D2027 1 13 R172 SERIES (1977 THRU 1981) Cessna_172XP_R172_1977 1981_MM_D2027 Cessna 172XP 1977 1981 MM
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Cessna
ATextron Comoanv
Service Manual
1977
Thru
1981
MODEL R172
SERIES
i)
Member of GAMA
FAA APPROVAL HAS BEEN OBTAINED ON TECHNICAL DATA IN THIS PUBLICATION THAT AFFECTS AIRPLANE TYPE DESIGN.
REVISION 1 TO THE BASIC MANUAL INCORPORATES TEMPORARY REVISION I, DATED 3 OCTOBER, 1994.
COPYRIGHT C 1995
CESSNA
21
AIRCRAFT COMPANY
WICHITA, KANSAS. USA
D2027-1-13
(RGI-50-8/00)
REVISION 1
APRIL 1980
2 OCTOBER 1995
Cessna
A Textron Company
TEMPORARY REVISION NUMBER 5
DATE 5 April 2004
MANUAL TITLE
Model R172 Series 1977 Thru 1981 Service Manual
MANUAL NUMBER - PAPER COPY
D2027-1-13
MANUAL NUMBER - AEROFICHE
D2027-1-13AF
TEMPORARY REVISION NUMBER
D2027-1TR5
MANUAL DATE
REVISION NUMBER
21 April 1980
1
DATE
2 October 1995
This Temporary Revision consists of the following pages, which affect and replace existing pages
in the paper copy manual and supersede aerofiche information.
SECTION
2
2
PAGE
24
27
AEROFICHE
FICHE/FRAME
1/B17
1/B20
SECTION
PAGE
AEROFICHE
FICHE/FRAME
REASON FOR TEMPORARY REVISION
1. To add the cleaning interval of the engine fuel injection nozzles.
FILING INSTRUCTIONS FOR THIS TEMPORARY REVISION
1. For Paper Publications, file this cover sheet behind the publication's title page to identify the
inclusion of the Temporary Revision into the manual. Insert the new pages into the publication
at the appropriate locations and remove and discard the superseded pages.
2.
For Aerofiche Publications, draw a line with permanent red ink marker, through any aerofiche
frame (page) affected by the Temporary Revision. This will be a visual identifier that the
information on the frame (page) is no longer valid and the Temporary Revision should be
referenced. For "added" pages in a Temporary Revision, draw a vertical line between the
applicable frames. Line should be wide enough to show on the edges of the pages. Temporary
Revisions should be collected and maintained in a notebook or binder near the aerofiche library
for quick reference.
© Cessna Aircraft Company
A
TEMPORARY REVISION NUMBER 4
DATE 7 October 2002
MANUAL TITLE
Model R172 Series 1977 Thru 1981 Service Manual
MANUAL NUMBER - PAPER COPY
D2027-1-13
MANUAL NUMBER - AEROFICHE
D2027-1-13AF
TEMPORARY REVISION NUMBER
D2027-1TR4
MANUAL DATE 21 April 1980
REVISION NUMBER
1
DATE 2 October 1995
This Temporary Revision consists of the following pages, which affect and replace existing pages
in the paper copy manual and supersede aerofiche information.
SECTION
2
2
2
2
2
2
15
15
15
PAGE
24
24A/Deleted
27
28
29
30
24A
24B
24C
AEROFICHE
FICHE/FRAME
SECTION
PAGE
AEROFICHE
FICHE/FRAME
1/B17
NA
1/B20
Added
Added
Added
2/B02
2/B03
Added
REASON FOR TEMPORARY REVISION
1. To add a Component Time Limits section and a fuel quantity indicating system operational test.
FILING INSTRUCTIONS FOR THIS TEMPORARY REVISION
1. For Paper Publications, file this cover sheet behind the publication's title page to identify the
inclusion of the Temporary Revision into the manual. Insert the new pages into the publication at
the appropriate locations and remove and discard the superseded pages.
2.
For Aerofiche Publications, draw a line with permanent red ink marker, through any aerofiche frame
(page) affected by the Temporary Revision. This will be a visual identifier that the information on the
frame (page) is no longer valid and the Temporary Revision should be referenced. For "added"
pages in a Temporary Revision, draw a vertical line between the applicable frames. Line should be
wide enough to show on the edges of the pages. Temporary Revisions should be collected and
maintained in a notebook or binder near the aerofiche library for quick reference.
COPYRIGHT © 2002
CESSNA AIRCRAFT COMPANY
WICHITA, KANSAS, USA
TEMPORARY REVISION NUMBER 3
DATED 7 January 2000
MANUAL TITLE
MODEL R172 SERIES 1977 THRU 1981 SERVICE MANUAL
MANUAL NUMBER - PAPER COPY D2027-1-13
AEROFICHE
TEMPORARY REVISION NUMBER PAPER COPY D2027-1TR3
MANUAL DATE
21 APRIL 1980
REVISION NUMBER
1
D2027-1-13AF
AEROFICHE N/A
DATE 2 OCTOBER 1995
This Temporary Revision consists of the following pages, which affect existing pages in the
paper copy manual and supersede aerofiche information.
SECTION
PAGE
AEROFICHE
FICHE/FRAME
2
24A
Added
2
28A
17
17
4A
4B
Added
SECTION
PAGE
AEROFICHE
FICHE/FRAME
Added
Added
REASON FOR TEMPORARY REVISION
To include the inspection requirements of Cessna Service Bulletin SEB99-18.
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:
File this cover sheet behind the publication's title page to identify the inclusion of the
Temporary Revision into the manual. Insert the new pages into the publication at the
appropriate locations. Draw a line, with a permanent red ink marker, through any
superceded information.
For Aerofiche Publications:
Draw a line through any aerofiche frame (page) affected by the Temporary Revision with a
permanent red ink marker. This will be a visual identifier that the information on the frame
(page) is no longer valid and the Temporary Revision should be referenced. For "added"
pages in a Temporary Revision, draw a vertical line between the applicable frames which is
wide enough to show on the edges of the pages. Temporary Revisions should be collected
and maintained in a notebook or binder near the aerofiche library for quick reference.
COPYRIGHT ©2000
CESSNA AIRCRAFT COMPANY
WICHITA, KANSAS, USA
TEMPORARY REVISION NUMBER 2
DATED
MANUAL TITLE
Model R172 Series Service Manual (1977 Thru 1981)
MANUAL NUMBER - PAPER COPY
D2027-1-13
TEMPORARY REVISION NUMBER - PAPER COPY
MANUAL DATE
April 3, 1998
21 April 1980
AEROFICHE
D2027-1TR2-13
REVISION NUMBER
D2027-1-13AF
AEROFICHE
1
DATE
N/A
2 October 1995
This Temporary Revision consists of the following pages, which affect and replace existing pages in the paper copy
manual and supersede aerofiche information.
CHAPTER/
SECTION/
SUBJECT
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
PAGE
AEROFICHE
FICHE/FRAME
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1A08
1A09
1A10
1A11
1A12
Added
Added
Added
Added
Added
Added
Added
Added
Added
Added
Added
CHAPTER/
SECTION/
SUBJECT
1
1
1
1
1
1
1
13
13
13
13
13
13
13
13
PAGE
AEROFICHE
FICHE/FRAME
17
18
19
20
21
22
23
1
2
3
4
5
6
7
8
Added
Added
Added
Added
Added
Added
Added
K18
1K19
1K20
1K21
1K22
1K23
1K24
Added
REASON FOR TEMPORARY REVISION
1. To add wet torque values for McCauley propeller hub bolts and add standard torque value tables.
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 the new pages in the publication at the appropriate locations and remove and discard the
superseded pages.
For Aerofiche Publications:
Draw a line, with a permanent red ink marker, through any aerofiche frame (page) affected by the temporary
revision. This will be a visual identifier that the information on the frame (page) is no longer valid and the
temporary revision should be referenced. For "added" pages in a temporary revision, draw a vertical line
between the applicable frames. Line should be wide enough to show on the edges of the pages. Temporary
revisions should be collected and maintained in a notebook or binder near the aerofiche library for quick
reference.
COPYRIGHT © 1998
CESSNA AIRCRAFT COMPANY
WICHITA, KANSAS, USA
MODEL R172 SERIES SERVICE MANUAL
LIST OF EFFECTIVE PAGES
INSERT LATEST REVISED PAGES. DESTROY SUPERSEDED PAGES.
NOTE
The portion of the text affected by the revisions is indicated by a vertical line in the outer margins of the
page. Changes to illustrations are indicated by miniature pointing hands.
Original ......
Revision ......
0 .......
1 .......
21 April 1980
2 October 1995
TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 444.
*The asterisk indicates pages changed, added or deleted by the current revision.
Page
No.
*Title ............................
*A ..............................
*i thru iv .........................
*1-1 .............................
1-2 thru 1-5 .......................
1-6 Blank ........................
*2-1 .............................
2-2 thru 2-9 .......................
*2-10 thru 2-12 ...................
*2-12A ...........................
*2-12B Blank .....................
2-13 thru 2-23 ..................
*2-24 ............................
2-25 thru 2-26 ....................
*2-27 ............................
2-28 Blank .......................
3-1 thru 3-8 .......................
*3-9 .............................
3-10 thru 3-22 ....................
*3-23 thru 3-24 ...................
4-1 thru 4-8 .......................
*5-1 ............................
5-2 thru 5-5 .......................
*5-6 .............................
5-7 thru 5-18 ......................
*5-19 ............................
5-20 thru 5-30 ....................
*5-31 ............................
5-32 .............................
*5-33 ............................
*5-34 Blank ......................
6-1 thru 6-7 .......................
6-8 Blank ........................
7-1 thru 7-5 .......................
*7-6 .............................
7-7 thru 7-10 ......................
8-1 thru 8-3 .......................
A Revision 1
Revision
No.
.
1
1
1
1
0
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1
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1
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Revision
No.
*8-4 .............................
8-5 thru 8-6 .......................
9-1 thru 9-7 .......................
9-8 Blank ........................
10-1 thru 10-8 ............ .. ......
11-1 thru 11-32 ...................
*11-33 ...........................
11-34 thru 11-38 ..................
12-1 thru 12-5 ....................
*12-6 thru 12-7 ...................
12-8 thru 12-16 ...................
*12-17 thru 12-18 .................
12-19 thru 12-23 ..................
12-24 Blank ......................
13-1 thru 13-7 ....................
13-8 Blank .......................
14-1 thru 14-5 ....................
14-6 Blank .......................
*15-1 ............................
15-2 thru 15-9 ....................
*15-10 ...........................
15-11 thru 15-14 ..................
*15-14A thru 15-14B ..............
*15-15 ...........................
15-16 thru 15-17 ..................
*15-18 thru 15-19 .
................
15-20 thru 15-22 ..................
*15-22A thru 15-22B ..............
*15-23 ...........................
15-24 thru 15-26 ..................
16-1 thru 16-54 ...................
17-1 thru 17-33 ...................
17-34 Blank ......................
18-1 thru 18-5 .. ......... .........
18-6 Blank .......................
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MODEL R172 SERIES SERVICE MANUAL
TABLE OF CONTENTS
PAGE NO.
SECTION
1.
2.
3.
4.
5.
5.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
AEROFICHE/MANUAL
GENERAL DESCRIPTION ..............................
GROUND HANDLING, SERVICING, CLEANING,
LUBRICATION AND INSPECTION ......................
FUSELAGE ............................................
WINGS AND EMPENNAGE .............................
LANDING GEAR AND BRAKES .........................
AILERON CONTROL SYSTEM ..........................
WING FLAP CONTROL SYSTEM ........................
ELEVATOR CONTROL SYSTEM ........................
ELEVATOR TRIM TAB CONTROL SYSTEM .............
RUDDER CONTROL SYSTEM ...........................
ENGINE ...............................................
FUEL SYSTEM .........................................
PROPELLER AND GOVERNOR .........................
UTILITY SYSTEMS ....................................
INSTRUMENTS AND INSTRUMENT SYSTEMS ..........
ELECTRICAL SYSTEMS ................................
STRUCTURAL REPAIR .................................
PAINTIN G .............................................
WIRING DIAGRAMS ...................................
1A8/1-1
1A16/2-1
1B24/3-1
1D2/4-1
1D13/5-1
1F1/6-1
1F14/7-1
1G6/8-1
1G18/9-1
1H7/10-1
1H22/11-1
1J16/12-1
1K18/13-1
1L5/14-1
2A2/15-1
2B8/16-1
2D20/17-1
2F11/18-1
2F22/19-1
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.
Revision 1
i
MODEL R172 SERIES SERVICE MANUAL
CROSS REFERENCE LISTING OF POPULAR
NAME VS. MODEL NUMBERS AND SERIALS
All aircraft, regardless of manufacturer, are certificated under model number designations. However,
popular names are often used for marketing purposes. To provide a consistent method of referring to the
various aircraft, model numbers will be used in this publication unless names are required to differentiate
between versions of the same basic model. The following table provides a listing of popular name, model
number and serial number.
POPULAR NAME
HAWK XP
HAWK XP II
REIMS/CESSNA HAWK XP
REIMS/CESSNA HAWK XP II
HAWK XP
HAWK XP H
MODEL
YEAR
SERIALS
MODEL
BEGINNING
ENDING
1977
R172K
R1722000
R1722724
1978
R172K
R1722725
R1722929
1977
FR172K
FR1720591
FR1720620
1978
FR172K
FR1720621
FR1720630
1979
R172K
R1720680,R1722930
R1723199
1980
R172K
R1723200
R1723399
(except R1723398)
REIMS/CESSNA HAWK XP
REIMS/CESSNA HAWK XP II
ii
1979
FR172K
FR1720631
FR1720655
1980
FR172K
FR1720656
FR1720665
HAWK XP
HAWK XP II
1981
R172K
R1723400
R1723454
REIMS/ CESSNA HAWK XP
REIMS/CESSNA HAWK XP II
1981
FR172K
FR1720666
FR1720675
Revision 1
MODEL R172 SERIES SERVICE MANUAL
INTRODUCTION
This manual contains factory-recommended procedures and instructions for ground handling, servicing, and
maintaining Cessna R172 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 R172 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, supplemented, and automatically amended by all information issued in Service News Letters, Service Bulletins, Supplier 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 various 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., RECOMMENDED BY CESSNA ARE SOLELY BASED ON THE USE OF NEW, REMANUFACTURED, 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, REPLACEMENT TIME LIMITS, OVERHAUL TIME LIMITS, THE METHOD OF INSPECTION, LIFE LIMITS, CYCLE LIMITS, ETC., FOR SUCH NON-CESSNA PARTS MUST
BE OBTAINED FROM THE MANUFACTURER AND/OR SELLER OF SUCH NONCESSNA PARTS.
1.
REVISIONS/CHANGES. These are issued to the Service Stations by Cessna Aircraft Company for
this publication as required, and include only pages that require updating.
2.
REISSUE. Manual is reissued to Service Stations 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 Service Station 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 Service Stations so that they have the latest authoritative recommendations for servicing these Cessna aircraft. Therefore,
it is recommended tuat Cessna owners utilize the knowledge and experience of the Service Station Organization.
Revision 1 iii
MODEL R172 SERIES SERVICE MANUAL
SUPPLEMENTAL TYPE CERTIFICATE INSTALLATIONS
Inspection, maintenance and parts requirements for supplemental type certificate (STC) installations are not included 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 CARE SUPPLIES AND PUBLICATIONS CATALOG
A Customer Care Supplies and Publications Catalog is available from your Cessna Service Station 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.
CUSTOMER COMMENTS ON MANUAL
Cessna Aircraft Company has endeavored to furnish you with an accurate, useful, up-to-date manual. This manual 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 1
MODEL R172 SERIES SERVICE MANUAL
SECTION 1
GENERAL DESCRIPTION
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
Page No.
Aerofiche/Manual
GENERAL DESCRIPTION ............
Model R172 and FR172 Series ........
Description .....................
Aircraft Specifications ............
Stations .........................
Material And Tool Cautions .......
Torque Data .....................
Safetying ........................
Control Cable Wire Breakage
And Corrosion Limitations ........
NA/1-1
NA/1-1
NA/1-1
NA/1-1
NA/1-1
NA/1-5
NA/1-6
NA/1-13
NA/1-22
1-1. GENERAL DESCRIPTION.
1-2. MODEL R172 AND FR172 SERIES
1-3. DESCRIPTION. Cessna Model R172 and FR172
Series aircraft, described in this manual, are high
wing monoplanes 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.
Standard seating accommodations consist of
individual reclining back pilot and copilot seats,
and dual reclining back, bench type center seats. A
fold-up auxiliary rear seat may be installed as
optional equipment. A baggage area is provided aft
of the center seats when the auxiliary seat is folded
up. These aircraft are powered by a Continental
six-cylinder, horizontally opposed, air cooled fuel
injected engine, driving an all-metal, constant
speed propeller. All aircraft feature rear side
windows, a "wrap-around" rear window and a
swept-back fin and rudder.
Temporary Revision Number 2
April 3, 1998
Leading
SPECIFICATIONS.
1-4. AIRCRAFT
particulars of these airplanes, with dimensions
based on gross weight, are given in Figure 1-1. If
these dimensions are used for constructing a hanger
or computing clearances, remember that such
factors as nose gear strut inflation , tire pressures,
tire sizes, and load distribution may result in some
dimensions that are considerably different from
those listed.
1-5.
STATIONS. A station diagram is shown in figure 12 to assist in locating equipment when a written
description is inadequate or impractical.
1-1
MODEL R172 SERIES SERVICE MANUAL
GROSS WEIGHT
Normal Category ...................
Utility Category ....................
FUEL CAPACITY
Total
(Standard) ................
Usable (Standard) ................
Total
(Extended Range) ...........
Usable (Extended Range) ...........
OIL CAPACITY
(Without External Filter) ..............
(With External Filter) ................
ENGINE MODEL ....................
PROPELLER(Constant Speed) ...........
MAIN WHEEL TIRE (Standard) ...........
Pressure ........................
NOSE WHEEL TIRE (Standard) ...........
Pressure ........................
NOSE GEAR STRUT PRESSURE
(Strut Extended) ...................
WHEEL ALIGNMENT (Aircraft Empty)
Camber
.........................
Toe-In ..........................
AILERON TRAVEL
Up .............................
FR172
2550 Pounds
2200 Pounds
2550 Pounds
2200 Pounds
52
49
68
66
52
49
68
66
Gallons
Gallons
Gallons
Gallons
..................
Gallons
Gallons
Gallons
Gallons
8 Quarts.
9 Quarts
CONTINENTAL 10-360
76 Inch McCauley
6.00 X 6, 6-Ply Rating
38 PSI
5.00 X 5, 6-Ply Rating
45 PSI
8 Quarts
9 Quarts
CONTINENTAL 10-360 SERIES
76 Inch McCauley
6.00 X 6, 6-Ply Rating
38 PSI
5.00 X 5, 6-Ply Rating
45 PSI
45 PSI
45 PSI
3
3
±1
0.0 to .18.0 Inch
Down ...........................
WING FLAP TRAVEL
R172
±1
0.0 to .18.0 Inch
20
±1°
20
±1°
15
±1°
15
±1
THRU R17203399
0° to 40 +0° -2
BEGINNING WITH
R17203400
0° to 30 +00 -20
THRU FR1720665
0° to 40° +0° -2
BEGINNING WITH FR1720666
0" to 30 +0° -2°
16°10' ±1°
16°10' ±10
16°10' ±1
16°10' ±1
17°44' +1°
17°44' ±10
17°44' +1°
17°44' ±1°
28°, +1
-0°
28,
+1° -0°
+1° -0°
23,
+10°
RUDDER TRAVEL (Parallel to Waterline)
Right
...........................
Left ............................
RUDDER TRAVEL (Perpendicular to Hinge Line)
Right ...........................
Left ............................
ELEVATOR TRAVEL
Up ............................
Down
23,
...........................
ELEVATOR TRIM TAB TRAVEL
Up
(Thru 1980 Model Year) .........
Down (Thru 1980 Model Year) .........
(Beginning 1981 Model Year)
Up
Down (Beginning 1981 Model Year)
.....
.....
-0
28°, + 1 -0
13°, +1 -0°
28°, +1° -0°
13, +1 -0°
+1° -0°
+1° -0
22°, +1° -0°
19, +1° -0°
22,
19,
PRINCIPAL DIMENSIONS
Wing Span (With Strobe Lights) ........
Track Width (Tubular Spring) ..........
Tail Span ........................
Length ..........................
Fin Height (Maximum With Nose Gear
Depressed and Flashing Beacon
Installed on Fin) ...................
BATTERY LOCATION ..................
429.84 Inches
429.84 Inches
97.6 Inches
135.14 Inches
327.14 Inches
97.6 Inches
135.14 Inches
327.14 Inches
105.48 Inches
Aft of Baggage Area
105.48 Inches
Aft of Baggage Area
Figure 1-1. Aircraft Specifications
1-2
Temporary Revision Number 2
April 3,1998
MODEL R172 SERIES SERVICE MANUAL
23.62 WS
FS 3.37
FS 65.33
cooo
Figure 1-2. Reference Stations (Sheet 1 of 2)
Figure 1-2.
Temporary Revision Number 2
April 3, 1998
Reference Stations (Sheet 1 of 2)
1-3
MODEL R172 SERIES SERVICE MANUAL
NOTE:
22.875 WS
71.125 WS
85.875 WS
showing integral fuel cell.
23.65 WS
136.00 WS
208.00 WS
Figure 1-2. Reference Stations (Sheet 2 of 2)
SHOP NOTES:
1-4
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
1-6. MATERIAL AND TOOL CAUTIONS -GENERAL
A. Mercury
TEST
AND
OTHER
THERMOMETERS
EQUIPMENT CONTAINING MERCURY, MUST
NOT BE USED ON THE AIRPLANE.
Mercury, by the amalgamation process, can penetrate
any break in the finish, paint or sealing coating of a
metal structural element. An oxide coating on a dry
metallic surface will tend to inhibit an immediate
action while a bright, polished, shining or scratched
surface will hasten the process. Moisture will also
promote the amalgamation process. Soils, greases or
other inert contaminants, present on the metal
surfaces, will prevent the start of the action. The
corrosion and embrittlement which results from an
initial penetration, can be extremely rapid in
structural members under load. Once it has begun,
there is no known method of stopping it. Complete
destruction of the load carrying capacity of the metal
will result.
b. Maintenance Precautions
WARNING
REPAIR AND
MAINTENANCE,
DURING
SERVICING OF THE AIRPLANE, MANY
AND
ENVIRONMENTS
SUBSTANCES
ENCOUNTERED MAY CAUSE INJURY IF
ARE
NOT
PRECAUTIONS
PROPER
OBSERVED.
Carefully read and follow all instructions, and
especially adhere to all cautions and warnings
provided by the manufacturer of the product being
used. Use appropriate safety equipment as required
including goggles, face shields, breathing apparatus,
protective clothing and gloves. Fuel, engine oil,
solvents, volatile chemicals, adhesives, paints and
strong cleaning agents may cause injury when
contacting the skin or eyes, or when vapors are
breathed. When sanding composites or metals or
otherwise working in an area where dust particles
may be produced, the area should be ventilated and
the appropriate respirator must be used.
c. General Usage Solvents
General usage solvents include the following:
Methyl Propyl Ketone
Toluene
Isopropyl Alcohol
Acetone
Methylene Chloride
1,1,1-Trichloroethane
Naptha
Trichloroethylene
Temporary Revision Number 2
April 3, 1998
These chemicals/solvents are generally colorless,
evaporate quicker than water, and tend to give off vapors
in higher quantities as their temperature increases. The
vapors are generally heavier than air, which causes them
collect
to in low lying areas or push normal oxygen and air
out of a confined area. This situation can lead to oxygen
deficient atmospheres. Many general usage solvents are
also flammable.
Solvents are hazardous to work with because of their
flammability, rate of evaporation and reaction to
oxidizers. Solvents can also be an irritant to the skin and
eyes.
A single spark, a smoldering cigarette, or even
atmospheric conditions can ignite solvent vapors. The
lower the flash point of the chemical, the more likely it is
to become flammable. Generally, flashpoints of less than
100°F (37.8°C) are considered flammables. Examples of
solvent flash points are shown below:
SOLVENT
FLASH-POINT
(7.2 ° C)
Methyl Propyl Ketone
45°F
Isopropyl Alcohol
53.6°F (12 ° C)
Touluene
39°F
(3.9 ° C)
Acetone
1.4 °
(-17°C)
The rate of evaporation is closely tied to flammability,
because normally the vapors must be present to ignite the
liquid. Vaporization also allows solvents, even those that
are not flammable, to get into the air and into the body's
blood stream through the lungs.
Solvents can also react explosively with oxidizers
(chemicals which release oxygen). A very violent and
uncontrollable reaction takes place which generates heat
rapidly. For this reason, it is very important for each
person to be aware of specific chemicals in use in the work
area, and to adhere to the labeling of containers. Chemical
manufacturers are required to label each container with a
diamond shaped symbol: red for flammable and yellow for
oxidizers.
Solvents can also damage the hands and skin. Solvents
dry out skin and dissolve the natural oils. The condition
can develop into an irritation, or if left untreated with
continuous exposure, it may progress to a dermatitis.
Damaged skin allows other contaminants to worsen the
condition, because the contaminants have easier access to
the deeper levels of the skin. In serious cases, blood
poisoning is also possible.
The best defense against skin irritation is not to be
exposed. If exposure is unavoidable, steps should be taken
to limit exposure times. Prolonged exposure to these
irritants can lead to long term liver damage.
1-5
MODEL R172 SERIES SERVICE MANUAL
1-7.
TORQUE DATA - MAINTENANCE PRACTICES
To ensure security of installation and prevent over
stressing of components during installation, the torque
values outlined in this section and other applicable
chapters of this manual should be used during
installation and repair of components.
The torque value tables, listed in this section, are
standard torque values for the nut and bolt
combinations shown. If a component requires special
torque values, those values will be listed in the
applicable maintenance practices section.
Torque is typically applied and measured using a
torque wrench. Different adapters, used in conjunction
with the torque wrench, may produce an actual torque
to the nut or bolt which is different from the torque
reading. Figure 1-3 is provided to help calculate actual
torque in relation to specific adaptors used with the
torque wrench.
Free Running Torque Value
Free running torque (friction torque) value is the
torque value required to rotate a nut on a threaded
shaft, without tightening. Free running torque
value does not represent the torque values listed in
the tables of this section. Torque values listed in the j.
tables represent the torque values above free
running torque.
EXAMPLE
If final torque required is to be 150 inch-pounds and
the free running torque is 25 inch-pounds, then the
free running torque must be added to the required
torque to achieve final torque of 150 +25 = 175
inch-pounds.
Breakaway torque value is the value of torque
required to start a nut rotating on a threaded shaft,
and does not represent free running torque value. It
should be noted that on some installations the
breakaway torque value cannot be measured.
e. Sheet metal screws should be tightened firmly, but
not to a specific torque value.
f. Countersunk washers used with close tolerance
bolts must be installed correctly to ensure proper
torquing (refer to Figure 1-4).
g. There is no satisfactory method of determining the
torque previously applied to a threaded fastener.
When retorquing, always back off approximately 1/4
turn or more before reapplying torque.
h. Tighten accessible nuts to torque values per Table
1-1. Screws attached to nutplates, or screws with
threads not listed in Table 201 should be tightened
firmly, but not to a specific torque value. Screws
used with dimpled washers should not be drawn
tight enough to eliminate the washer crown.
i. Table 1-1 is not applicable to bolts, nuts and screws
used in control systems or installations where the
required torque would cause binding or would
interfere with proper operation of parts. On these
installations, the assembly should be firm but not
binding.
Castellated Nuts.
Self-locking and non self-locking castellated nuts,
except MS17826, require cotter pins and should be
tightened to the minimum torque value shown in
Table 1-1. The torque may be increased to install the
cotter pin, but this increase must not exceed the
alternate torque values.
MS17826 self-locking, castellated nuts shall be
torqued per Table 1-1.
The end of the bolt or screw should extend through
the nut at least two full threads including the
chamfer.
General Torquing Notes:
DO NOT REUSE SELF-LOCKING NUTS.
a. These requirements do not apply to threaded parts
used for adjustment, such as turnbuckles and rod
ends.
b. Torque values shown are for clean, nonlubricated
parts. Threads should be free of dust, metal filings,
etc. Lubricants, other than that on the nut as
purchased, should not be used on any bolt
installation unless specified.
c. Assembly of threaded fasteners, such as bolts,
screws and nuts, should conform to torque values
shown in Table 1-1.
d. When necessary to tighten from the bolt head,
increase maximum torque value by an amount
equal to shank friction. Measure shank friction
with a torque wrench.
1-6
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
NOTE:
WHEN USING A TORQUE WRENCH ADAPTER WHICH
CHANGES THE DISTANCE FROM THE TORQUE WRENCH
DRIVE TO THE ADAPTER DRIVE, APPLY THE FOLLOWING FORMULAS TO OBTAIN THE CORRECTED TORQUE
READING.
SHORT OPEN END
ADAPTER
HANDGRIP
TORQUE
CENTERLINE
WRENCH
/(PREDETERMINED)
WRENCH
DRIVE
CENTERLINE
ADAPTER
DRIVE
CENTERLINE
SETSCREW
ADAPTER
FORMULA TxL
EXAMPLE (WITH "E" AS PLUS DIMENSION)
T
Y
E
L
HOSE CLAMP
ADAPTER
=
=
=
=
y= 135x10 =117.39
135IN-LB
UNKNOWN
1.5 N
10.0 IN
Y = 117 IN-LB
LEGEND
T = ACTUAL (DESIRED) TORQUE
OPEN-END WRENCH
ADAPTER
WRENCH
DRIVE
CENTERLINE
ADAPTER
DRIVE
CENTERLINE
HANDGRIP
CENTERLINE
(PREDETERMINED)
FLARE NUT WRENCH
ADAPTER
FORMULA Tx
L=
Y
L-E
TORQUE
WRENCH
EXAMPLE (WITH "E" AS MINUS DIMENSION)
SPANNERWRENCH
SPANNER
WRENCH
ADAPTER
T =
Y =
LL=
=
=
135 IN-LB
UNKNOWN
10.0
IN
10.0IN
1.5 IN
y = 135x10 =1350 = 158.82
85
10 -1.5
Y = 159 IN-LB
5598C2005
Torque Wrench and Adapter Formulas
Figure 1-3 Sheet 1
Temporary Revision Number 2
April 3, 1998
1-7
MODEL R172 SERIES SERVICE MANUAL
EXTERNAL WRENCHING HEAD
CORRECT INSTALLATION
INSTALL WASHER WITH COUNTERSUNK
FACE NEXT TO BOLT HEAD RADIUS
INTERNAL WRENCHING HEAD
I
.
