
in
the
skin
of
the
main
landing
gear
bulkhead
areas
must
not
be
considered
negligible.
The
skin
panel
must
be
opened
sufficiently
to
permit
a
thorough
examination
of
the
lower
portion
of
the
landing
gear
bulkhead
and
its
tie-in
structure.
Wrinkles
occurring
in
open
areas
which
disappear
when
the
rivets
at
the
edge
of
the
sheet
are removed
or
a
wrinkle
which
is
hand
removable,
may
often
be
repaired
by
the
addition
of
a
1/2
x
1/2
x
.060
inch
2024-T4
extruded
angle,
riveted
over
the
wrinkle
and
extended
to
within
1/16
to
1/8
inch
of
the
nearest
structural
members.
Rivet
pattern
should
be
identical
to
existing
manufactured
seam
at
edge of
sheet.
Negligible damage
to
stringers,
formed
skin
flanges,
bulkhead
channels,
and
like
parts
is
similar
to
that
for
the
wing
skin,
given
in
paragraph
18-13.
18-57.
REPAIRABLE
DAMAGE.
Fuselage
skin
repairs
may
be
accomplished
in
the same
manner
as wing
skin repairs
outlined
in
paragraph
18-14.
Stringers.
formed
skin flanges. bulkhead
channels
and
similar parts
may
be
repaired
as
shown
in
figure
18-5.
18-58.
DAMAGE
NECESSITATING
REPLACEMENT
OF PARTS.
Fuselage
skin
major
repairs
may
be
accomplished
in
the same
manner
as
the
wing
repairs
outlined
in
paragraph
18-15.
Dam-
aged
fittings
must
be
replaced.
Seat
rails
serve
as
structural
parts
of
the
fuselage
and
must
be
replaced
if
damaged.
Refer
to
Section
3.
18-58A.
BONDED DOORS.
18-58B.
REPAIRABLEDAMAGE.Bonded
doors
may
be
repaired
by
the
same
methods
used
for
riveted
structure.
Rivets
are
a
satisfactory
substitute
for
bonded
seams
on
these
assemblies.
The
strength
of
the
bonded
seams
in
doors
may
be
replaced
by
a
single
3/32.
2117-AD
rivet
per
running
inch
of
bond
seam.
The
standard
repair
procedures
outlined
in
AC43.13-1
are
also
applicable
to
bonded
doors.
18-59.
BULKHEADS.
18-60.
LANDING
GEAR BULKHEADS.
Since these
bulkheads
are
highly
stressed
members.
irregularly
formed
to
provide
clearance
for
control
cables.
fuel
lines.
etc..
the
patch-type
repairs
will
be,
for the
most
part,
impractical.
Minor
damage.
consisting
of
small
nicks
or
scratches,
may
be
repaired
by
dressing
out
the
damaged
area.
or
by
replacement
of
rivets.
18-7
MODEL
172
SERIES
SERVICE
MANUAL
Any
other
damage
must
be
repaird
by
replacing
the
landing
gear
support
assembly
as
an
aligned
unit.
18-61.
REPAIR
AFTER
HARD
LANDING.
Buckled
skin
or
floorboards.
and
loose
or
sheared
rivets
in
the
area
of
the
main
gear
support
will
give
evidence
of
damage
to
the
structure
from
an
extrmely
hard
landing.
When
such
evidence
is
present.
the
entire support
structure
must
be
examined,
and
all
support
forgings
must
be
checked
for
cracks,
using
a
dye
penetrant
and
proper
magnification.
Bulkheads
in
the
damaged
area
must
be
checked
for
alignment,
and
deformation
of
the
bulkhead
webs
must
be
determined
with
the
aid
of
a
straightedge.
Damaged
support
structure,
buckled
floorboards
and
skins,
and
damaged
or questionable
forgings
must
be
replaced.
18-62.
FIREW
ALL
DAMAGE.
Firewall
sheets
may
be
repaired
by
removing
the
damagedmaterial
(MIL-S-5059)
corrosion-resistant
(18-8)
steel.
and
splicing
in a
new
section.
The
new
portion
must
be
lapped over
the
old
material, sealed
with
Pro-Seal
#700
(Coast
Pro-Seal
Co..
Chemical
Division.
2235
Beverly
Blvd..
Los
Angeles.
California),
compound
or
equivalent.
and
secured with
steel
(MS20450)
rivets.
Patches. splices
and
joints
should
be
repaired
with
steel
rivets.
Angles around
the
periphery
of
the
firewall
are
secured
with
steel
rivets,
except
where
engine
shock
mount
brackets
are
attached
with
aluminum
(MS20470)
rivets.
The
diagonal
support
angles
on
the
upper
firewall
are
secured
with
steel
rivets.
Nutplates
are
attached with
alumunum
rivets.
The
diagonal
support angles
on
the
lower
firewall
are
secured
with
aluminum
rivets.
18-63.
FASTENERS.
Fasteners
used
in
the
aircraft
are generally
solid
aluminum
rivets,
blind
rivets,
and
steel-threaded
fasteners.
Usage
of
each is primarily
a
function
of
the
loads
to
be
carried,
accessibility,
and
frequency
of
removal. Rivets
used
in
aircraft
construction
are
usu-
ally
fabricated
from
aluminum
alloys.
In
special
cases, monel,
corrosion-resistant
steel
and
mild
steel,
copper.
and
iron rivets
are
used.
18-63A.
RIVETS.
Standard
solid-shank
MS
rivets are
those
generally
used
in
aircraft
construction.
They
are
fabricated
in
the following
head
types:
roundhead,
flathead,
countersunk
head,
and
brazier
head.
Flathead
rivets
are
generally
used
in
the
aircraft
interior
where
head clearance
is
required.
MS20426
countersunk
head
rivets are
used
on
the
exterior
surfaces
of
the
air-
craft
to
minimize
turbulent
airflow.
MS20470
brazier
head
rivets
are
used
on
the
exterior
surfaces
of
the
aircraft
where
strength
requirements
necessitate
a
stronger
rivet
head
than
that
of
the
countersunk
head
rivet.
Both
the
brazier
head
and
the
countersunk
head
rivets
are
used
on
the
exterior
of
the
aircraft
where
head
clearance
is
required. Hi-shear
rivets
are
special,
patented
rivets
having
a
hi-shear
strength
equivalent
to
that
of
standard
AN
bolts.
They
are
used
in
special
cases
in
locations
where
hi-shear
loads
are
present, such
as
in
spars,
wings,
and
in
heavy
bulkhead
ribs.
This
rivet
consists
of
a
cadmium-plated pin
of
alloy steel.
Some
have
a
collar
of
aluminum
alloy.
Some
of
these rivets
can
be
readily
iden-
tified
by
the
presence
of
the
attached
collar
in
place of
the
formed head
on
standard
rivets.
Blind
rivets are
used, where
strength
requirements
permit,
where
one
side
of
the
structure
is inaccessible,
making
it
impossible or
impractical
to
drive
standard
solid-hank
rivets.
18-63B.
REPLACEMENT
OF
HI-SHEAR
RIVETS.
Replacement
of
hi-shear
rivets
with
close-tolerance
bolts
or
other
commercial
fasteners
of
equivalent
strength
properties
is
permissible.
Holes
must
not
be
elongated,
and
the
hi-shear
substitute must
be
a
smooth,
push-fit.
Field
replace-
ment
of
main
landing
gear
forgings
on
bulkheads
may
be
accomplished
by
using
the
follow-
ing
fasteners.
a.
NAS464P-*
bolt,
MS21042-*
nut
and
AN960-*
washer
in
place
of Hi-shear
rivets
for
forgings
with
machined
flat
surfaces
around
attachment
holes.
18-8
MODEL
172
SERIES SERVICE
MANUAL
b.
NAS464P-*
bolt,
ESNA2935-*
mating
base
washer
and
ESNA
RM52LH2935-*
self-
aligning
nut
for
forgings
(with
draft
angle
of
up
to
a
maximum
of
8°)
without
machined
flat
surfaces
around
attachment
holes.
*Dash numbers
to
be
determined
according
to
the
size of
the
holes
and
the
grip
lengths
re-
quired
Bolt
grip
length
should
be
chosen
so
that
no
threads
remain
in
the
bearing
area.
18-63C.
SUBSTITUTION
OF
RIVETS.
a.
Solid-shank
rivets
(M20426AD
and
MS20470AD).
When
placing
rivets
in
installa-
tions
which
require
raised
head
rivets,
it
is
desirable
to
use
rivets
identical
to
the
type
of
rivet
removed.
Countersunk-head rivets
(MS20426)
are
to
be
replaced
by
rivets
of
the
same
type and degree
of
countersink.
When
rivet
holes
become
enlarged,
deformed,
or
otherwise
damaged,
use
the
next
larger
size
rivet
as
a
replacment.
Re-
placement
shall
not
be
made
with
rivets
of
lower
strength
material.
b.
Hi-shear
Rivets.
When
hi-ahear
rivets are not
available,
replacement
of
sizes
3
16-
inch
or
greater
rivets
shall
be
made
with
bolts
of
equal
or greater
strength
than
the
rivet
being
replaced,
and
with self-locking
nuts
of
the
same
diameter
c.
The
following
pages contain
approved
solid-shank
and
hi-shear rivet
substitutions.
18-9
MODEL
172
SERIES
SERVICE
MANUAL
Replace
In
thickness
With
(or
thicker)
MS20470AD3
025
NAS1398B4,
NAS1398D4
.020
NAS1738B4, NAS1738D4.
NAS1768D4,
CR32134,
CR3243-4
MS20470AD4
.050
NAS1398B4,
NAS139804
.040
NAS1398B5.
NAS1398D5,
NAS1738B4,
NAS1738E4,
NAS1768D4,
CR32134
.032
NAS173885,
NAS1738E5.
NAS1768D5,
CR3213-5, CR3243-4
.025
CR3243-5
MS20470AD5
.063
NAS1398B5.
NAS1398D5
.050
NAS139886,
NAS1398D6, NAS1398B5
NAS1738E5.
CR3213-5
.040
NAS1738B6.
NAS1738E6,
NAS176805,
CR3213-6, CR3243-5
.032
CR3243-6
MS20470AD6
.080
NAS1398B6
.071
NAS139806
.063
NAS1738B6,
NAS1738D6,
NAS1768D6,
CR3213-6
.050
CR3243-6
MS20426AD3
.063
NAS1399B4,
NAS1399D4
(Countersunk)
.040
NAS1769D4,
CR3212-4
(See
Note
1)
025
NAS1769B4,
NAS1739E4,
CR3242-4
MS20426AD4
.080
NAS1399B4,
NAS1399D4
Countersunk)
.063
NAS1739B4, NAS1739D4.
CR3212-4
.050
NAS1769D4
.040
CR3242-4
(See
Note
1)
.050
CR3212-5
.040
NAS1739B5. NAS1739D5,
NAS1769D4
.032
CR3242-5
MS20426AD4
.063
NAS1739B4,
NAS1739D4
(Dimpled)
18-10
MODEL
172
SERIES
SERVICE
MANUAL
Replace
In
thickness
With
(or
thicker)
MS20426AD5
.090
NAS1399B5,
NAS1399D5
(Countersunk)
.080
CR3212-5
.071
NAS1739B5,
NAS1739E5
.063
NAS1769D5
.050 CR3242-5
(See
Note
1)
.063
NAS1739B6, NAS1739D6, NAS1769D6,
CR3212-6
.040
CR3242-6
.032
AN509-10
Screw
with
MS20365
Nut
MS20426AD5
.071
NAS1739B5, NAS1739D5
(Dimpled)
MS20426AD6
.090
NAS1739B6,
NAS1739D6,
CR3212-6
(Countersunk)
.071
NAS1769D6
.063
CR3242-6
.032
AN509-10 Screw
with
MS20365
Nut
MS20426AD6
.090
NAS1739B6.
NAS1739D6
(Dimpled)
.032
AN509-10 Screw
with
MS20365
Nut
NOTE
1:
Rework
required. Countersink
oversize
to
accommodate
oversize
rivet.
NOTE
2:
Do
not
use
blind
rivets
in
high
vibration
areas
or to
pull
heavy
sheets
or
extrusions
to-
gether.
High
vibration
areas
include
the
nacelle
or
engine
compartment
including
the
fire-
wall.
Heavy
sheets
or
extrusions
include
spar
caps.
18-11
MODEL
172
SERIES
SERVICE
MANUAL
REPLACE
DIAMETER
WITH
Fastener
Collar
Fastener
Collar
NAS178
NAS179
(See
Note
1)
NAS1054
NAS179, NAS528
(See
Note
1) NAS14XX
NAS1080C,
NAS1080E,
NAS
1080G
(See
Note
1)
NAS529 NAS524A
(See
Notes
1
and
2)
NAS1446
NAS1080C.
NAS1080A6
(See
Note
1)
NAS7034 NAS1080K
(See
Note
1)
NAS464
AN364.
MS20364, MS21042
NAS1103
NAS1303
NAS6203
AN173
AN305,
MS20305,
MS21044.
MS21045
NAS1054 NAS179, NAS528 NAS14XX
NAS1080C,
NAS1080E
NAS529
NAS524A
(See
Note
2)
NAS1446
NAS1080C,
NAS1080A6
NAS7034 NAS1080K
NAS464
AN364. MS20304,
MS21042
NAS1103
NAS1305
NAS6203
NAS14XX
NAS1080C
NAS529
NAS524A
NAS1080E
NAS1446
NAS1080C,
NAS1080A6
NAS1080G NAS7034 NAS1080K
NAS464 AN364.
MS20364,
MS21042
NAS1103
NAS1303
NAS6203
NAS529
NAS524A
(See
Note
3)
NAS1446
NAS1080C. NAS1080A6
NOTE
1
See
appropriate
tables
for
nominal
diameters
available.
NOTE
2:
Available
in
oversize
for repair
of
elongated
holes.
Ream
holes to
provide
a
.001
inch
interference
fit.
NOTE
3:
NAS1446
oversize
only
permitted
as
a
replacement
for
NAS529.
Steel
shank
fastener
designed
for drive-on
collars.
Steel
shank
fastener
designed
for
squeeze-on
collars.
Installation
requires
sufficient
space
for
the
tool
and
extended
shank
of
the
fastener.
Threaded
fastener.
18-12
MODEL
172
SERIES SERVICE
MANUAL
18-64.
ENGINE
MOUNT.
18-65.
DESCRIPTION.The
"dynafocal"
type
engine
mount
is
constructed
of
4130
chrome-
molybdenum
steel tubing.
A
truss
structure,
fastened
to
the
firewall
at
four
points.
provides
a
mount
for
the nose
landing
gear
as well as the
engine.
The
engine
is
attached
radially
to
the
four
mounting
lugs
by
Lord
type.
bonded
sandwich
mounts.
18-66.
GENERAL
CONSIDERATIONS.
All
welding
on
the
engine
mount
must
be
of
the
highest
quality
since
the
tendency
of
vibration
is
to
accentuate
any
minor
defect
present
and
cause
fatigue
cracks.
Engine mount
members
are
preferably
repaired
by
using
a
larger
diameter
replacement
tube,
telescoped
over
the
stub
of
the
original
member
using
fishmouth
and
rosette type
welds.
However,
reinforced
30-degree
scarf
welds
in
place
of
the
fishmouth
welds
are
considered
satisfactory
for
engine mount
repair
work.
Refer
to
Section
19
for
engine
mount
painting.
18-67.
ENGINE
MOUNT
RADIAL SUPPORT DAMAGE.Minor
damage
such
as
a
crack adjacent
to
an
engine
attaching
lug
may
be
repaired
by
rewelding
the
support
tube
and
extending
a
gussett
past
the damaged
area. Extensively
damaged
parts
must
be
replaced.
18-68.
DAMAGE
INVOLVING
ENGINE
MOUNTING
LUGS
AND
ENGINE
MOUNT
TO
FUSE-
LAGE
ATTACHING
FITTINGS.
Engine
mounting
lugs
and
engine
mount-to-fuselage
attaching fittings
should
not
be
repaired
but
must
be
replaced.
18-69.
BAFFLES.
Baffles
ordinarily
require
replacement
if
damaged
or
cracked.
However.
small
plate
reinforcements riveted
to
the baffle
will
often
prove
satisfactory
both
to
the
strength
and
cooling
requirements
of
the
unit.
18-70.
ENGINE
COWLING.
18-71.
REPAIR
OF
COWLING
SKINS.
If
extensively
damaged,
complete sections
of
cowling
must
be
replaced.
Standard
insert-type
skin
patches, however.
may
be
used
if
repair
parts
are
formed
to
fit.
Small
cracks may
be
stop-drilled
and
dents
straightened
if
they
are
reinforced
on
the
inner
side
with
a
doubler
of
the
same
material.
Bonded
cowling
may
be
repaired
by
the
same
methods
used
for
riveted
structure.
Rivets
are
a
satisfactory substitute
for
bonded
seams
on
these
assemblies.
The
strength
of
the
bonded
seams
in
cowling
may
be
replaced
by
a
single
3/32,2117-AD
rivet
per
running
inch
of
bond
seam.
The
standard
repair
procedures
outlined
in
AC43.13-1
are
also
applicable
to
cowling.
18-72.
REPAIR
OF
REINFORCEMENT
ANGLES.
Cowl
reinforcement
angles.
if
damaged,
must
be
replaced.
Due
to
their
small
size,
they
are
easier
to
replace
than
to
repair.
18-73.
REPAIR OF
GLASS-FIBER
CONSTRUCTED
COMPONENTS.
Glass-fiber
constructed
compo-
nents
on
the
aircraft
may
be
repaired
as
stipulated
in
instructions
furnished
in
Service
Kit
SK182-12.
Observe
the
resin
manufacturer's
recommendations
concerning
mixing
and
ap-
plcation
of
the
resin.
Epoxy
resins
are
preferable
for making
repairs.
since
epoxy
com-
pounds
are
usually
more
stable
and
predictable
than
polyester
and,
in
addition,
give
better
adhesion.
In
addition,
repair
kits
are
also
available
for the
repair
of
cracks
in
ABS,
PBC.
PVPC,
graphite,
and
fiberglass
material.
These
kits,
Part
No.
51543
thru
51548,
are
avail-
able
from
the
Cessna
Supply
Division.
18-74.
CORROSION
AND
CORROSION
CONTROL.
NOTE
For
information
on
corrosion
and
corrosion
control
for
aircraft,
refer
to
FAA
Advisory
Circular
AC43-4.
18-13
MODEL
172
SERIES
SERVICE
MANUAL
WING
12
INCH
WIDE
HEAVY
CANVAS
1
X
12
X
48
1
X 12
X 11
1
X
12
X
8
30-3/4
2
X
4
X 20
5
INCH
COTTON
WEBBING
Figure
18-1.
Wing
and
Fuselage
Support
Stands
3/8
INCH
DIAMETER
BOLTS
2
X
6
NOTE
ALL
DIMENSIONS
ARE
IN
INCHES
Figure
18-1.
Wing
and
Fuselage
Support
Stands
18-14
MODEL
172
SERIES
SERVICE
MANUAL
GRIND
C
-
A
B
C
WING
STATION
2.00
1.00 29.50
39.00
2.
00
1.00
29.50
100.50
.45
1.00 24.00
208.00
ALL
WING
TWIST OCCURS
BETWEEN
STA. 100.
50
AND
STA.
208.
00.
(Refer
to
paragraph
18-7
for
angle
of
incidence).
MEASURING
WING
TWIST
If
damage
has occurred
to
a
wing, it
is
advisable
to
check
the
twist.
The
following method
can
be
used
with
a
minimum
of
equipment,
which
includes
a
straightedge
(32"
minimum
length
of
angle,
or
equivalent),
three
modified
bolts
for
a
specific
wing,
and
a
protractor
head
with
level.