COUNTERSUNK
STANDARD
INCORRECT INSTALLATION
CAUTION:
NEVER INSTALL STANDARD
WASHER OR COUNTERSUNK
WASHER IN REVERSE WHEN
USING BOLTS WITH RADIUS
UNDER THE HEAD
5598C1004
5598C1004A
Washer Installation Close Tolerance Bolts
Figure 1-4 Sheet 1
1-8
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
Table 1-1: Torque Requirements For Steel Bolts, Screws and Nuts (Inch-Pounds)
FINE THREADED SERIES
COARSE THREADED SERIES
Size
TENSION
TYPE NUTS
Standard
Torque
SHEAR TYPE NUTS
EXCEPT MS17826
Standard
Torque
Size
TENSION
TYPE NUTS
Standard
Torque
SHEAR
TYPE NUTS
Standard
Torque
8-36
10-32
1/4-28
5/16-24
3/8-24
7/16-20
1/2-20
9/16-18
5/8-18
3/4-16
7/8-14
1-14
1-1/8-12
1-1/4-12
12 to 15
20 to 25
50 to 70
100 to 140
160 to 190
450 to 500
480 to 690
800 to 1000
1100 to 1300
2300 to 2500
2500 to 3000
3700 to 4500
5000 to 7000
9000 to 11000
7 to 9
12 to 15
30 to 40
60 to 85
95 to 110
270 to 300
290 to 410
480 to 600
660 to 780
1300 to 1500
1500 to 1800
2200 to 3300
3000 to 4200
5400 to 6600
8-32
10-24
1/4-20
5/16-18
3/8-16
7/16-14
1/2-13
9/16-12
5/8-11
3/4-10
7/8-9
1-8
1-1/8-8
1-1/4-8
12 to 15
20 to 25
40 to 50
80 to 90
160 to 185
235 to 255
400 to 480
500 to 700
700 to 900
1150 to 1600
2200 to 3000
3700 to 5000
5500 to 6500
6500 to 8000
7 to 9
12 to 15
25 to 30
48 to 55
95 to 110
140 to 155
240 to 290
300 to 420
420 to 540
700 to 950
1300 to 1800
2200 to 3000
3300 to 4000
4000 to 5000
Fine Thread Tension application nuts include: AN310, AN315, AN345, MS17825, MS20365, MS21044 through MS21048,
MS21078, NAS679, NAS1291.
Fine Thread Shear application nuts include: AN316, AN320, MS21025, MS21042, MS21043, MS21083, MS21245, NAS1022,
S1117.
Coarse Thread application nuts include: AN340, MS20341, MS20365, MS35649.
Size
8-36
10-32
1/4-28
5/16-24
3/8-24
7/16-20
1/2-20
9/16-18
5/8-18
3/4-16
7/8-14
1-14
1-1/8-12
1-1/4-12
SELF-LOCKING CASTELLATED
MS17826 NUT (Shear Nut)
ALTERNATE TORQUE LIMITS FOR
CASTELLATED STEEL NUTS
Standard
Torque
TENSION NUTS
Alternate
Torque
Alternate
Torque
-
12 to 15
30 to 40
60 to 80
95 to 110
180 to 210
240 to 280
320 to 370
480 to 550
880 to 1010
1500 to 1750
2200 to 2700
3200 to 4200
5900 to 6400
SHEAR NUTS
Alternate
Torque
-
12 to 20
30 to 45
60 to 90
95 to 125
180 to 225
240 to 300
320 to 400
480 to 600
880 to 1100
1500 to 1900
2200 to 3000
3200 to 5000
5900 to 7000
20 to 28
50 to 75
100 to 150
160 to 260
450 to 560
480 to 730
800 to 1070
1100 to 1600
2300 to 3350
2500 to 4650
3700 to 6650
5000 to 10000
9000 to 16700
12 to 19
30 to 48
60 to 100
95 to 170
270 to 390
290 to 500
480 to 750
660 to 1060
1300 to 2200
1500 to 2900
2200 to 4400
3000 to 6300
5400 to 10000
Castellated steel tension application nuts include: AN310, MS17825.
Castellated steel shear application nuts include: AN320.
NOTE: Use alternate torque values only if alignment between the bolt and nut cotter pin slots can not be reached using the
standard torque values.
The torque values contained in this table are recommended for all installation procedures contained in this manual,
except were other values are stipulated. These torque values are not to used for checking the tightness of of installed
parts during service.
Temporary Revision Number 2
April 3, 1998
1-9
MODEL R172 SERIES SERVICE MANUAL
Table 1-1: Torque Values Nuts, Bolts and Screws (Newton Meters)
FINE THREADED SERIES
COARSE THREADED SERIES
TENSION
SHEAR TYPE NUTS
TENSION
SHEAR
TYPE NUTS
EXCEPT MS17826
TYPE NUTS
TYPE NUTS
Size
Standard
Torque
Standard
Torque
Size
Standard
Torque
Standard
Torque
8-36
10-32
1/4-28
5/16-24
3/8-24
7/16-20
1/2-20
9/16-18
5/8-18
3/4-16
7/8-14
1-14
1-1/8-12
1-1/4-12
1.4 to 1.7
2.3 to 2.8
5.6 to 7.9
11.3 to 15.8
18.1 to 21.5
50.8 to 56-5
54.2 to 78.0
90.4 to 113.0
124.3 to 146.9
259.9 to 282.5
282.5 to 339.0
418.0 to 508.4
564.9 to 790.9
1016.9 to 1242.8
0.8 to 1.0
1.4 to 1.7
3.4 to 4.5
6.8 to 9.6
10.7 to 12.4
30.5 to 33.9
32.8 to 46.3
54.2 to 67.8
74.6 to 88.1
146.9 to 169.5
169.5 to 203.4
248.6 to 372.9
339.0 to 474.5
610.1 to 745.7
8-32
10-24
1/4-20
5/16-18
3/8-16
7/16-14
1/2-13
9/16-12
5/8-11
3/4-10
7/8-9
1-8
1-1/8-8
1-1/4-8
1.4 to 1.7
2.3 to 2.8
4.5 to 5.6
9.0 to 10.1
18.1 to 20.9
26.6 to 28.8
45.2 to 54.2
56.5 to 54.2
79.1 to 101.7
129.9 to 180.8
248.7 to 338.9
418.0 to 564.9
621.4 to 734.4
734.4 to 903.9
0.8 to 1.0
1.4 to 1.7
2.8 to 3.4
5.4 to 6.2
10.7 to 12.4
15.8 to 17.5
27.1 to 32.8
33.9 to 47.4
47.5 to 61.0
79.1 to 107.3
146.9 to 203.3
248.6 to 338.9
372.9 to 451.9
451.9 to 564.9
Fine Thread Tension application nuts include: AN310, AN315, AN345, MS17825, MS20365, MS21044 through MS21048,
MS21078, NAS679, NAS1291.
Fine Thread Shear application nuts include: AN316, AN320, MS21025, MS21042, MS21043, MS21083, MS21245, NAS1022,
S1117.
Coarse Thread application nuts include: AN340, MS20341, MS20365, MS35649.
SELF-LOCKING CASTELLATED
MS17826 NUT (Shear Nut)
ALTERNATE TORQUE LIMITS FOR
CASTELLATED STEEL NUTS
TENSION NUTS
SHEAR NUTS
Size
Standard
Torque
Alternate
Torque
Alternate
Torque
Alternate
Torque
8-36
10-32
1/4-28
5/16-24
3/8-24
7/16-20
1/2-20
9/16-18
5/8-18
3/4-16
7/8-14
1-14
1-1/8-12
1-1/4-12
1.4 to 1.7
3.4 to 4.5
6.8 to 9.0
10.7 to 12.4
20.3 to 23.7
2 7.1 to 31.6
36.2 to 41.8
4.2 to 62.1
99.4 to 114.1
169.5 to 197.7
248.6 to 305.1
361.6 to 474.5
666.6 to 723.1
1.4 to 2.3
3.4 to 5.1
6.8 to 10.1
10.7 to 14.1
20.3 to 25.4
27.1 to 33.9
36.2 to 45.2
54.2 to 67.8
99.4 to 124.3
169.5 to 214.7
248.6 to 339.0
361.6 to 564.9
666.6 to 790.9
2.3 to 3.2
5.6 to 8.5
11.3 to 16.9
18.1 to 29.4
50.8 to 63.3
54.2 to 82.5
90.4 to 120.9
124.3 to 180.8
259.9 to 378.5
282.5 to 525.4
418.0 to 751.3
564.9 to 1129.9
1016.9 to 1886.9
1.4 to 2.1
3.4 to 5.4
6.8 to 11.3
10.7 to 19.2
30.5 to 44.1
32.8 to 56.5
54.2 to 84.7
74.6 to 119.8
146.9 to 248.6
169.5 to 327.7
248.6 to 497.1
339.0 to 711.8
610.1 to 1129.9
Castellated steel tension application nuts include: AN310, MS17825.
Castellated steel shear application nuts include: AN320.
NOTE: Use alternate torque values only if alignment between the bolt and nut cotter pin slots can not be reached using the
standard torque values.
The torque values contained in this table are recommended for all installation procedures contained in this manual,
except were other values are stipulated. These torque values are not to used for checking the tightness of of installed
parts during service.
1-10
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
Torque Requirements for Hi-Lok Fasteners
Use Table 1-2 to determine torque requirements for Hi-Lok fasteners.
NOTE:
This table is used in conjunction with MS21042 self-locking nuts.
Table 1-2. Torque Values Hi-Lok Fasteners (Used with MS21042 Self-Locking Nuts)
NOMINAL
FASTENER
DIAMETER
6-32
8-32
10-32
1/4-28
5/16-24
3/8-24
7/16-20
1/2-20
ALLOY STEEL
180 - 200 KSI
(INCH POUNDS)
8
12
20
50
100
160
450
480
to
to
to
to
to
to
to
to
10
15
25
70
140
190
500
690
ALLOY STEEL
180 - 200 KSI
(NEWTON METERS)
0.9
1.4
2.3
5.6
11.3
18.1
50.8
54.2
to
to
to
to
to
to
to
to
1.1
1.7
2.8
7.9
15.8
21.5
56.5
78.0
Torque Requirements for Electrical Current Carrying And Airframe Ground Fasteners
Use Table 1-3 to determine torque requirements for threaded electrical current carrying fasteners.
Torque values shown are clean, nonlubricated parts. Threads shall be free of dust and metal filings. Lubricants, other than on
the nut as purchased, shall not be used on any bolt installations unless specified in the applicable chapters of this manual.
All threaded electrical current carrying fasteners for relay terminals, shunt terminals, fuse limiter mount block terminals
and bus bar attaching hardware shall be torqued per Table 1-3.
NOTE:
There is no satisfactory method of determining the torque previously applied to a threaded fastener. When
retorquing, always back off approximately 1/4 turn or more before reapplying torque.
Use Table 1-4 to determine torque requirements for threaded fasteners used as airframe electrical ground terminals.
Table 1-3. Torque Values Electrical Current Carrying Fasteners
FASTENER
DIAMETER
TORQUE VALUE
(INCH POUNDS)
6-32
8-32
10-32
3/16
1/4
5/16
3/8
1/2
8
13
20
20
40
80
105
130
Temporary Revision Number 2
April 3, 1998
to 12
to 17
to 30
to 30
to 60
to 100
to 125
to 150
TORQUE VALUE
(NEWTON METERS)
0.9
1.5
2.3
2.3
4.5
9.0
11.9
14.7
to
to
to
to
to
to
to
to
1.4
1.9
3.4
3.4
6.8
11.3
14.1
16.9
1-11
MODEL R172 SERIES SERVICE MANUAL
Table 1-4. Torque Values Airframe Electrical Ground Terminals
FASTENER
DIAMETER
TORQUE VALUE
(INCH POUNDS)
TORQUE VALUE
(NEWTON METERS)
5/16
3/8
130 to 150
160 to 190
14.7 to 16.9
18.1 to 21.5
Torque Requirements for Rigid Tubing and Hoses
Use Table 1-5 to determine torque requirements for tubes and hoses.
Table 1-5. Tubing/Hose Torque Limits (Inch-Pounds)
Flared or Flareless Fitting with
Aluminum or Annealed Stainless Steel
Tubing, and Hose with Aluminum Inserts
Hose
Size
Tubing
O.D.
-2
1/8
Min
45
Max
55
Min
65
Max
75
-3
-4
3/16
1/4
75
105
85
115
95
135
105
150
-5
-6
-8
-10
5/16
3/8
1/2
5/8
135
160
265
340
145
175
290
375
180
260
475
665
200
285
525
735
-12
-16
3/4
1
425
710
470
785
855
1140
945
1260
Flared or Flareless Fitting with Steel
Tubing, and Hose with Steel Inserts
Table 1-5. Tubing/Hose Torque Limits (Newton Meters)
Hose
Size
Tubing
O.D.
-2
-3
-4
-5
-6
-8
-10
-12
-16
1/8
3/16
1/4
5/16
3/8
1/2
5/8
3/4
1
1-12
Flared or Flareless Fitting with
Aluminum or Annealed Stainless Steel
Tubing, and Hose with Aluminum Inserts
Flared or Flareless Fitting with Steel
Tubing, and Hose with Steel Inserts
Min
Max
Min
Max
5.1
8.5
11.5
15.3
18.1
29.9
38.4
48.0
80.2
6.2
9.6
13.0
16.4
19.8
32.8
42.4
53.1
88.7
7.3
10.7
15.3
20.3
29.4
53.7
75.1
96.6
128.8
8.5
11.9
16.9
22.6
32.2
59.3
83.0
106.8
142.4
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
1-8. SAFETYING - MAINTENANCE PRACTICES
Safety Wire Inconel (Uncoated), Monel (Uncoated).
Used for general safety wiring purposes. Safety wiring
is the application of wire to prevent relative movement
of structural or other critical components subjected to
vibration, tension, torque, etc. Monel to be used at
temperatures up to 700°F (370°C) and inconel to be
used at temperatures up to 1500 F (815 C). Identified
by the color of the finish, monel and inconel color is
natural wire color.
Copper, is cadmium plated and dyed yellow in accordance
with FED-STD 595.
This wire will be used for shear and seal wiring
applications. Shear applications are those where it is
necessary to purposely break or shear the wire to
permit operation or actuation of emergency devices.
Seal applications are those where the wire is used with
a lead seal to prevent tampering or use of a device
without indication. Identified by the color of the finish,
copper wire is dyed yellow,
Aluminum Alloy (Alclad 5056), is anodized and dyed blue
in
with FED-STD
FED-STD 595.
595.
in accordance
accordance with
This wire will be used exclusively for safety wiring
magnesium parts.
NOTE
Surface treatments which obscure visual identification
of safety wire is prohibited.
Inconel or monel, wire can be substituted for same
diameter and length of carbon steel or corrosion resistant
Safety Wire Installation (Refer to Figure 1-5).
SCREWS IN CLOSELY SPACED GEOMETRIC
PATTERNS WHICH SECURE HYDRAULIC OR
AIR SEALS, HOLD HYDRAULIC PRESSURE, OR
USED IN CRITICAL AREAS SHOULD USE THE
OF SAFETY WIRING.
DOUBLE TWIST METHOD
DOUBLE TWIST METHOD OF SAFETY WIRING.
Single wire method of safety wiring shall use the largest
nominal size wire listed in Table 1-6, which will fit the
hole.
The double twist method of safety wiring shall be used as
the common method of safety wiring. It is really one wire
twisted on itself several times. The single wire method of
safety wiring may be used in a closely spaced, closed
geometrical pattern (triangle, square, circle, etc.), on
parts in electrical systems, and in places that would make
advisable. Closely spaced
the
more advisable. Closely spaced
method more
wire method
the single
single wire
shall be considered a maximum of two inches between
centers.
Use single wire method for shear and seal wiring
application. Make sure the wire is installed so that it can
be easily broken when required in an emergency
situation. For securing emergency devices where it is
necessary to break the wire quickly, use copper only.
Safety wiring by the double twist method shall be done as
follows:
wire.
Wires are visually identifiable by their colors: natural for
inconel and monel, yellow for copper, and blue for
aluminum.
Cotter Pin.
The selection of material shall be in accordance with
temperature, atmosphere and service limitations.
Safety Wire.
The size of the safety wire shall be in accordance with
the requirements of Table 1-6.
0.032 inch diameter safety wire is for general
purpose use; however, 0.020 inch diameter safety
wire may be used on parts having a nominal hole
diameter of less than 0.045 inch, on parts having a
nominal hole diameter between 0.045 and 0.062
inch with spacing between parts of less than two.
inches, or on closely spaced screws and bolts of 0.25
inch diameter and smaller.
0.020 inch diameter copper wire shall be used for
shear and seal wire applications.
When employing the single wire method of locking,
the largest nominal size wire for the applicable
material or part in which the hole will
accommodate shall be used.
Temporary Revision Number 2
April 3, 1998
One end of the safety wire shall be inserted through
one set of safety wire holes in the bolt head. The other
end of the safety wire shall preferably be looped firmly
around the head to the next set of safety wire holes in
the same unit and inserted through this set of safety
wire holes. The "other end" may go over the head when
the clearances around the head are obstructed by
adjacent parts.
The strands, while taut, shall be twisted until the
twisted part is just short of the nearest safety wire hole
in the next unit. The twisted portion shall be within 1/8
inch of the holes in each unit. The actual number of
twists will depend upon the wire diameter, with
smaller diameters being able to have more twists than
larger diameters. The twisting shall keep the wire taut
without over stressing or allowing it to become nicked,
kinked or mutilated. Abrasions from commercially
available twist pliers shall be acceptable.
1-13
MODEL R172 SERIES SERVICE MANUAL
STEP 1.
INSERT WIRE THROUGH BOLT A AND
BEND 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 AGAINST PART.
NOTE:
RIGHT THREADED PARTS SHOWN:
REVERSE DIRECTIONS FOR LEFT PARTS.
CLOCKWISE
BOLT B
DOUBLE-WIRE SAFETYING
COUNTERCLOCKWISE
CLOCKWISE
COUNTERCLOCKWISE
CLOCKWISE
MULTIPLE FASTENER
APPLICATION DOUBLE
TWIST - MULTIPLE
HOLE METHOD.
DOUBLE-TWIST SAFETYING
SINGLE HOLE METHOD
5598C2001
5599C2001
6598C1029
Lockwire Safetying
Figure 1-5, Sheet 1
1-14
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
EXTERNAL SNAP RING
SINGLE-WIRE METHOD
BOLTS IN CLOSELY SPACED, CLOSED
GEOMETRICAL PATTERN. SINGLE
WIRE METHOD
SINGLE FASTENER APPLICATION
SMALL SCREWS IN CLOSELY SPACED, CLOSED
GEOMETRICAL PATTERN, SINGLE WIRE METHOD
NOTE:
RIGHT THREADED
PARTS SHOWN. REVERSE
DIRECTION FOR LEFT
THREADS
5598C1003
5598C1024
5598C1024
5598C1024
Lockwire Safetying
Figure 1-5, Sheet 2
Temporary Revision Number 2
April 3, 1998
1-15
MODEL R172 SERIES SERVICE MANUAL
AN500A
SCREW
5598C1001
5598C1001
Lockwire Safetying
Figure 1-5, Sheet 3
1-16
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
Table 1-6. Safety Wire
SIZE AND NUMBER (MS20995-XXX)
MATERIAL
0.015
0.020
Ni-Cu Alloy
(Monel)
Ni-Cr-Fe Alloy
(Inconel)
_
Carbon Steel
0.032
0.040
0.041
0.047
0.051
0.091
NC20
NC32
NC40
_
_
NC51
NC91
N20
N32
N40
_
N51
N91
F20
F32
F41
F47
F91
C41
C47
C91
AB41
AB47
Corrosion Resistant
Steel
C15
C20
C32
Aluminum Alloy
(Blue)
_
AB20
AB32
Copper (Yellow)
CY15
CY20
The wire shall be twisted to form a pigtail of 3 to 5
twists after wiring the last unit. The excess wire shall
be cut off. The pigtail shall be bent toward the part to
prevent it from becoming a snag. Safety wiring
multiple groups by the double twist double hole
method shall be the same as the previous double twist
single hole method except the twist direction between
subsequent
fasteners
may
be
clockwise
or
counterclockwise.
Spacing
When safety wiring widely spaced multiple groups by
the double twist method, three units shall be the
maximum number in a series.
When safety wiring closely spaced multiple groups,
the number of units that can be safety wired by a
twenty four inch length of wire shall be the maximum
number in a series.
Widely spaced multiple groups shall mean those in
which the fastenings are from four to six inches apart.
Safety wiring 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 the span of the safety wire to less than six
inches.
Tension
Parts shall be safety wired in such a manner that the
safety wire shall be put in tension when the part tends
to loosen. The safety wire should always be installed
and twisted so that the loop around the head stays
down and does not tend to come up over the bolt head
and leave a slack loop.
NOTE
This does not necessarily apply to castellated nuts
when the slot is close to the top of the nut, the wire
will be more secure if it is made to pass along the
side of the stud.
Care shall be exercised when installing safety wire to
ensure that it is tight but not over stressed.
Temporary Revision Number 2
April 3, 1998
_
_
AB91
Usage
A pigtail of 0.25 to 0.50 inch (3 to 5 twists) shall be
made at the end of the wiring. This pigtail shall be bent
back or under to prevent it from becoming a snag.
Safety wre shall be new upon each application.
When castellated nuts are to be secured with safety
wire, tighten the nut to the low side of the selected
torque range, unless otherwise specified, and if
necessary, continue tightening until a slot aligns with
the hole.
In blind tapped hole applications of bolts or castellated
nuts on studs, the safety wiring shall be as described in
these instructions.
the manner
Hollow head bolts are safetied in
prescribed for regular bolts.
Drain plugs and pet cocks may be safetied to a bolt, nut
or other part having a free lock hole in accordance with
the instructions described in this text.
External snap rings may be locked, if necessary, in
accordance with the general locking principles as
described and illustrated. Internal snap rings shall not
be safety wired.
When safety wiring is required on electrical connectors
which use threaded coupling rings, or on plugs which
employ screws or rings to fasten the individual parts of
the plug together, they shall be safety wired with 0.020
inch diameter wire in accordance with the safety
wiring principles as described and illustrated. It is
preferable to safety wire all electrical connectors
individually. Do not safety wire one connector to
another unless it is necessary to do so.
Drilled head bolts and screws need not be safety wired
if installed into self-locking nuts or installed with lock
washers. Castellated nuts with cotter pins or safety
wire are preferred on bolts or studs with drilled shanks
but self-locking nuts are permissible within the
limitations ofMS33588.
1-17
MODEL R172 SERIES SERVICE MANUAL
Larger assemblies, such as hydraulic cylinder heads
for which safety wiring is required but not specified,
shall be safety wired as described in these instructions.
Safetying Turnbuckles
Use of Safety Wire.
Some turnbuckles are secured using safety wire. These
Safety wire shall not be used to secure nor shall safety
safetying procedures are detailed and illustrated in
wire be dependent upon fracture as the basis for
Federal Publication AC 43-13.1A, Safety Methods For
operation of emergency devices such as handles,
Turnbuckles.
switches, guards covering handles, etc., that operateurnbuckles.
emergency mechanism such as emergency exits, fire
Use of Locking Clips
extinguishers, emergency cabin pressure release,
emergency landing gear release and the like.
General instruction for the selection and application of
However, where existing structural equipment or
locking clips (Refer to Figures 1-7 and 1-8).
safety of flight emergency devices require shear wire
to secure equipment while not in use, but which are
Prior to safetying, both threaded terminals should be
dependent upon shearing or breaking of the safety
screwed an equal distance into the turnbuckle barrel,
wire for successful emergency operation of equipment,
and should be screwed in, at a minimum, so no more
particular care shall be exercised to that wiring under
than three threads of any terminal are exposed outside
these circumstances shall not prevent emergency
the body.
operations of these devices.
After the turnbuckle has been adjusted to its locking
Cotter Pin Installation
position, with the groove on terminals and slot
General instruction for the selection and application of
indicator notch on barrel aligned, insert the end of the
cotter pins (Refer to Figure 1-6).
locking clip into the terminal and barrel until the "U"
Select cotter pin material in accordance with
curved end of the locking clip is over the hole in the
center of the barrel.
temperature, atmosphere and service limitations,
Cotter pins shall be new upon each application,
When nuts are to be secured to the fastener with cotter
pins, tighten the nut to the low side (minimum) of the
applicable specified or selected torque range, unless
otherwise specified, and if necessary, continue
tightening until the slot aligns with the hole. In no
case shall the high side (maximum) torque range be
exceeded.
Castellated nuts mounted on bolts may be safetied
with cotter pins or safety wire. The preferred method is
with the cotter pin. An alternate method where the
cotter pin is mounted normal to the axis of the bolt
may be used where the cotter pin in the preferred
method is apt to become a snag.
In the event of more than 50 percent of the cotter pin
diameter is above the nut castellation, a washer
should be used under the nut or a shorter fastener
should be used. A maximum of two washers may be
permitted under a nut.
The largest nominal diameter cotter pin listed in
MS24665, which the hole and slots will accommodate,
shall be used; but in no application to a nut, bolt or
screw shall the pin size be less than the sizes described
in Figure 1-6.
Install the cotter pin with the head firmly in the slot of
the nut with the axis of the eye at right angles to the
bolt shank, and bend prongs so that the head and
upper prong are firmly seated against the bolt.
a. Press the locking clip into the hole to its full extent.
b. The curved end of the locking clip will latch in the
hole in the barrel.
c. To check proper seating of locking clip, attempt to
remove pressed "U" end from barrel hole with
fingers only.
NOTE
Do not use a tool as the locking clip could be
distorted.
Locking clips are for one time use only and should not
be reused.
Both locking clips may be inserted in the same hole of
the turnbuckle barrel or in opposite holes of the
turnbuckle barrel.
In the pin applications, install the cotter pin with the
axis of the eye parallel to the shank of the clevis pin or
rod end. Bend the prongs around the shank of the pin
or rod end.
Cadmium plated cotter pins shall not be used in
applications bringing them in contact with fuel,
hydraulic fluid or synthetic lubricants.
1-18
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
TO PROVIDE CLEARANCE
PRONG MAY BE CUT HERE
v
'
CASTELLATED NUT ON BOLT
ALTERNATE METHOD
CASTELLATED NUT ON BOLT
PREFERRED METHOD
THREAD SIZE
MINIMUM
PIN SIZE
(INCH)
6
0.028
8
0.044
10
0.044
1/4
0.044
5/16
0.044
9/16
5/8
0.086
0.086
3/4
0.086
7/8
0.086
13/8
0.116
1 1/2
0.116
TANGENT
TO PIN
MAXIMUM
COTTER PIN
LENGTH
60 DEGREES
MINIMUM
PIN APPLICATION
Cotter Pin Safetying
Figure 1-6, Sheet 1
Temporary Revision Number 2
April 3, 1998
1-19
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MODEL R172 SERIES SERVICE MANUAL
TURNBUCKLE
LOCKING CLIP
CLEVIS
MS21256
TURNBUCKLE EYE
THIMBLE
TURNBUCKLE BARREL
MS21251
LOCKING CLIP
MS21256
TYPICAL TURNBUCKLE ASSEMBLY
SWAGED
TERMINAL
METHOD OF ASSEMBLING LOCKING CLIPS, TURNBUCKLE BARREL AND TERMINALS
NOMINAL
CABLE DIA.
THREAD
UNF-3
LOCKING
CUP
MS21256
(NOTE 1)
1/16
No. 6-40
-1
-2S
3/32
No. 10-32
-1
-3S
-2
-3L
-1
-4S
-2
-4L
-1
-5S
-2
-5L
-1
-6S
1/8
5/32
3/16
1/4-28
5/16-24
7/32
TURNBUCKLE
BODY
MS21251
-2
-2
1/4
3/8-24
-2
-8L
9/32
7/16-20
-3
-9L
5/16
1/2-20
-3
-10L
NOTE 1:
TWO LOCKING CLIPS REQUIRED FOR EACH
TURNBUCKLE.
5598C1023
5598C1 023
Safetying Tumbuckle Assemblies
Figure 1-8, Sheet 1
Temporary Revision Number 2
April 3, 1998
1-21
MODEL R172 SERIES SERVICE MANUAL
WIRE BREAKAGE
1-9.
CORROLCABLEWIRNE
CORROSION LIMITATIONS BREAKAGE
AND
AND
Examination of Control Cables.
Control cable assemblies are subject to a variety of
environmental conditions and forms of deterioration.
Some deterioration, such as wire or strand breakage, is
easy to recognize. Other deterioration, such as internal
corrosion or cable distortion, is harder to identify. The
following information will aid in detecting these cable
conditions.
Broken Wire Examination (Refer to Figure 1-8).
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 rub 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 cable be bent in a loop to confirm broken
wires. Loosen or remove cable to allow it to be bent in a
loop as shown. While rotating cable, inspect bent area
for broken wires.
1-22
Wire breakage criteria for cables in flap, aileron,
rudder, and elevator systems are as follows:
Individual broken wires at random locations are
acceptable in primary and secondary control cables
when there are no more than six broken wires in
any given ten-inch cable length.
Corrosion.
Carefully examine any cable for corrosion that has a
broken-wire in a section not in contact with wearproducing airframe components, such as pulleys,
fairleads, rub blocks, etc. It may be necessary to
remove and bend cabe
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 metalbrightened, the cable shall be examined closely for
corrosion.
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
BROKEN WIRE UNDETECTED BY
WIPING CLOTH ALONG CABLE
BROKEN WIRE DETECTED VISUALLY
WHEN CABLE WAS REMOVED
AND BENT
DO NOT BEND INTO LOOP SMALLER
THAN 50 CABLE DIAMETERS
NORMAL TECHNIQUE FOR
BENDING CABLE AND
CHECKING FOR BROKEN WIRES
5561C1119
Cable Broken Wire Examination
Figure 1-8 Sheet 1
Temporary Revision Number 2
April 3, 1998
1-23
MODEL R172 SERIES SERVICE MANUAL
SECTION 2
GROUND HANDLING, SERVICING, CLEANING, LUBRICATION AND INSPECTION
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.
TABLE OF CONTENTS
GROUND HANDLING ............
Towing .......................
Hoisting ......................
Jacking ......................
Leveling .....................
Weighing Aircraft ............
Parking ......................
..
Tie-Down ..................
Flyable Storage ...............
Returning Aircraft to Service ...
Temporary Storage ............
Inspection During Storage .....
Returning Aircraft to Service ...
Indefinate Storage ............
Inspection DuringStorage .....
Returning Aircraft to Service ...
SERVICING ......................
Fuel ........................
Fuel Additives ................
Fuel Drains ...................
Engine Oil ....................
Engine Induction Air Filter ....
Vacuum System Air Filter .....
2-1.
Page No.
Aerofiche/Manual
Page No.
Aerofiche/Manual
1A16/2-1
1A 16/2-1
1A19/2-4
1A19/2-4
1A19/2-4
1A19/2-4
1A19/2-4
1A19/2-4
1A19/2-4
1A19/2-4
1A19/2-4
1A20/2-5
1A20/2-5
1A20/2-5
1A21/2-6
1A21/2-6
1A22/2-7
1A22/2-7
1A22/2-7
A22/2-7
1A23/2-8
1A24/2-9
Battery
.
..............
Tires .................. .....
Nose Gear Shock Strut ........
Nose Gear Shimmy Dampener .
Hydraulic Brake Systems .....
CLEANING .....................
Windshield and Windows .....
Plastic Trim .................
Painted Surfaces .............
AluminumSufaces ..........
Engine and Engine
Compartment ................
Upholstery and Interior .......
Propeller ....................
.
.
...... ...
Wheels
LUBRICATION .................
Tachometer Drive Shaft ......
W heel Bearings ..............
Nose Gear Torque Links ......
Wing Flap Actuator .........
Fuel Selector Valve ..........
Rod End Bearings ............
1A24/2-9
INSPECTION
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.
...................
1A24/2-9
1B1/2-10
1B1/2-10
1B1/2-10
1B1/2-10
1B1/2-10
1B12-10
1B3/2-12
1B3/2-12
1B3/2-12
1B3/2-12
1B3/2-12
1B3/2-12
1B3/2-12
1B3/2-12
1B4/2-12A
1B4/2-12A
1B4/2-12A
1B4/2-12A
1B4/2-12A
1B4/2-12A
1B13/2-20
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
Revision 1
2-1
MODEL R172 SERIES SERVICE MANUAL
TOW BAR: PART NUMBER 0501019-1 IS AVAILABLE
FROM THE CESSNA SERVICE PARTS CENTER.