1.
Check
chart
for
applicable dimension
for
bolt
length
(A
or
B).
2.
Grind bolt
shanks to
a
rounded
point
as
illustrated,
checking
length
periodically.
3.
Tape
two
bolts
to
straightedge
according
to
dimension
C.
4.
Locate
inboard
wing
station
to
be
checked
and
make
a
pencil
mark
approximately one-half
inch
aft
of
the
lateral
row
of
rivets
in
the
wing
leading
edge
spar
flange.
5.
Holding
straightedge
parallel
to
wing
station
(staying as
clear
as
possible
from "cans",
place
longer bolt
on
pencil
mark
and
set
protractor
head
against
lower
edge
of
straightedge
6.
Set
bubble
in
level
to
center
and
lock
protractor
to
hold
this
reading.
7.
Omitting
step
6,
repeat
procedure
for
each
wing
station,
using
dimensions
specified
in
chart.
Check
to
see
that
protractor
bubble
is
still
centered.
8.
Proper
twist
is
present
in
wing
if
protractor
readings
are
the
same
(parallel).
Forward
or
aft
bolt
may
be
lowered
from
wing
.
10
inch
maximum
to
attain
parallelism.
Figure
18-2.
Checking
Wing
Twist
18-15
MODEL
172
SERIES
SERVICE
MANUAL
FLIGHT
CONTROL
SURFACE
BALANCING
FIXTURE
KIT
(PART
NUMBER
5180002-1)
5180002-12
WEIGHT
ASSEMBLY
WASHER
AND
BOLT
SLIDING WEIGHT
*5180002-14
MANDRELS
5180002-2
BEAM
ASSEMBLY
INCLUDED
IN
5180002-1
FLIGHT
CONTROL
SURFACE
BALANCING
FIXTURE
KIT.
GENERAL NOTES
1
Balance
control
surfaces
in
a
draft-free
area.
2.
Place
hinge
bolts
through
control
surface hinges
and position
on
knife
edge
balancing
mandrels.
Be
sure
hinge
bolt
shank
rests
on
knife
edge.
3.
Make
sure
all
control
surfaces
are
in
their
approved
flight
configurations:
painted
(if applicable),
trim
tabs
installed,
all
foreign
matter
removed from
inside
of
control
surface,
elevator
trim
tab
push-pull
rod
installed and
all
tips
installed.
4.
Place
balancing
mandrels
on
a
table
or
other
suitable
flat
surface.
5.
Adjust
trailing
edge
support
to
fit
control
surface
being
balanced
while
cen-
ter
of
balancing
beam
is
directly
over
hinge
line.
Remove
balancing
beam
and
balance
the
beam
itself
by
moving the
adjustable
weight
(fastened
by
bolt
and
washer).
Fine balance
may
be
accomplished
by
use
of
washers
at
long
screw
on
end
of
beam.
6.
When
positioning
balancing
beam
on
control
surface.
avoid
rivets
to
provide
a
smooth
surface
for
the beam
and
keep
the beam
90
°
to
the
hinge
line
of
the
control
surface.
Figure
18-3.
Control
Surface
Balancing
(Sheet
1
of
5)
18-16
MODEL
172
SERIES
SERVICE
MANUAL
7.
Paint
is
a
considerable weight
factor.
In
order
to
keep
balance
weight
to
a
minimum.
it is
recommended
that
existing
paint
be
removed
before
adding
paint
to
a
control
surface.
Increase
in
balance weight
will
also
be
limited
by
the
amount
of
space
available
and
clearance
with
adjacent
parts.
Good
workmanship
and
standard
repair
practices
should
not
result
in
unreasonable
balance
weight.
8.
The
approximate
amount
of
weight
needed
may
be
determined
by
taping
loose
weight
at
the
balance
weight
area.
9.
Lighten balance
weight
by
drilling
off
part
of
weight.
10.
Make
balance
weight
heavier
by.
fusing
bar
stock
solder
to
weight
after
removal
from
control
surface.
The
ailerons
should
have
balance
weight increased
by
or-
dering
additional weight,
listed
in
applicable
Parts
Catalog
and
installing
next
to
existing
inboard
weight
the
minimum
length
necessary
for correct
balance.
CENTERLINE
ON
BEAM
MUST
BE
ALIGNED
WITH
CONTROL SURFACE
BEAM
ASSEMBLY
HINGE
CENTERLINE
HANGAR
ASSEMBLY
HINGE
CENTERLINE
CONTROL
SURFACE
CHORD
ADD
WASHERS A
NECESSARY
TO
FINE
BALANCE
THE
BEAM
ASSEMBLY
ADJUSTABLE
WEIGHT
MANDREL
HANGAR
ASSEMBLY
(TO BE
IN
PROPER
POSITION)
READ
CONTROL
SLIDING
SURFACE
MOMENT
WEIGHT
AT
CENTER
OF
WEIGHT
BEAM
ASSEMBLY
-
CHORD
LINE
MANDREL FLAT
SURFACE
Figure
18-3.
Control Surface
Balancing
(Sheet
2
of
5)
18-17
MODEL
172
SERIES
SERVICE
MANUAL
A
balance
in
this
range
is
"overbalance
" .
A
balance
in
this
range
is
"underbalance".
BALANCING
MANDREL
Detail
F
RUDDER
90-
Detail
G
SPIRIT-LEVEL
TRAILING
EDGE
SLIDING
CENTER
LINE
WEIGHT
CHORD
LINE
BALANCING
MANDREL
Detail
H
LEVELED
SURFACE
HINGE
POINT
ELEVATOR
Figure
18-3.
Control
Surface
Balancing
(Sheet
3
of
5)
18-18
MODEL
172
SERIES
SERVICE
MANUAL
1/16"
SLOT:
3/4"
DEEP
(To
fit a
il
er on
hi
nge )
KNIFE
EDGE
Detail
B
MANDREL
.
SPIRIT-LEVEL
Detail
A
PROTRACTOR
KNIFE
EDGES
SUPPORT
aileron
is
straight
in
this
area.
BALANCING
MANDREL
Detail
D
Figure
18-3.
Control Surface
Balancing
(Sheet
4
of
5)
Revision
2 18-19
MODEL
172
SERIES
SERVICE
MANUAL
CONTROL
SURFACE
BALANCE
REQUIREMENTS
NOTE
Balance
limits
for
control
surfaces
are
expressed
for
"Approved
Flight"
configuration.
"Approved
Flight"
configuration
is
that
condition
of
the
control
surface
as
prepared
for
flight
of
the
airplane
whether
it
be
painted
or
unpainted.
"Approved
Flight"
limits
must
never
be
exceeded
when
the
surface
is in
its
final
configuration
for
flight.
DEFINITIONS:
UNDERBALANCE
is
defined
as
the
condition
that
exists
when
surface
is
trailing
edge
heavy
and
is
defined
by
a
symbol
(+).
If
the
balance
beam
sliding weight
must
be
on
the
leading
edge side
of
the
hinge
line
(to
balance
the
control
surface), the
control surface
is
considered
to
be
underbalanced.
OVERBALANCE
is
defined
as
the
condition
that
exists
when
surface
is
leading
edge
heavy
and
is
defined
by
a
symbol
(-).
If
the
balance
beam
sliding
weight
must
be
on
the
trailing
edge side of
the
hinge
line (to
balance
the
control
surface),
the control
surface
is
considered
to
be
overbalanced.
CONTROL
SURFACE
APPROVED
FLIGHT
CONFIGURATION
BALANCE
LIMITS
(Inch-Pounds)
AILERON
0.0
to
+11.31
RUDDER
0.0
to
+
9.0
RIGHT
ELEVATOR
0.0
to +
24.
5
LEFT
ELEVATOR
0.0
to
+
18.
5
Figure
18-3.
Control
Surface
Balancing
(Sheet
5
of
5)
18-20
MODEL
172
SERIES
SERVICE
MANUAL
PATCH
1/4"
MINIMUM
EDGE
MARGIN
USE
EXISTING
RIVET
PATTERN
ORIGINAL
PART
ORIGINAL
PART
REPAIR
PATCH
IN
CROSS
SECTION
A-A
Figure
18-3A.
Corrugated
Skin
Repair
18-21
MODEL
172
SERIES
SERVICE
MANUAL
PATCHES
AND
DOUBLERS
-
2024-T3
ALCLAD
MS20470AD4
RIVETS
24
REQD
SKIN
SECTION
THRU
PATCH
3.00
DIA.
HOLE
PATCH
REPAIR
FOR
3
INCH
DIAMETER
HOLE
MS20470AD4
RIVETS
16
REQD
22
1/2°
3.00
DIA.
PATCH
EXISTING
DOUDLER
SKIN
2.00
DIA.
HOLE
SECTION
THRU PATCH
PATCH
REPAIR
FOR
2
INCH
DIAMETER
HOLE
2. 50
DIA.
MS20470AD4
RIVETS
EXISTING
8
REQD
SKIN
PATCH
(NO
DOUBLER
REQD)
1.00
DIA.
HOLE
SECTION
THRU
PATCH
PATCH
REPAIR
FOR
1
INCH
DIAMETER
HOLE
ORIGINAL
PARTS
REPAIR
PARTS
OVERLAPPIN
REPAIR
PARTS
IN
CROSS
SECTION CIRCULAR
PATCH
Figure
18-4.
Skin
Repair
(Sheet
1
of
6)
18-22
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
THRU
ASSEMBLED
PATCH
A-A
EDGE
MARGIN
2
X
RIVET
DIA.
PATCH
-
2024-T3
ALCLAD
CLEAN
OUT
DIAMETER
1/2"
RADIUS
RIVET
SPACING
=
6
X
RIVET
DIA.
1/2"
RADIUS
EDGE
MARGIN
=
2
X
RIVET
DIA.
.-
DOUBLER
-
2024-T3
ALCLAD
RIVET
TABLE
OVERLAPPING
REC-
SKIN
GAGE
RIVET
DIA.
TANGULAR
PATCH .020
1/8
025
1/8
ORIGINAL
PARTS
.032
1/8
040
1/8
REPAIR
PARTS
.051
5/32
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-4.
Skin
Repair
(Sheet
2
of
6)
18-23
MODEL
172
SERIES
SERVICE
MANUAL
PATCH
EXISTING
SKIN
NOTE
For
optimum
appearance
and
airflow,
use
flush
rivets,
dim-
pled
skin
and
patch,
and
counter-
SECTION
THRU
ASSEMBLED
PATCH
sunk
doubler.
A-A
EDGE
MARGIN
=
2
X
RIVET
DIA.
PATCH
-
2024-T3
ALCLAD
1/2"
RADIUS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-4.
Skin
Repair
(Sheet
3
of
6)
18-24
MODEL
172
SERIES SERVICE
MANUAL
NOTE
DOUBLER
dimple
skin
and
patch.
A-A
2024-T4
ALCLAD
EXISTING
SKIN
-
CARRY
EXISTING
RIVET PATTERN
-
THRU
PATCH
EDGE
DISTANCE
PITCH
4-8D
2D
MIN.
TYPICAL
.50
R.
MIN.
TYPICAL
RIVET
TABLE
SKIN
GAGE
RIVET
DIA.
.020 1/8
.025
1/8
.032
1/8
.040
1/8
.051
5/32
2024-T3
ALCLAD
FLUSH
PATCH
AT
STRINGER/BULKHEAD
INTERSECTION
ORIGINAL
PARTS
REPAIR
PARTS
NOTE
REPAIR
PARTS
IN
CROSS
SECTION
This
procedure
is
not
rec-
ommended
in
areas
where
stringers
are
riveted
to
bulkheads.
Figure
18-4.
Skin
Repair
(Sheet
4
of
6)
18-25
MODEL
172
SERIES SERVICE
MANUAL
DOUBLERS
EXISTING
1/4
B
(BUT
NOT
LESS
THAN
4D)
SKIN
RIVET PATTERN
DOUBLER
-
PATCH
PITCH
TYPICAL
FOR
PATCH
SKIN
&
DOUBLER
EXISTING
SKIN
0.
5"
MIN.
RADIUS
EDGE DISTANCE
RIVET
TABLE
2D
MIN
SKIN GAGE
RIVET
DIA.
SPACER-
.020
1/8
2024-T3
ALCLAD
.025
1/8
.032
1/8
.040
1/8
.051
5/32
OVERLAPPING
PATCH
AT
STRINGER/BULKHEAD
INTERSECTION
ORIGINAL
PARTS
PATCH
-
2024-T3
ALCLAD
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-4.
Skin
Repair
(Sheet
5 of
6)
18-26
MODEL
172
SERIES SERVICE
MANUAL
FUSELAGE
SKIN
CLEAN
OUT
DAMAGED
AREA
SKIN
RIVET
PATTERN
1/4"
RADIUS
10
RIVETS
EACH
SIDE
OF
DAMAGED AREA
FILLER -2024-T4
ALCLAD
DOUBLER
-2024-T4
1/4"
EDGE
MARGIN
ALCLAD
MS20470AD4
RIVETS
ORIGINAL
PARTS
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-4. Skin
Repair
(Sheet
6
of
6)
18-27
MODEL
172
SERIES
SERVICE
MANUAL
DOULBLER
4"
EDGE
MARGIN.
RIVET
SPACING
TO
MATCH
PATTERN
IN
SKIN
5
RIVETS
EACH
SIDE
STRINGER
OF
DAMAGED
AREA
CLEAN
OUT DAMAGED
AREA
FILLER
-2024-T4
ALCLAD
A-A
MS20470AD4
RIVETS
SKIN
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-5.
Stringer
and
Channel
Repair
(Sheet
1
of
4)
18-28
MODEL
172
SERIES SERVICE
MANUAL
FILLER
2024-T4
ALCLAD
A-A
STRIP
-
2024-T3
ALCLAD
5
RIVETS
EACH
SIDE
OF
DAMAGED
AREA
STRINGER
PICK
UP EXISTING
SKIN
RIVETS
MS20470AD4
RIVETS
ORIGINAL
PARTS
REPAIR
PARTS
A
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-5.
Stringer
and
Channel
Repair
(Sheet
2
of
4)
18-29
MODEL
172
SERIES
SERVICE
MANUAL
STOP
DRILL
CRACK-
ORIGINAL
PARTS
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-5.
Stringer
and
Channel
Repair
(Sheet
3
of
4)
18-30
MODEL
172
SERIES SERVICE
MANUAL
FILLER
-
2024-T4
ALCLAD
DOUBLER
-
2024-T3
ALCLAD
A-A
CLEAN OUT DAMAGED
AREA
3/4"
RIVET
.--
.
SPACING
-
1/4"
RADIUS
2 ROWS
RIVETS
OUTBOARD
OF
LIGHTENING
HOLE
1/4"
MARGIN
CHANNEL
DOUBLER
- 2024-T4
ALCLAD
AN470AD4
RIVETS
A
ORIGINAL
PARTS
,
REPAIR
PARTS
REPAIR
IN
CROSS
SECTION
Figure
18-5.
Stringer
and
Channel
Repair
(Sheet
4
of
4)
18-31
MODEL
172
SERIES
SERVICE
MANUAL
STOPDRILL
CRACK
IF
CRACK
DOES
NOT
EXTEND
TO
EDGE
OF
PART
DOUBLER-
2024-T3
ALCLAD
1/4"
EDGE MARGIN
A-A
MS20470AD4 RIVETS
ORIGINAL
PARTS
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-6.
Rib
Repair
(Sheet
1
of
2)
18-32
MODEL
172
SERIES
SERVICE
MANUAL
FILLER
-
2024-T4
ALCLAD
DOUBLER
-
2024-T3
ALCLAD
RIVET
ORIGINAL
PARTS
REPAIR
PARTS
A-A
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-6.
Rib
Repair
(Sheet
2
of
2)
18-33
MODEL
172
SERIES
SERVICE
MANUAL
FILLER
-
2024-T4
ALCLAD
FILLER
-
2024-T4
ALCLAD
DOUBLER-
CLEAN
OUT
DAMAGED
AREA
ANGLE
2024-T4
ORIGINAL
PARTS
(TYPICA
L)
MS20470A4
RIVET
ORIGINAL
PARTS
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
A-A
Figure
18-7.
Wing
Spar
Repair
(Sheet
1 of 3)
18-34
MODEL
172
SERIES
SERVICE
MANUAL
NOTE
FILLER
-
2024-T4
ALCLAD
This
repair
applies
to
either
front
or
rear
spar
if
the
spar
is
a
single
channel.
1/4"
EDGE
MARGIN
(TYP.
)
CLEAN
OUT
DAMAGED
AREA
2024-T3
ALCLAD
ANGLE
4
RIVET
SPACING
EDGE
MARGIN
DAMAGED
AREA
(TYPICAL
ALL
PARTS)
DOUBLER
2024-T4
ALCLAD
1/4"
EDGE
MARGIN
(TYP.)
MS20470AD4
RIVETS
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
A-A
Figure
18-7.
Wing
Spar
Repair
(Sheet
2
of
3)
18-35
18-35
MODEL
172
SERIES SERVICE
MANUAL
FILLER
-
2024-T4
ALCLAD
3/4"
RIVET
SPACING
CLEAN
OUT
DAMAGED
A-REA
1/4"
EDGE
MARGIN
MS20470AD4
RIVETS
ORIGINAL
PARTS
REPAIR
PARTS
.
-
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-7.
Wing
Spar
Repair
(Sheet
3
of
3)
18-36
MODEL
172
SERIES
SERVICE
MANUAL
DOUBLER
-
2024-T4
ALCLAD
CLEAN
OUT
DAMAGED
AREA
A-A
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-8.
Auxiliary
Spar Repair
18-37
MODEL
172
SERIES
SERVICE
MANUAL
NOTES:
1.
Dimple leading
edge
skin
and
filler material,
countersink
the
doubler.
2.
Use
MS20426AD4
rivets
to
install
doubler.
3.
Use
MS20426AD4
rivets
to
install
filler,
except
where
bucking
is
impossible.
Use CR162-4
Cherry
(blind)
rivets
where
regular
rivets
cannot
be
bucked.
4.
Contour
must
be
maintained;
after
repair
has
been
completed,
use
epoxy
filler
as
necessary
and
sand
smooth
before
painting.
5.
Vertical
size
is
limited
by
ability
to
install
doubler
clear
of
front
spar.
6.
Lateral
size
is
limited
to
seven
inches
across
trimmed
out
area.
7.
Number
of
repairs
is
limited
to
one
in
each
bay.
1"
MAXIMUM
RIVET
SPACING
(TYPICAL)
DOUBLER
NEED
NOT
BE
CUT
OUT
IF
ALL
5/16"
MINIMUM
EDGE
RIVETS
ARE
ACCESSIBLE
/
MARGIN
(TYPICAL)
FOR
BUCKING
TRIM
OUT
DAMAGED AREA
REPAIR
DOUBLER
2024-T3
ALCLAD
.040"
THICKNESS
LEADING
EDGE
SKIN
FILLER
MATERIAL
ORIGINAL
PARTS
SAME
THICKNESS
AS
SKIN
REPAIR
PARTS
Figure
18-9.
Leading
Edge
Repair
18-38
MODEL
172
SERIES
SERVICE
MANUAL
1"
MAXIMUM
RIVET
SPACING
1/4"
MINIMUM EDGE MARGIN
4
MINIMUM
EDGE
MARGIN
DOUBLER
-
2024-T3
ORIGINAL
PARTS
REPAIR
PARTS
Figure
18-10.
Flap
Leading
Edge
Repair
18-39
MODEL
172
SERIES
SERVICE
MANUAL
S-1443-1
DOUBLER
VIEWED
FROM
INSIDE
WING LOOKING
DOWN
AT
TOP
OF
LOWER
WING SKIN.