NOTE
Use tow bar carefully to
avoid scarring finish on
speed fairing.
Figure 2-1. Tow Bar
REFER TO SHEET 2
FOR JACKING
INFORMATION
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 R172 SERIES SERVICE MANUAL
JACKING INFORMATION
ITEM NUMBER
TYPE AND NUMBER
REMARKS
1
Block
1x4x4 padded with 1/4" rubber
2
Jack
Any short jack of capable capacity
Universal tail stand
Any tail stand of capable capacity
Cessna #SE-576 (41-1/2" high)
Universal jack stand (FOR USE WITH ITEM 2)
3
4
5 Built-in jack pad
Part of step bracket (SEE CAUTION)
#2-170 Basic jack (includes#2-71
Slide tube: Liftstroke 22-1/2")
#2-70 Slide tube: Liftstroke
22-1/2"
#2-64 Extension cap
#2-109 Leg extension
Min.
Max.
Min.
Max.
Adds
Adds
closed height: 34"
extension height: 56-1/2"
closed height: 57-1/2"
extension height: 80"
4"
12"
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 of adequate strength.
2.
Attach a suitable stand to the tie-down ring. Be sure tail stand weighs enough to
keep tail down and under all conditions that it is strong enough to support 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 (4) and (6) are available from the Cessna Service Parts Center.
Figure 2-2.
Jacking and Leveling (Sheet 2 of 2)
2-3
MODEL R172 SERIES SERVICE MANUAL
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 jig may be
fabricated to apply vertical force to the eyebolts.
2-4. JACKING.
procedures.
Refer to figure 2-2 for jacking
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. Refer to figure 2-2 for
screw locations.
2-6. WEIGHING AIRCRAFT.
Operating Handbook.
Refer to Pilot's
2-7. 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
2-8 if a hangar is not available.
2-8. 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 during cold weather
when accumulated moisture may freeze the
brakes or when the brakes are overheated.
After completing the preceding, proceed to moor the
aircraft as follows:
a. Tie ropes, cables, or chains to the wing tiedown 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.
2-9. FLYABLE STORAGE. Flyable storage is defined as a maximum of 30 days non-operational stor2-4
age and/or the first 25 hours of intermittent engine
operation.
NOTE
The aircraft is delivered from Cessna with
a corrosion preventative aircraft engine oil
(MIL-C-6529, Type II). This engine oil is
a blend of aviation grade straight mineral
oil and a corrosion preventative compound.
This engine oil should be used for the first
25 hours of engine operation. In the event
it is necessary to add oil during the first 25
hours of operation, use only aviation grade
straight mineral oil of the correct viscosity.
During the 30 day non-operational storage or the first
25 hours of intermittent engine operation, every seventh day the propeller shall be rotated by hand without
running the engine. After rotating the engine five revolutions, stop the propeller 45 ° to 90 ° from the position
it was in. If the aircraft is stored outside, tie-down
in accordance with paragraph 2-8. 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. If at the end of thirty (30) days aircraft
will not be removed from storage, the engine shall
be started and run. The preferred method would be
to fly the aircraft for thirty (30) minutes, and up to,
but not exceeding normal oil and cylinder temperatures.
CAUTION
Excessive ground operation shall be avoided.
2-10. RETURNING AIRCRAFT TO SERVICE. After
flyable storage, returning the aircraft to service is
accomplished by performing a thorough pre-flight inspection. At the end of the first 25 hours of engine
operation, drain engine oil and clean oil screens (or
change spin on filter). Service engine with correct
grade and quantity of engine oil. Refer to figure 2-5
and paragraph 2-22 for correct grade of engine oil.
2-11. TEMPORARY STORAGE. Temporary storage
is defined as aircraft in a non-operational 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 with correct grade of gasoline.
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.
MODEL R172 SERIES SERVICE MANUAL
e. Lubricate all airframe items and seal or cover
all openings which could allow moisture 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 the battery periodically and charge as required.
NOTE
An engine treated in accordance with the following may be considered protected against
normal atmospheric 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-L-46002, Grade 1 or equivalent.
h. Using a portable pressure sprayer, 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 propeller so that blades as
near horizontal as possible to provide maximum clearance with 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 outlined in paragraph 2-8. 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.
2-12. INSPECTION DURING STORAGE.
a. Inspect airframe for corrosion at least once a
month and remove dust collections as frequently as
possible. Clean and wax 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 non-operational storage, again perform the procedural steps "g" thru "o" of paragraph
2-11.
2-13. 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. (Refer to Section 1.)
b. Check and install battery.
c. Check oil sump for 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, clean and gap spark plugs.
g. While spark plugs are removed, rotate propeller
several revolutions to clear excess rust preventive
oil from cylinders.
h. Install spark plugs. Torque spark plugs to value
specified in Section 11 and connect spark plug leads.
i. Check fuel strainer. Remove and clean filter
screen if necessary. Check fuel tanks and fuel lines
for moisture and sediment. Drain enough fuel to
eliminate moisture and sediment. Torque bottom nut
of strainer to 25-30 lb-in and safety wire to top assembly of strainer. Wire must have right-hand wrap,
at least 45 degrees.
j. Perform a thorough pre-flight inspection, then
start and warm-up engine.
2-14. INDEFINITE STORAGE. Indefinite storage is
defined as aircraft in a non-operational 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 2-15 are performed
at the intervals specified.
a. Operate engine until oil temperature reaches
normal operating range. Drain engine oil sump then
reinstall and safety drain plug.
b. Fill oil sump to normal operating capacity with
corrosion preventative mixture which has been thoroughly mixed and pre-heated (221°F to 250° F) at the
time it is added to the engine.
2-5
MODEL R172 SERIES SERVICE MANUAL
NOTE
Corrosion preventative mixture consists of one
part compound MIL-C-6529, Type I, mixed
with three parts new lubricating oil of the
grade recommended for service. During all
spraying operation corrosion mixture is preheated to 221 ° to 250°F.
c. Immediately after filling the oil sump with corrosion preventative mixture, fly the aircraft for a
period of time not to exceed a maximum of 30 minutes.
d. With engine operating at 1200 to 1500 RPM and
induction air filter removed, spray corrosion preventative mixture into induction airbox, at the rate
of one-half gallon per minute, until heavy smoke
comes from exhaust stack, then increase the spray
until the engine is stopped.
ICAUTION
Injecting corrosion-preventative mixture
too fast can cause a hydrostatic lock.
e. Do not rotate propeller after completing step
"d. "
f. Remove all spark plugs and spray corrosionpreventative mixture, which has been pre-heated
(221 ° to 250°F,) into all spark plug holes to thoroughly cover interior surfaces of cylinders.
NOTE
To thoroughly cover all surfaces of the
cylinder interior, move the nozzle of the
spray gun from the top to the bottom of
the cylinder. If by accident the propeller
is rotated following this spraying, respray
the cylinders to insure an unbroken coverage
on all surfaces.
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.
1. 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
2-6
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-engineis in storage.
p. Prepare airframe for storage as outlined in
paragraph 2-11 thru step "f."
NOTE
As an alternate method of indefinite storage,
the aircraft may be serviced in accordance
with paragraph 2-11 providing the aircraft is
run up at maximum intervals of 90 days and
then reserviced per paragraph 2-11.
2-15. 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-preventative mixture and replace all
desiccant and protex plugs.
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 mechanism.
2-16. RETURNING AIRCRAFT TO SERVICE.
After indefinite storage, use the following procedure
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 external oil filter, install new filter element.
f. Remove oil sump drain plug (or open quick-drain
valve) and drain oil sump. Install and safety drain
plug (or close quick-drain valve) and service engine
with oil per figure 2-5.
MODEL R172 SERIES SERVICE MANUAL
NOTE
The corrosion-preventative mixture will mix
with the engine lubricating oil, so flushing
the oil system is not necessary. Draining
the oil sump is sufficient.
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 corrosionpreventative mixture from cylinders.
i. Clean, gap, and install spark plugs. Torque
plugs to the value listed in Section 11.
j. Check fuel strainer. Remove and clean filter
screen. Check fuel tanks and fuel lines for moisture
and sediment, and drain enough fuel to eliminate.
k. Perform a thorough pre-flight inspection, then
start and warm-up engine.
l. Thoroughly clean aircraft and flight test aircraft.
2-17.
SERVICING.
2-18. Requirements are shown in figure 2-5. The
following supplements this figure by adding details.
2-19. FUEL. Fill tanks immediately after flight to
lessen condensation. Fuel capacities are listed in
Section 1 and fuel grades are shown in figure 2-5.
2-20. 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
occurring under these unusual conditions it is permissible to add isopropyl alcohol or ethyelene glycol
monomethyl ether (EGME) compound to the fuel supply. See Figure 2-3 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,
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 fuel
nozzle.
2. An alternate method that may be used is to
premix the complete alco ol dosage with some fuel
in a separate clean container (approximately 2-3
gallon capacity) and then transfer this mixture to the
tank 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 PFA55MB, 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 recommended (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.
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 buildup 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.
2-21. FUEL DRAINS. Fuel drains are located at
various places throughout the fuel system. Refer to
Section 12 for location of the various drains in the
system. The fuel tanks and fuel strainer have drain
valves. To activate the tank drain valve for fuel
sampling, place cup up to valve and depress valve
with rod protruding from cup. See Section 12 for
illustration of fuel tank drain valve. The strainer
drain 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 the
intervals specified in figure 2-5. Also, during daily
inspection of the fuel strainer or fuel tanks, if water
is found in the fuel system, all fuel drain plugs should
be removed and all water drained from the system.
2-7
MODEL R172 SERIES SERVICE MANUAL
140
-
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 positive draining of any sludge which may have
collected in the engine oil sump. Engine oil should
be changed every six months, even though less than
the specific hours have accumulated. 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 clean oil screens (when no full-flow
oil filter is installed) whenever oil on the dipstick
appears dirty. Ashless dispersant oil, conforming
to Continental Motors Specification No. MHS-24
shall be used in these engines. Multi-viscosity oil
may be used to extend the operating temperature
range, improve cold engine starting and lubrication
of the engine during the critical warm-up period, thus
permitting flight through wider ranges of climate
change without the necessity of changing oil. The
multi-viscosity grades are recommended for aircraft
engines subjected to wide variations in ambient air
temperatures when cold starting of the engine must
be accomplished at temperatures below 30°F.
2-8
The aircraft is delivered from Cessna with
a corrosion preventative aircraft engine
oil (MIL-C-6529, Type II). If oil must be
added during the first 25 hours, use only
aviation grade straight mineral oil conforming to Specification MIL-L-6082. After
the first 25 hours of operation, drain engine
oil sump and clean both the oil suction strainer and the oil pressure screen if an optional
full-flow oil filter is not installed. If an optional full-flow oil filter is installed, change
the spin on oil filter. Refill sump with aviation grade straight mineral oil and use until
a total of 50 hours has accumulated or oil
consumption has stabilized, then change to
ashless dispersant oil.
Newly-overhauled engines should also be
operated on aviation grade straight mineral
oil until a total of 50 hours has accumulated
or oil consumption has stabilized.
When changing engine oil, remove and clean oil
screens if aircraft is not equipped with an optional
external oil filter. If aircraft is equipped with external oil filter, install new filter and clean suction
screen. Refer to Section 11 for filter removal and
installation. An oil quick-drain valve may be installed in the oil drain port of the oil sump. This
valve provides a quicker and cleaner method of draining engine oil. Drain the engine oil as follows:
MODEL R172 SERIES SERVICE MANUAL
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 oil sump. Push up on quickdrain valve until it locks open, and allow oil to drain
through hose into container.
c. (Without Quick-Drain Valve.) Remove oil drain
plug from oil sump and allow oil to drain into a contaner.
d. After oil has drained, close quick-drain valve
as shown in figure 2-4 and remove hose or reinstall
and safety oil drain plug.
Valve shown open. To close, twist
screwdriver until valve unlocks and
snaps down to closed position.
c. After cleaning as outlined in step "b," filter may
be washed, if necessary, with a mild household detergent and warm water solution. A cold water solution
may be used.
CAUTION
Do not use solvent or cleaning fluids to wash
filter. Use only a mild household detergent
and water solution when washing the filter.
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. The filter should be replaced after 500 hours of engine operation or one year, whichever should
occur first. However, the filter should be
replaced anytime it is damaged. A damaged
filter may have the perforated band broken on
the inside or the outside of the filter, or the
filtering media may have sharp or broken
edges. However, any filter that appears
doubtful should be replaced.
d. After washing, rinse filter in clean water until
rinse water runs clear from filter. Allow water to
from
drain filter and dry with compressed air (not
over 100 psi).
Figure 2-4. Quick-Drain Valve
NOTE
e. Remove and clean oil screens. If optional oil filter is installed, change filter and clean suction screen.
f. Service engine with correct quantity and grade of
engine oil. Refer to figure 2-5 and Section 2.
2-23. ENGINE INDUCTION AIR FILTER. The engine
induction air filter keeps dust and dirt from entering
the induction system. The value of maintaining the
induction air filter in a good clean condition can never
be overstressed. More engine wear is caused through
the use of dirty and/or damaged air filters than is
generally believed. The frequency with which the filter should be removed and cleaned will be determined
primarily by the airplane operating conditions. A
good general rule, however, is to remove, clean,
and inspect filters at least every 50 hours of engine
operating time and more frequently if warranted by
operating conditions. Under extremely dusty conditions, daily servicing of the filters is recommended.
a. Remove filter from airplane as outlined in Section 11.
b. Clean filter by blowing with compressed air (not
over 100 psi) from direction opposite of normal air
flow. Normal air flow for the cylindrical filter is
from outside to inside.
NOTE
Use care to prevent d:%amage to filter element
when cleaning with compressed air. Never
use air pressure greater than 100 psi to clean
filter.
The filtering panels of the filter may become
distorted when wet, but they will return to
e. Be sure induction air box and air inlet ducts to
the engine are clean, inspect and replace filter, if it
is damaged.
f. Install filter as outlined in Section 11.
2-24. VACUM SYSTEM FILTER. The vacuum system central air filter keeps dust and dirt from entering the vacuum operated instruments. Inspect filter
every 200 hours for damage. Change central air filter
element every 500 hours of operating time and whenever suction gage reading drops below 4.6 inches of
mercury. Also, do not operate the vacuum system
with the filter removed, or a vacuum line disconnected
as particles of dust or other foreign matter may enter
the system and damage the gyros.
2-25. BATERY. Battery sericingvoes add2-2
BATTERY
ing distilled water to maintain the electrolyte even
with the horizontal baffle plate a the bottom of the
filler holes, checking the battery cable connections,
and neutralizing and cleaning off and spilled electrolyte or corrosion. Use bicarbonate of sod (baking
soda) and water to neutralize electrolyte or corrosion. Follow with a thorough 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
2-9
MODEL R172 SERIES SERVICE MANUAL
or "rejuvenators", should be used to maintain electrolyte level. Check the battery every 50 hours (or at least
every 30 days) oftener in hot weather. See Section 16
for detailed battery removal, installation and testing.
2-26. TIRES. Maintain tire pressure at the air pressures specified in Section 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
Recomended tire pressures should be maintained. Especially-in-cold weather.-remember
that any drop in temperature of the air inside a
tire causes a corresponding drop in air pressure.
2-27. 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.
2-28. NOSE GEAR SHIMMY DAMPENER. The
shimmy dampener should be serviced at least every 50
hours. The shimmy dampener must be filled completely with fluid, free of entrapped air, to serve it's
purpose. To service the shimmy dampener, proceed as
follows:
a. Remove shimmy dampener from aircraft.
b. While holding the dampener in a vertical position
with fitting end pointed downward, pull fitting end of
the dampener shaft to its limit of travel.
c. While holding dampener in this position, fill
dampener 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
dampener is installed on the aircraft.
NOTE
Keep the shimmy dampener, especially the
exposed portions of the dampener piston
shaft, clean to prevent collection of dust and
grit which could cut the seals in the
dampener 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 excess hydraulic
fluid.
2-29. HYDRAULIC BRAKE SYSTEMS. Check brake
master cylinders and refill with MIL-H-5606 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.
NOTE
2-30. CLEANING.
The nose landing gear shock strut will normally require only a minimum amount of service. Maintain the strut extension pressure as
shown in Section 1. Lubricate landing gear as
shown in figure 2-6. 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 excess hydraulic fluid.
NAME
2-10
2-31. Keeping the aircraft clean is important. Besides
maintaining the trim appearance of the aircraft,
cleaning lessens the possibility of corrosion and makes
inspection and maintenance easier.
2-32. CLEANING WINDSHIELD AND WINDOWS
2-32A. MATERIALS REQUIRED.
MANUFACTURER
USE
Mild soap or detergent
hand dishwashing type
without abrasives).
Commercially available.
Cleaning windshields and
windows.
Aliphatic naphtha Type II
conforming to Federal
Specification TT-N-95.
Commercially available.
Removing deposits which cannot
be removed with mild soap
solution on acrylic windshields
and windows.
Revision 1
MODEL R172 SERIES SERVICE MANUAL
2-32A. MATERIALS REQUIRED CONT).
NAME
Polishing Wax.
MANUFACTURER
Turtle Wax.
Turtle Wax, Inc.
Chicago. IL 60638
Great Reflections
Paste Wax.
E.I. duPont de Nemours
and Co. (Inc.)
Wilmington, DE 19898
Slip-Stream Wax
paste).
Acrylic polish conforming to
Federal Specification
P-P-560 such as:
Classic Chemical
Grand Prairie, TX 75050
Permatex plastic cleaner
No. 403D.
Permatex Company, Inc.
Kansas City, KS 66115
Cleaning and polishing
acrylic windshields and
windows.
Soft cloth, such as:
Cotton flannel or
cotton terry cloth
material.
USE
Waxing acrylic windshields and
windows.
Applying and removing
wax and polish.
Commercially available.
*These are the only polishing waxes tested and approved for use by Cessna Aircraft Company.
CAUTION
Windshields and windows are easily damaged by impoper handling and cleaning
techniques.
a. Place airplane inside hangar or in shaded area
and allow to cool from heat of sun's direct rays.
b. Using clean (preferably running, water, flood
surface. Use bare hands with no jewelry to feel and
dislodge any dirt or abrasive materials.
c. Using a mild soap or detergent such as dishwashing liquid) in water, wash surface. Again use
only bare hands to provide rubbing force. (A clean
cloth may be used to transfer soap solution to
surface, but extreme care must be excercised to
prevent scratching surface.)
d. 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 cloth may be used as a cleaning solvent. Be sure
to frequently refold cloth to avoid redepositing soil
and or scratching windshield with any abrasive
particles.
e. 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
tetrachloride, laquer thinners, commercial
or household window cleaning sprays.
2-32B. WAXING.
a. Hand polishing wax should be applied to acrylic
surfaces. (The wax has an index of refraction nearly
the same as transparent acrylic and tends to mask
any shallow scratches on windshield surface
b. Acrylic surfaces may be polished using a polish
meeting Federal Specification P-P-560 applied per
manufacturer's instructions.
----CAUTION
DO NOT use rain repellent on acrylic
surfaces.
NOTE
When applying and removing wax and
polish, use a soft cloth.
2-32C. PREVENTIVE MAINTENANCE.
NOTE
Utilization of the following techniques will
help minimize windshield and window
crazing.
Revision 1
2-11
MODEL R172 SERIES SERVICE MANUAL
a. Keep all surfaces of windshields and windows
clean.
b. If desired, wax acrylic surfaces.
c. 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. laquer
thinners, commercial or household window cleaning
sprays, paint strippers, or other types of solvents.
d. DO NOT use solar screens or shields installed on
inside of airplane orleave sun visors up against
windshield. The reflected heat from these items causes
elevated temperatures which accelerate crazing and
may cause formation of bubbles in inner ply of
multiple ply windshields.
2-33. 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 2-32, must never be used
since they soften and craze the plastic.
2-34. PAINTED SURFACES. The painted exterior
surfaces of the aircraft, under normal conditions,
require a minimum of polishing and buffing.
Approximately 15 days are required for acrylic or
laquer paint to cure completely: in most cases, the
curing period will have been completed prior to
delivery of the aircraft. In the event that polishing or
buffing is required within the curing period, it is
recommended that the work be done by an experienced
painter. Generally. the painted surfaces can be kept
bright by washing with water and mild soap, followed
by a rinse with water and drying with cloths or
chamois. Harsh or abrasive soaps or detergents which
could cause corrosion or make scratches should never
be used. Remove stubborn oil and grease with a cloth
moistened with Stoddard solvent. After the curing
period, the aircraft may be waxed with a good
automotive wax. A heavier coating of wax on the
leading edges of the wing and tail and on the engine
nose cap will help reduce the abrasion encountered in
these areas.
2-35. 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 detergent 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.
2-36. ENGINE AND ENGINE COMPARTMENT.
The engine should be kept clean and dry since dirty
cooling fins and baffle plates can cause overheating of
the engine. Also, cleaning is essential to minimize any
danger of fire and provide for easier inspection of
components. The entire engine cowling may be
2-12
Revision 1
removed to acilitate engine and interior cowl
cleaning. Wash down the engine and components with
a suitable solvent, such as Stoddard solvent or
equvalent, then dry thoroughly with compressed air.
CAUTION
Particular care should be given to electrical
equipment before cleaning. Solvent should
not be allowed to enter magnetos, starters.
alternators, voltage regulators and the like.
Hence, these components should be protected
before saturating the engine with solvent.
Any fuel, oil and air openings should be
covered-before washing-the-engine with
solvent. Caustic cleaning solutions should
not be used. After cleaning the engine, relubricate all control arms and moving parts.
2-37. 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
the 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.
2-38. 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.
2-39. 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.
2-40. LUBRICATION.
2-41. Lubrication requirements are shown in figure 26. 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 2-6
by adding details.
MODEL R172 SERIES SERVICE MANUAL
2-42. TACHOMETER DRIVE SHAFT. Refer to
Sections 11 and 15.
c. With oil can, apply light coat of No. 10-weight, nondetergent oil to threads of jack screw.
2-43. WHEEL BEARINGS. Clean and repack the
wheel bearings at the first 100 hour inspection and at
each 500 hour inspection thereafter. If more than the
usual number of take-offs 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.
2-46. 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.
2-44. NOSE GEAR TORQUE LINKS. Lubricate nose
gear torque links every 50 hours. When operating in
dusty conditions, more frequent lubrication is
required.
2-45. 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
2-47. 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 bungee, 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 respective units.
If corrosion is detected during the inspection, install
new rod ends.
It is not necessary to remove actuator from
aircraft to clean or lubricate threads.
SHOP NOTES:
Revision 1
2-12A, 2-12B Blank)
MODEL R172 SERIES SERVICE MANUAL
NOTE
Refer to Sheet 2 for specified
Hydraulic Fluid, Fuel and Oil
Figure 2-5.
Servicing (Sheet 1 of 4)
2-13
2-13
MODEL R172 SERIES SERVICE MANUAL
HYDRAULIC FLUID:
SPEC. NO. MIL-H-5606
SPECIFIED AVIATION GRADE FUELS.
WARNING
ONLY AVIATION GRADE FUELS ARE APPROVED FOR USE.
ENGINE MODEL
APPROVED FUEL GRADES
CONTINENTAL IO-360-K
NOTE
100LL(blue)
1
100 (green) (formerly 100/130)
1
NOTE
1.
Compliance with Continental Aircraft Engine Service Bulletin M77-3,
and all supplements or revisions thereto, must be accomplished.
SPECIFIED AVIATION GRADE OIL:
AVERAGE AMBIENT TEMPERATURE (°F) / OIL GRADE
0°
10 °
----
20 °
30 °
40 °
50 °
60°
70°
30
-SAE
80 °
90°
AE 50-
SAE 20W-50
Aviation Grade ashless dispersant oil, conforming to Continental Motors Specification MHS-24 and
all revisions and supplements thereto, must be used except as noted in paragraph 2-22, herein.
Refer to Continental Engine Service Bulletin M75-2, and any other superseding bulletins, revisions
or supplements thereto, for further recommendations.
NOTE
Oil capacities for the aircraft are given in the following chart. To minimize loss of oil through
the breather, fill to specified oil level on dipstick for normal operation (flight of less than three
hours duration). 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 required when filter element is changed.
CAPACITY
(TOTAL)
8
CAPACITY (TOTAL
WITH FILTER)
9
Figure 2-5.
2-14
NORMAL
OPERATION
7
Servicing (Sheet 2 of 4)
MINIMUM
FOR FLIGHT
6
MODEL R172 SERIES SERVICE MANUAL
DAILY
3
FUEL TANK FILLER
Service after each flight.
details.
Keep full to retard condensation.
Refer to paragraph 2-19 for
4 FUEL TANK SUMP DRAINS
Drain off any water and sediment before first flight of the day.
6
PITOT AND STATIC PORTS
Check for obstructions before first flight of the day.
10 FUEL STRAINER
Drain off any water and sediment before the first flight of the day.
2-21 for details.
13
INDUCTION AIR FILTER
Inspect and service under dusty conditions.
16
OIL DIPSTICK
Check oil on preflight.
Refer to paragraph
Refer to paragraph 2-23 for details.
Add oil as necessary.
Refer to paragraph 2-22 for details.
18 OIL FILLER CAP
Whenever oil is added, check that filler cap is tight and oil filler door is secure.
FIRST 25 HOURS
15 17
ENGINE OIL SYSTEM
Refill with straight mineral oil, non-detergent, and use until a total of 50 hours
has accumulated or oil consumption has stabilized, then change to ashless dispersant oil.
"50
HOURS
13
INDUCTION AIR FILTER
Clean filter per paragraph 2-23.
Replace as required.
14 BATTERY
Check electrolyte level and clean battery compartment each 50
hours or each 30 days.
15 17
ENGINE OIL SYSTEM
Change oil each 50 hours if engine is NOT equipped with external oil filter;
if equipped with external oil filter, change filter element each 50 hours and
oil at each 100 hours, or every 6 months.
12 SHIMMY DAMPENER
Check fluid level and refill as required with hydraulic fluid.
7 TIRES
Maintain correct tire pressure as listed in chart of Section 1.
2-26 for details.
Figure 2-5.
Refer to paragraph 2-28.
Also refer to paragraph
Servicing (Sheet 3 of 4)
2-15
MODEL R172 SERIES SERVICE MANUAL
50 HOURS (Cont)
NOSE GEAR SHOCK STRUT
Keep strut filled and inflate to correct pressure.
Refer to paragraph 2-27 for details.
19 SPARK PLUGS
Rotate from top to bottom.
Refer to Section 11.
100 HOURS
10 FUEL STRAINER
Disassembly and clean strainer bowl and screen.
19 SPARK PLUGS
Rotate from top to bottom.
Refer to Section 11.
--
200 HOURS
1 VACUUM RELIEF FILTER
Change each 1000 hours, or to coincide with engine overhauls.
5 SELECTOR VALVE DRAIN
Remove plug and drain off any water or sediment.
Also refer to paragraph 2-21.
9 BRAKE MASTER CYLINDERS
Check fluid level and refill as required with hydraulic fluid.
Refer to paragraph 2-29.
500 HOURS
2
VACUUM SYSTEM CENTRAL AIR FILTER
Replace every 500 hours.
/\
8
GROUND SERVICE RECEPTACLE
Connect to 24-volt DC, negative-ground power unit.
details.
Figure 2-5.
2-16
AS REQUIRED
Refer to Section 11 for
Servicing (Sheet 4 of 4)
MODEL R172 SERIES SERVICE MANUAL
METHOD OF APPLICATION
FREQUENCY (HOURS)
HAND
GREASE
GUN
OIL
CAN
SYRINGE
(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
............
GR- MIL-G-81322A ..........
GHMIL-G-23827A ..........
GLMIL-G-21164C ..........
OGMIL-L-7870A ..........
PL - VV-P-236 .............
GSMIL-S-8660 ............
GP-- .................
OLVV-L-800A ...........
POWDERED GRAPHITE
GENERAL PURPOSE GREASE
AIRCRAFT AND INSTRUMENT GREASE
MOLYBDENUM DISLULFIDE GREASE
GENERAL PURPOSE OIL
PETROLATUM
DC4 DOW CORNING
NO. 10-WEIGHT, NON-DETERGENT OIL
LIGHT OIL
.
GR
STEERING
NEEDLE
PARAGRAPH 2-43
BEARINGS
ALSO REFER TO
PARAGRAPH 2-43
SHIMy
DAMPENER
PIVOTS
--TORQUE LINKS
ALSO REFER TO
PARAGRAPH 2-43
STEERING ARM
MAIN GEAR
WHEEL BEARINGS
WHEEL BEARINGS
NOSE GEAR
Figure 2-6.
Lubrication (Sheet 1 of 3)
2-17
MODEL R172 SERIES SERVICE MANUAL
CONTROL
WHEEL SHAFT
BUSHINGS AND
BEARINGS
----
-
BUSHINGS AND
ELEVATOR
TRIM TAB
ACTUATOR
ALSO REFER TO INSPECTION
CHART IN THIS SECTION AND
TO SECTION 9 OF THIS MANUAL
CONTROL "U"
PL
BATTERY
-
ENGINE CONTROLS
USE NO LUBRICANT UNDER
EXTREME DUSTY CONDITIONS
PG
ALL PIANO
AILERON BELLCRANK
NEEDLE BEARINGS
.
SELECTOR
DRIVE SHAFT
ATTACH POINTS
.
"/
.-
TYPICAL
CABIN DOOR WINDOW
INSERT GROOVES
DOORSTOP
Figure 2-6.
2-18
Lubrication (Sheet 2 of 3)
OG
REFER TO
PARAGRAPH 2-46
I
MODEL R172 SERIES SERVICE MANUAL
OILITE BEARINGS
(RUDDER BAR ENDS)
NEEDLE
BEARINGS
ALL LINKAGE
POINT PIVOTS
ROD END
BEARINGS
\ G
THREADS
THREADS
PARAGRAPH 2-45
NOTES
Sealed bearings require no lubrication.
Do not lubricate roller chains or cables except under seacoast conditions.
dry cloth.
Wipe with a clean,
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 2-6.
Lubrication (Sheet 3 of 3)
2-19
MODEL R172 SERIES SERVICE MANUAL
I
INSPECTION REQUIREMENTS.
As required by Federal Aviation Regulations, all civil aircraft of U.S. registry must undergo a
COMPLETE INSPECTION (ANNUAL) each twelve calendar months. In addition to the required
ANNUAL inspection, aircraft operated commercially (for hire) must also have a COMPLETE
AIRCRAFT INSPECTION every 100 hours of operation.
In lieu of the above requirements, an aircraft may be inspected in accordance with a
progressive inspection schedule, which allows the work load to be divided into smaller
operations that can be accomplished in shorter time periods.
Therefore, the Cessna Aircraft Company recommends PROGRESSIVE CARE for aircraft that
are being flown 200 hours or more per year, and the 100 HOUR inspection for all other aircraft.
II
INSPECTION CHARTS.
The following charts show the recommended intervals at which items are to be inspected.
As shown in the charts, there are items to be checked each 50 hours, each 100 hours, each
200 hours, and also Special Inspection items which require servicing or inspection at
intervals other than 50, 100 or 200 hours.
m
a.
When conducting an inspection at 50 hours, all items marked under EACH 50 HOURS would be
inspected, serviced or otherwise accomplished as necessary to insure continuous
airworthiness.
b.
At each 100 hours, the 50 hour items would be accomplished in addition to the items
marked under EACH 100 HOURS as necessary to insure continuous airworthiness.
c.
An inspection conducted at 200 hour intervals would likewise include the 50 hour
items and 100 hour items in addition to those at EACH 200 HOURS.
d.