#40
(.098)
HOLE
(10
REQD)
LOWER
WING
SKIN
(REF)
5.062
DIA
S-225-4F
COVER
MS20426AD3
RIVETS
NOTE
PARTS
ARE
AVAILABLE
FROM
THE
CESSNA
S-1022Z-8-6
SCREWS
SUPPLY DIVISION
PRECAUTIONS
1.
Add
the
minimum
number
of
access
holes
necessary.
2.
Any
circular
or
rectangular
access
hole
which
is
used
with
approved optional
equipment
installations
may be
added
in
lieu
of
the
access
hole
illustrated.
3.
Do
not
add
access
holes
at
outboard
end
of
wing;
remove
wing
tip
instead.
4.
Do
not
add
an
access
hole
in
the
same
bay
where
one
is
already
located.
5.
Locate
new
access
holes
near
the
center
of
a
bay
(spanwise).
6.
Locate
new
access
holes
forward
of
the
front
spars
as
close
to
the
front
spar
as
practicable.
.Locate
new
access
holes
aft
of
the
front
spar
between
the
first
and
second
stringers
aft
of
the
spar.
When
installing
the
doubler.
rotate
it
so
the
two
straight
edges
are
closest
to
the
stringers.
8.
Alternate
bays.
with
new
access
holes
staggered
forward
and
aft
of
the
front
spar,
are
pre-
ferable.
9.
A
maximum
of
five
new
access
holes
in
each
wing
is
permissible:
if
more
are
required.
contact
the
Cessna
Service
Department.
10.
When
a
complete
leading
edge
skin
is
being
replaced,
the
wing
should
be
supported
in
such
a
manner
so
that
wing
alignment
is
maintained.
a.
Establish
exact location
for inspection cover
and
inscribe
centerlines.
b.
Determine position
of
doubler
on
wing
skin
and
center
over
centerlines.
Mark
the
ten
rivet
hole
locations
and
drill
to
size
shown.
c.
Cutout
access
hole.
using
dimension
shown.
d.
Flex
doubler
and
insert
through
access
hole,
and
rivet
in
place.
e.
Position
cover
and
secure,
using
screws
as
shown.
Figure
18-11.
Access
Hole
Installation
18-40
MODEL
172
SERIES SERVICE
MANUAL
CLEAN
OUT
DAMAGED
AREA
A-A
ANGLE
-
2024-T4
ALCLAD
10
RIVETS
EACH SIDE
OF
DAMAGED
AREA
FIREWALL
ANGLE
FILLER
-
2024-T4
ALCLAD
MS20470AD4
RIVETS
FIREWALL
FUSELAGE SKIN
ORIGINAL
PARTS
REPAIR
PARTS
REPAIR
PARTS
IN
CROSS
SECTION
Figure
18-12.
Firewall
Angle
Repair
18-41
MODEL
172
SERIES SERVICE
MANUAL
1
Use
rivet
pattern
at
wing
station
23. 65
for
repair
from
wing
station
23. 65
to
wing
station
85.87.
Use
rivet
pattern
at
wing
station
100.
50
for
lap
splice
patterns
from
wing
station
100.
50
to
wing
station
190.
00.
See
figure
1-2
for
wing
stations.
2
Use
rivet
spacing
similar
to
the
pattern
at
wing
station
100.
50
at
leading
edge
ribs
between
.
lap
splices.
Select
number
of
flush
rivets
to
be
used
at
each
wing
station
leading
edge
rib
from
table.
RIBS
AND
STRINGERS:
-
Blind
rivets
may
be
substituted
for
solid
rivets
in
proportionally
increased
numbers
in
accordance
with
the
table.
SPARS:
Blind
rivets
may
be
installed
in
wing
spars
only
in
those
locations
NUMBER OF
FLUSH
RIVETS
IN
DIMPLED
SKIN
RE-
where
blind
rivets
were
used
during
QUIRED
IN
REPLACEMENT
LEADING
EDGE
SKIN
original
manufacture,
ie
fuel
bay
area
of
front
spars
on
aircraft
WING
SOLID
BLIND
with
integral
fuel
bays.
STATION MS20426-4
CR2248-4
RIB
118
18
22
136
15
18
EXISTING
TACK
RIVET
PATCH
EXISTING
RIVET
PATTERN
TYPICAL
LEADING
EDGE
SECTION
Figure
18-13.
Bonded
Leading
Edge
Repair
18-42
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
19
PAINTING
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
ACRYLIC
LACQUER
MATERIALS
3C4/19-2
Clean-Up
.................
3C7
19-5
Painting
of
ABS
...........
3C4/19-2
Prepriming
.............
3C8 19-6
Interior
Parts
.............
3C5/19-3
Priming
.................
3C8
19-6
Exterior
Parts
.............
3C5/19-3
Prepainting
...............
3C9
19-7
Refinishing
Engine
Mounts
...
3C6/19-4
Painting
.................
3C9
19-7
MODIFIED
URETHANE
MATE-
Overall
.................
3C9
19-7
RIALS
...................
3C7'19-5
Masking
...............
3C9 19-7
Facility
..................
3C7/19-5
Touch-Up
...............
3C10
19-8
Repair
of Dents
..........
3C10
19-8
NOTE
This
section
contains
standard
factory
materials
listing
and
area
of
application.
For
paint
number
and
color,
refer
to
Aircraft
Trim
Plate
and
Parts
Catalog.
In
all
cases
determine
the
type
of
paint
on
the
aircraft
as
some
types
of
paint
are
not
com-
patible.
Materials
may
be
obtained
from
Cessna
Supply
Division.
NOTE
Control
surfaces,
except
for
wing
flaps,
must
be
balanced
after
painting.
Refer
to
Section
18,
figure
18-3
for
balancing
procedures.
Revision
1
19-1
MODEL
172
SERIES
SERVICE
MANUAL
MATERIAL
NO/TYPE
DOMESTIC
FRENCH
AREA
OF
APPLICATION
PAINT
ACRYLIC
LACQUER
*
X
NOTE
1
LACQUER
X
CES
1054-215
Heat
Resistant
X
X
NOTE
6
Enamel
PRIMER
P60G2
With
R7K44
Reducer
X
X
NOTE
2
Ex-Er-7
With
T-Er-4
Reducer
X
X
THINNER
T-8402A
X
NOTE
4
T6094A
X X
NOTE
3
SOLVENT
Methyl
Ethyl
Ketone
(MEK)
X X
NOTE
5
NOTE
1.
Used
on
aircraft
exterior.
2.
Used
with
lacquer
or
acrylic lacquer
on
aircraft
exterior.
3.
Used
to
thin
lacquer
and
for burndown.
4.
Used
to
thin
acrylic lacquer
and
for
burndown.
5.
Used
to
clean
aircraft exterior
prior
to
priming.
6.
Used
on
aircraft
engine
mount.
*
THROUGH
SERIALS
17269309,17269311
THRU
17269549.
17269551
THRU
17269556.
17269561
THRU
17269566.
1729557,
17269583,17269584.
19-1.
PAINTING
OF
FORMED
ABS
PLASTIC
PARTS.
The
following
procedures
outline
some
basic
steps
which
are
useful
during
touch
up
or
painting
of
formed
ABS
plastic
parts.
19-2
MODEL
172
SERIES
SERVICE
MANUAL
19-2.
INTERIOR PARTS
(Finish
Coat
of
Lacquer).
a.
Painting
of
Spare
Parts.
1.
Ensure
a
clean
surface
by
wiping
with
Naphtha
to
remove
surface
contamina-
tion.
CAUTION
Do
not use
strong
solvents
such as
Xylol.
Toluol
or
Lacquer
Thinner
since
prolonged exposure
can
soften
or
embrittle
ABS.
2.
After
the
part
is
thoroughly
dry
it is
ready
for
the
lacquer
topcoat.
Paint
must
be
thinned
with lacquer
thinner
and
applied
as
a
wet
coat
to
ensure
adhesion.
b.
Touch
Up
of
Previously
Painted
Parts.
1.
Light
sanding
is
acceptable
to
remove
scratches
and
repair the
surface
but
care
must
be
exercised
to
maintain
the
surface
texture
or
grain.
2.
Ensure
a
clean
surface
by
wiping
with
Naptha
to
remove
surface
contamination.
CAUTION
Do
not
use
strong
solvents
such
as
Xylol. Toluol
or
Lacquer
Thinner
since
prolonged
exposure
can
soften
or
embrittle
ABS.
3.
After
the
part
is
thoroughly
dry
it is
ready
for the
lacquer
topcoat.
Paint
must
be
thinned
with
lacquer
thinner
and
applied as
a
wet
coat
to
ensure
adhesion.
NOTE
Lacquer
paints
can
be
successfully
spotted
in.
19-3.
EXTERIOR
PARTS
(Acrylic
Topcoat).
a.
Painting
of
Spare
Parts.
1.
Light
scuff
sand
to
remove
scratches
and
improve
adhesion.
2.
Ensure
a
clean
surface
by
wiping
with
Naphtha
to
remove
surface
contamina-
tion.
CAUTION
Do
not
use
strong
solvents
such
as
Xylol.
Toluol
or
Lacquer
Thinner
since
prolonged exposure can
soften
or
embrittle
ABS.
3.
After
the
part
is
thoroughly
dry
it
is
ready
for
the
topcoat. Paint
must
be
thinned
with
appropriate
acrylic
thinner
and
applied
as
a
wet
coat
to
ensure
adhesion.
b.
Touch
Up
of
Previously
Painted
Parts.
1.
Lightly scuff
sand
to
remove
scratches
and
improve
adhestion.
2.
Ensure
a
clean
surface
by
wiping
with
Naphtha
to
remove
surface
contamination.
19-3
MODEL
172
SERIES
SERVICE
MANUAL
CAUTION
Do
not
use
strong
solvents
such
as
Xylol.
Toluol
or
lacquer
Thinner
since prolonged
exposure can
soften
or
embrittle
ABS.
3.
Apply
a
compatible
primer
-
surfacer
and
sealer.
4.