The numbers appearing in the SPECIAL INSPECTION ITEMS column refer to data listed
at the end of the inspection charts. These items should be checked at each inspection
interval to insure that applicable servicing and inspection requirements are accomplished
at the specified intervals.
e.
A COMPLETE AIRCRAFT INSPECTION includes all 50, 100 and 200 hour items plus those
Special Inspection Items which are due at the time of the inspection.
INSPECTION PROGRAM SELECTION.
AS A GUIDE FOR SELECTING THE INSPECTION PROGRAM THAT BEST
SUITS THE OPERATION OF THE AIRCRAFT, THE FOLLOWING IS
PROVIDED.
1.
IF THE AIRCRAFT IS FLOWN LESS THAN 200 HOURS ANNUALLY.
a. IF FLOWN FOR HIRE
An aircraft operating in this category must have a COMPLETE AIRCRAFT INSPECTION
each 100 hours and each 12 calendar months of operation. A COMPLETE AIRCRAFT
INSPECTION consists of all 50, 100, 200 and Special Inspection Items shown in the inspection charts as defined in paragraph II above.
b. IF NOT FLOWN FOR HIRE
An aircraft operating in this category must have a COMPLETE AIRCRAFT INSPECTION each
12 calendar months (ANNUAL). A COMPLETE AIRCRAFT INSPECTION consists of all 50,
100, 200 and Special Inspection Items shown in the inspection charts as defined in paragraph II
above. In addition, it is recommended that between annual inspections, all items be inspected
at the intervals specified in the inspection charts.
2-20
MODEL R172 SERIES SERVICE MANUAL
2.
IF THE AIRCRAFT IS FLOWN MORE THAN 200 HOURS ANNUALLY.
Whether flown for hire or not, it is recommended that aircraft operating in this category
be placed on the CESSNA PROGRESSIVE CARE PROGRAM. However, if not placed on
Progressive Care, the inspection requirements for aircraft in this category are the
same as those defined under paragraph III 1. (a) and (b).
Cessna Progressive Care may be utilized as a total concept program which
insures that the inspection intervals in the inspection charts are not exceeded.
Manuals and forms which are required for conducting Progressive Care inspections are available from the Cessna Service Parts Center.
IV
INSPECTION GUIDE LINES.
(a) MOVABLE PARTS for: lubrication, servicing, security of attachment, binding, excessive wear,
safetying, proper operation, proper adjustment, correct travel, cracked fittings, security of
hinges, defective bearings, cleanliness, corrosion, deformation, sealing and tension.
(b) FLUID LINES AND HOSES for: leaks, cracks, dents, kinks, chafing, proper radius, security,
corrosion, deterioration, obstruction and foreign matter.
(c)
METAL PARTS for: security of attachment, cracks, metal distortion, broken spotwelds,
corrosion, condition of paint and any other apparent damage.
(d) WIRING for: security, chafing, burning, defective insulation, loose or broken terminals,
heat deterioration and corroded terminals.
(e) BOLTS IN CRITICAL AREAS for: correct torque in accordance with torque values given in the
chart in Section 1, when installed or when visual inspection indicates the need for a
torque check.
NOTE
Torque values listed in Section 1 are derived from oil-free cadmium-plated threads,
and are recommended for all installation procedures contained in this book except
where other values are stipulated. They are not to be used for checking tightness of
installed parts during service.
(f)
FILTERS, SCREENS & FLUIDS for: cleanliness, contamination and/or replacement at specified
intervals.
(g)
AIRCRAFT FILE.
Miscellaneous data, information and licenses are a part of the aircraft 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 United States
Federal Aviation Regulations. Since the regulations of other nations may require
other documents and data, owners of exported aircraft should check with their
own aviation officials to determine their individual requirements.
To be displayed in the aircraft at all times:
1. Aircraft Airworthiness Certificate (FAA Form 8100-2).
2.
Aircraft Registration Certificate (FAA Form 8050-3).
3.
Aircraft Radio Station License, if transmitter is installed (FCC Form 556).
To be carried in the aircraft at all times:
1.
Weight and Balance, and associated papers (Latest copy of the Repair and Alteration
Form, FAA Form 337, if applicable).
2. Aircraft Equipment List.
3.
Pilot's Operating Handbook.
To be made available upon request:
1.
Aircraft Log Book and Engine Log Book.
2-21
MODEL R172 SERIES SERVICE MANUAL
(h)
ENGINE RUN-UP.
Before beginning the step-by-step inspection, start, run up and shut down the engine in
accordance with instructions in the Pilot's Operating Handbook. During the run-up observe the
following. making note of any discrepancies or abnormalities:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Engine temperatures and pressures.
Static RPM. (Also refer to Section 11 of this Manual.)
Magneto drop. (Also refer to Section 11 of this Manual.)
Engine response to changes in power.
Any unusual engine noises.
Fuel selector and/or shut-off valve; operate engine(s) on each tank (or cell) position
and OFF position long enough to ensure shut-off and/or selector valve functions
properly.
Idling speed and mixture; proper idle cut-off.
Alternator and ammeter.
Suction gage.
Fuel flow indicator.
After the inspection has been completed, an engine run-up should again be performed to determine
that any discrepancies or abnormalities have been corrected.
SHOP NOTES:
2-22
MODEL R172 SERIES SERVICE MANUAL
IMPORTANT
SPECIAL INSPECTION ITEM
EACH 200 HOURS
EACH 100 HOURS
EACH 50 HOURS
READ ALL INSPECTION
REQUIREMENTS PARAGRAPHS
PRIOR TO USING THESE CHARTS.
PROPELLER
1. Spinner
......................................................................
0
2. Spinner bulkhead ..............................................................
3. B lades
.......................................................................
.
0
4. Bolts and/or nuts ...............................................................
5. Hub ..........................................................................
* 16
6. Governor and control ...........................................................
ENGINE COMPARTMENT
Check for evidence of oil and fuel leaks, then clean entire engine and compartment,
if needed, prior to inspection.
1. Engine oil, filler cap, dipstick, drain plug and oil screen or external full-flow oil filter ......
2. Oil cooler ...................................................
................
3. Induction air filter...............................................................
1
*
a
2
*
4. Induction airbox, air valves, doors and controls .....................................
.
5. Cold and hot air hoses .........................................................
6. Engine baffles ...................................................
.
............
.
7. Cylinders, rocker box covers and push rod housings ................................
*
8. Crankcase, oil sump, accessory section and front crankshaft seal.....................
*
9. Hoses, metal lines and fittings ...................................................
10. Intake and exhaust systems .....................................................
11. Ignition harness ...................................................
12. Spark plugs ...................................................................
·
3
*
4
·
18
...........
13. Compression check ..........................................................
14. Crankcase and vacuum system breather lines .....................................
15. Electrical wiring ................................................................
*
16. Vacuum pump and oil separator .................................................
S
·
17. Vacuum relief valve filter (cabin area) ............................................
18. Engine controls and linkage .....................................................
19. Engine shock mounts, mount structure and ground straps ...........................
© Cessna Aircraft Company
a
5
6
0
2-23
MODEL R172 SERIES SERVICE MANUAL
SPECIAL INSPECTION ITEIV
EACH 200 HOURS
EACH 100 HOURS
EACH 50 HOURS
20. Cabin heat valves, doors and controls ............................................
21. Starter, solenoid and electrical connections ........................................
21
22. Starter brushes, brush leads and commutator......................................
23. Alternator and electrical connections ...................
.......................
*
19
7
24. Alternator brushes, brush leads, commutator or slip ring.............................
25. Voltage regulator mounting and electrical leads ....................................
26. Magnetos (external) and electrical connections .....................................
27. Magneto timing ...................................................
8
28. Firewall .......................................................................
29. Fuel-air (metering) control unit ...................................................
30. Fuel injection system ...........................................................
*
31. Auxiliary fuel pump .............................................................
*
22
32. Engine-driven fuel pump ........................................................
33. Engine cowling and cowl flap ....................................................
*
FUEL SYSTEM
1. Fuel strainer, drain valve and control ..............................................
*
2. Fuel strainer screen and bowl ...................................................
3. Fuel tank vents, caps and placards ...............................................
4. Fuel tanks, sump drains and fuel line drains .......................................
5. Drain fuel and check tank interior attachment and outlet screens .....................
5
6. Fuel vent valves ...............................................................
7. Fuel vent line drain ................................
.........
8. Fuel shut-off valve and placard ..................................................
9. Fuel selector valve and placard ....................
.............................
*
10. Engine primer ......... ........................................................
11. Perform a fuel quantity indicating system operational test. Refer to Section 15
for detailed accomplishment instructions ........................................
23
24
12. Fuel injection nozzles...........................................................
LANDING GEAR
1. Main gear wheels and fairings ............................................
...
2. Nose gear wheel, torque links, steering tubes, boots, fairing ..........................
3. W heel bearings................................................................
2-24
Revision 1
·
17
17
9
D2027-1-13 Temporary Revision Number 5 - Apr 5/2004
© Cessna Aircraft Company
MODEL R172 SERIES SERVICE MANUAL
SPECIAL INSPECTION ITEM
EACH 200 HOURS
EACH 100 HOURS
EACH 50 HOURS
4.
Nose gear strut and shimmy dampener (service as required)
5.
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
6.
Brake fluid, lines and hoses, linings, discs, brake assemblies and master
cylinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.
Parking brake system
8.
Main gear springs
9.
Nose gear steering arm lubrication
. . . . ...
..
...
. ..
............
..
. ...
.
. ...
20
. . ..
. . . . . . . . . . . . . . . . . . . . . . . .
.......................
10.
Torque link lubrication ..
11.
Park brake and toe brakes - operational test
. ....
. ...
...
...
..
..
. ...
. . ..
...............
..
.
AIRFRAME
1.
Aircraft exterior ...............................
.
2.
Aircraft structure
.
3.
Windows, windshield, doors and seals
4.
Seat belts and shoulder harnesses ........
5.
Seat stops, seat rails, upholstery, structure and mounting ...
6.
Control "U" bearings, sprockets, pulleys, cables, chains and turnbuckles ......
7.
Control lock, control wheel and control "U" mechanism
8.
Instruments and markings ..
9.
Gyros central air filter .......................
...................
...
..
..............
.
.......
. ..
..
.....
.
..........
..............
...
. ..
..
. ...
. . ..
.......
10.
Magnetic compass compensation .......................
11.
Instrument wiring and plumbing
12.
Instrument panel, shockmounts, ground straps, cover, decals
and labeling ...............
....
.
10
. .5
.........................
13.
Defrosting, heating and ventilation system controls
14.
Cabin upholstery, trim, sunvisors and ash trays
15.
Area beneath floor, lines, hoses, wires and control cables ..
16.
Lights, switches, circuit breakers, fuses and spare fuses
17.
Exterior lights
18.
Pitot and Static Systems
19.
Stall warning system ....................
. . . . . . ... . ....
...........................
...
.....
. ..
................
..
.
. . . . ....
. .
.
......
. .
...
.....
. . ..... . . . . . . .
..
.
.
2-25
MODEL R172 SERIES SERVICE MANUAL
SPECIAL INSPECTION ITEM
EACH 200 HOURS
EACH 100 HOURS
EACH 50 HOURS
20.
Radios, radio controls, avionics and flight instruments ...............
21.
Antennas and cables
22.
Battery, battery box and battery cables ...
23.
Battery electrolyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
24.
Emergency locator transmitter
...............
..................
.
.........................
12
CONTROL SYSTEMS
In addition to the items listed below, always check for correct direction of
movement, correct travel and correct cable tension.
1.
Cable, terminals, pulleys, pulley brackets, cable guards, turnbuckles
and fairleads
. . . . . . . . . . . . . . . . .
2.
Chains, terminals, sprockets and chain guards
3.
Trim control wheels, indicators, actuator and bungee
4.
Travel stops . . . . . . . . . . . . . . . . .
5.
Decals and labeling . ...
6.
Flap control switch, flap rollers and tracks and flap indicator
7.
Flap motor, transmission, limit switches, structure, linkage,
bellcranks, etc .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.
Elevator and trim tab hinges, tips and control rods
9.
Elevator trim tab actuator lubrication ............................
13
10.
Elevator trim tab free-play inspection. .....................
14
11.
Rudder pedal assemblies and linkage . . .
...................
12.
Skins (external) of control surfaces and tabs
...............
13.
Internal structure of control surfaces.......................
14.
Balance weight attachment............................
15.
Flap actuator jack screw threads
16.
Ailerons, hinges and push/pull rods ........................
2-26
..
. ..
. ..
..
.......
......
.
..........
..
. . ...
..........
..
. ....
........
...
...
..
......
......
..
15
MODEL R172 SERIES SERVICE MANUAL
SPECIAL INSPECTION ITEM
1. First 25 hours: refill with straight mineral oil and use until a total of 50 hours have accumulated or oil
consumption has stabilized, then change to ashless dispersant oil. Change oil each 50 hours if engine is NOT
equipped with external oil filter; if equipped with external oil filter, change filter each 50 hours and oil at each
100 hours; or every six months, whichever comes first.
2.
Clean filter per paragraph 2-23. Replace if required.
3.
Replace engine compartment rubber hoses (Cessna-installed only) every 5 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 replaced within 120 days after receiving
the new hose(s) from Cessna. Replace drain hoses on condition. For engine flexible hoses (Continental
Motors-installed) refer to Continental Motors Maintenance Manual and Continental Motors Engine Service
Bulletins:
4.
General inspection every 50 hours. Refer to Section 11 for 100 hour inspection.
5.
Each 1000 hours, or to coincide with engine overhauls.
6.
Each 100 hours for freedom of movement, general condition. These controls are not repairable and must be
replaced at engine overhaul.
7.
Each 500 hours.
8.
Internal timing and magneto-to-engine timing are described in detail in Section 11.
9.
First 100 hours and each 500 hours thereafter. More often if operated under prevailing wet or dusty
conditions.
10.
Replace each 500 hours.
11.
Check electrolyte level and clean battery compartment each 50 hours or each 30 days.
12.
Refer to Section 16.
13.
Lubrication for the actuator is required each 1000 hours or 3 years, whichever comes first. Refer to Figure 2-5
for grease specifications.
14.
Refer to Section 9 for free-play limits, inspection, replacement and/or repair.
15.
Refer to paragraph 2-45 for detailed instructions.
16.
If leakage is evident, refer to McCauley Service Manual.
17.
If aircraft is flown from surfaces with mud, snow or ice, the speed fairings should be checked to be sure that
there is no accumulation which could prevent normal tire rotation.
18.
Rotate spark plugs every 50 hours of operation and clean and rotate every 100 hours.
19.
Following the first 25 hours of operation, check alternator belt tension in accordance with procedures outlined
in Section 17.
20.
Each 5 years, replace all hoses, packings, and backup rings in the brake system.
21.
For Prestolite starters only, inspect the commutator and brushes every 1500 hours.
22.
Each 10 years, replace or overhaul the auxiliary fuel pump in accordance with Dukes Inc. Service Bulletin No.
003.
23.
Fuel quantity indicating system operational test is required every 12 months. Refer to Section 15 for detailed
accomplishment instructions.
24.
At the first 100-hour inspection on new, rebuilt or overhauled engines, remove and clean the fuel injection
nozzles. Thereafter, the fuel injection nozzles must be cleaned at 300-hour intervals or more frequently if fuel
stains are found.
D2027-1-13 Temporary Revision Number 5 - Apr 5/2004
©Cessna Aircraft Company
Revision 1
2-27
MODEL R172 SERIES SERVICE MANUAL
2-48.
COMPONENT TIME LIMITS
1. General
A. Most components listed throughout Section 2 should be inspected as detailed elsewhere in this
section and repaired, overhauled or replaced as required. Some components, however, have
a time or life limit, and must be overhauled or replaced on or before the specified time limit.
NOTE:
The terms overhaul and replacement as used within this section are defined as
follows:
Overhaul - Item may be overhauled as defined in FAR 43.2 or it can be replaced.
Replacement - Item must be replaced with a new item or a serviceable item that is
within its service life and time limits or has been rebuilt as defined in FAR 43.2.
B. This section provides a list of items which must be overhauled or replaced at specific time
limits. Table 1 lists those items which Cessna has mandated must be overhauled or replaced
at specific time limits. Table 2 lists component time limits which have been established by an
outside supplier on their product.
C.
2.
In addition to these time limits, the components listed herein are also inspected at regular time
intervals set forth in the Inspection Charts, and may require overhaul/replacement before the
time limit is reached based on service usage and inspection results.
Cessna-Established Replacement Time Limits
A. The following component time limits have been established by The Cessna Aircraft Company.
Table 1: Cessna-Established Replacement Time Limits
1 2-28
COMPONENT
REPLACEMENT
TIME
OVERHAUL
Restraint Assembly Pilot, Copilot,
and Passenger Seats
10 years
NO
Trim Tab Actuator
1,000 hours or 3 years,
whichever occurs first
YES
Vacuum System Filter
500 hours
NO
Vacuum System Hoses
10 years
NO
Pitot and Static System Hoses
10 years
NO
Vacuum Relief/Regulator Valve Filter
(If Installed)
500 hours
NO
Engine Compartment Flexible Fluid
Carrying Teflon Hoses (CessnaInstalled) Except Drain Hoses
(Drain hoses are replaced
on condition)
10 years or engine overhaul,
whichever occurs first
(Note 1)
NO
D2027-1-13 Temporary Revision Number 4 - Oct 7/2002
0 Cessna Aircraft Company
MODEL R172 SERIES SERVICE MANUAL
SPECIAL INSPECTION ITEMS (Continued from page 2-27)
23. Fuel quantity indicating system accuracy test is required every 12 months. Refer to Cessna Service
Bulletin SEB99-18, Fuel Quantity Indicating System Inspection (or latest revision) for detailed
accomplishment instructions.
Temporary Revision Number 3
7 January 2000
2-28A
MODEL R172 SERIES SERVICE MANUAL
3.
COMPONENT
REPLACEMENT
TIME
OVERHAUL
Engine Compartment Flexible Fluid
Carrying Rubber Hoses (CessnaInstalled) Except Drain Hoses
(Drain hoses are replaced
on condition)
5 years or engine overhaul,
whichever occurs first
(Note 1)
NO
Engine Air Filter
500 hours or 36 months,
whichever occurs first
(Note 9)
NO
Engine Mixture, Throttle, and
Propeller Controls
At engine TBO
NO
Engine Driven Dry Vacuum Pump
Drive Coupling
(Not lubricated with engine oil)
6 years or at vacuum
pump replacement,
whichever occurs first
NO
Engine Driven Dry Vacuum Pump
(Not lubricated with engine oil)
500 hours
(Note 10)
NO
Standby Dry Vacuum Pump
500 hours or 10 years,
whichever occurs first
(Note 10)
NO
Supplier-Established Replacement Time Limits
A.
The following component time limits have been established by specific suppliers and are
reproduced as follows:
Table 2: Supplier-Established Replacement Time Limits
COMPONENT
REPLACEMENT
TIME
OVERHAUL
ELT Battery
(Note 3)
NO
Vacuum Manifold
(Note 4)
NO
Magnetos
(Note 5)
YES
Engine
(Note 6)
YES
Engine Flexible Hoses
(TCM-Installed)
(Note 2)
NO
Auxiliary Electric Fuel Pump
(Note 7)
YES
Propeller
(Note 8)
YES
Temporary Revision Number 4
7 October 2002
© 2002 Cessna Aircraft Company
2-29
MODEL R172 SERIES SERVICE MANUAL
NOTES:
Note 1: This life limit is not intended to allow flexible fluid-carrying Teflon or rubber hoses in a deteriorated or
damaged condition to remain in service.
Replace engine compartment flexible Teflon
(AE3663819BXXXX series hose) fluid-carrying hoses (Cessna-installed only) every ten years or at
engine overhaul, whichever occurs first. Replace engine compartment flexible rubber fluid-carrying
hoses (Cessna-installed only) 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 2: Refer to Teledyne Continental Service Bulletin SB97-6, or latest revision.
Note 3: Refer to FAR 91.207 for battery replacement time limits.
Note 4: Refer to Airborne Air & Fuel Product Reference Memo No. 39, or latest revision, for replacement
time limits.
Note 5: For airplanes equipped with Slick magnetos, refer to Slick Service Bulletin SB2-80C, or latest
revision, for time limits.
For airplanes equipped with TCM/Bendix magnetos refer to Teledyne Continental Motors Service
Bulletin No. 643, or latest revision, for time limits.
Note 6: Refer to Teledyne Continental Service Information Letter SIL98-9, or latest revision, for time limits.
Note 7: Refer to Cessna Service Bulletin SEB94-7 Revision 1/Dukes Inc. Service Bulletin NO. 0003, or
latest revision.
Note 8: Refer to the applicable McCauley Service Bulletins and Overhaul Manual for replacement and
overhaul information.
Note 9: The air filter may be cleaned, refer to Section 2 of this service manual and for airplanes equipped
with an air filter manufactured by Donaldson. Refer to Donaldson Aircraft Filters Service
Instructions P46-9075 for detailed servicing instructions.
The address for Donaldson Aircraft Filters is:
Customer Service
115 E. Steels Corners RD
Stow OH. 44224
Do not overservice the air filter, overservicing increases the risk of damage to the air filter from
excessive handling. A damaged/worn air filter may expose the engine to unfiltered air and result in
damage/excessive wear to the engine.
Note 10: Replace engine driven dry vacuum pump not equipped with a wear indicator every 500 hours of
operation, or replace according to the vacuum pump manufacturer's recommended inspection and
replacement interval, whichever occurs first.
Replace standby vacuum pump not equipped with a wear indicator every 500 hours of operation or
10 years, whichever occurs first, or replace according to the vacuum pump manufacturer's
recommended inspection and replacement interval, whichever occurs first.
For a vacuum pump equipped with a wear indicator, replace pump according to the vacuum pump
manufacturer's recommended inspection and replacement intervals.
2-30
© 2002 Cessna Aircraft Company
Temporary Revision Number 4
7 October 2002
MODEL R172 SERIES SERVICE MANUAL
SECTION 3
FUSELAGE
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
FUSELAGE
............
Windshield and Windows . ... .
Description .......
Cleaning
.....
. . ...
Waxing
.
.
....
Repairs ...........
Scratches .
.......
Cracks
...
.
...
Windshield.
.......
Removal. ..
....
Installation .......
Windows. ............
Movable
....
Removal and Installation.
Wrap-Around Rear ......
Removal and Installation.
Overhead ......
Removal and Installation.
Fixed .....
Cabin Doors ...........
Description .........
Removal and Installation. .
Adjustment.
Weatherstrip ...
Latches .....
Description
Adjustment.
Lock
.........
...
Indexing Inside Handle ....
Baggage Door ..........
Removal and Installation . .
Weatherstrip
..
.
Seats ........
Pilot and Copilot.
. . .
.
3-1.
1B24/3-1
1B24/3-1
. 1B24/3-1
1B24/3-1
1B24/3-1
.
.
.
.
.
.
.
.
1C3/3-4
1C3/3-4
1C3/3-4
1C3/3-4
1C3/3-4
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C4/3-5
1C9/3-10
1C9/3-10
1C9/3-10
1C9/3-10
1C9/3-10
1C9/3-10
1C9/3-10
FUSELAGE.
3-2. WINDSHIELD AND WINDOWS.
and 3-2.)
(See figures 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. No. 579. 6
sealer (Inmont Corp., St. Louis. Missouri) is applied to all edges of the windshield and windows.
with exception of wing root area. The wing root fairing has a heavy felt strip that completes the windshield sealing.
3-4.
CLEANING.
(Refer to Section 2.)
3-5. WAXING. Waxing will fill in minor scratches
in clear plastic and help protect the surface from
further abrasion. Use a good grade of commercial
wax applied in a thin, even coat. Bring wax to a
high polish by rubbing lightly with a clean, dry flannel cloth.
3-6.
REPAIR.
(See figure 3-1.)
Reclining Back/ForeAnd-Aft Adjust . .
. C9/3-10
Articulating Recline/
Vertical Adjust .
...
C9/3-10
Description ...
C9/3-10
Removal and
Installation
.
C9/3-10
Center ...........
1C9/3-10
Double-Width/Single
Reclining Back ..
C9/3-10
Double-Width/Individual
Reclining Backs . . . . 1C9/3-10
Description .
..
1C9/3-10
Removal and
Installation ....
1C9/3-10
Auxiliary .........
1C9/3-10
Fold-Up
.......
C9/3-10
Description.
.
. C9/3-10
Removal and
Installation .
. . 1C9/3-10
Repair.
...........
1C9/3-10
Cabin Upholstery .
. . .C14/3-15
Materials and Tools ..
. .1C14/3-15
Soundproofing
...
....
1C14/3-15
1C14/3-15
Cabin Headliner
...
...
Removal and Installation .1C14/3-15
1C20/3-21
Upholstery Side Panels ....
Carpeting .1......
1C20/3-21
Safety Provisions . .....
1C20/3-21
Carg6 Tie-Downs
..... 1C20/3-21
1C20/3-21
....
Safety Belts
Shoulder Harness
....
1C20/3-21
Glider Tow Hook .....
. 1C20/3-21
Rear View Mirror ......
1C20/3-21
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 crack
and prevents 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
3-1
MODEL R172 SERIES SERVICE MANUAL
CORRECT
INCORRECT
STOP DRILLED
WOOD
REINFORCEMENT
CRACK---
CUSHION OF
RUBBER OR
SOFT WIRE LACING
FABRIC
AVOID SHARP CORNERS
CORNERS
BEVELED EDGE
SURFACE PATCH FOR
IRREGULAR SHAPED DAMAGE
SURFACE PATCH-
-
ROUND HOLE
PATCH SHOULD BE
PATCH SHOULD BE
THICKER
BEVELED EDGE
-
PATCHES
SURFACE PATCH FOR ROUND HOLES
PATCH TAPERED
ON SHARPER
ANGLE THAN
STOP
CRACK
MATERIAL.
PATCH AND HOLE
SHOULD BE TRIMMED
DURING CEMENTING. PRESSURE
NEED BE APPLIED ONLY ON TOP
WITH TAPERED EDGES.
SURFACE. TAPER ASSURES EQUAL
PRESSURE ON ALL SIDES.
HEAT EDGES OF
PATCH UNTIL
SURFACE PATCH FOR CRACKS
Figure 3-1.
3-2
SOFT AND
FORCE IT INTO HOLE.
HOLD IT IN PLACE UNTIL
COOL AND HARD TO
ASSURE PERFECT FIT.
THEN REMOVE PATCH
FOR CEMENTING BATH.
AFTER CEMENT HAS HARDENED.
SAND OR FILE EDGES LEVEL
WITH SURFACE.
Repair of Windshield and Windows
MODEL R172 SERIES SERVICE MANUAL
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.
.
Detail C
.
Detail
--
A
Detail F
Detail
DetailE
D
NOTE
No. 579.6 sealer (Inmont Corp., St. Louis, Missouri)
should be applied to all edges of windshield and windows
when felt sealing strip (3) is used.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Inner Retainer
Windshield
Felt Seal
Outer Retainer
Cabin Top Skin
Overhead Cabin Window
External Centerstrip
Rear Window Sealer
Fuselage Structure
Window
11.
Cover
Figure 3-2.
4
TYPICAL METHODS OF RETAINING FIXED WINDOWS
Windshield and Fixed Window Installation
3-3
MODEL R172 SERIES SERVICE MANUAL
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 procedure 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. Scratches on clear plastic surfaces can be removed by hand-sanding operations
followed by buffing and polishing, if 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.
320 is of maximum coarseness.
No.
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 3-1.)
a. When a crack appears, drill a hole at end of
crack to prevent further spreading. Hole should be
approximately 1/8 inch in 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 surface and inserting small bolts through
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.
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 partides. The entire sanded area will be clouded with
minute scratches which must be removed to restore
transparency.
d. Apply fresh tallow or buffing compound to a
motor-driven buffing wheel. Hold wheel against plastic surface, moving it constantly over damaged area
until cloudy appearance disappears. A 2000-foot-perminute surface speed is recommended to 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.
3-4
WINDSHIELD.
(See figure 3-2.)
3-10. REMOVAL. (See figure 3-2.)
a. Drill out rivets securing front retainer strip.
b. Remove wing fairings over windshield edges.
c. Pull windshield straight forward, out of side
and top retainers. Remove top retainer if necessary.
3-11. INSTALLATION. (See figure 3-2.)
a. Apply felt strip and sealing compound or sealing
tape to all edges of windshield to prevent leaks.
b. Reverse steps in preceding paragraph for installation.
c. When installing a new windshield, check fit and
carefully file or grind away excess plastic.
d. Use care not to crack windshield when installing.
If not previously removed, top retainer may be removed if necessary. Starting at upper corner and
gradually working windshield into position is recommended.
NOTE
Screws and self-locking nuts may be used
instead of rivets which fasten front retaining
strip to cowl deck. If at least No. 6 screws
are used, no loss of strength will result.
MODEL R172 SERIES SERVICE MANUAL
3-12.
WINDOWS.
(See figure 3-2.)
3-13. MOVABLE. (See figure 3-3.) A standard
movable window, hinged at the top, is installed in
the left cabin door. An optional movable window is
available for installation 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. (See figure 3-2.)
The rear window is a one-piece acrylic plastic panel
set in sealing strips and held in place by retaining
strips.
i
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 attached the door
latch assembly, a remote inside handle, a pair of
external hinges and an integral doorstop assembly.
A 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 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.
3-16. REMOVAL AND INSTALLATION. (See figure
3-2.)
a. Remove 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
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 hence 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 . 09 inch
window aft. If difficulty is encountered, rivets se-
or less.
curing 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 when installing.
3-17. OVERHEAD. (See figure 3-2.) 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
3-2.)
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 3-2.) 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 compound to all edges of
window to prevent leaks. Check fit and file or grind
away excess plastic. Use care not to crack plastic
when installing.
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 surfaces 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-880 adhesive (3-M 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.
DOOR LATCHES.
(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.
3-5
MODEL R172 SERIES SERVICE MANUAL
NOTE
Right-hand door installation is shown.
Openable window is optional equipment
on RH door and standard equipment on
.
LATE 1977 AND ON
A
Detail
5
THRU
B
23
Detail
9.
5. Window Stop
19
DetailD
Detail
1.
2.
3.
4.
4.
5.
6.
D
Lower Hinge
Upper Hinge
Upholstery Panel
Spring
Window Stop
Window Hinge
Window
11.Figure
Cam 3-3. Cabin
THRU 1979 MODEL-S
THRU 1979 MODELS
7.
8.
9.
10.
11.
12.
Latch Striker Plate
Door Structure
Window Frame
Window
Cam
Lock Assembly
Figure 3-3.
3-6
Frame
5.
.
inge
17. Armrest
Installationly.
(Sheet
LH door of 2)
Detaie
DetailC
8
13.
14.
15.
16.
17.
18.
p
in21f...rimetern
Washer
Latch Handle
Hinge Pin
Inside Handle
Armrest
Washer
Cabin Door Installation (Sheet 1 of 2)
23. Weatherstrip
23
As
required
for
(Typical
entire
perimeter)
19.
20.
21.
22.
22.
23.
Doorstop Bracket
Doorstop Spring
Clevis Pin
Clevis Pin
Weatherstrip
MODEL R172 SERIES SERVICE MANUAL
Section
A- A
Section B-B
BEGINNING
WITH R1723385
Section C
C
D- D
Section
BEGINNING WITH
WITH 1980
1980 MODELS
MODELS
BEGINNING
1.
2.
3.
4.
4.
5.
5.
6.