After
the
part
is
thoroughly
dry
it is
ready
for the
topcoat.
Paint
must
be
thinned
and
applied as
a
wet
coat
to
ensure
adhesion.
NOTE
Acrylic
topcoats can
be
successfully
spotted
in.
19-4.
REFINISHING
ENGINE
MOUNTS.
After
completing
a
repair
as
directed
in
Section
18.
refinish
with
Part
Number
EX2219
(Ameron-Enmar
Finished.
16116
E.
13th.
Andover.
Kansas
67230)
(316)
733-1361
heat-resistant
black
enamel.
Degrease
and
scuff
sand
or
grit
blast
entire
area
to
bare
metal
Spray
enamel
to
a
dry
film
thickness
of
0.001"
to
0.0013".
and
cure
at
250°F
for
15
minutes.
Part
can
be
handled
as
soon
as
cool
to
touch.
NOTE
BEGINNING
SERIAL
17269310. 17269550. 17269557,
17269562
THRU
17269565.
17269568
THRU
17269582.
and
17269585.
IMRON
MODIFIED URETHANE
MATERIAL
NO/TYPE
AREA
OF
APPLICATION
PAINT
IMRON
ENAMEL
Used
as
corrosion
proof
topcoat
IMRON
192S
Activator Catalyst
for
Imron
Enamel
PRIMER
WASH
PRIMER
P60G2
Used
to
prime
aircraft
for
Imron
Enamel
REDUCER/
IMRON
Y8485S
Reducer
Used
to
thin Imron
Enamel
THINNER
Catalyst
Reducer
R7K44
Used
to
reduce
P60G2
NOTE
Do
not
paint pitot
tube,
gas
caps.
or
aileron
gap
seals.
Also
do
not
paint
antenna covers
which
were
not painted
at
the
factory.
19-4
MODEL
172
SERIES
SERVICE
MANUAL
REQUIRED
MATERIALS
MATERIAL
NO/TYPE
AREA
OF APPLICATION
STRIPPER
Strypeeze
Stripper
Used
to
strip
primer
overspray
CLEANER
DX440
Wax
and Grease
Used
to
clean
aircraft
exterior
Remover
Imperial
Cleaner
Used
to
remove
grease,
bug
stains
etc.
Klad
Polish
Used
to
clean
aluminum
finish
808
Polishing
Compound Used
to
rub out
overspray
SOLVENT
Naphtha
Used
to
clean
plexiglass
and
ABS
Methly
Ethyl
Used
to
tack
aircraft prior
to
topcoat
Ketone
(MEK)
CLOTH
HEX
Wiping
Cloth
Used
with
solvent
to
clean
aircraft
exterior
FILLER
White
Streak
Used
to
fill
small
dents
MASKING
Class
A
Solvent
Proof
Used
to
mask
areas
not
to
be
painted
Paper
Tape
Y218
Used
for
masking
small
areas
Tape
Y231
Used
for
masking
small
areas
19-5.
FACILITY.
Painting
facilities
must
include
the
ability
to
maintain
environmental
control
to
a
minimum
temperature
of
65°F.,
and
a
positive
pressure
inside
to
preclude
the
possibility
of
foreign
material
damage.
All
paint
equipment
must
be
clean,
and
accurate
measuring
containers
available
for
mixing
protective coatings.
Modified
Urethane
has
a
pot
life
of
four
to
eight
hours,
depending
on
ambient
temperature
and
relative
humidity.
Use
of
approved
respirators
while
painting
is
a
must,
for
personal
safety.
All
solvent
containers
should
be
grounded
to
prevent
static
build-up.
Catalyst
materials
are toxic,
therefore.
breathing
fumes
or
allowing
contact with
skin
can
cause
serious
irritation.
Material
stock
should
be
rotated
to
allow
use
of
older
materials
first,
because
its
useful
life
is
limited.
All
supplies
should
be
stored
in
an
area
where
temperature
is
higher
than
50°F.,
but
lower
than
90°F.
Storage
at
90°F.
is
allowable
for
no
more
than
sixty
days
providing
it is
returned
to
room
temperature
for
mixing
and
use.
Modified
urethane
paint requires
a
minimum
of
seven
days
to
cure
under
normal
conditions.
if
humidity
and
temperature
is
lower,
curing
time
will
be
extended
to a
maximum
of
14
days.
During
the
curing
period,
indiscriminate
use
of
masking
tape,
abrasive polishes,
or
cleaners
can
cause damage
to
finish.
Desirable
curing
temperature
for
modified
urethane
is
60°F.
for
a
resulting
satisfactory
finish.
19-6.
CLEAN
UP.
a.
Inspect
airplane
for
any
surface
defects,
such
as dents
or
unsatisfactory previous
repairs,
and
correct
according
to
paragraph
19-13.
19-5
MODEL
172
SERIES
SERVICE
MANUAL
b.
Wipe
excess
sealer
from
around
windows
and
skin laps
with
naptha.
Mask
windows,
ABS
parts,
and
any
other
areas
not
to
be
primed,
with
3M
tape
and
Class
A
Solvent
Proof
Paper.
Care
must
be
exer-
cised
to
avoid
cuts,
scratches
or
gouges
by
metal
objects
to
all
plexiglass
surfaces,
because cuts
and
scratches
may
contribute
to
crazing
and
failure
of
plexiglass
windows.
NOTE
Do
not
use
strong
solvents
such
as
xytol,
toluol,
MEK,
or
lacquer
thinner
on
plexiglass
as
crazing
will occur.
c.
Methyl
Ethyl
Ketone
(MEK)
solvent
should
be
used
for
final
cleaning
of
airplanes
prior
to
painting.
The
wiping
cloths
shall
be
contaminant
and
lint
free
HEX.
Saturate
cloth
in
the
solvent
and
wring
out
so
it
does
not
drip.
Wipe the
airplane
surface
with
the
solvent
saturated
cloth
in
one
hand,
and
immediately
dry
with
a
clean
cloth
in
the
other
hand.
It
is important
to
wipe
dry
solvent
before
it
evaporates.
When
an
airplane
has
paint
or
zinc chromate
overspray
on
the
exterior,
stripper
may
be
used
to
remove
the
overspray.
The
stripper
may
be
applied
by
brush
and
will
require
a
few
minutes
to
soften
the
overspray.
Heavy
coatings
may
require
more
than
one
application
of
the
stripper.
Use
extreme
care
to
prevent
stripper
from
running
into
faying
surfaces
on
corrosion
proofed
airplanes.
After
removal
of
the
overspray,
clean
the
airplane
with
Methyl
Ethyl
Ketone
(MEK)
solvent
in
the
prescribed
manner.
NOTE
It is
imperative
that
clean
solvent
be
used
in
cleaning
airplanes.
Dispose
of
contaminated
solvent immediately.
Fresh
solvent
should
be
used
on
each
airplane.
WARNING
Use
explosion proof containers
for
storing
wash
solvents
and
other
flammable
materials.
19-7.
PRE-PRIMING.
a.
For
all
standard
aircraft.
P60G2
primer
shall
be
mixed
one
part
primer
to
one
and
one
half
parts
R7K44
catalyst
by
volume.
Mix
only
in
stainless
steel
or
lined
containers.
After
mixing,
allow
primer
to
set
for
thirty
minutes
before
spraying.
Pot
life
of
the
mixed
primer
is
six
hours.
All
mixed
material
should
be
discarded
if
not
used
within
this
time.
Pot
pressure
during
spray
operation should
be
approximately
10
±1
psi.
Air
pressure
should
be
40
to
50
psi
at
the
gun.
Blow
loose
contaminant
off
the
airplane
with
a
jet
of
clean.
dry
air.
Cover
the
flap
tracks,
nose
gear
strut
tube, wheels,
and
shimmy
dampener
rod
ends.
ABS
parts
and
other
pre-primed
parts
do
not
receive
wash
primer.
19-
MODEL
172
SERIES
SERVICE
MANUAL
WARNING
AIRCRAFT
SHOULD
BE
GROUNDED
PRIOR
TO
PAINTING
TO
PREVENT
STATIC ELECTRICITY
BUILD-UP
AND
DISCHARGE.
19-8.
PRIMING.
a.
Apply
primer
in
one
wet
even coat.
Dry
film
thickness
to
be
.0003
to
.0005
inches.
Do
not
topcoat
until
sufficiently
cured.
When
scratching
with
firm
pressure
of
the
fingernail
does
not
penetrate
the
coating,
the
primer
is
cured.
Primer
should
be
topcoated
within four hours
after
application.
19-9.
PREPAINTING.
a.
On
standard
aircraft
mix
the
required
amount
of
Imron
with
Imron
192S
Activator
in
a
3
to
1
ratio.
Mix
thoroughly
(no
induction
time required
before
spraying).
Imron
shall
be
thinned
with
Y8485S
Imron Reducer
to
obtain
a
spraying
viscosity
of
18
to
20
seconds
on
a
No.
2
Zahn
Cup.
Viscosity
should
be
checked
after
4
hours
and
adjusted
if
necessary.
b.
When
applying
modified
urethane
finishes,
the
painter
should
wear
an
approved
respirator,
which
has
a
dust
filter
and organic
vapor
cartridge,
or
an
air
supplied
respirator.
All
modified
urethane
finishes
contain
some
isocyanate.
which
may
cause
irritation
to
the
respiratory
tract
or
an
allergic
reaction.
Individuals
may
become
sensitized
to
isocyanates.
c.
The
pot
life
of
the
mixture
is
approximately
6-8
hours
at
75°F.
Pot
pressure
should
be
approximately
12
psi
during application.
Air
pressure
at
the
gun
should
be
40
to
50
psi.
d.
Scuff
sand
the
primer
only
where
runs
or
dirt
particles are
evident
Minor
roughness
or
grit
may
be
removed
by
rubbing
the
surface
with
brown
Kraft
paper
which
has
been
thoroughly wrinkled.
Unmask
ABS
and
other
preprimed
parts
and
check
tapes.
Clean
surface
with
a
jet
of
low
pressure,
dry
air.