Trim Panel
Panel
Arm Rest
Rest
Inside Handle
Escutcheon
Escutcheon
Door
Door Pull
Pull Assembly
Assembly
Lock Assembly Mounting
Hole
Hole
Figure 3-3.
7.
7.
8.
8.
9.
10.
11.
11.
12.
Latch Assembly
Weatherstrip
Weatherstrip
Push-Pull
Push-Pull Rod
Rod
Window Assembly
Assembly
Hinge
Hinge Assembly
Assembly
Spring
Section
E
3-7
13.
13. Latch
Latch Assembly
Assembly
14. Channel
Channel
14.
15.
15. Hinge
Hinge Pin
Pin
16.
Upper Hinge
Hinge
16. Upper
17.
17. Base
Base Plate
Plate
18. Lower
LowerHinge
Hinge
19.
Upholstery Clip
19. Upholstery
Cabin Door Installation (Sheet
(Sheet 2 of 2)
3-7
MODEL R172 SERIES SERVICE MANUAL
NOTE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Bearing Assembly
Nut
Spacer
Push-Pull Rod
Base Plate
Roll Pin
Bolt
Housing
Outside Handle
Spring
Support
Shaft Assembly
Screw
Upholstery Panel
Armrest
Screw
Inside Handle
Placard
Pivot Base Plate
Door bolt adjustment thru 1977 and some early
1978 models is accomplished with adjustable
push-pull rod (4). On some early 1978 models
and on adjustment is made with pivot base plate
(19) which incorporates elongated mounting holes.
A
4
,
19
15
18
10
Detail A
Rotated 180 °
Figure 3-4. Door Latch Installation
3-8
MODEL R172 SERIES SERVICE MANUAL
~
NOTE
.
Detail
B
Reforming of the bonded door by
striking with a soft mallet etc. is
NOT permissible due to possible
damage to the bonded areas.
2.
3.
4.
5.
6.
7.
.
8.
9.
Spacer
Shim
Screws
Hinge
Hinge Bracket
Scuff Plate
Chain
Chain
Bolt
11.
12.
13.
14.
15.
16.
1.
17.
Nut
Baggage Door
Cam
Screw
Washer
Nut
Washer
Washer
Figure 3-5.
19. Latch
20. Screw
21. Lock Assembly
22. Washer
23. Nut
24. Lock Assembly
2.
Mounting Padssembly
25. MountingPad
26. Latch Assembly
Baggage Door Installation
Revision 1
3-9
MODEL R172 SERIES SERVICE MANUAL
NOTE
Lubricate door latch per Section 2. No lubrication is recommended for 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 one 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 HANDLE. (See figure 3-4.)
When inside handle is removed, reinstall in relation
to position of bolt (7) which is spring-loaded to 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).
3-30.
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 (90 securing door to hinges.
e. Reverse preceding steps for installation.
CAUTION
ReforminTofbonde
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.
3-34.
3-10
(See figure 3-6.)
PILOT AND COPILOT.
(See figure 3-6.)
a. RECLINGING BACK/FORE-AND-AFT ADJUST.
b. ARTICULATING RECLINE/VERTICAL ADJUST.
b
3-35. DESCRIPTION. These seats are manuallyoperated throughout their full range of operation.
Seat stops are provided to limit fore-and-aft traveL
3-36. REMOVAL AND INSTALLATION. (See figure
3-6.)
a Remove seat stops from rails.
b. Slide seat fore-and-aft to disengage seat rollers
from rails.
c. Lift seat out.
d. Reverse preceding steps for installation. Ensure all seat stops are reinstalled.
WARNI
It is extremely important that pilot's seat
stops are installed. since acceleration and
deceleration could possibly 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
RECLIKNING 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.' (See figure 3-6.)
a. FOLD-UP.
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. However, a cracked
framework may be welded, provided the crack is not
in an area of stress concentration (close to a hinge or
bearing point). The square-tube framework is 6061
aluminum, heat-treated to a T-6 condition. Use a
heliarc weld on these seats, as torch welds will destroy heat-treatment of frame structure. Figure 3-7
outlines instructions for replacing defective cams on
MODEL R172 SERIES SERVICE MANUAL
PILOT AND COPILOT
(STANDARD)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Link Seat Back Adjust
Torque Tube
Seat Back Adjustment Cam
Bushing
Spacer
Spring
Seat Adjustment Pawl
Roller
Bracket
RECLINING BACK/
FORE-AND-AFT ADJUST
17.w'
NOTE
Refer to figure 3-7 for seat
back cam replacement.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Washer
Pin
Adjustment Pin
Seat Stop
Seat Rail
Fore/Aft Adjustment Handle
Recline Handle
Roll Pin
Seat Belt Retainer
Trim
Install seat stop in eleventh
hole from the front of the
outboard seat rail.
Figure 3-6.
,
NOTE
Beginning with late 1977 models, seat belt
retainer (18) is separate from seat trim (19)
and is attached directly to seat frame with
four screws.
Seat Installation (Sheet 1 of 9)
3-11
MODEL R172 SERIES SERVICE MANUAL
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Vertical Adjustable
Handle
Pin
Bearing Block
Bearing
Collar
Vertical Adjust
Screw
Vertical Adjust
Nut
Seat Adjust Handle
Seat Adjust Pin
Spring (LH Side Only)
Seat Back Adjust
Handle
Jack Screw
Assembly
RH Crank Assembly
LH Crank Assembly
Seat Adjust Bellcrank
Cover
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
PILOT AND COPILOT SEATS
(OPTIONAL)
Fwd Torque Tube
Fwd Torque Tube
Bellcrank
Aft Torque Tube
Bellcrank
Aft Torque Tube
Seat Pivot Bracket
Seat Skirt Trim
Seat Back Trim
Pocket
Seat Back Retainer
Clip
Former Bracket
Former Assembly
Bracket
Head Rest
2
15
34
31
.
33
32
16
29
INFINITELY
ADJUSTABLE
12
17.
18.
19.
20.
Cushion
Seat Stop
11
Torque Tube Interconnect Channel
Pedestal
35.
36.
Collar
Link
27
35
Detail
28
14
19
25
A
24
Install seat stop 36
in first and thirteenth holes from
front of outboard
seat rail.
NOTE
22
*35
Beginning with R1723098, extended bosses
of bellcranks (22) delete collars (*35).
Figure 3-6.
3-12
Seat Installation (Sheet 2 of 9)
MODEL R172 SERIES SERVICE MANUAL
CENTER SEAT
(STANDARD)
1. Recline Shaft
,
DOUBLE
WIDTH BOTTOM/
SINGLE RECLINING
BACK
1.
2.
3.
4.
5.
6.
Recline Shaft
Seat Bottom
Seat Back
Trim
Headrest
Recline Pawl
7.
Link
A
8. Bushing
9. Bellcrank
10. Knob
Figure 3-6.
Seat Installation (Sheet 3 of 9)
3-13
MODEL R172 SERIES SERVICE MANUAL
CENTER SEAT
(OPTIONAL)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Seat Bottom
Spring
Spacer
Seat Back
Bushing
Recline Handle
Pawl
Control Shaft
Headrest
Plate
13.
Link
9
INDiVIDUAL RECLINING
WITH 1981
THRU 1980
3-14
THRU 1980
Figure 3-6.
Seat Installation (Sheet 4 of 9)
Figure 3-6.
Seat Installation (Sheet 4 of 9)
BEGINNING
WITH 1981
MODEL R172 SERIES SERVICE MANUAL
Detail A
1.
2.
3.
4.
5.
6.
Attach Bracket
Seat Bottom Structure
Seat Bottom
Seat Back
Floorboard
Mounting Bracket
,,
Figure 3-6. Seat Installation (Sheet 5 of 9)
reclining bench-type seat backs.
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 procedures which
will serve as a guide 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 unfamiliary with upholstery practices, the mechanic should make careful notes during
removal of each item to facilitate replacement later.
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 glassfiber 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 orig-
inal position any time 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 HEADLINERS.
(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 concealed by headliner
for security. Use wide cloth tape to secure loose
wires to fuselage and to seal openings in wing roots.
3-15
MODEL R172 SERIES SERVICE MANUAL
SEAT PEDESTAL ASSEMBLY
^BEGINNING
WITH 1980 MODELS
3
NOTE
Beginning with R1723098, extended bosses
of bellcranks (3) delete collars (*4).
1.
Seat Back Adjust
Bellcrank
2. Pivot Bracket
3. Bellcrank
4. Spacer
5. Spring
6. Seat Adjust Pin
7.
8.
9.
10.
11.
Vertical Adjust Handle
Seat Adjust Handle
Torque Tube Bellcrank
Forward Torque Tube
Aft Torque Tube
Figure 3-6.
3-16
Seat Installation (Sheet 6 of 9)
12.
13.
14.
15.
16.
17.
LH Crank Assembly
Splice
Jack Screw
Seat Back Adjust
Handles
Link
MODEL R172 SERIES SERVICE MANUAL
PILOT AND COPILOT SEAT ASSEMBLY
BEGINNING WITH 1980 MODELS
4. Cushion
10. Bracket
5. Cover
6. Grommet
11.
12.
Figure 3-6.
Clip
Pocket
16.
Bracket
17.
18.
Pin
Roller
Seat Installation (Sheet 7 of 9)
3-17
3-17
MODEL R172 SERIES SERVICE MANUAL
INFINITELY-ADJUSTABLE SEAT ASSEMBLY
BEGINNING WITH 1980 MODELS
10
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Cushion
Seat Bottom Cover
Cushion
Seat Back Cover
Head Rest
Head Rest Cover
Former Bracket
Former Assembly
12
13
Bracket
Clip
11. Seat Back Retainer
12. Seat Back Trim
13. Pocket Assembly
14. Seat Belt Retainer
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
14
Trim
RH Crank Assembly
Splice
LH Crank Assembly
Aft Torque Tube
Pivot Bracket
31
Seat Back Adjust Bellcrank
LH Pedestal
Bellcrank
Vertical Adjust Handle
Forward Torque Tube
Seat Handle Adjust
27
Seat Back Adjust Handle
RH Pedestal
Seat Adjust Pin
Jack Screw
32
Collar
Link
3
31
17
19
21
NOTE
22
Beginning with R1723098, extended bosses
of bellcranks (23) delete collars (*31).
23
24
Figure 3-6. Seat Installation (Sheet 8 of 9)
3-18
MODEL R172 SERIES SERVICE MANUAL
SPLIT BACK REAR SEAT
BEGINNING WITH 1980 MODELS
8
3
Detail
B
1. Cover
11.
Bracket
2. Cushion
3. Skirt
4. Lock
5. Grommet
6. Back Panel
7. Head Rest
12.
13.
14.
15.
16.
17.
Link
Spacer
Spacer
Lock
Hex Nut
End Fitting
8. Seat Bottom
18.
Spacer
19.
20.
Lock Cylinder
Spacer
9.
10.
Seat Back Legs
Seat Belt Stirrup
Figure 3-6.
11
DetailA
Seat Installation (Sheet 9 of 9)
3-19
MODEL R172 SERIES SERVICE MANUAL
SEAT BACK (REF)
CLEVIS BOLT (REF)-
50" R. (CONSTANT AT EACH NOTCH)
-REPLACEMENT
Z
(E)
CAM
PAWL (REF)
INDENT PROFILE
(TYP)
.170" MINIMUM-(TYP)
NOTE
Ensure replacement cam conforms
to dimensions shown in Detail A
before installation.
REPLACEMENT PROCEDURE:
-. 060"R
(TYP)
a. Remove seat from aircraft.
Detail A
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) engages 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.
3-20
Seat Back Cam Replacement
MODEL R172 SERIES SERVICE MANUAL
1.
2.
3.
4.
5.
6.
7.
8.
Stud
Spar Shield
Headliner Assembly
Inertia Reel Cover
Tiara
Inertia Reel Cover Support
Speaker Cover
Skylight Retainer
PROVISIONS FOR
OPTIONAL INERTIA
REEL INSTALLATION
Figure 3-8. Cabin Headliner Installation
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 overtighten screws. Larger screws may be used in enlarged holes as long as area behind hole is checked
for electrical wiring, fuel lines and other components
which might be damaged by using a longer screw.
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 one as a pattern for
trimming and marking screw holes.
3-51.
can be located at various points. The sliding tiedown lug also utilizes eyebolt and attaches to a seat
rail.
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.
3-54. SHOULDER HARNESS. (See figure 3-11.)
Individual shoulder harnesses may be installed for
each seat except auxiliary. 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 paragraph.
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.
SAFETY PROVISIONS.
i
3-52. CARGO TIE-DOWNS. Cargo tie-downs are
used to ensure baggage cannot enter seating area
during flight. Methods of attaching tie-downs are
illustrated in figure 3-9. The eyebolt and nutplate
REAR VIEW MIRROR. A rear view mirror
may be installed on the cowl deck above the instrument panel. Figure 3-10 illustrates details for rear
view mirror installation. Optional thru R1722930.
3-21
MODEL R172 SERIES SERVICE MANUAL
TIE-DOWN
-CARGO
SLIDE ASSEMBLY
CARGO TIE-DOWN RING
SEAT RAIL
Figure 3-9.
Cargo Tie-Down Rings
.1.Cover
I
. Mirror
3. Grommet
4. Nut
5. Washer
6. Deck Skin
e
Optional thru R1722930
Figure 3-10.
SHOP NOTES:
3-22
Rear View Mirror Installation
MODEL R172 SERIES SERVICE MANUAL
/
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Shoulder Harness
Spacer
Washer
Cover
Bolt
Inertia Reel Assembly
Spar
Mounting Plate
Latch Assembly
Seat Belt
Bracket
Link
Detail
B
1
..-
10
Detail
E
* NOTE
Used on LH outboard side only
Detail D
Detail
E
and
F
Figure 3-11.
Seat Belt and Shoulder Harness Installation
Revision 1 3-23
MODEL R172 SERIES SERVICE MANUAL
Counts as one crack. Usable if
not closer than one inch.
1
Unusable
REPLACE SEAT RAIL WHEN:
a. Any portion of web or flange is cracked tindex 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 permissable on seat
rails with cracks.
Figure 3-12. Seat Rail Inspection
3-24
Revision 1
MODEL R172 SERIES SERVICE MANUAL
SECTION 4
WINGS AND EMPENNAGE
TABLE OF CONTENTS
WINGS AND EMPENNAGE . ......
Wings ............
Description .........
Removal ...........
Repair ...........
Installation .........
Adjustment .........
Wing Struts .......
...
Description .........
Removal and Installation
Repair
...........
Fin ...............
4-1.
WINGS AND EMPENNAGE.
4-2.
WINGS.
Page No.
Aerofiche/Manual
D2/4-1
. 1D2/4-1
1D2/4-1
1D2/4-1
D2/4-1
1D5/4-4
1D5/4-4
1D5/4-4
1D5/4-4
. . 1D5/4-4
1D5/4-4
. 1D5/4-4
(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 corplete the structure. An all-metal, piano-hinged aileron, flap and a detachable wing tip are mounted on
each wing assembly. Colored navigation lights are
mounted at each wing tip.
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 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, then disconnect cables at aileron bellcranks.
Disconnect flap cables at turnbuckles above headliner, and pull cables into wing root area.
NOTE
To ease rerouting of the cables, a guide wire
may be attached to each cable before it is
pulled free from the wing. The cable may
then be disconnected from the wire. Leave
the guide wire routed through the wing; it
may be attached again to the dable during
installation, and used to pull the cable into
place.
Description .........
Removal .........
Repair ...........
Installation .........
Horizontal Stabilizer .......
Description........
Removal and Installation
Repair ...........
Stabilizer Abrasion Boots .....
Description .......
Removal
..........
Installation ....
1D5/4-4
. 1D6/4-5
1D7/4-6
1D7/4-6
D9/4-8
1D9/4-8
. . .1D9/4-8
1D9/4-8
1D9/4-8
1.D9/4-8
1D9/4-8
.1D9/4-8
f. Remove screws from strut fairings and slide
fairings toward center of strut.
g. Support wing at outboard end and remove strutto-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 unsecured 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 may be repaired in
accordance with instructions outlined in Section 18,
which supplements Federal Aviation Regulation, Part
43. Extensive repairs 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.
4-1
MODEL R172 SERIES SERVICE MANUAL
B
--
--
2.
6.
Fuel Gage Access
7. Cover
13. Wing Tip
1.
2.
3.
4.
5.
5.
6.
7.
Fairing
Fuel Tank
Lower Rear Fairing
Inspection Plate
Fuel
Fuel Tank
Tank Cover
Cover
Fuel Gage Access Cover
Bolt
8.
9.
10.
11.
12.
12.
13.
Figure 4-1.
4-2
19. Washers
STANDARD FUEL SYSTEM
Eccentric Bushings
Washer
Nut
Wing Flap
Aileron
Aileron
Wing Tip
14.
15.
16.
17.
18.
18.
19.
20.
Wing Installation (Sheet 1 of 2)
Navigation and Strobe Lights
Deleted
Wing Assembly
Cover Plate
Stall
Stall Warning
Warning Unit
Unit
Washers
Nut
MODEL R172 SERIES SERVICE MANUAL
300 LB IN (MIN)
690 LB IN (MAX)
TORQUE:
300 LB IN (MIN)
690 LB IN (MAX)
OPTIONAL FUEL SYSTEM
Detail
1. Fairing
2. Lower Rear Fairing
3. Wing Flap
4. Aileron
B
5.
6.
7.
8.
Wing Tip
Navigation and Strobe Lights
Courtesy Light
Fuel Filler Cap
Figure 4-1.
9. Bolt
10. Eccentric Bushings
11. Washers
12. Nut
Wing Installation (Sheet 2 of 2)
4-3
MODEL R172 SERIES SERVICE MANUAL
4-6.
INSTALLATION.
(See figure 4-1.)
NOTE
The forward wing spar fittings are attached to
the fuselage 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.
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.
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.
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 strutfitting with 579. 6 Sealer (Inmont
Corp., St. Louis, Missouri) or equivalent.
a. 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 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. 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.
k. Install all wing inspection plates, interior panels
and upholstery.
4-7. ADJUSTMENT (CORRECTING "WING-HEAVY"
CONDITION.) (See figure 4-1.) If considerable
4-4
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, Missouri) or equivalent.
4-11. REPAIR. Wing strut repair is limited to replacement of tie-downs and attaching parts. A badly
dented, cracked, or deformed wing strut 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.
MODEL R172 SERIES SERVICE MANUAL
Lubricate bolt and
hole per Section 2.
,
Seal across top of lower strut fitting
at skin cutout with 576.1 Permagum.
o.
^g)
0
S
-8.
Figure 4-2.
4-14. REMOVAL. The fin may be removed without
first removing the 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,
1.
2.
3.
Wing Strut
Tie-Down Ring
Wing Attachment Fitting
5.
6.
7.
Screw
Upper Fairing
Lower Fairing
Fuselage Attachment Fitting
Wing Strut
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.
4-5
MODEL R172 SERIES SERVICE MANUAL
Fairing (1) and Dorsal (2)
are riveted to Fuselage (13).
*Tighten forward stabilizer attach 5
bolts first, install required thickness of washers to allow a maximum
.010 gap between washer and stab-
Detail
.
13
Figure 4-3.
4-15.
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 install. an shm reoe
fo bewe
,
th
„A
a. Reinstall any shims removed from between the
4-6
C
4.
2.
3.
Nutplates
Dorsal Right Fairing
Upper
6.
7.
8.
9.
10.
11.
12.
13.
14.
Fin Tip
Upper Rudder Hinge
Center Rudder Hinge
Lower Rudder Hinge
Shim
Tailcone
Upper Left Fairing
Fuselage
Washer
Vertical Fin
fin rear spar and the fuselage fitting.
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")
maximum of one shim per bolt is permissible.
MODEL R172 SERIES SERVICE MANUAL
NOTE
See figure 4-3 for stabilizer
rear attach bolt installation.
NOTE
A kit is available from
Cessna Service Parts
Center for installation
of abrasion boots on
aircraft not so equipped.
1.
2.
3.
Stabilizer Tip
Outboard Elevator Hinge
Bushing
4.
5.
6.
7.
Inboard Elevator Hinge
Bracket
Upper Right Fairing
Upper Left Fairing
8.
9.
10.
11.
Horizontal Stabilizer
Forward Left Fairing
Forward Right Fairing
Abrasion Boot
Figure 4-4. Horizontal Stabilizer
4-7
MODEL R172 SERIES SERVICE MANUAL
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.
4-23. 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-EthylKetone.
4-24. INSTALLATION. Install abrasion boots as
outlined in the following procedures.
a. 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 of abrasion boot with Methyl-EthylKetone and a Scotch brite pad to ensure complete removal of paraffin/talc. Then a normal wipedown
with MEK 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, lintfree rag, soaked with solvent, and then wiping
the surfaces dry, before the solvent has time
to evaporate, with a clean, dry lint-free rag.
NOTE
Tighten forward stabilizer-attach bolts first.
Install required 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 Service Parts
Center.
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.
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 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
4-20. REPAIR. Horizontal stabilizer repair should
be accomplished in accordance with applicable instructions in Section 18.
4-21.
STABILIZER ABRASION BOOTS.
NOTE
An Accessory Kit (AK182-217) is available
from the Cessna Service Parts Center 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.
4-8
Should boot be attached "off-course", pull it
up immediately 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.
MODEL R172 SERIES SERVICE MANUAL
SECTION 5
LANDING GEAR, WHEELS AND BRAKES
Page No.
Aerofiche/Manual
TABLE OF CONTENTS
LANDING
GEAR ...........
Description
...........
Trouble Shooting ...
Main Landing Gear ........
Description .
........
Removal...........
Installation .
........
Step Bracket Installation .....
Fairings .............
1D14/5-2
1D14/5-2
1D14/5-2
1D17/5-5
1D17/5-5
1D17/5-5
1D17/5-5
1D17/5-5
1D18/5-6
Description .
........
Removal and Insallation...
Speed Fairing Removal ...
.
Speed Fairing Installation . . .
Wheel Removal.D19/5-7
Wheel (McCauley 2-piece) .....
Disassembly .
........
Inspection and Repair .
...
Reassembly .........
Wheel (Cleveland) ........
Disassembly .........
Inspection and Repair .
..
Reassembly
.........
Wheel Installation. ........
Wheel Axle Removal ....
Wheel Axle Installation ......
Bonded Axle Removal. ......
Bonded Axle Installation. ....
Wheel Alignment Check ......
Wheel Balancing .........
Nose Gear ...
.........
Description .........
TroubleShooting .......
Removal. .........
1D18/5-6
1D18/5-6
1D19/5-7
1D19/5-7
Inspection and Repair . . .
. . Installation ..
Shimmy Dampener .
...
Description
.
.....
1E13/5-25
1E13/5-25
1E14/5-26
1E14/5-26
1D19/5-7
1D19/5-7
1D19/5-7
1D19/5-7
1D23/5-11
1D23/5-11
Removal. ........
Disassembly
and Reassembly ......
Installation .........
Steering System .......
Description
.......
Steering Rod Assembly . .
1E14/5-26
1D23/5-11
Reassembly.
........
Wheel (McCauley with
Hub and Capscrews) .....
Disassembly ..
.......
Inspection and Repair .....
1D23/5-11
. 1D23/5-11
1D23/5-11
1)D23/5-11
1D24/5-12
...
Installation .........
.6/51
1lation
Fairing Removal .......
1D24/5-12
1D24/5-12
1D24/5-12
1E1/5-13
. 1E2/5-14
1E2/5-14
1E2/5-14
1E2/5-14
1E2/5-14
1B4/5-16
. 1E6/5-18
Description
.
Description
1E6/5-18
......
with FR1720611 and R172-
1E8/5-20
1E8/5-20
1E8/5-20
.
.
. .
Description ......
Brake Assemblies .....
Description
.......
Removal.........
Disassembly .......
Inspection and Repair . ..
Reassembly
......
Installation .......
Chec
........
Linie Installation
1E8/5-20
1E14/5-26
1E14/5-26
1E14/5-26
1E15/5-27
1E15/5-27
1E15/5-27
Removal. ......
Disassembly (Thru 1978)
Inspection and Repair
(Thru 1978)....
Reassembly (Thru 1978)
Disassembly (Beginning
with 1979) .....
Inspection and Repair
(Beginning with 1979)
Reassembly (Beginning
with 1979) .....
Hydraulic Brake Lines
1E14/5-26
1E14/5-26
1E14/5-26
1E14/5-26
1E14/5-26
1E14/5-26
.
Steering Adjustment. . . .
Brake System. ........
Description .......
Trouble Shooting
.....
Brake Master Cylinder
....
Fairing Installation ....
. 1E6/5-18
Wheel Removal .......
1E6/5-18
Wheel Disassembly (Thru
FR1720610). ........
1E6/5-18
Wheel Inspection and Repair
(Thru FR1720610). .....
1E7/5-19
Wheel Reassembly (Thru
FR1720610)........
1E7/5-19
Wheel Disassembly (Beginning
02000)...........
Wheel Inspection and Repair
(Beginning with FR1720611
and R172000) ........
Wheel Reassembly (Beginning
with FR1720611 and R17202000)........
. .
Wheel Disassembly (Cleveland).
Wheel Inspection and Repair
(Cleveland), .. ......
Wheel Reassembly (Cleveland) . 1E10/5-22
Wheel Installation .
.....
1E10/5-22
Wheel Balancing .......
1E10/5-22
Strut Disassembly ...
..
.1E12/5-24
Strut Inspection and Repair
.
1E12/5-24
Strut Reassembly .......
1E12/5-24
Torque Links .
........
1E13/5-25
Description
......
1E13/5-25
Removal . . ........
1E13/5-25
....
1E15/5-27
1E15/5-27
1E16/5-28
1E16/5-28
1E16/5-28
1E16/5-28
1E16/5-28
1E16/5-28
1E16/5-28
1E16/5-28
1E16/5-28
116/5-28
1E16/5-28
1E16/5-28
1E16/5-28
1E19/5-31
1E19/5-31
1E19/5-31
1E19/5-31
System Bleeding ............
Brake Lining Burn-In .......
Parking Brake System ...........
Description ................
Removal and
Installation .................
Inspection and Repair .......
1E195-31
1E19,5-31
1E20 5-32
1E20,5-32
1E20,5-32
1E20:5-32
1E10/5-22
Revision 1
5-1
MODEL R172 SERIES SERVICE MANUAL
5-1.
LANDING GEAR.
5-2. DESCRIPTION. The aircraft is equipped with a
non-retractable tricycle landing gear, consisting of
Cessna tubular spring-steel main gear struts and an
air/oil steerable nose gear shock strut. A bracket to
attach a step to each strut is bonded to the main gear
strut with a thermo-setting, high-strength cement.
Wheels with disc-type brakes and tube-type tires are
5-3.
installed. The brake disc is attached with the wheel
thru-bolts or capscrews and becomes an integral
part of the wheel. The nose gear is a combination of
a conventional air/oil (oleo) strut and fork, incorporating a shimmy dampener. 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 travel of 30 degrees right or left of center.
TROUBLE SHOOTING.
TROUBLE
AIRCRAFT LEANS TO ONE SIDE.
TIRES WEAR EXCESSIVELY.
PROBABLE CAUSE
REMEDY
Incorrect tire inflation.
Inflate to pressure specified
in figure 1-1.
Landing gear attaching parts
not tight.
Tighten loose parts; replace
defective parts with new parts.
Landing gear spring excessively
sprung.
Remove and install new part(s).
Bent axles.
Install new part(s).
Incorrect tire inflation.
Inflate to pressure specified
in figure 1-1.
Main wheels out of alignment.
Remove and install new part(s).
Landing gear spring excessively
sprung.
Remove and install new part(s).
Bent axles.
Install new part(s).
Dragging brakes.
Refer to paragraph 5-70.
Wheel bearings excessively tight.
Adjust properly.
Wheels out of balance.
Correct in accordance
with paragraph 5-30.
WHEEL BOUNCE EVIDENT
ON SMOOTH SURFACE.
5-2
Loose torque links.
Add shims or install new parts
as required.
Out of balance condition.
Reier to paragraph 5-30.
MODEL R172 SERIES SERVICE MANUAL
AFT LANDING GEAR BULKHEAD
FUSELAGE
FUSELAGE
STA. 56.70
FWD LANDING GEAR BULKHEAD
1. Inboard Forging
2. Bolt
3. Outboard Forging
4. Bushing
5. Bushing Retainer Ring
6. Tubular Strut
7. Brake Line
8. Clamp
9. Step
10. Step Bracket
11. Axle
12. Brake Torque Plate
13. Nut
14. Hub Cap
Figure 5-1.
Main Landing Gear
15.
16.
17.
18.
19.
20.
21.
Wheel Assembly
Wheel Brake Assembly
Fuselage Fairing
Tubular Strut Fairing
Step Bracket Cover
Cap Fairing
Brake Fairing
(Sheet 1 of 2)
5-3
MODEL R172 SERIES SERVICE MANUAL
Fuselage fairings (17) are split thru production model
Serial R1722284. Beginning with production Serial
R1722885. one-piece fairings are installed. However.
service replacement fairings. ordered through the
Cessna Service Parts Center. will be split, and can be
installed without disassembling the main landing gear.
Apply Y-8560 (3M Corporation) polyurethane tape
(1" wide) to upper amd lower surface of spring
and above and below step bracket to prevent chafing of spring fairing.
1
2
17
7
19
SECTION A-A
8
20
<
21*
A
11
12
Torque bolt (2) to 1100-1300 lb-in.
* Torque elbow to a maximum of 60 lb in.
Lube/seal with Liquid-O-Ring #404:
(Oil Center Research, P.O. Box 51971,
Lafayette, Louisiana 70501).
*
USED ONLY WITH WHEEL FAIRINGS
13
14
16
15
Figure 5-1.
5-4
Main Landing Gear (Sheet 2 of 2)
MODEL R172 SERIES SERVICE MANUAL
5-4.
mately 11 inches of upper end of landing gear tubular
strut.
MAIN LANDING GEAR.
5-5. DESCRIPTION. The tubular, spring-steel main
landing gear struts are attached to the 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.
5-1.)
(See figure
-bolt
NOTE
The following procedure removes the landing
gear as a complete assembly. Refer to applicable paragraph for removal of individual
components.
a. Remove seats as necessary, and remove access
cover over strut being removed.
b. Hoist or jack aircraft in accordance with procedures outlined in Section 2 of this manual.
c. Remove screws attaching fairing (17) to fuselage.
Remove screws at splice in fairing and work fairing
off strut fairing.
d. Drain hydraulic brake fluid from brake line (7)
on gear strut being removed.
NOTE
Fluid can be drained at the top of the strut
next to the fuselage or brake fairing (21) and
cap fairing (20) can be removed to drain
fluid at brake assembly.
e. Disconnect brake line (7) in fuselage so that brake
line is removed with gear strut. Cap or plug disconnected fittings to prevent entry of foreign material.
f. Remove nut, washer and bolt (2) attaching inboard end of gear strut to inboard landing gear bulkhead forging (1).
g. Remove retaining ring (5) and pull landing gear
strut from forgings (1) and (3) and bushing (4), using
care to prevent damage to hydraulic brake line.
NOTE
The tubular landing gear strut (6) is a corpression fit in bushing (4) in outboard forging (3).
5-7. MAIN LANDING GEAR INSTALLATION.
figure 5-1.)
(See
NOTE
The following procedure installs the landing
gear as a complete assembly. Refer to applicable paragraph for installation of individual components.
a.
b.
Install all parts removed from strut.