19-10.
PAINTING
ALL-OVER
WHITE
OR
COLOR.
a.
Complete
painting
of
the
plane
should
be
done
with
2
or
3
wet,
even
coats.
Dry
coats
will
not
reflow,
and
will
leave
a
grainy
appearance.
b.
Allow
5
minute period for
the
finish
to
flash
off
before
moving
aircraft
to
the
oven.
c.
Move
to
the
force
dry
oven
and
dry
for
approximately
1
1/2
hours
at
120°F
to
140°F.
d.
Dry
film
thickness
of
the
overall
color
should
be
between
approximately
2.0
mils.
Films
in
excess
of
3.0
mils
are not
desirable.
19-11.
MASKING FOR
STRIPES.
a.
Remove
airplane
from
the
oven.
Allow
airplane
to
cool
to
room
temperature
before
masking.
b.
Mask
stripe
area
using
3M
Tape
Y231
or
3M
Tape
Y218
and Class
A
solvent
proof
paper.
Double
tape
all
skin
laps
to
prevent
blow
by.
c.
Airplanes
which
will
have
a
stripe
only configuration
shall
be
masked. cleaned,
and
primed,
in
stripe
area
only.
d.
If
the
base
coat
is
not
over
72
hours
old,
the
stripe
area
does
not
require
sanding.
If
sanding
is
necessary
because
of
age
or
to
remove
surface
defects,
use
#400
or
#600
sandpaper.
Course
paper
will
leave
sand marks
which
will
decrease
gloss
and
depth
of
gloss
of
the
finish.
The
use
of
power
sanders
should
be
held
to
a
minimum,
if
used.
exercise
care
to
preclude
sanding through
the
white
base
coat.
Wipe
surface
to
be
striped
with
a
tack
cloth
and
check
all
tapes.
19-7
MODEL
172
SERIES
SERVICE
MANUAL
e.
Stripe
colors
on
Imron
base
coat
will
be
Imron
Enamel.
Mix
as
outlined
in
paragraph
19-9.
f.
Painting
of
the
stripe
should
be
done
with
2
or
3
wet-even
coats.
Dry
coats
will
not
reflow,
and
will
leave
a
grainy
appearance. Stripes
may
be
force
dried or
air
dried.
Film
thickness
of
a
stripe
is
approximtely
1.5
mil
to
2.0
mils.
g.
Do
not remove
masking
tape
and
paper
until
the
paint
has dried
to
a
"dry
to
touch"
condition. Care
should
be
exercised
in
removal
of
the
masking
to
prevent
damage
to
the finish
h.
Modified
urethane
finishes
are
sensitive
to
moisture.
therefore.
should
be
stored
out
of
rain
until
cured.
19-12.
TOUCH UP.
When
necessary
to
touch
up
or
refinish
an area.
the
defect
should
be
sanded
with
#400
and
followed
by
#600
sandpaper.
Avoid.
if
possible,
sanding
through
the
primer.
If
the
primer
is
penetrated
over an
area
1/2
inch
square
or
larger.
repriming
is
necessary.
Avoid
spraying
primer
on
the
adjacent
paint
as
much
as
possible.
Since
urethane
finishes
cannot
be
"spotted
in"
repairs
should
be
in
sections extending
to
skin
laps
or stripe
lines.
a.
Dry
overspray
and
rough
areas
may
be
compounded
out
with
DuPont
#808
rubbing
compound.
b.
Grease, bug
stains.
etc..
may
be
removed
from
painted surfaces
with
DX440
Wax
and
Grease Remover
or
Imperial
Cleaner.
Klad
Polish may
be
used
on
bare
aluminum
to
remove
stains,
oxides, etc.
c.
Rework
areas,
where
paint
or
primer
removal
is
required.
may
be
stripped
with
Strypeeze
Paint
Remover.
All
traces
of
stripper
must
be
removed
before
refinishing.
19-13.
REPAIR
OF
DENTS.
NOTE
Refer
to
Section
18
for
repair
of
damaged area(s).
Dent
repair
as
described
in
this
Section
is
applicable
only
to
smooth
dents
in
the
skin
that
are
free
from
cracks,
sharp
corners,
are not
stress
wrinkles
and
do
not
interfere
with
any
internal
mechanism.
a.
To
repair
dents
use
White
Streak
Filler
or
equivalent.
Mix
White
Streak
in
the
correct
proportion
as
recommended
by
the
manufacturer.
b.
Do
not
apply
White
Streak
Filler
over paint.
All
paint
shall
be
removed
in
the
repair
area
and
the
aluminum
surface sanded
lightly
to
increase
adhesion. Apply
the
White
Streak
to
a
level
slightly
above
the
surrounding
skin.
After
drying
for
10-15
minutes.
sand
the
filler
flush
with
the
skin
surface,
using
care
to
feather the
edges.
NOTE
Application
of
a
top
coat
thickness
in
excess
of
5.0
mils,
requires
a
control
surface balance
check.
19-8
MODEL
172
SERIES
SERVICE
MANUAL
SECTION
20
WIRING
DIAGRAMS
12
VOLT
Page
No.
TABLE
OF
CONTENTS
Aerofiche/
Manual
Code
Letters
...............
3C18/20-2
Clock
...................
3D1320-21
Cross
Reference
Listing
......
3C19/20-3
LIGHTING
D.C.
POWER
Map/Auxiliary
Instrument
Light
Ground
Service
Receptacle
.....
3C20/20-4
..........................
3D14/20-22
Bus
Bar.
Primary,
Alternator
Compass/Instrument
Light
...
3D15/20-23
and Electronic
...........
3C21.20-5
Compass/Instrument
Light
....
3D16
20-24
Alternator
System,
60
Amp
. . .
3C23/20-7
Instrument
Panel
Post
Alternator
System,
60 Amp
. ..
3C24/20-8
Lighting
................
3D1720-25
Ammeter
.................
3D1/20-9
Instrument
Panel
Post
Battery
Circuit
...........
3D2,20-10
Lighting
...............
3D18/20-26
IGNITION
Dome/Courtesy
Lights
.......
3D19,20-27
Magneto
.. ..........
...
3D3/20-11
Landing/Taxi
Light
.........
3D20/20-28
FUEL
AND OIL
Landing/Taxi
Light
.........
3D21/20-29
Oil
Temperature
...........
3D4
20-12
Landing/Taxi
Light
.........
3D22
20-30
ENGINE
INSTRUMENTS
Navigation
Lights
..........
3D23
20-31
Fuel Gage
Transmitter
.......
3D5
20-13
Flashing
Beacon
Light
.......
3D24
20-32
Hourmeter
.. .........
3D6/20-14
Map
Light
-
Control
Wheel
....
3E1/
20-33
Cylinder
Head
Temperature
. . .
3D7
20-15
Wing
Tip
Strobe
Light
.......
3E2
20-34
Carburetor
Air
Temperature
HEATING,
VENTING/DE-ICING
Gage
............... .
3D8/20-16
Cigar
Lighter
.............
3E3'20-35
FLIGHT INSTRUMENTS
Pitot Heater
...............
3E4
20-36
Turn
Coordinator
.....
3D9.20-17
CONTROL
SURFACE
SECTION
Turn
and Bank
Indicator
.....
3D10/20-18
Wing
Flaps
-
Electric
........
3E5
20-37
Encoding
Altimeter
........
3D11/20-19 Wing
Flaps
-
Electric
........
3E6
20-38
Blind
Encoder
.... ........
3D12 20-20
24
VOLT
D.C
POWER
FUEL
AND
OIL
Battery
Circuit
...... ....
3E7/20-39
Oil
Temperature
...........
3E24
20-56
Ground
Service
Receptacle
....
3E8
20-40
Oil
Temperature
...........
3F1
20-57
Bus
Avionics
Master Switch
. . .
3E9'20-41
ENGINE
INSTRUMENTS
Alternator
System
.........
3E10/20-42
Fuel
Pump
...............
3F2
20-58
Alternator
System
..........
3E1120-43
Fuel
Gage
and
Transmitter
...
3F3
20-58A
Ammeter
. ....
3E12
20-44
Hourmeter
...............
3F5
20-59
Alternator
System
........
3E13/20-45
Hourmeter
...............
3F6
20-60
Bus Bar
Avionics
Master
Switch
Hourmeter
...............
3F7
20-61
.. ... ..... .
3E14/20-46
Carburetor
Air
Temperature
Bus Bar
Avionics
Master
Switch
Gage
...................
3F8
20-62
....... ...... ... ....
3E16
20-48
Instrument
Clusters
Trans
Battery
Circuit
.
.....
...
3E17'20-49
mitter
..................
3F9
20-62A
Ammeter
...... ........
3E18
20-50
Fuel
GageTransmitter
.......
3F11 20-63
Ground
Service
Receptacle
....
3E19/20-51
Hourmeter
...............
3F12
20-64
Ground
Service
Receptacle
. .
3E20
20-52
Hourmeter
...............
3F13
20-65
Alternator
System
..........
3E21
20-53
Carburetor
Air
Temperature
IGNITION
Gage
..................
3F14
20-66
Magneto...
...........
3E22
20-54
FLIGHT
INSTRUMENTS
Magneto
.................
3E23
20-55
Turn
Coordinator
Turn
and
Bank
Indicator
.....
3F17
20-67
Revision
1
20-1
MODEL
172
SERIES
SERVICE
MANUAL
OTHER
INSTRUMENTS
Flashing
Beacon
Light
......
3G7
20-81
Clock
...
.......
3F18
20-68
Map
Light
-
Control
Wheel
....
3G8
20-82
Digital
Clock
......... ....
3F19
20-69
Wing
Tip
Strobe
Light
.......
3G9
20-83
Clock
...................
3F20
20-70
Landing
Taxi
Lights
....
...
3G10
20-84
LIGHTING
HEATING.
VENTING
DE-ICING
Map
Auxiliary
Instrument
Light
3F21
20-71
Cigar
Lighter
............
3G11
20-85
Compass.
Instrument
Pitot
Heater
...............