Apply Dow Corning Compound DC7 to approxi-
Avoid use of Dow Corning DC7 on surfaces
to be painted. DC7 contains silicone which
is harmful to painted areas.
c. Work strut into place through bushing (4) in outboard forging (3).
d. Align strut (6) in inboard forging (1) and install
(2) through fitting and tubular strut. Install
washer and nut on bolt and tighten to torque value of
1100-1300 lb-in.
e. Fill and bleed brake system in accordance with
procedures outlined in applicable paragraph in this
Section.
f. Install all fairings removed during gear removal.
g. Lower aircraft and install all access covers,
carpets and seats removed for access.
5-8.
STEP BRACKET INSTALLATION.
NOTE
The step bracket is secured to the tubular
gear strut with EA9309, EC2216, EC2214,
EC3445, or similar epaxy base adhesive.
a. Remove landing gear fairing, if installed.
b. Mark position of removed step bracket so that
the new step bracket will be installed in approximately
the same position on the strut.
c. Remove all traces of the original bracket and
adhesive, as well as any rust, paint or scale with a
wire brush and coarse sandpaper. Brush or scraping
motion should be longitudinally with the strut.
d. Leave surfaces of strut slightly roughened or
abraded, but deep scratches or nicks should be avoided. Also, roughen bonding surface of new bracket.
e. 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 thoroughly dry.
f. Check fit of the step bracket on the landing gear
strut. A small gap is permissible between the bracket and the strut.
g. Mix adhesive (any of those listed in note preceding step "a") in accordance with manufacturer's
directions.
h. Spread a coat of mixed adhesive on bonding surfaces of strut and bracket, and place step in position
on tubular gear strut. Clamp bracket to strut to ensure a good, tight fit.
i. Form a small fillet of the adhesive at all edges
of the bonded surfaces. Remove excess adhesive
with lacquer thinner.
j. Allow adhesive to thoroughly cure according to
manufacturer's recommendations before flexing
landing gear spring-strut or applying loads to the
step.
k. Paint landing gear strut and step bracket after
curing is completed.
1. If aircraft is equipped with landing gear strut
fairings, install them at this time, then install step
to bracket.
5-5
MODEL R172 SERIES SERVICE MANUAL
:
1.
Stiffener
2.
Mounting Plate
4.
Fairing
5.
6.
7.
8.
Scraper
Axle Nut
Door.
Plug
NOTE
Begnninng with R1723269 & FR1720666,
access door (7) is replaced with a 2.00-inch
hole and a removable plug button (8)
6
Figure 5-2.
5-9. MAIN LANDIIG GEAR FAIRINGS.
5-1 and 5-2.)
Main Wheel Speed Fairing
(See figures
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 at the upper end
and to cap fairings at the lower end. The cap fairings
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 cap 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:
5-6
Revision 1
1. Remove screws attaching fairing to tubular
spring strut.
2. Disconnect clamp from tubular strut and
spring clamp over strut; remove cap fairing.
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 1978 Models, remove screws from nutplates
holding fairings together; spring fairings over strut
fairings. Beginning with 1979 Models, 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.
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.
MODEL R172 SERIES SERVICE MANUAL
5-12. MAIN WHEEL SPEED FAIRING REMOVAL.
(See figure 5-2.)
a.
Remove wheel brake fairing (item 21, 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 mounting
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 the 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 21, 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. 38-inch. Elongated holes are provided in the
scraper for clearance adjustment.
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 rotation. 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.
5-15. 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 seal 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.
5-16. 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, 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 (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 worn or chracked thru-bolts (24) or nuts
(10). Inspect brakes per paragraph 5-87.
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
of this manual.
5-17. MAIN WHEEL REASSEMBLY. (McCauley TwoPiece 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).
5-7
MODEL R172 SERIES SERVICE MANUAL
1
1.
4
Retaining Ring
2. Grease Seal Retainer
3.
4.
5.
Grease Seal Felt
Grease Seal Retainer
Bearing Cone
6.
Wheel Half
7. Tire
8.
9.
10.
11.
12.
13.
Tube
Washer
Nut
Brake Disc
Torque Plate
Pressure Plate
14.
Ancho r Bolt
15.
16.
17.
18.
19.
Elbow
Brake Cylinder
Bolt
Bleeder Screw
Dust Cover
20.
Bleeder Fitting
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Piston O-Ring
Brake Piston
Lining
Thru-Bolt
Washer
Back Plate
Bearing Cup
Snap Ring
Grease Seal Ring
Torque Plate Bushing
31.
Bleeder Screw
23
15
24
22
17
21
20
MC CAULEY WHEEL
(Two-Piece)
18
19
Figure 5-3. Main Wheel and Brake (Sheet 1 of 3)
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 (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.
5-8
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.
MODEL R172 SERIES SERVICE MANUAL
29
-
3
Figure 5-3.
Main Wheel and Brake (Sheet 2 of 3)
MODEL R172 SERIES SERVICE MANUAL
-
.
2 Grease Seal Retainer (Inboard)
3. Grease Seal Felt (Inboard)
4. Brake Disca
etier(utord
14
(With Hub and Capscrews)
7. Pnchor Bolt
18.
12.
ElIbow
Grease Seal Retainerr
29.
16.
TorquBack
PlatePlate
Pressure
Anchor Bolt
Elbow
17.
18.
NOTES17
Torque elbow
NOTE
19. Brake
Cylinder
5-10b-in.
21. Bleeder Screw
22.
23.
Torque
(She
lbow (18) to of
a maximum
O-Ring #404: (Oil Research, P.O.
Box 51971, Lafayette, Louisiana
7050. )
Dust Cup
Bleeder Fitting
bolt (20) to 120-130
Torque bleeder screw (21) to 30-40
28.
29.
Washer
Back Plate
Figure 5-3.
5-10
Main Wheel and Brake
(Sheet 3 of 3)
MODEL R172 SERIES SERVICE MANUAL
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 of this manual.
5-18. MAIN WHEEL 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 a 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 5-87.
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 of this manual, before installing in wheel half.
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 thrubolts. Tighten nuts evenly to the torque value of 90 lbin.
CAUTI
Uneven or improper torque of thru-bolt nuts
can cause failure of bolts, resulting in wheel
failure.
d. Clean and pack bearing cones with clean aircraft
wheel bearing grease, as outlined in Section 2 of this
manual.
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
of this manual for correct tire pressure.
5-21. MAIN WHEEL DISASSEMBLY. (McCauley
Wheel with Hub and Capscrews.) (See figure 5-3,
sheet 3 of 3.)
Injury can result from attempting
to remove
wheel flanges with tize 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. Separate wheel flanges from wheel hub. Retain
spacers on each side of wheel hub.
f. 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 an 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
5-11
MODEL R172 SERIES SERVICE MANUAL
and
. Inspect wheel flanges and wheel hub for cracks.
C racked 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 area should be cleaned thoroughly,
pi .:ned with zinc chromate and painted with aluminum
lacquer.
c. Carefully inspect bearing cones and cups for
tdamage and discoloration. After cleaning, pack bearing cones with clean aircraft wheel bearing grease.
Refer to Section 2 of this manual for grease type.
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 rotation. Refer to paragraph
5-12A for correct scraper-to-tire clearance.
5-25.
5-23. MAIN WHEEL REASSEMBLY. (McCauley
Wheel with Hub anc Capscrews.) (See figure 5-3,
Sheet 3 of 3.)
a. Place wheel hub in tire and tube with tube inflatiun stem in hole of wheel hub.
b. Place spacer and wheel flange on inboard side
i,) 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 the value
specified.
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 (27) evenly and torque to 190
to 200 Ib-in.
h. Clean and pack bearing cones with clean aircraft
wheel bearing grease. Refer to Section 2 of this manual for grease type.
i. Assemble bearing cones, grease seal felts and
retainer into wheel hub.
j. Inflate tire to seat tire beads, then adjust to correct pressure. Refer to chart in Section 1 of this
manual for correct tire pressure.
5-24. MAIN WHEEL INSTALLATION.
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 axle nut to the nearest castellation and install cotter pin.
c. Place brake back plate in position and secure
with bolts and washers.
d. Install valve extension and hub cap. Install
speed fairing (if used) as outlined in paragraph 5-13.
5-12
MAIN WHEEL AXLE REMOVAL.
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.
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 5-27.
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.
nstall 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 applicable paragraph in this section.
g. Install speed fairing, if used, in accordance with
paragraph 5-13.
MODEL R172 SERIES SERVICE MANUAL
CAUTION
Do not place tape in
direct contact with
tubular gear spring.
IWARNING
^
.
Due to aging of the aluminum axle, caused
by the heating tape, a new axle will have to
be installed.
1. Axle
2.
3.
Tubular Gear Strut
Electrical Heating Tape
4. Plug
Figure 5-4.
Main Wheel Axle Removal
5-27. BONDED MAIN WHEEL AXLE REMOVAL.
(See figure 5-4.)
Parts Center. 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.
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 strut.
a. Remove speed fairings, if installed, according
to procedures outlined in applicable paragraph of
this section.
b. Remove wheels in accordance with procedures
outlined in applicable paragraph of this section.
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.
NOTE
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
Service Parts Center.
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 the figure.
Axles are bonded to the struts of some tubular
gear aircraft with EA9309-25GR adhesive,
which is available from the Cessna Service
SHOP NOTES:
5-13
MODEL R172 SERIES SERVICE MANUAL
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 dry with 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.
,
mum allowable
looseness between
tbolt and bolt holes
in gear strut and
axle.
A
.
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 Service Parts Center, in accordance with instructions in the package. Spread adhesive thinly
and evenly on outer surface of landing gear spring
in area that will 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 applicable paragraph of this section.
h. Connect hydraulic brake line to wheel brake cylinder.
i. Fill and bleed hydraulic brake system in accordance with applicable paragraph in this section.
j. Install speed fairings, if used, in accordance
with applicable paragraph in this section.
5-29. MAIN WHEEL ALIGNMENT CHECK. (See figure 1-1.) No provisions are made for aligning
main wheels. Figure 5-6 contains procedures
for checking toe-in and camber.
If wheel alignment is out of these limitations, a new
tubular spring strut will have to be installed.
5-30. WHEEL BALANCING. Sinceuneventirewear
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 sidewall, 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.
1.
2.
3.
Tire
Attaching Bolt
Axle
Figure 5-5.
4.
5.
6.
Tubular Gear Strut
Brake Line
Brake
Checking Axle Looseness
NOTE
See figure 5-5 for checking looseness of
axle on tubular gear strut. If a maximum
looseness of . 0023-inch between mounting
bolt and holes in tubular gear strut and
axle is encountered, it is permissible to
bond the axle to the strut. Do not allow
the adhesive to enter the holes in gear
strut or axle, or to contact bolt threads.
The following procedure outlines the method for bonding axle to strut.
5-14
If a wheel shows evi-
dence of unbalance during service, it may be statically
balanced. Wheel balancing equipment is available
from the Cessna Service Parts Center.
5-31.
NOSE GEAR.
(See figure 5-7.)
5-32. DESCRIPTION. A steerable nose wheel, mounted
ed 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
linking 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.
MODEL R172 SERIES SERVICE MANUAL
PLACE CARPENTER'S SQUARE
AGAINST STRAIGHTEDGE AND
LET IT TOUCH WHEEL JUST
BELOW AXLE NUT.
A
NOTE
Rock wheels before
checking wheel alignment.
GREASE BETWEEN PLATES
-ALUMINUM PLATES APPROXIMATELY
18" SQUARE, PLACED UNDER WHEELS.
REFER TO FIGURE 1-1
FOR TOE-IN AND CAMBER
VALUES.
BLOCK STRAIGHTEDGE AGAINST
TIRES JUST BELOW AXLE HEIGHT-
FRONT VIEW OF CAMBER CHECK
TOP VIEW OF TOE-IN CHECK
Measure camber by reading protractor level
held vertically against outboard flanges of
wheel.
Measure toe-in at edges of wheel flange. Difference in measurements is toe-in for one wheel.
(half of total toe-in.)
CNEGATIVE CAMBER
POSITIVE CAMBER
P
CARPENTER'S SQUARE
FORWARD
STRAIGHTEDGE
NOTE
These procedures are specifically for checking wheel alignment.
No provisions are made for aligning the main wheels. Refer to
the chart in figure 1-1 of this manual for camber and toe-in
limitations.
Figure 5-6.
Main Wheel Alignment
5-15
MODEL R172 SERIES SERVICE MANUAL
5-33.
TROUBLE SHOOTING THE NOSE urAR.
TROUBLE
NOSE WHEEL SHIMMY.
NOSE STRUT DOES NOT HOLD
loose.
Nose strut
SHOP NOTES:
5-16
Tighten nose strut attaching bolts.
Loose or worn nose wheel
steering linkage.
Tighten. Replace defective
parts with new parts.
Nose wheel out lf
Refer to paragraph 5-49.
balance.
Wheel bearings too loose.
Adjust properly.
Defective shimmy dampener.
Repair, or install new dampener.
Shimmy dampener fluid low.
Service in accordance with
Section 2.
Loose torque links.
Add shims, or install new parts
as required.
Defective oi lIoose air lillet valve.
Check gasket and tighten loose valve.
Install new valve if defective.
AIR PRESSURE.
HYDRAULIC FLUID LEAKAGE
FROM NOSE STRUT.
REMEDY
PROBA BLE CAUSE
Defective strut seals.
Install new seals.
Defective strut seals.
Install new seals.
MODEL R172 SERIES SERVICE MANUAL
....
,
"Detail
i\-j
and holes
MS20365-1032
boltsrivet
enshould be nut.
existing
Detail
RIVETA HOLEt
--
The
fitting (4) to firewall work loose, it
rivets with the appropriate length
When
fitting before attaching bolts are tightened.If greplace
Gap toleranceit
Ad5
rivets with the appropriatethe
length
MS20365-002
Replace cap if gap is
less than mini5.30"
(MAX)
Installe
be
larged should
to . 13 inch to accomodate
the
'
maximum tolerance, install shims (16), Part No. 0543042-1
obtain gap tolerance.
When install
1. Bolt
2.
3.
4.
5.
6.
7.
ing ca p (14), check
between
sidescap
gap
and strut
8. Lower Strut Fitting
15. Shimmy Dampener
before
maximum
shims
(16), Part
No. 0543042-1
(.
016")gap
andtolerance,
Part No. install
0543042-2
(. 032"),
to
5.15"
obtain
tolerance.
Replace cap
if gap as
is required,
less than mini5.30" (MIN)
(MAX)
Strut
Assembly
Bolt
Upper Nose Gear Fitting
RH Steering Tube
LH Steering Tube
Clamp
9.
10.
11.
12.
13.
14.
Bolt
Rod End Arm Assembly
Steering
Wheel Assembly
Shimmy Dampener Arm
Strut Clamp Cap
Figure 5-7.
16.
17.
18.
19.
20.
21.
Shim
Rivet
Ball Joint
Nut
Check Nut
Clevis
SectionD-D
Nose Gear Installation
5-17
MODEL R172 SERIES SERVICE MANUAL
5-34. NOSE GEAR REMOVAL. (See figure 5-7.)
.Remove cowling for access.
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 at top of strut or before disconnecting torque links.
e. Deflate strut completely and telescope strut to
its shortest length.
f. Remove bolt at top of strut.
g. Pull strut assembly down and 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 on firewall and attach
with bolt.
b. Telescope strut to mate strut clamp cap with
lower strut fitting on firewall.
c. Install shims and strut clamp cap attaching strut
to lower strut fitting, observing CAUTION in
figure 5-7.
Inflate and -service shock strut in accordance
procedures outlined in Section 2 of this manual.
. Rig nose wheel steering tubes as outlined in applicable paragraph in Section 10 of this manual.
5-36. NOSE WHEEL SPEED FAIRING REMOVAL.
a. Weight or tie down tail of aircraft to raise nose
wheel off the floor.
b. Remove nose wheel axle stud.
WARNING
Nose wheel fairing cover plate is secured by
the lower torque link attaching bolt. Deflate
strut before removing this bolt. (Refer to
Section 2 of this manual.)
c. Deflate strut and remove bolt securing cover
plate to strut; remove cover plate.
d. -Remove bolt securing speed fairing and tow bar
spacers to strut.
NOTE
Bolt attaching tow bar spacers also holds
base plug in place. Cut head off an AN5
bolt and cut bolt approximately 3-inches in
length. When driving attaching bolt out,
drive 3-inch headless bolt in to hold base
plug and bushing in place.
Slide speed fairing up and remove nose wheel.
sen scraper as necessary.
Rotate speed fairing 90 degrees and work fairing
f.
down over nose gear fork to remove.
5-18
5-37. NOSE WHEEL SPEED FAIRING INSTALLATION.
WARNING
Do not inflate or service shock strut until
after speed fairing is installed.
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.
c. Tighten axle stud nut until a slight bearing drag
is obvious when the wheel is rotated. Back off nut
to the nearest castellation and install cotter pins.
d. Install bolt, tow bar spacers, washers and nut
attaching fairing to strut, driving out 3-inch headless
bolt.
e. Install cover plate and bolt attaching cover plate
to strut.
f. Inflate and service shock strut in accordance
with applicable paragraph in Section 2 of this manual.
- g. Adjust wheel scraper clearance in accordance
with the following CAUTION.
CAUTION
Always check scraper clearance after installing speed fairings, whenever a tire has been
changed and whenever scraper adjustment
s ben disturbed. Set clearance between
tire and scraper for a minimum of 0.25-inch
to a maximum of 0.38-inch. Elongated holes
are provided in the scraper for clearance
adjustments. If the aircraft is flown from
with mud, snow, or ice, the speed
surfaces
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.
5-38. NOSE WHEEL REMOVAL.
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 wheel fairings.
5-39 NOSE WHEEL DISASSEMBLY. (Thru
FR1720610.) (See figure 5-9.)
a. Remove hub caps, completely deflate tire and
break tire beads loose at wheel flanges.
WARNING
Injury can result from attempting to remove
wheel anges with tire and tube inflated.
Avoid damaging wheel flanges when breaking
tire beads loose.
b. Remove capscrews and washers.
c. Separate wheel flanges from wheel hub. Retain
spacers between wheel flanges and wheel hub.
d. Remove wheel hub from tire and tube.
e. Remove retainer rings and remove grease seal
MODEL R172 SERIES SERVICE MANUAL
-
NOTE
Beginning with R1723269 & FR1720666,
access door (9) is replaced with a 2.00-inch
hole and a removable plug button
2.
3.
4.
Speed Fairing
Tow-Bar Spacer
Cover Plate
Fork Bolt
6.
7.
8.
9.
-
Axle Stud
Ferrule
S2111-1 Washer
Door, Access
Figure 5-8.
Nose Wheel Speed Fairings
retainers grease seal felts and bearing cones from
wheel hub.
NOTE
The 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 1210C (250'F). Using an
arbor press, if available, press out the
bearing cup and press in the new bearing
cup while the wheel hub is still hot.
5-40. NOSE WHEEL INSPECTION AND REPAIR.
(Thru FR1720610.) (See figure 5-9.)
a. Clean all metal parts, grease seal felts and
phenolic spacers in cleaning solvent and dry thoroughly.
b. Inspect wheel flanges and wheel hub for cracks.
Discard cracked wheel flanges or hub and install new
parts. Sand out nicks, gouges and corroded areas.
When protective coating has been removed, clean the
area thoroughly, prime with non zinc chromate primer, and
paint with aluminum laquer.
c Carefully inspect bearing cones and cups for
damage and discoloration. After cleaning, pack bearing cones with clean aircraft wheel bearing grease
(Section 2) before installing in the wheel hub.
5-41. NOSE WHEEL REASSEMBLY. (Thru
FR1720610.) (See figure 5-9.)
a. Insert tube in tire, aligning index marks on tire
and tube.
b. Place wheel in tire with valve stem in cutout of
wheel hub.
c. Place spacer and wheel flange on one side of
wheel hub and place washer under head of each capscrew and start capscrews into wheel hub threads.
d. Place spacer and wheel flange on other side and
align valve stem in cutout in wheel flange.
e. Place washer under head of each capscrew and
start capscrews into wheel hub threads.
(CAUTIONi
Be sure that spacers and wheel flanges are
seated on flange of wheel hub. Uneven or
improper torque of capscrews can cause
failure of the capscrews with resultant
wheel failure.
Revision 1
5-19
MODEL R172 SERIES SERVICE MANUAL
f. Tighten capscrews (15) evenly and torque to 190
to 200 lb-in.
g. Clean and pack bearing cones with clean aircraft
wheel bearing grease. (Refer to Section 2 for grease
type. )
h. Assemble bearing cones, grease seal felts and
retainers into wheel hub.
i. Inflate tire to seat tire beads, then adjust to correct tire pressure. (Refer to Section 1. )
5-42. NOSE WHEEL DISASSEMBLY. (Beginning with
FR1720611 and R17202000.) (See figure 5-9.)
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 ring (1), grease seal retainer
(2), felt grease seal (3), grease retainer (2) and bearing cone (9) from each wheel half (6).
oughly, then applying one coat of clear lacquer paint.
k. Pack bearings with grease specified in Section 2
of this manual.
5-44. NOSE WHEEL REASSEMBLY. (Beginning with
FR1720611 and R17202001.) (See figure 5-9.)
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 thrubolt (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.
f. Prior to torquing nuts (4), inflate tube with approximately 10-15 psi air pressure to seat tire.
CAUTION
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 a new bearing cup while
wheel half is still hot.
Do not use impact wrenches on thru-bolts
or nuts.
g. Dry torque all nuts (4) evenly to a torque value of
of 140 to 150 lb-in.
h. Inflate tire to correct pressure specified in figure 1-1 of this manual.
5-45. DISASSEMBLY.
Sheet 2 of 2.)
5-43. NOSE WHEEL INSPECTION AND REPAIR.
(Beginning with FR1720611 and R17202001.) (See
figure 5-9.)
a. Clean all metal parts and felt grease seals in
Stoddard solvent or equivalent, and dry thoroughly.
IWARNING
Injury can result from attempting to separate
wheel halves with tire inflated. Avoid damaging wheel flanges when breaking tire beads
loose.
NOTE
A soft bristle brush may be used to remove
hardened
hardened grease,
grease, dust
dust or
or dirt.
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
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 thor5-20
(Cleveland) (See figure 5-9,
a
a.
b.
c.
Deflate
Deflate tire
tire and
and break
break tire
tire beads
beads loose.
loose.
Remove
thru-bolts
and
separate
wheel halves.
Remove tire and tube.
d. Remove snap ring, grease seal felt, grease seal
rings and bearing cones from both wheel halves.
Bearing cups are a press-fit in the wheel
halves and should not be removed unless
halves and should not be removed unless
replacement is necessary. To remove
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.
MODEL R172 SERIES SERVICE MANUAL
BEGINNING WITH FR1720611 & R17202000
1. Retainer Ring
2. Grease Seal Retainer
3. Felt Grease Seal
4. Nut
5. Washer
6. Wheel Half
7. Bearing Cup
8. Bolt
9. Bearing Cone
10.
Tube
11.
12.
13.
Tire
Wheel Flange
Phenolic Spacer
15.
Capscrew
THRU FR1720610
Figure 5-9.
Nose Wheel and Tire (Sheet 1 of 2)
5-21
5-21
MODEL R172 SERIES SERVICE MANUAL
1. Snap Ring
2. Grease Seal Ring
3. Grease Seal Felt
4. Bearing Cone
5. Outer Wheel Half
6. Tire
7. Tube
8. Inner Wheel Half
9.
10.
Bearing Cup
Thru-Bolt
.
10
CLEVELAND WHEEL
Figure 5-9.
Nose Wheel and Tire
5-46. INSPECTION AND REPAIR. (Cleveland)
(See figure 5-9, Sheet 2 of 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 5-33A.
5-47. REASSEMBLY. (Cleveland) (See figure
5-9, Sheet 2 of 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 hall, 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
5-22
(Sheet 2 of 2)
wheel halves.
f. Inflate tire to seat tire beads, then adjust to
correct pressure.
g. install wheel in accordance with paragraph 5-34.
5-48. NOSE WHEEL INSTALLATION.
a. Install axle tube in nose wheel.
b. Install nose wheel assembly in fork and install
nose wheel axle stud.
c. Tighten axle stud nut until a slight bearing drag
is obvious when wheel is rotated. Back nut off to the
nearest castellation and insert cotter pins.
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 clearance adjustment has been
disturbed. Set scraper clearance in
accordance with instructions outlined in
paragraph 5-37.
5-49. 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 sidewall,
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
MODEL R172 SERIES SERVICE MANUAL
NOTE
11
Use shims (2) as required between steering 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.
.
1
9
24
14
24
16
SECTION
13
B-B
15
16
17
SECTION A-A
27
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Washer
Shim (As Required)
11.
12.
Rod End
Steering Arm Assembly (Collar) 13.
14.
Retaining Ring
15.
Decal
16.
Upper Strut
17.
Orifice Piston Support
18.
O-Ring
19.
Filler Valve
Lock Ring
20.
21.
Bearing
22.
Lower Strut
Packing Support Ring 23.
24.
Scraper Ring
25.
Retaining Ring
26.
Lock Ring
27.
Metering Pin
Figure 5-10.
O-Ring
O-Ring
Base Plug
Fork
Bushing
Back-Up Ring
O-Ring
O-Ring
Tow Bar Spacer
21
Nose Gear Strut
5-23
MODEL R172 SERIES SERVICE MANUAL
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 Service Parts Center.
5- 50. NOSE GEAR SHOCK STRUT DISASSEMBLY.
(See figure 5-10. )
l.
NOTE
The following procedures apply to the nose
gear shock strut after it has been removed
from the aircraft and the speed fairing and
the 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
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.
Remove filler valve from orifice support.
5-51. NOSE GEAR SHOCK STRUT INSPECTION AND
REPAIR. (See figure 5-10.)
a. Thoroughly clean all parts in cleaning solvent
and inspect them carefully.
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.
5-52.
NOSE GEAR SHOCK STRUT REASSEMBLY.
(See figure 5-10.)
NOTE
Be sure shock strut is completely deflated
before removing 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-rings and back-up rings from packing
support ring.
h. Remove bolt securing tow bar spacers.
NOTE
Bolt attaching tow bar spacers also holds
bushing and base plug in place.
i. Remove bolt attaching fork to strut barrel and
remove bushing, base plug and metering pin from
lower strut. Remove O-rings and metering pin from
base plug.
Used sparingly, Dow Corning Compound DC4
is recommended for O-ring lubrication. All
other internal parts should be liberally coated
with hydraulic fluid during reassembly.
a. Install washer (1) and shim(s) (2), if installed.
b. Lubricate needle bearings in steering collar (4),
as shown in Section 2 of this manual, and install
steering collar and retaining ring (5).
c. Check steering collar for snug fit against washer.
Shims of variable thicknesses and available from the
Cessna Service Parts Center 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 in place.
Part numbers of available shims and their thicknesses
are listed as follows:
1243030-5 ...
1243030-6 .......
1243030-7 ........
5-24
. ..
0.006
0.012
. .0.020
d. Install rod ends (3) in steering collar (4) and
adjust rod ends to dimension specified in Section
view 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
NOTE
Lower strut barrel and nose gear fork are a
press fit, drilled on assembly. Separation
of these parts is not recommended except
for installation of a new part.
.
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
MODEL R172 SERIES SERVICE MANUAL
NOTE
inches, then safety the bolts by
bending tips of safety lug (10).
Tighten nuts (7) snugly, then
tighten to align next castellation
with cotter pin hole.
Shims (3) are available to use as
required to remove any looseness.
3
[
j
1. Spacer
G. Upper Torque Link
2.
7.
Nut
8.
Bolt
Grease Fitting
3. Shim
4.
5.
1
5-11.
(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 the 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 5-32.
q. After strut is installed on aircraft, fill and inflate shock strut in accordance with procedures outlined in Section 2 of this manual.
5-53.
TORQUE LINKS.
(See figure 5-11.)
5-54. DESCRIPTION. Torque links keep the lower
strut aligned with the nose gear steering system, but
permit shock strut action,
5-55.
TORQUE LINK REMOVAL.
Bushing
Stop Lug
9.
10.
Lower Torque Link
Safety Lug
Torque Links
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.
5-56. TORQUE LINK INSPECTION AND REPAIR.
(See figure 5-11.) Torque links bushings should not
be removed except for replacement of parts; replace
if excessively worn.
5-57. TORQUE LINK INSTALLATION.
5-11.)
(See figure
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 of this manual.
5-25
MODEL R172 SERIES SERVICE MANUAL
3
2
1.
2.
3.
Retainer Ring
Barrel
O-Ring
.4.Shaft Assembly
5. Head Bearing
6. Piston
5
7. Pin
3
Figure 5-12.
5-58,
SHIMMY DAMPENER.
(See figure 5-12.)
5-59. DESCRIPTION. The shimmy dampener, provided for the nose gear, offers resistance to shimmy
by forcing hydraulic fluid through small orifices in a
piston. The dampener piston shaft is secured to a
bracket, welded on the bottom of the upper strut tube.
The shimmy dampener housing is secured to the
steering arm assembly, which moves as the nose
wheel is turned, causing relative motion between the
dampener shaft and housing.
5-60. SHIMMY DAMPENER REMOVAL.
a. Remove cotter pin, nut, washer and bolt attaching shaft clevis to bracket welded on bottom of upper
strut tube.
b. Remove cotter pin, nut, spacer and bolt attaching dampener housing to steering arm assembly.
c. Remove shimmy dampener.
5-61. SHIMMY DAMPENER DISASSEMBLY AND
REASSEMBLY. (See figure 5-12.) Refer to the
figure during disassembly and assembly of the
shimmy dampener. When reassembling the dampener, install all new O-rings. Lubricate all
parts with clean hydraulic fluid. When dampener
is completely assembled, service in accordance
with procedures outlined in Section 2 of this manual.
5-62. SHIMMY DAMPENER INSTALLATION.
a. Attach shimmy dampener housing to steering
arm assembly with bolt, spacer, nut and cotter pin.
b. Attach dampener piston rod clevis to bracket
welded on bottom of upper strut tube with bolt,
washers (as required) and nut.
5-63.
5-26
NOSE WHEEL STEERING SYSTEM.
Shimmy Dampener
5-64. DESCRIPTION. Nose wheel steering is accomplished through the use of the rudder pedals. Springloaded 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, the 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 assemblies.
5-65.
NOSE WHEEL STEERING ROD ASSEMBLIES.
5-66. 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.
5-67. NOSE WHEEL STEERING ADJUSTMENT.
Before attaching nose wheel steering rods to the rod
ends extending from the steering arm assembly, adjust rod ends to the dimension specified in Section
view A-A in figure 5-10. Since the nose gear steering
system and the rudder system are interconnected,
adjustment to one system might affect the other system. Refer to Section 10 of this manual for instructions for rigging the nose wheel steering system and
the rudder system.
5-68.
BRAKE SYSTEMS.
(See figure 5-14.)
5-69. DESCRIPTION. The hydraulic brake system
is comprised of two master cylinders, located immediately forward of the pilot's rudder pedals, brake
lines and hoses connecting each master cylinder to
its wheel brake cylinder, and the single-disc, floating
cylinder-type brake assembly, located at each main
gear wheel.
MODEL R172 SERIES SERVICE MANUAL
5-70.
TROUBLE SHOOTING THE BRAKE SYSTEM.
TROUBLE
DRAGGING BRAKES.
BRAKES FAIL TO OPERATE.
5-71.
13.)
BRAKE MASTER CYLINDER.
PROBABLE CAUSE
REMEDY
Brake pedal binding.
Check and adjust properly.
Parking brake linkage holding
brake pedal down.
Check and adjust properly.
Worn or broken piston return
spring (in master cylinder.)
Repair, or install new cylinder.
Insufficient Clearance at LockO-Seal or correct adjustment of
cylinder overall length.
Adjust as outlined in paragraph 5-76.
Restriction in hydraulic lines or
restrictions in compensating port
in brake master cylinder,
Drain brake line and clear the
inside of the brake line with
filtered compressed air. If
cleaning the lines fails to give
satisfactory results, the master
cylinder may be faulty and
should be repaired.
Worn, scored or warped brake disc.
Install new disc and brake linings.
Damaged or accumulated dirt
restricting free movement of wheel
brake parts.
Clean and repair or install new
parts as necessary.
Leak in system.
If brake master cylinders or wheel
cylinder assemblies are leaking,
repair, or install new parts.
Air in system.
Bleed system.
Lack of fluid in master cylinders.
Fill and bleed system.
Defective master cylinder.
Repair, or install new parts.
(See figure 5-
5-72. 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 cylinders.
5-73. BRAKE MASTER CYLINDER REMOVAL.
a. Remove bleeder screw at wheel brake assembly
and drain hydraulic fluid from brake cylinders.
b. Remove front seats and rudder bar shield for
access to the brake master cylinders.
c. Disconnect parking brake linkage 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, hoses and lines.
to prevent entry of foreign material.
5-74. DISASSEMBLY, (Thru 1978 Models.) (See
figure 5-13, Sheet 1 of 2.)
a. Unscrew clevis (1) and jam nut (2).
b. 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)
5-27
MODEL R172 SERIES SERVICE MANUAL
plug (3).
i.
Remove Lock-O-Seal (15).
5-75. INSPECTION AND REPAIR. (Thru 1978 Models.) (See figure 5-13, Sheet 1 of 2.) Repair is
limited to installation of new parts, cleaning and
adjusting. (Refer to assembly 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 0-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.
5-76. REASSEMBLY. (Thru 1978 Models.) (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 (3) through spring (11).
f. Slide compensating sleeve (16) over rod (3).
g. Install cover (4), washer (19) and screw (18).
5-77. DISASSEMBLY. (Beginning with 1979 Models.)
(See figure 5-13, Sheet 2 of 2.)
a. Unscrew clevis (1) and jam nut (2).
b. Remove filler plug (3).
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).
5-78. INSPECTION AND REPAIR. (Beginning with
1979 Models.) (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 cylinder. 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.
5-79. REASSEMBLY. (Beginning with 1979 Models.)
(See figure 5-13, Sheet 2 of 2.)
a. Install spring (8) into 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).
e. Install nut (2) and clevis (1).
5-28
sure vent hole is
5-80. 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 linkage.
c. Install rudder bar shield and install front seats.
d. Install bleeder screw at wheel brake assembly
and fill and bleed brake system in accordance with
applicable paragraph in this Section.
5-81.
HYDRAULIC BRAKE LINES.
5-82. 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.
5-83.
5-3.)
WHEEL BRAKE ASSEMBLIES.
(See figure
5-84. DESCRIPTION. The wheel brake assemblies
emply a floating brake assembly and a disc which is
attached to the main wheel.
5-85. WHEEL BRAKE REMOVAL. (See figure 5-3.)
Wheel brake assemblies can be removed by disconnecting the brake line(drain hydraulic fluid when disconnecting line)and removing the brake back plate.
The brake disc is removed after the wheel is
removed and disassembled. To remove the torque
plate, remove wheel and axle.
5-86. 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.
5-87. WHEEL BRAKE INSPECTION AND REPAIR.
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 saturated 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.
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 O-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,
MODEL R172 SERIES SERVICE MANUAL
VENT HOLE---
Filler plug (17) must be vented so
pressure cannot build up in the
operation.
during
reservoir
3hole,
drill 1/16"
and brake
Remove plug
ASSEMBLY OF PISTON
THRU 1978 MODELS
1.
Clevis
7. Body
2.
3.
Jam Nut
Piston Rod
8.
9.
10.
11.
12.
4. Cover
5. Setscrew
6. Cover Boss
*&
l13.
Figure 5-13.
Reservoir
0-Ring
Cylinder
Piston Return Spring
Nut
Piston Spring
14. Piston
15.
16.
Lock-O-Seal
Compensating Sleeve
17. Filler Plug
18. Screw
19. Washer
Brake Master Cylinder (Sheet 1 of 2)
5-29
MODEL R172 SERIES SERVICE MANUAL
--
2.
3.
4.
5.
6
7.
8
.
9.
Filler plug (3) must be vented so
pressure cannot build up in the
reservoir during brake operation.
Remove plug and drill 1/16" hole,
30' from vertical (as shown in
view A-A), if plug is not vented.
Clevis
Nut
Filler Plug
Cover
Piston
Back-up Ring
Packing
Spring
Clindr
Cylinder Body
BEGILNING WITH
1979 MODELS
Figure 5-13.
5-30
Brake Master Cylinder (Sheet 2 of 2)
MODEL R172 SERIES SERVICE MANUAL
press out old bolts and install new bolts with a soft
mallet.
f. Inspect wheel brake discs for a minimum thickness of 0.190-inch (McCauley) or 0. 190-inch (Cleveland). If disc is below minimum, replace disc.
5-88. WHEEL BRAKE REASSEMBLY.
B5-3.) in
(See figure
NOTE
Lubricate parts with clean hydraulic fluid
during brake reassembly.
a. Refer to figure 5-3 as a guide while reassembling
wheel brakes.
5-89. 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.
5-90. 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 3/32inch 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.
5-91. 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. R561, is available from the Cessna Service Parts Center.
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 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 lining 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.
5-92.
BRAKE SYSTEM BLEEDING.
NOTE
Bleeding with a clean hydraulic pressure
source connected to the wheel cylinder
bleeder is recommended.
a. Remove brake master cylinder filler plug and
screw flexible hose with appropriate fitting into the
filler hole at top of the master cylinder.
b. Immerse opposite end of flexible hose into a
container with enough hydraulic fluid to cover 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 master 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.
5-93. BRAKE LINING BURN-IN. The brake pads are
equipped with either a non-asbestos organic 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 throttie 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.
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 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.
Revision 1 5-31
MODEL R172 SERIES SERVICE MANUAL
1
--
6
.-
OF BRAKE MASTER
1.
Brake Hose
2.
3.
Brake Master
Control Assembly
4.
Tube
,
,
10.
Clamp
Housing
Spring
Tube
Positioning Pin
Positioning Rack
Rudder Pedals
Cable
Pulley
Bellcrank
Bracket
Spring
Brake Line
..
--
.
DetailB
INSTRUMENT PANEL
·
-
Figure 5-14.
5-32
19
.
,
5. Angle
6. Washer
7. Catch
8. Handle
10.
11.12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
.
Brake Systems
MODEL R172 SERIES SERVICE MANUAL
5-94.
PARKING BRAKE SYSTEM.
(See figure 5-14.)
5-95. DESCRIPTION. The parking brake system
consists of a handle and ratchet mechanism, connected by a cable to linkage at the brake master cylinders.
Pulling out on the handle depresses both brake master cylinder piston rods and the handle ratchet locks
the handle in this position until the handle is turned
and released.
5-96. REMOVAL AND INSTALLATION. See figure
5-14 for relative location of system components. The
illustration may be used as a guide during removal
and installation of components.
5-97. INSPECTION AND REPAIR OF SYSTEM COMPONENTS. Inspect lines for leaks, cracks, dents,
chafing, proper radius, security, corrosion, deterioration, obstructions and foreign matter. Check
brake master cylinders and repair as outlined in
applicable paragraph in this Section. Check parking
brake handle and ratchet for proper operation and
release. Replace worn or damaged parts.
SHOP NOTES:
Revision 1
5-33/(5-34 blank)
MODEL R172 SERIES SERVICE MANUAL
SECTION 6
AILERON CONTROL SYSTEM
Page No.
Aerofiche/Manual
TABLE OF CONTENTS
1F4/6-4
Repair ..........
1F4/6-4
Installation.
1F4/6-4
Cables and Pulleys .......
1F4/6-4
Removal and Installation . .
1F4/6-4
Ailerons ........
1F4/6-4
Removal .
F4/6-4
....
. . . ..
Installation
1F6/6-6
.
Repair ........
1F6/6-6
Rigging .............
1F1/6-1
AILERON CONTROL SYSTEM .....
. 1F1/6-1
Description ........
1F1/6-1
Trouble Shooting .........
1F2/6-2
.......
Control "U" .
. 1F2/6-2
Description .......
1F2/6-2
Removal and Installation . .
1F4/6-4
. .....
Repair ....
1F4/6-4
Aileron Bellcrank ........
1F4,/6-4
..........
Removal
6-1. AILERON CONTROL SYSTEM.
6-1.)
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.
(See figure
6-2. DESCRIPTION. The aileron control system
consists of two control wheels, one for the pilot and
6-3.
TROUBLE SHOOTING.
NOTE
Due to remedy procedures in the following trouble shooting
chart it may be necessary to rerig system, refer to paragraph 6-18.
TROUBLE
LOST MOTION IN CONTROL
WHEEL.
PROBABLE CAUSE
REMEDY
Loose control cables.
Adjust cables to proper tension.
Broken pulley or bracket,
cable off pulley or worn
rod end bearings.
Replace worn or broken parts,
install cables correctly.
Sprung bellcranks.
Replace bellcranks.
Loose chains.
Adjust to proper tension.
6-1
MODEL R172 SERIES SERVICE MANUAL
6-3.
TROUBLE SHOOTING
(CONT)
PROBABLE CAUSE
TROUBLE
RESISTANCE TO CONTROL
WHEEL MOVEMENT.
REMEDY
Cables too tight.
Adjust cables to proper tension.
Pulleys binding or cable off.
Replace defective pulleys.
cables correctly.
Bellcrank distorted or damaged.
Replace bellcrank.
Clevis bolts in system too
tight.
Loosen, then tighten properly
and safety.
Rusty chain.
Replace chain.
Chain binding with sprockets.
Replace defective parts.
Defective U-joints.
Replace defective U-joints.
Improper adjustment of chains
or cables.
With control wheel centered,
aileron bellcrank stop bushing
should be centered in slot (both
left and right bellcranks).
Adjust in accordance with
paragraph 6-18.
Improper adjustment of aileron
push-pull rods.
If chains and cables are properly
rigged and bellcrank stop bushings
are not centered in slots, pushpull rods are adjusted incorrectly.
Adjust push-pull rods to obtain
proper alignment.
DUAL CONTROL WHEELS
NOT COORDINATED.
Chains improperly adjusted.
Adjust in accordance with
paragraph 6-18.
INCORRECT AILERON
TRAVEL.
Push-pull rods not adjusted
properly.
Adjust in accordance with
paragraph 6-18.
Worn bellcrank stop bushings
or bellcrank slots.
Replace worn parts.
CONTROL WHEELS NOT
LEVEL WITH AILERONS
NEUTRAL.
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.
6-6. REMOVAL AND INSTALLATION.
a. Disconnect battery cables and insulate terminals
as a safety precaution,
b. Remove pedestal cover as outlined in paragraph
9-13.
c. Remove rudder bar shields, carpeting and plates
as necessary for access to lower end of control "U".
6-2
Install
d. Remove radios, radio cooling plans, 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 attaching roller
(beginning R17203200 and FR1720655) to LH side
of control "U". Remove bearing, roller and
attaching hardware.
MODEL R172 SERIES SERVICE MANUAL
11
Detail
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Spacer
3
8
Detail D
A
4
1.
Detail B
.
A
THRU R1722822 & FR17206640
BEGINNING WITH R1722823 & FR1720641
DetailG
DetailF
Pulley
Cable Guard
Carry-Thru Cable Turnbuckle
Bellcrank
Aileron
Carry-Thru Cable
RH Direct Cable
Bushing
LH Direct Cable
Pulley Bracket
RH Direct Cable Turnbuckle
LH Direct Cable Turnbuckle
CAUTION
MAINTAIN SPECIFIED CABLE TENSION
CABLE TENSION:
40 LBS ± 10 LBS ON AILERON CARRYTHRU CABLE (AT AVERAGE TEMPERATURE FOR THE AREA.)
SEE FIGURE 1-1 FOR TRAVEL.
Figure 6-1. Aileron Control System
6-3
MODEL R172 SERIES SERVICE MANUAL
k. Drill out rivets attaching instrument panel support (after completion of step "j") and remove support.
l. Drill out rivets attaching right hand side panel to
pedestal structure and remove panel.
m. Remove safety wire and disconnect 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.
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.
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 turnbuckles (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.)
6-9. 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).
6-4
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."
6-14.
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.
MODEL R172 SERIES SERVICE MANUAL
NOTES
NOTE
Install cable drum (8) with wide
When dual controls are NOT installed, spacer (3) replaces co-
groove aft.
Primary cable (7) is wrapped
piot'scolumn (23) and universl
joint (13).
(13)-.
once around aft groove in cable
drum (8) with cable lock (9) on
Transition cable (16) is installed
in forward groove of cable drum
(8) with lock (14) on top.
2
1.procket
\
^\
..
-..-
5
J
.
Roller- .
.
*
THRU R1723199 AND FR1720655
# BEGINNING WITH R1723200 AND
FR1720656
5. Secondary Cable
6. Primary Cable Turnbuckle
7. Primary Cable
Drum
9. Primary Cable Lock
-- 10. Bushing
11. Bearing
12. Bolt
13. Universal Joint
14. Transition Cable Lock
15. Secondary Cable Turnbuckle
16. Transition Cable
17. Direct Cable Turnbuckle
18. Elevator Push-Pull Tube
9. Bolt
20. Bolt
22.
23.
24.
25.
26.
27.
28.
29.
30.
Copilot's Control Wheel
Control Column
Shaft
Retainer
Pilot's Control Wheel
Bearing
Countersunk Washer
Shaft
Washer
Figure 6-2. Control "U" Installation
6-5
MODEL R172 SERIES SERVICE MANUAL
Detail A
1.
2.
3.
Aileron
Hinge
Balance Weight
4.
Pivot Bolt
5.
6.
7.
8.
Bushing
Needle Bearing
LH Bellcrank
Push-Pull Rod
9. Channel
Lower Wing Skin
12.
Spacer
13.
Direct Cable
Brass Washer
/
11.
Carry-thru cable turnbuckle (17)16.
is located at RH aileron bellcrank
thru R1722823 & FR1720641
10.
14.
15.
Bushing
Bushing
Bolt
17.
,
17. Carry-Thru
Cable
,,,
, -----
18. Carry-Thru Cable
Carry-thru cable turnbuckle (17)
is located above headliner
beginning R1722824 & FR1720642
Figure 6-3. Aileron Installation
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 17.
Before installation, ensure balance weights and hinges
are securely attached.
6-18. RIGGING. (See figure 6-2.)
a. Check primary control 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 transition cable lock (14) is installed at
top.
b. With control wheels neutral, check chain ends
(4) are approximately same distance from sprockets
(1).
6-6
c. Keeping control wheels neutral, tighten 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 primary cable turnbuckles (6) and
tightening secondary cable turnbuckle (15) at center
of control "U" will move inboard sides of both control wheels down.
2. Tightening either primary control cable turnbuckle and loosening secondary cable turnbuckle at
center of control "U" will move outboard side of applicable 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)
MODEL R172 SERIES SERVICE MANUAL
AVAILABLE FROM CESSNA SERVICE PARTS CENTER (TOOL NO. SE 716)
.
Figure 6-4.
Inclinometer for Measuring Control Surface Travel
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 trailing edge of wing flaps. Be sure wing flaps are
fully up when making this adjustment.
g. Remove bar from control wheels.
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
using 0.040-inch monel safety wire.
j. Install all items removed for access.
WARNING
Be sure ailerons move in correct direction
when operated by control wheel.
SHOP NOTES:
6-7/(6-8 blank)
MODEL R172 SERIES SERVICE MANUAL
SECTION 7
WING FLAP CONTROL SYSTEM
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
WING FLAP CONTROL SYSTEM . ..
Description
.
.......
....
Operation Check . .......
Trouble Shooting ..........
Motor and Transmission
Assembly ...........
Removal and Installation. ..
Repair
...........
Drive Pulleys ...........
Removal and Installation .
Repair
..........
7-1. WING FLAP CONTROL SYSTEM.
figure 7-1.)
. 1F14/7-1
1F14/7-1
1F14/7-1
1F15/7-2
1F17/7-4
. 1F17/7-4
1F17/7-4
1F17/7-4
. 1F17/7-4
1F17/7-4
(See
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 syster 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 thedesired 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 on flap actuator assembly prevent
over-travel of the flaps in the full UP or DOWN positions.
Flaps ......
..
. ..
.
. 1F17/7-4
Removal and Installation. . . . 1F17/7-4
Repair..
.
..........
F17/7-4
Cables and Pulleys ....
..
. 1F17/7-4
Removal and Installation . . 1F17/7-4
Rigging .........
....
1F20/7-7
Follow-Up and Indicating System . . 1F21/7-8
Description . ........
F21/7-8
Removal and Installation . . . F21/7-8
Rigging . .........
lF21/7-8
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 Oc. 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
Service Parts Center. See figure 6-4.
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.
7-1
MODEL R172 SERIES SERVICE MANUAL
7-4.
TROUBLE SHOOTING;.
NOTE
Due to remnedy procedures in the following trouble shooting
ch.rt it may be necessary to re-rig system, refer to paragraphs 7-16 and 7-20.
TROUBLE
BOTH FLAPS FAIL TO MOVE.
PROBABLE CAUSE
REMEDY
Popped circuit breaker.
Reset and check continuity.
Replace breaker if defective.
Defective switch.
Place jumper across switch.
Replace switch if defective.
Defective motor.
Remove and bench test.
Replace motor if defective.
Broken or disconnected wires.
Run continuity check of wiring.
Connect or repair wiring as
necessary.
Disconnected or defective
transmission.
Connect transmission. Remove,
bench test and replace transmission if defective.
Defective limit switch.
Check continuity of switches. Replace switches found defective.
Cables not riding on pulleys.
Open access plates and observe
pulleys. Route cables correctly
over pulleys.
Bind in drive pulleys.
Check drive pulleys in motion.
Replace drive pulleys found
defective.
Broken or binding pulleys.
Check pulleys for free rotation or
breaks. Replace defective pulleys.
Frayed cable.
Check condition of cables.
defective cables.
Flaps binding on tracks.
Observe flap tracks and rollers.
Replace defective parts.
Disconnected or broken cable.
Check cable tension.
Connect or replace cable.
Disconnected push-pull rod.
Attach push-pull rod.
FLAPS FAIL TO RETRACT.
Defective or disconnected flaps
UP operating switch
Check continuity of switch.
Connect or replace switch.
INCORRECT FLAP TRAVEL.
Incorrect rigging.
Refer to paragraph 7-16.
Defective operating switch.
Check continuity of switches. Replace switches found defective.
BINDING IN SYSTEM AS FLAPS
ARE RAISED AND LOWERED.
LEFT FLAP FAILS TO MOVE.
7-2
Replace
MODEL R172 SERIES SERVICE MANUAL
Detail
A
SEE FIGURE 7-3
..
...
- -
....
.
,
...
1.....Cable Guard
2. Pulley
3. Washer
4. Direct Cable
5. Retract Cable
6. Turnbuckle
7. Bolt
8.
9.
10.
11.
BEGINNING R1723395
AND FR17200666
Detail
B
Screw
Bracket
Follow-Up Control
Flap Control Lever
12. FLap
14.2Spacer
CAUTION
MAINTAIN SPECIFIED CONTROL
CABLE TENSION.
9
.... 2ATURE
Figure 7-1.
CABLE TENSION:
30 LBS ± 10 LBS (AT AVERAGE TEMPERFOR THE AREA.)
SEE FIGURE 1-1 FOR TRAVEL,
Wing Flap Control System
7-3
MODEL R172 SERIES SERVICE MANUAL
7-4.
TROUBLE SHOOTING (Cont).
TROUBLE
PROBABLE CAUSE
FLAPS FAIL TO EXTEND.
7-5.
Defective or disconnected flaps
DOWN operating switch.
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;
however, on some aircraft, it nay 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 inch-pounds.
1. Complete operational check as outlined in paragraph 7-3 and rerig system in accordance with paragraph 7-16.
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.
7-4
REMEDY
Check continuity of switch.
Connect or replace switch.
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
on 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.
7-1.)
CABLES AND PULLEYS.
(See figure
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
MODEL R172 SERIES SERVICE MANUAL
NOTE
Use Loctite grade CV adhesive on
threads of setscrew (6) and collar
(24) whenever actuating tube (5) is
removed. Torque setscrew to 60
inch-pounds.
.
Bolt2
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Bolt
Wing Structure
Jackscrew
Bolt
Actuating Tube
Setscrew
Transmission Assembly
Electrical Wiring
Motor Assembly
Hinge Assembly
Bolt
Cable Lock
Drive Pulley
Push-Pull Rod
Attach Bracket
Bolt
Direct Cable
Retract Cable
19.
Bolt
20.
21.
22.
23.
24.
25.
Bolt
Set Screw
Switch Adjustment Block flaps
Up-Limit Switch
Switch Actuating Collar
Support
26.
Down-Limit Switch
-
-
,
--
.
in the FLL
UP position
-
VIEW A-A
Figure 7-2.
Flap Motor and Transmission Installation
7-5
MODEL R172 SERIES SERVICE MANUAL
NOTE
NOTE
*Airplanes R1722000 thru R1723454 and FR17200001
thru FR17200675 incorporating SK180-44. When incorporating SK180-44 only stainless steel washers (12) are
used.
Bushings (4), rollers (3) and spacers (9) are
first positioned through slots in flap tracks,
then are secured to the flap roller supports (2)
with attaching bolts, washers and nuts. Nylon
plug buttons (11) prevent wing flap from chafing
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 lateral movement of flap is inherant due to the width
of rollers. This movement should be considered
when positioning spacers and direction of bolts.
8
9
Detail B
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Access Plate
Flap Support
Roller Assembly
Bushing
Bolt
Push-Pull Rod
Flap Bracket
Bolt
Spacer
Plug Button
Nylon Plug Button
Stainless Steel Washer
9
9
9
Detail C
Detail C
THRU 1980 MODELS
BEGINNING WITH
1981 MODELS
OUTBOARD HINGE
Figure 7-3.
7-6
Revision 1
Flap Installation
MODEL R172 SERIES SERVICE MANUAL
FLAP MOTOR AND
FWD
TRANSMISSION
DRIVE PULLEY-
DRIVE PULLEY
SET SCREW
FLAP MOTOR
ACTUATING
TUBE
TURNBUCKLES
-- LEFT PUSHPULL ROD
-RIGHT
PUSHPULL ROD
TO LEFT
TO RIGHT
WING FLAP
WING FLAP
VIEWED
FROM
Figure 7-4.
ABOVE
Flap System Schematic
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 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. Re-rig flap system in accordance with paragraph
7-16 and safety turnbuckles.
h. Re-rig follow-up system in accordance with paragraph 7-20 and reinstall all items removed in step
"a."
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 installing drive pulleys
in the wings as illustrated in figure 7-4.
f. Adjust both push-pull rods (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.
NOT E
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.
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 R172 SERIES SERVICE MANUAL
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
pully (13).
i. Apply Loctite grade CV sealant (or equivalent)
to threads of setscrew (6) and torque to 60 inchpounds.
NOTE
If actuating tube (5) is too long to allow
attachment to drive pully after completion
of step "h", proceed to step "j".
j. Disconnect push-pull rod (14) at drive pully (13)
to allow connecting actuating tube (5) to drive pully.
k. Manually hold RIGHT flap in full UP postion and
readjust push-pull rod (14) to align with attachment
hole in drive pully. 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.
1. 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 4, 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 pully grooves
and cable ends are postioned correctly at
drive pullys before tightening turnbuckles.
o. Disconnect push-pull rod at left drive pully.
Run motor to extend flaps approximately 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.
7-8
to 0°.
r. Run flaps to full DOWN postion and adjust
DOWN limit switch (26) 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
one end of which is attached to the flap operating
switch mounting arm and 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, moving the pointer along
a scale as the flaps are extended or retracted. When
this motion of the switch mounting arm, to which the
flap operating switches are attached, positions the
"active" operating switch to clear a cam on the flap
lever, the circuit to the flap motor is broken and the
flaps stop at the selected position.
7-19. REMOVAL AND INSTALLATION. Figure 7-5
can be used as a guide to removal and installation of
the flap follow-up and indicating system.
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 through
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
NOTE
An inclinometer for measuring control surface travel is available from the Cessna
vice Parts Center. See figure 6-4.
An inclinometer for measuring control surface travel is available from the Cessna
Service Parts Center. See figure 6-4.
MODEL R172 SERIES SERVICE MANUAL
DetailDa
l
Lubricate slots of guide (1) and bellcrank
(2) with molybdenum or graphite
THRU R1723090 AND FR1720656
* BEGINNING R1723091 AND FR1720657
8.
9.
10.
11.
Washer
Teflon Washer
Support
Bracket
19. Cam
20. Flaps UP Operating Switch
21. Spring
Position center cable of flap
follow-up (4) between washers
(22)
Figure 7-5. Flap Follow-Up Control and Position Indicator
7-9
MODEL R172 SERIES SERVICE MANUAL
g. 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
SHOP NOTES:
7-10
(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 at full DOWN position.
k. Check flaps through several cycles. recheck all
components for security and replace items removed
for access.
MODEL R172 SERIES SERVICE MANUAL
SECTION 8
ELEVATOR CONTROL SYSTEM
Page No.
Aerofiche/Manual
TABLE OF CONTENTS
.
1G10/8-5
Forward. . .
.. ..
Removal and Installation. . 1G10/8-5
1G10/8-5
Rear ............
Removal and Installation.
1G10/8-5
Cables and Pulleys ....
1G10/8-5
Removal and Installation . . . 1G10/8-5
Rigging . .........
1G11/8-6
1G6/8-1
ELEVATOR CONTROL SYSTEM ....
........
1G6/8-1
Description ..
....
1G6/8-1
Trouble Shooting .....
1G7/8-2
Elevators ..
. . .....
..
1G7/8-2
Removal and Installation.
Repair.
.........
. 1G10/8-5
Bellcranks... .
........
1.G1 /8-5
8-1.
ELEVATOR CONTROL SYSTEM.
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.
8-2. 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
8-3.
TROUBLE SHOOTING.
NOTE
Due to remedy procedures in the following trouble shooting
chart it may be necessary to re-rig system, refer to paragraph 8-14.
TROUBLE
NO RESPONSE TO CONTROL
WHEEL FORE-AND-AFT
MOVEMENT.
PROBABLE CAUSE
REMEDY
Forward or aft end of push-pull
tube disconnected.
Check visually and attach
push-pull tube correctly.
Cables disconnected.
Check visually, attach cables
and rig system in accordance
with paragraph 8-14.
8-1
MODEL R172 SERIES SERVICE MANUAL
8-3.
TROUBLE SHOOTING (Cont).
TROUBLE
BINDING OR JUMPY MOTION
FELT IN MOVEMENT OF ELEVATOR SYSTEM.
ELEVATORS FAIL TO ATTAIN
PRESCRIBED TRAVEL.
PROBABLE CAUSE
REMEDY
Defective forward or rear bellcrank or bellcrank pivot bearing.
Move to check for play or binding.
Replace bellcranks found defective.
Cables slack.
Check tension and adjust to
tension specified in figure 8-1.
Cables not riding correctly on
pulleys.
Open access plates and observe
pulleys. Route cables correctly
over pulleys.
Nylon bearing on instrument
panel binding.
Disconnect universal joint and
check for binding.
Replace bearing if binding is felt.
Defective control "U"
pivot bearing,
Disconnect elevator push-pull
tube at lower end of "U" and check
that control moves freely. Replace
bearing if defective.
Defective elevator hinges.
Move elevators by hand, checking
hinges. Replace hinges found
defective.
Lubrication needed.
Lubricate in accordance with
Section 2.
Clevis bolts too tight.
Check and readjust bolts to
eliminate binding.
Defective pulleys or cable
guards.
Open access plates and check
visually. Replace defective
parts and install guards
properly.
Stops incorrectly set.
Check elevator travel with inclinometer. Rig in accordance with
paragraph 8-14.
Cables tightened unevenly.
Rig in accordance with paragraph
8-14.
Interference at instrument
panel.
Rig in accordance with paragraph
8-14.
(See figure 8-2.)
8-4.
ELEVATORS.
8-5.
REMOVAL AND INSTALLATION.
b. Remove bolts (6) securing elevators to bellcrank
(9).
NOTE
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.
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.
8-2
c.
d.
Remove bolts (16) from elevator hinges.
Using care, remove elevator.
MODEL R172 SERIES SERVICE MANUAL
FIGURE 8-2
SEE FIGURE 6-2
-
1. Pulley
2.
Bolt
3. Rear Up Cable
4. Bolt
1
5. Cable Guard
6.
7.
8.
9.
10.
11.
12.
13.
Rear Down Cable
Rear Bellerank
Forward Up Cable
Forward Down Cable
Push-Pull Tube
Forward Bellcrank
Bracket
Turnbuckle
Detail
..
9
E
Detail
D
MAINTAIN SPECIFIED CABLE TENSION
CABLE TENSION:
30 LBS =10 LBS (AT AVERAGE TEMPERATURE
FOR THE AREA.) SEE FIGURE 1-1 FOR TRAVEL.
Detail
F
Figure 8-1. Elevator Control System
8-3
MODEL R172 SERIES SERVICE MANUAL
Do not paint cable terminals, bolts, or ends of elevator
bellcrank.
NOTE
Install push-pull channel (3) with channel opening up on all
floatplanes and landplanes through Serials R1723399 and
FR17200665. Beginning with landplanes Serials R1723400 and
FR17200666, install push-pull channel (3) with channel opening
down.
3
Detail A
* NOTE
Install upper bolt with head to the
right and lower bolt with head to
the left. The cable endclevises
must be free to swivel.
6
1. Elevator Tip
2. Elevator Trim Tab
3. Push-Pull Channel
4. Trim Tab Horn
5. Balance Weight
6. Bolt
7.
Tube Assembly
8.
9. Bolt
Rear Bellcrank
10. Hinge Bracket
11.
Bonding Strap
12. Horizontal Stabilizer
13. Screw
14. Travel Stop Bolt
15.
Jamnut
8-4 Revision 1
,
MODEL R172 SERIES SERVICE MANUAL
e. To remove left elevator use same procedure,
omitting step "a".
f. Reverse preceding steps for installation. Rig
system in accordance with applicable paragraph in
this section 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 applicable paragraph in
this section, 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).
NOTE
It may be necessary to remove one of the
stabilizer attaching bolts for clearance
when removing the bellcrank pivot bolt.
e. Reverse preceding steps for installation. Rig
system in accordance with applicable paragraph in
this section, safety turnbuckles and reinstall all items
removed for access.
8-12.
8-1.)
CABLES AND PULLEYS.
(See figure
8-13. REMOVAL AND INSTALLATION.
a. Remove seats, upholstery and 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 applicable paragraph in this section, safety turnbuckles and reinstall all items removed in step "a".
SHOP NOTES:
8-5
MODEL R172 SERIES SERVICE MANUAL
.. .
2
2.
3.
4.
Neutral Rigging Tool
Instrument Panel
Pilot's Control Column
Fabricate from .125 inch steel plate and
.209 inch dia. drill rod according to dimensions shown.
Figure 8-3. Control Column Neutral Position Rigging Tool
NOTE
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
Disregard counterweight areas of elevators
when streamlining since these areas are
contoured to streamline elevator tips in
cruise flight.
c. Holding elevators in neutral position, 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 0 ° .
8-6
An inclinometer for measuring control surface travel is available from Cessna Service
Parts Center. Refer to 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
W
Be sure elevators move in the correct direction when operated by controls.
MODEL R172 SERIES SERVICE MANUAL
SECTION 9
ELEVATOR TRIM CONTROL SYSTEM
Page No.