3G12
20-86
Light
..................
3F22/20-72
Air
Conditioner
............
3G13
20-87
CompassInstrument
Light
....
3F23,20-73
Circulation
Fan
............
3G14
20-88
Instrument
Panel
Post
Air
Conditioner
............
3G15
20-89
Lighting
................
3F24/20-74
CONTROL
SURFACE
SECTION
Instrument
Panel
Post
Wing
Flaps
-
Electric
........
3G16
20-90
Lighting
................
3G1/20-75
Wing
Flaps
-
Electric
........
3G17
20-91
Dome/Courtesy
Lights
.......
3G2/20-76
Wing
Flaps
-
Electric
........
3G18
20-92
Landing
Taxi
Light
........
3G3/20-77
MISCELLANEOUS
LandingTaxi
Light
.........
3G4/20-78
Vacuum
Out
Warning
Navigation
Lights
..........
3G5/20-79
System
.................
3G19
20-93
Navigation
Lights
..........
3G6/20-80
Standby Vacuum
Pump
......
3G20
20-94
CIRCUIT
FUNCTION
AND
SPECIFIC
CIRCUIT
CODE
LETTERS
A
-
Armament
DH
-
De-Ice
B
-
Photographic
HE
-
Air
Conditioners
C
-
Control
Surface
HF
- Cabin
Ventilation
CA
-
Automatic
Pilot
J
- Ignition
CC
-
Wing
Flaps
JA -
Magneto
CD
-
Elevator
Trim
K
-
Engine
Control
D
-
Instrument
(Other
Than
Flight
or
Engine
KA
-
Starter
Control
Instrument)
KB
-
Propeller
Synchronizer
DA
-
Ammeter
L
-
Lighting
DB
-
Flap
Position Indicator
LA
-
Cabin
DC
-
Clock
LB
-
Instrument
DD
-
Voltmeter
LC
-
Landing
DE
-
Outside
Air
Temperature
LD
-
Navigation
DF
-
Flight
Hour
Meter
LE
- Taxi
E
-
Engine
Instrument
LF
-
Rotating
Beacon
EA
-
Carburetor
Air
Temperature
LG
-
Radio
EB
-
Fuel
Quantity
Gage
and
Transmitter
LH
-
De-ice
EC
-
Cylinder
Head
Temperature
LJ
-
Fuel
Selector
ED
-
Oil
Pressure
LK
-
Tail
Flood
Light
EE
-
Oil
Temperature
LL
-
Recognition Lighting
EF
-
Fuel
Pressure
M
-
Miscellaneous
EG
-
Tachometer
MA
-
Cowl
Flaps
EH
-
Torque
Indicator
MB
-
Electrically
Operated
Seats
EJ
-
Instrument
Cluster
MC
-
Smoke
Generator
EK
-
Turbine
Inlet
Temperature
MD
-
Spray
Equipment
EL
-
Fuel
Flow
ME
-
Cabin
Pressurization
Equipment
F
-
Flight
Instrument
MF
-
Chem
O
2
-
Indicator
Light
FA
-
Bank
and
Turn
P
-
D.
C.
Power
FB
-
Pitot
Static
Tube
Heater
and
Stall
Warning
PA
-
Battery
Circuit
Heater
PB
-
Generator
Circuits
FC
-
Stall
Warning
PC
-
External
Power
Source
FD
-
Speed
Control
System
PH
-
Anti-Ice
Power
Source
FE
-
Indicator
Lights
Q
-
Fuel
and
Oil
G
-
Landing
Gear
QA
-
Auxiliary
Fuel
Pump
,GA
-
Actuator
QB
-
Oil
Dilution
GB
-
Retraction
QC
-
Engine
Primer
GC
-
Warning
Device
(Horn)
QD
-
Main
Fuel
Pumps
GD
-
Limit
Switches
QE
-
Fuel
Valves
GE
-
Indicator
Lights
R
-
Radio
(Navigation
and
Communication)
H
-
Heating.
Air
Conditioning.
Ventilating
RA
-
Instrument
Landing
and
De-Icing
RB
-
Command
HA
-
Anti-Icing
RC
- Radio
Direction
Finding
HB
-
Cabin
Heater
RD
-
VHF
HC
-
Cigar
Lighter
RE
-
Homing
20-2
Revision
1
MODEL
172
SERIES SERVICE
MANUAL
RF -
Marker
Beacon
S
-
Rada
RG
-
Navigation
U
-
Miscellaneous
Electronic
RH
-
High
Frequency
US
-
Identification
-
Friend
or
Foe
RJ
-
Interphone
W-
Warning
and
Emergency
RK
-
UHF
WA
-
Flare
Release
RL
-
Low
Frequency
WB
-
Chip
Detector
RM
-
Frequency
Modulation
WC
-
Fire
Detection System
RP -
Audio
System
and
Audio
Amplifier
WD
-
Low
Level
Fuel
RR
-
Distance
Measuring
Equipment
(DME)
WE
- Vacuum
Warning
System
RS
-
Airborne
Public
Address System
X
-
A.
C.
Power
CIRCUITS
FUNCTION
GAUGE
BASE
COLOR
(or
solid)
STRIPE COLOR
16
Red
None
18
Red
Black
A.
Power
Red
White
20
Red
Green
22
Red
Yellow
Ground
16
Black
None
18
Black
White
Mike
Ground
22
Black
None
Radio
Lights
Dim
18
Yellow
None
Mike
Audio
22
Tan
None
Tan
(Shielded)
None
Mike
Key
22
White Black
Radio
Speaker
20
Green
None
Headphones
22
Blue
None
Dev
22
Gray
Red
Dev
-
22
Gray Green
"Dev."and
"Dev-
circuits
are
for
use
in
Nav-o-matic
300
autopilots
and
any
associated
omni
indicator
circuit
to
which it
connects.
NOTE
All
other
color-coded
wires
are
for
general
use
in
multiconductor
radio
and autopilot
harness
assemblies.
CROSS
REFERENCE
LISTING
OF
SERIAL REQUEST
NUMBERS
LISTED
ON
DIAGRAMS
VS.
AIRCRAFT
SERIAL
NUMBERS.
SR
NO
AIRCRAFT
SERIAL
NO.
SR
NO.
AIRCRAFT
SERIAL
NO.
SR
NO.
AIRCRAFT
SERIAL
NO.
SR7692
17263459
SR8773
17271035
&F17201750
SR9624
17274010
SR7903
17265685
&
F17201385
SR8774
R1722910
&FR17200631 SR9625
R17203400
SR7904
FR17200562
SR9014
17270900&
F17201750
SR9742 17274183
&
F17202040
SR8133
17265685
&
F17201515
SR9104
17272885
SR10034
17275035
&
F17202135
SR8134
FR17200591 SR9105
R1723200
SR10056
17275035
&
F17202135
SR8146
R1722000
SR9145
17270790
SR10092
17275800
&
F17202195
SR8259 17265782
&
F17201445
SR9187
17271576
SR10185 17275675
SR8453
17269310
&
F17201640
SR9270 17272885.
F17201910
&
SR10248
17275361
&
F17202136
SR8454
R1722725
&FR17200621
R1723200
SR10412
17276260
&
F17202234
SR8490 17267585.
F17201515
SR9429
R17272383
SR10523
17276080
&
F17202216
R1722000
&
FR17200591 SR9435
17271744
&
F17201830
SR10581
17275869
SR8552 17268213
&
R1722141
SR9583
17273154
SR11072
17276517
SR8596
17269310,
R1722825
SR9608
17269310
thru
17272884
F17201640
thru
F17201909
Revision
1
20-3
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
20-5
MODEL
172
SERIES SERVICE
MANUAL
Bus Bar. Primary. alternator
&
Electronic (Sheet 2 of 2)
MODEL
172
SERIES SERVICE
MANUAL
20-7
MODEL
172
SERIES SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
20-9
MODEL
172
SERIES
SERVICE
MANUAL
::I 'AtP
MODEL
172
SERIES SERVICE
MANUAL
EQUIPMENT
TABLELE_____-
MODEL
172
SERIES
SERVICE
MANUAL
20-12
MODEL
172
SERIES
SERVICE
MANUAL
20-13
MODEL
172
SERIES SERVICE
MANUAL
20-14
MODEL
172
SERIES SERVICE
MANUAL
20-15
MODEL
172
SERIES
SERVICE
MANUAL
20-16
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
20-18
MODEL
172
SERIES
SERVICE
MANUAL
20-19
20-20
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
OO
m
I (!tF)C 'w
l
_______
LICSrt
&4sy
____
a_
WIRING
DIAGRAM_
20-22
MODEL
172
SERIES
SERVICE
MANUAL
20-23
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
20-25
MODEL
172
SERIES SERVICE
MANUAL
MODEL
172
SERIES
SERVICE
MANUAL
MODEL 172 SERIES SERVICE MANUAL
20-28
MODEL
172
SERIES
SERVICE
MANUAL
20-29
MODEL
172
SERIES
SERVICE
MANUAL
BLK/wr
);
20-30
MODEL
172
SERIES
SERVICE
MANUAL
0, ~141Q c~e~ ~
*r,
CIINQ
20-31
MODEL
172
SERIES SERVICE
MANUAL
-. -
I -"/I i/.u N_
mom
C
t,. I
;
20-32
MODEL
172
SERIES SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
L.M
'~IduI
I
Cm
1"11)
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
MODEL
172
SERIES
SERVICE
MANUAL
20-37
MODEL
172
SERIES
SERVICE
MANUAL
20-38
MODEL
172
SERIES SERVICE
MANUAL
20-39
MODEL
172
SERIES SERVICE
MANUAL
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES
SERVICE
MANUAL
^NOTE8.
SR
845
3)
:R
I54)
A-
ZO
|
GF
R
20-42
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES
SERVICE
MANUAL
MODEL
172
SERIES SERVICE
MANUAL
20-45
MODEL
172
SERIES SERVICE
MANUAL
Bus
Bar
&
Avionics
Master
Switch
(Sheet
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