Aerofiche/Manual
TABLE OF CONTENTS
1G22/9-5
...
..
Reassembly ...
1G22/9-5
Tab Free-Play Inspection .....
. G22/9-5
.
Tab Control Wheel ...
.1G22/9-5
Removal and Installation .
1G24/9-7
Cables and Pulleys ........
Removal and Installation . . . 1G24/9-7
G24/9-7
Pedestal Cover ..........
Removal and Installation . . . 1G24/9-7
. 1G24/9-7
........
Rigging ..
ELEVATOR TRIM CONTROL SYSTEM . 1G18/9-1
Description .1.....G18/9-1
1G18/9-1
Trouble Shooting .........
1G19/9-2
Trim Tab ............
1G19/9-2
.
Removal and Installation
1G19/9-2
Tab Actuator ...
1G19/9-2
Removal and Installation .
1G19/9-2
Disassembly .....
Cleaning, Inspection and
1G22/9-5
Repair ..........
9-1. ELEVATOR TRIM CONTROL SYSTEM.
figure 9-1.)
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.
(See
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
9-3.
TROUBLE SHOOTING.
NOTE
Due to remedy procedures in the following trouble shooting
chart it may be necessary to re-rig system, refer to paragraph 9-18.
TROUBLE
TRIM CONTROL WHEEL MOVES
WITH EXCESSIVE RESISTANCE.
PROBABLE CAUSE
REMEDY
Cable tension too high.
Check and adjust tension as
specified in figure 9-1.
Pulleys binding or rubbing.
Open access plates and check
visually. Repair or replace as
necessary.
Cables not in place on pulleys.
Open access plates and check
visually.
Install cables correctly.
Trim tab hinge binding.
Disconnect actuator and move tab
to check resistance. Lubricate
or replace hinge as necessary.
Defective trim tab actuator.
Remove chain from actuator
sprocket and operate actuator
manually.
Replace actuator if defective.
Rusty chain.
Check visually.
Replace chain.
Damaged sprocket.
Check visually.
Replace sprockets.
Bent sprocket shaft.
Observe motion of sprockets.
Replace bent sprocket shafts.
9-1
MODEL R172 SERIES SERVICE MANUAL
9-3.
TROUBLE SHOOTING (Cont).
TROUBLE
PROBABLE CAUSE
LOST MOTION BETWEEN
CONTROL WHEEL AND
TRIM TAB.
REMEDY
Cable tension too low.
Check and adjust tension as
specified in figure 9-1.
Broken pulley.
Open access plates and check
visually. Replace defective
pulley.
Cable not in place on pulleys.
Open access plates and check
visually. Install cables
correctly.
Worn trim tab actuator.
Remove and replace worn actuator.
Actuator attachment loose.
Check actuator for security.
Tighten as necessary.
TRIM INDICATOR FAILS TO
INDICATE CORRECT TRIM
POSITION.
Indicator incorrectly engaged
on wheel track.
Check visually and reset
indicator as necessary.
INCORRECT TRIM TAB
TRAVEL.
Stop blocks loose or incorrectly
adjusted.
Adjust stop blocks on cables.
Refer to figure 9-2.
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 working out.
c.
Reverse preceding steps for installation.
9-6.
TRIM TAB ACTUATOR.
9-7. REMOVAL AND INSTALLATION.
ure 9-1.)
(See fig-
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).
9-2
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 9-4.)
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).
MODEL R172 SERIES SERVICE MANUAL
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Pulley (Sheet 2)
Chain Guard
Actuator
Aft Chain
Left Aft Cable
Left Forward CableRight Aft Cable
Turnbuckle
Right Forward Cable
Stop Block
Bushing
Chain
Forward Chain
Trim Wheel
Sprocket
Pointer
Retainer
Pedestal
Roll Pin
-
SHEET 2)
* THRU R1722924 & FR1720630
WITH R1722925
& FR1720631
-.
*-BEGINNING
SEE FIGURE 8-2.........
- Detail
..
FIGURE 9-2 --
Detail A
E
.
..
.
(SEE SHEET 2)
.
Detail
Detail
-..-
...
G
CAUTION
MAINTAIN SPECIFIED CONTROL
CABLE TENSION
........ .
SHEET
,
2)
* SAFETY WIRE ROLL PIN (19)
Detail J
Figure 9-1.
CABLE TENSION:
15 TO 20 LBS (AT AVERAGE TEMPERATURE FOR THE AREA.)
SEE FIGURE 1-1 FOR TRAVEL.
Elevator Trim Tab Control System
(Sheet 1 of 2)
9-3
MODEL R172 SERIES SERVICE MANUAL
Tab Up
Tab Up
Tab Up
Down
Tab Down
Tab Down
DetailAl
Detail J1
Detail
Tab Down
B1
Tab Up
Down
Tab Up
Detail Dl
Detail
Figure 9-1.
HI
Elevator Trim Tab Control System (Sheet 2 of 2)
-HINGE POINT
HINGE POINT
TRAILING EDGE
CHORD LENGTH
-----
G TRSAILING
TRAILING EDGE
.
TRIM TAB
Detail
A
Detail
B
0
*
FREE-PLAY UP
NEUTRAL POSITION
O FREE-PLAY DOWN
*
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 allowable. Refer to detail B.
Figure 9-2.
9-4
Trim Tab Free-Play Inspection.
TOTAL FREE-PLAY
MODEL R172 SERIES SERVICE MANUAL
9-9.
CLEANING, INSPECTION AND REPAIR.
(See figure 9-4. )
a. DO NOT remove bearing (16) Irom 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)
0.373" MIN.
INSIDE DIAMETER
INSIDE DIAMETER
0. 374" MAX.
BEARING (14)
INSIDE DIAMETER
0. 248" MIN.
SMALL HOLE
0.249" MAX.
SMALL HOLE
0. 373" MIN.
LARGE HOLE
0. 374" MAX.
LARGE HOLE
THREADED ROD END (15)
OUTSIDE DIAMETER
(SHANK)
SCREW (9)
OUTSIDE DIAMETER
0. 245" MIN.
0.246" MAX.
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 9-4.)
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).
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 groovpins (10) are 1/16 inch in diameter, therefore, requiring a 1/16 (0.0625) 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).
1. 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 9-2.
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 assembly.
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.
9-1.)
(See figure
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.
9-5
MODEL R172 SERIES SERVICE MANUAL
TURNBUCKLE
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 9-3.
Elevator Trim Tab Travel Adjustment
A
10
10
Detail
1.
2.
3.
4.
5.
6.
7.
8.
2
Figure 9-4.
9-6
Actuator Assembly
Nut
Chain Guard
Screw
Sprocket
Bearing
Collar
Groov-Pin
Elevator Trim Tab Actuator Assembly
9.
10.
11.
12.
13.
14.
15.
16.
Screw
Groov-Pin
Retaining Ring
Housing
O-Ring
Bearing
Threaded Rod End
Bearing
MODEL R172 SERIES SERVICE MANUAL
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.)
d. Check cable tension and readjust turnbuckle (8)
if necessary.
NOTE
If chains and/or cables are being installed,
permit actuator 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
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.
Full forward (nose down) position of trim
wheel is where further movement is prevented by chain or cable ends contacting
sprockets or pulleys.
NOTE
f. With elevator and trim tab both in neutral
(streamlined), place inclinometer on tab and set to
zero.
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 turnbuckle and re
install 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.
NOTE
An inclinometer for measuring control
surface travel is available from Cessna Service Parts Center. Refer to 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 9-3 to limit travel as outlined 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 operated by trim wheel. Nose down
trim corresponds to tab up position.
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.
9-7 /(9-8 blank)
MODEL R172 SERIES SERVICE MANUAL
SECTION 10
RUDDER AND RUDDER TRIM CONTROL SYSTEM
Page No.
Aerofiche/Manual
TABLE OF CONTENTS
RUDDER CONTROL SYSTEM . . . .. 1H7/10-1
Description ..........
1H7/10-1
Trouble Shooting ..
...
1H7/10-1
Pedal Assembly .........
H8/10-2
Removal and Installation. .
. 1H8/10-2
Rudder .
.
...... .
.1H12/10-6
Removal and Installation. . .
1H12/10-6
10-1. RUDDER CONTROL SYSTEM.
10-1.)
Repair .
..........
1H12/10-6
Cables and Pulleys ..
.
1H12/10-6
Removal and Installation . . . 1H12/10-6
Rigging ......
......
1H13/10-7
RUDDER TRIM CONTROL SYSTEM. . . 1H13/10-7
Description ............
H13/10-7
Rigging .........
. . 1H13/10-7
(See figure
prised 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.
10-2. DESCRIPTION. Rudder control is maintained
through use of conventional rudder pedals which also
control nose wheel steering. The system is com-
10-3.
TROUBLE SHOOTING.
NOTE
Due to remedy procedures in the following trouble shooting
chart it may be necessary to re-rig system, refer to paragraph 10-11.
TROUBLE
RUDDER DOES NOT RESPOND
TO PEDAL MOVEMENT.
PROBABLE CAUSE
Broken or disconnected cables.
REMEDY
Open access plates and check
visually. Connect or replace
cables.
10-1
MODEL R172 SERIES SERVICE MANUAL
10-3.
TROUBLE SHOOTING (Cont).
REMEDY
PROBABLE CAUSE
TROUBLE
BINDING OR JUMPY MOVEMENT OF RUDDER PEDALS.
Cables too tight.
Refer to figure 10-2 for distance
between firewall and pedals. Rig
system in accordance with paragraph 10-11.
Cables not riding properly
on pulleys.
Open access plates and check
visually. Route cables correctly over pulleys.
Binding, broken or defective
pulleys or cable guards.
Open access plates and check
visually. Replace defective
pulleys and install guards
properly.
Pedal bars need lubrication.
Refer to Section 2.
Defective rudder bar bearings.
If lubrication fails to eliminate
binding. Replace bearing blocks.
Defective rudder hinge bushings.
Check visually.
bushings.
Clevis bolts too tight.
Check and readjust bolts to
eliminate binding.
Steering rods improperly
adjusted.
Rig system in accordance with
paragraph 10-11.
LOST MOTION BETWEEN
RUDDER PEDALS AND
RUDDER.
Insufficient cable tension.
Refer to figure 10-2 for distance
between firewall and pedals. Rig
system in accordance with paragraph 10-11.
INCORRECT RUDDER TRAVEL.
Incorrect rigging.
Rig in accordance with paragraph
10-11.
10-4. RUDDER PEDAL ASSEMBLY.
10-2.)
(See figure
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. Releive cable tension at cevises (index 11, figure
10-1).
f. Disconnect cables, return springs, trim bungee,
and steering tubes from rudder bars.
10-2
Replace defective
g. Remove bolts securing bearing blocks (8) and
work rudder bars out of tunnel area.
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 binding.
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
MODEL R172 SERIES SERVICE MANUAL
1. Shackle
2. Bellcrank
3. Travel Stop
4. Right Rear Cable
5. Left Rear Cable
6. Turnbuckle
7. Cable Guard
8. Pulley
9. Rudder Bar
12
10.
11.
12.
13.
14.
Rudder Cable
Clevis
Washer
Bushing
Stop Nut
1.
1
15.
16.
Left Front Cable
Right Front Cable
B1
C
.
2
(
Detail
B
8
Detail A
Detail
14
B (Typical)
* Safety wire rudder travel stop bolt (3).
NOTE-. Shaded pulleys used in
this system only.-
.
*
Detail
E
...
.
.....
.
SEE FIGURE 10-5
CABLE TENSION:
REFER TO PARAGRAPH 10-11.
Detail D1
SEE FIGURE 1-1 FOR TRAVEL.
Figure 10-1.
Rudder Control System
10-3
MODEL R172 SERIES SERVICE MANUAL
FIREWALL
6. 50 INCHES
CLEARANCE HOLE
AFT RUDDER BAR
16
CLEARANCE HOLE ON
FORWARDRUDDER BAR
1. Shaft
2. Rudder Pedal
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Pivot Shaft
Aft Rudder Bar
Bearing Block
Return Spring
Brake Torque Tube
Forward Rudder Bar
Master Cylinder
Bracket
Bearing
Bellcrank
Single Controls Hub
Rudder Pedal Extension
NOTE
Brake links (5), bellcranks (15) and attaching
parts are replaced with hubs when dual controls
are NOT installed.
Nylon washers may be installed between shaft
(1) and brake link (5) as required to eliminate
excessive clearance when dual controls ARE
installed.
Figure 10-2.
10-4
Rudder Pedals Installation
Detail
B
MODEL R172 SERIES SERVICE MANUAL
BALANCE WEIGHT
2
Detail A
Detail B
C
Detail
1.
2.
3.
4.
C
Bolt
Upper Hinge
Bushing
Nutplate
5.
6.
7.
8.
9.
Figure 10-3.
Center Hinge
Washer
Nut
Lower Hinge
Upper Tip
10.
11.
12.
13.
Trim Tab
Lower Tip
Bellcrank
Quick-Disconnect
Rudder Assembly
10-5
MODEL R172 SERIES SERVICE MANUAL
BLOCK RUDDER
TANCE BETWEEN
STRAIGHTEDGES
MEASURING
RUDDER
TRAVEL
ESTABLISHING NEUTRAL
POSITION OF RUDDER
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,
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".
mark rudder at point corresponding to soft wire indexing point (neutral).
Figure 10-4.
10-6.
RUDDER.
Checking Rudder Travel
(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 devises 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.
10-6
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.
MODEL R172 SERIES SERVICE MANUAL
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.
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
automatically 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 recommended 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 devises 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
devises after alignment. Preload is built
into steering tubes.
i.
Install devises on rod ends.
NOTE
DO NOT adjust rudder trim with steering
tubes. 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 correction.
WARNING
Be sure rudder moves in correct direction
when operated by pedals.
10-12. RUDDER TRIM CONTROL SYSTEM.
figure 10-5.)
(See
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 or "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 fig 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 direction.
10-7
MODEL R172 SERIES SERVICE MANUAL
1. Knob
Console Structure
2.
3.
Lever Assembly
4. Bracket
5. Trim Bungee
6.
Rudder Bar
7.
Bellcrank
8. Pushrod
Figure 10-5. Rudder Trim Control System
10-8
MODEL R172 SERIES SERVICE MANUAL
SECTION 11
ENGINE
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.
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
ENGINE COWLING .........
1H24/11-3
Description ..........
1H24/11-3
Removal and Installation ....
1H24/11-3
Cleaning and Inspection .....
. 1H24/11-3
Repair.
............
111/11-4
Cowl Flap ...........
11/-4
Description ..
......
111/11-4
Removal and Installation
. 111/11-4
Rigging .
.........
111/11-4
ENGINE ............
..111/11-4
Description ..........
111/11-4
Engine Data ..........
113/11-6
Time Between Overhaul (TBO) .
113/11-6
Overspeed Limitations .....
113/11-6
Trouble Shooting ........
114/11-7
Static Run-Up Procedures ....
117/11-10
Engine Removal ........
118/11-11
Cleaning. .
............
118/11-11
Accessories Removal
......
118/11-11
Inspection ..............
119/11-12
Build-Up
...........
119/11-12
Installation ..........
119/11-12
Flexible Fluid Hoses ......
1110/11-13
Pressure fest .
......
1110/11-13
Replacement .
...
...
1110/11-13
Tachometer Drive Adapter Seal . 1110/11-13
Removal and Installation..
. 1110/11-13
Engine Baffles .........
Description ........
Cleaning and Inspection . .
Removal and Installation
Repair ..........
Engine Mount .........
Description . ..
......
Removal and Installation . .
Repair ..........
Painting ..........
Shock Mount Pass .....
ENGINE OIL SYSTEM. .....
Description........
Capacity..........
Trouble Shooting ...
Oil Cooler
......
...
Description ......
Full-Flow Oil Filter ....
Description ...
.
.
Removal and Installation
(Filter) .......
(Adapter) ....
.
ENGINE FUEL SYSTEM. ....
Description ........
Trouble Shooting ......
Fuel-Air Control Unit. . .
Description ......
Removal and Installation.
Adjustment (Idle Speed
and Idle Mixture) .
.
1111/11-14
1111/11-14
1111/11-14
1111/11-14
1113/11-16
1113/11-16
1113/11-16
1113/11-16
1113/11-16
1113/11-16
1113/11-16
1113/11-16
1113/11-16
1114/11-17
1114/11-17
1116/11-19
1116/11-19
1116/11-19
1116/11-19
1116/11-19
1116/11-19
1117/11-20
1117/11-20
1119/11-22
1120/11-23
1120/11-23
1120/11-23
1120/11-23
11-1
MODEL R172 SERIES SERVICE MANUAL
TABLE OF CONTENTS (Cont.)
....
Fuel Manifold Valve
.
Description ....
Removal and Installation.
......
..
Cleaning
Fuel Discharge Nozzles . . .
....
Description .
Removal. ........
Cleaning and Inspection .
....
Installation .
Fuel Injection Pump . ...
....
Description .
Removal and Installation.
Adjustment ......
Auxiliary Electric Fuel Pump
Flow Rate Adjustment ..
INDUCTION AIR SYSTEM . . .
......
Description ..
Removal and Installation .
.. ...
.
IGNITION SYSTEM.
....
Description ..
Trouble Shooting ...
MAGNETOS (Bendix) ...
.....
Description ..
.........
.
Removal
Internal Timing ...
Installation and Timing
.....
to Engine ..
.......
Maintenance .
Magneto Check .......
MAGNETOS (Slick) .......
.....
Description ..
........
.
Removal
Internal Timing. .......
SHOP NOTES:
11-2
1I22/11-25
1I22/11-25
1I22/11-25
1I22/11-25
1I22/11-25
1I22/11-25
1I22/11-25
1I22/11-25
1I22/11-25
1I23/11-26
1I23/11-26
1I23/11-26
1I23/11-26
1I23/11-26
1I23/11-26
1I23/11-26
1I24/11-27
1I24/11-27
1I24/11-27
1J1/11-28
1J2/11-29
1J2/11-29
1J2/11-29
1J2/11-29
1J2/11-29
1J3/11-30
1J5/11-32
1J5/11-32
1J5/11-32
1J5/11-32
1J5/11-32
Installation and Timing
to Engine ........
Disassembly, Inspection and
Reassembly .......
Magneto Check .......
.
Spark Plugs ......
ENGINE CONTROLS ......
Description . .......
.........
Rigging .
..
Throttle Control ..
..
Mixture Control ..
Propeller Governor
Control .......
Rigging Throttle Operated
Microswitch .......
EXHAUST SYSTEM .......
Description ........
Economy Mixture Indicator
(EGT) ..........
.
...........
Removal
.
.......
Inspection .
Installation ........
STARTING SYSTEM ......
Description ........
.
Trouble Shooting ...
Primary Maintenance ....
Starter Motor .......
Removal and Installation.
EXTREME WEATHER MAINTENANCE
.
Cold Weather ......
Dusty Conditions ........
. .
Sea Coast and Humid Areas
1J6/11-33
1J6/11-33
1J6/11-33
1J6/11-33
1J6/11-33
1J6/11-33
1J7/11-34
1J7/11-34
1J7/11-34
1J8/11-35
1J8/11-35
1J8/11-35
1J9/11-36
1J9/11-36
1J9/11-36
1J9/11-36
1J9/11-36
1J9/11-36
1J9/11-36
1J10/11-37
1J10/11-37
1J11/11-38
1J11/11-38
1J11/11-38
1J11/11-38
1J11/11-38
1J11/11-38
MODEL R172 SERIES SERVICE MANUAL
11-1.
NOTE
ENGINE COWLING.
When the new shock mounts or brackets are
being installed, careful measurements should
be made to position 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 are correctly aligned. Sheet aluminum may be used
as shims between bracket halves to provide
proper cowling contour.
11-2. DESCRIPTION. The upper and lower engine
cowling is shock-mounted. Instead of attaching directly to the fuselage, the cowling attaches to shock
mounts which, in turn, are fastened to the fuselage.
Screws are used to attach the right and left nosecaps
together which, in turn, is fastened to the cowlings
with quick release fasteners. A door in the top cowl
provides access to the engine oil dipstick, and oil
filler neck. Landing and taxi lights are installed in
the lower cowl assembly and a single, retractable
cowl flap is installed in the aft end of the lower cowl
to air in controlling engine temperature.
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.
11-3. REMOVAL AND INSTALLATION.
a. Release the quick-release fasteners (2, figure
1-1), attaching the cowling at the shock mounts and
at the parting surfaces of the upper and lower cowl.
b. Disconnect the landing and taxi light wires at the
quick-disconnects.
c. Disconnect cowl flap control clevis at cowl flap
shock mount.
d. Reverse the preceding steps for reinstallation.
Be sure the baffle seals are turned in the correct direction to confine and direct air flow around the engine. The vertical seals must fold forward and the
side seals must fold upwards.
.......
.. ....
....
...........
.
...
.....................
.
..
.
1.
.
A
Figure 11-1.
Detail
........
A
Engine Cowling
2.. Quick-Release Fastener
4.
Asbestos Seal
5.
Shock Mount
6.
7.
Bracket
Firewall
Engine Cowling Shock Mounts
11-3
MODEL R172 SERIES SERVICE MANUAL
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 stopdrilled 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.
COWL FLAP.
(See figure 11-2.)
11-7. DESCRIPTION. A single, retractable cowl
flap is installed in the aft end of the lower cowl to
aid in controlling engine temperature.
11-8. REMOVAL AND INSTALLATION. (See figure
11-2.)
a. Place cowl flap lever (3) in the open position.
b. Disconnect cowl flap control clevis (1) from
cowl flap shock mount (8).
c. Remove safety wire securing hinge pin (11) to
cowl flap, pull pin from hinge and remove flap.
d. Reverse the preceding steps for reinstallation.
Rig cowl flap, if necessary, in accordance with paragraph 11-9.
11-9. RIGGING. (See figure 11-2.)
a. Disconnect cowl flap control clevis (1) from cowl
SHOP NOTES:
11-4
flap shock-mount (8).
b. Check to make sure that the flexible control
reaches its internal stops in each direction. Mark
control so that full travel can be readily checked and
maintained during the remaining rigging procedures.
c. Place cowl flap lever (3) in the closed position.
If the control lever cannot be placed in the closed
position, adjust control at upper clevis (1) to position control lever in bottom hole of position bracket
(2).
d. With the control lever in closed position, hold
cowl flap closed, streamlined with trailing edge of
lower cowl. Loosen jam nut and adjust clevis (1) on
the control to hold cowl flap in this position and install bolt. Tighten jam nut.
11-10.
ENGINE.
11-11. DESCRIPTION. An air-cooled, wet-sump,
six-cylinder, horizontally-opposed, Continental
IO-360-K engine, equipped with fuel injection, is
used to power the aircraft. The engine features
inclined valves, with individual rocker box covers
for each valve. The intake ports are located on the
opposite side of the cylinders from the exhaust ports.
An oil cooler is located at the rear (accessory case)
end of the engine on the 2-4-6 side. Refer to paragraph 11-12 for engine data. For repairs and overhaul of the engine, accessories and propeller, refer
to the applicable publications issued by their manufacturers.
MODEL R172 SERIES SERVICE MANUAL
Figure 11-2.
Cowl Flap Installation
Figure 11-2.
Cowl Flap Installation
MODEL R172 SERIES SERVICE MANUAL
11-12.
ENGINE DATA.
Model (Continental)
IO-360-K
BHP at RPM
195 at 2600 RPM
Number of Cylinders
6-Horizontally Opposed
Displacement
Bore
Stroke
360 Cubic Inches
4,438 Inches
3,875 Inches
Compression Ratio
8. 5:1
Magnetos THRU R1723199 & FR1720655
Right Magneto
Left Magneto
Bendix - Scintilla S6LN - 25 *
Fires 20° -BTC-1-3-5 Upper and 2-4-6 Lower Spark Plugs
Fires 20 ° BTC 2-4-6 Upper and 1-3-5 Lower Spark Plugs
BEGINNING WITH R1723200 & FR1720656
Right Magneto
Left Magneto
Slick 6214 *
Fires 20 ° BTC 1-3-5 Upper and 2-4-6 Lower Spark Plugs
Fires 20 ° BTC 2-4-6 Upper and 1-3-5 Lower Spark Plugs
Firing Order
1-6-3-2-5-4
Spark Plugs
Torque Value
18mm (Refer to Continental Service Bulletin M68-4)
330 # 30 lb-in
Fuel Metering System
Unmetered Fuel Pressure
Continental Fuel Injection
6 to 8 PSI at 600 RPM
23 to 26 PSI at 2600 RPM
2. 5 to 4.0 PSI at 600 RPM
14. 0 to 16.0 PSI at 2600 RPM
Nozzle Pressure
Oil Sump Capacity
With Filter Change
8 U. S. Quarts
9 U.S. Quarts
Tachometer
Mechanical
Oil Pressure
Minimum Idling
Normal
Maximum
10 PSI
30 to 60 PSI
100 PSI
Oil Temperature
Normal Operation
Maximum Permissible
Within Green Arc (100°F to 240°F)
Red Line (240 ° F)
Cylinder Head Temperature
460° F Maximum Allowable
Dry Weight with Accessories
325 lb (Weight is approximate, excluding baffles, propeller vacuum pump and tachometer drive)
Direction of Crankshaft Rotation as Viewed from
Propeller End of Engine
Counterclockwise.
* Magneto rotors rotate clockwise as viewed
from the magneto drive end.
11-13. TIME BETWEEN OVERHAUL (TBO). Teledyne Continental Motors recommends engine overhaul at 2000 hours operating time for this 10-360
series engine. Refer to Continental Aircraft Engine
Service Bulletin M79-14, and to any superseding bulletins, revisions or supplements thereto, for further
recommendations. At the time of engine overhaul the
accessories should be overhauled.
11-6
11-14. OVERSPEED LIMITATIONS The engine must
not be operated above specified maximum continuous
RPM. However, should inadvertent overspeed occur,
refer to Continental Aircraft Engine Service Bulletin
M75-16, and to any superseding bulletins, revisions or
supplements thereto, for further recommendations.
MODEL R172 SERIES SERVICE MANUAL
11-15.
TROUBLE SHOOTING.
TROUBLE
ENGINE WILL NOT START.
PROBABLE CAUSE
REMEDY
Improper use of starting
procedure.
Review starting procedure.
Refer to Pilot's Operating Handbook.
Defective aircraft fuel system.
Refer to Section 12.
Spark plugs fouled or defective.
Remove and clean. Check gaps and
insulators. Use new gaskets. Check
cables to persistently fouled plugs.
Replace if defective.
Defective magneto switch or
grounded magneto leads.
Check continuity, repair or replace
switch or leads.
Defective ignition system.
Refer to paragraph 11-75.
Excessive induction air leaks.
Check visually.
air leaks.
Dirty screen in fuel control unit
or defective fuel control unit.
Check screen visually. Check fuel
flow through control unit. Replace
defective fuel control unit.
Defective electric fuel pump.
Refer to Section 12.
Defective fuel manifold valve
or dirty screen.
Check fuel flow through valve.
Remove and clean. Replace if
defective.
Clogged fuel injection lines or
discharge nozzles.
Check fuel through lines and nozzles.
Clean lines and nozzles. Replace if
defective.
Fuel pump not permitting fuel
from auxiliary pump to bypass.
Check fuel flow through engine-driven
fuel pump. Replace engine-driven
pump.
Vaporized fuel in system.
Refer to Pilot's Operating
Handbook.
Correct cause of
Fuel tanks or bays empty.
Visually inspect tanks or bays
Fill with proper grade and
quantity of gasoline.
Fuel contamination or water in
fuel system.
Open fuel strainer drain and check
for water. Drain all fuel and flush
out fuel system. Clean all screens,
fuel lines, strainer, etc.
Mixture control in the IDLE
CUT-OFF position.
Move control to the full RICH
position.
Fuel selector valve in OFF
position.
Place selector valve in the ON
position to tanks known to contain gasoline.
Magneto impulse coupling
failure.
Repair or install new coupling.
11-7
MODEL R172 SERIES SERVICE MANUAL
11-15.
TROUBLE SHOOTING (Cont).
TROUBLE
ENGINE STARTS BUT
DIES, OR WILL NOT
IDLE.
11-8
PROBABLE CAUSE
REMEDY
Idle stop screw or idle mixture
incorrectly adjusted.
Refer to paragraph 11-55.
Spark plugs fouled or improperly
gapped.
Remove, clean and regap plugs.
Replace if defective.
Water in fuel system.
Open fuel strainer drain and check
for water. If water is present,
drain fuel tank or bay sumps, lines
and strainer.
Defective ignition system.
Refer to paragraph 11-75.
Induction air leaks.
Check visually.
cause of leaks.
Manual primer leaking.
Disconnect primer outlet line.
If fuel leaks through primer,
repair or replace primer.
Dirty screen in fuel control unit
or defective fuel control unit.
Check screen visually. Check
Fuel flow through control unit.
Clean screen. Replace fuel
control unit if defective.
Defective manifold valve or
clogged screen.
Check fuel flow through valve.
Replace if defective. Clean screen.
Defective engine-driven fuel
pump.
If engine continues to run with
electric pump turned on, but
stops when it is turned off, the
engine-driven pump is defective.
Replace pump.
Defective engine.
Check compression. Listen for
unusual engine noises. Engine
repair is required.
Propeller control set in high
pitch position (low RPM).
Use low pitch (high RPM) position
for all ground operation.
Defective aircraft fuel system.
Refer to Section 12.
Restricted fuel injection lines
or discharge nozzles.
Check fuel flow through lines and
nozzles. Clean lines and nozzles.
Replace if defective.
Obstructed air intake.
Check visually. Remove obstruction;
service air filter, if necessary.
Improper positioning of
discharge nozzle shield.
Position lower edge of nozzle
shield approximately 1/16"
above wrench pads on nozzle.
Correct the
MODEL R172 SERIES SERVICE MANUAL
11-15.
TROUBLE SHOOTING (Cont).
TROUBLE
ENGINE RUNS ROUGHLY,
WILL NOT ACCELERATE
PROPERLY.
POOR IDLE CUT-OFF.
PROBABLE CAUSE
REMEDY
Propeller control in high pitch
(low RPM) position.
Use low pitch (high RPM) for
all ground operations.
Restriction in aircraft fuel
system.
Refer to Section 12.
Restriction in fuel injection
system.
Clean system. Replace any
defective units.
Engine-driven fuel pump pressure improperly adjusted.
Refer to paragraph 11-68.
Worn or improperly rigged
throttle or mixture control.
Check visually. Rig properly.
Replace worn linkage.
Spark plugs fouled or improperly
gapped.
Clean and regap.
defective.
Defective ignition system.
Refer to paragraph 11-75.
Defective engine.
Check compression. Listen for
unusual engine noises. Engine
repair is required.
Propeller out of balance.
Check and balance propeller.
Interference between engine
mount and cowling.
Edges of cowling stiffeners and
doublers may be ground for clearance.
Defective engine shock
mount.
Replace defective parts.
Engine or engine mount attaching bolts loose or broken.
Torque properly. Replace if
defective.
Worn or improperly rigged
mixture control.
Rig properly.
linkage.
Defective or dirty manifold valve.
Operate electric fuel pump and
check that no fuel flows through
manifold valve with mixture control in IDLE CUT-OFF. Remove
and clean. Replace if defective.
Auxiliary fuel pump ON.
Turn to OFF position.
Defective fuel control unit.
If none of the preceding causes
corrects the problem, the control unit is probably at fault.
Replace control unit.
Fuel contamination.
Drain fuel, flush out fuel system.
Clean all screens, strainer, manifold valve, nozzles, and fuel lines.
Defective mixture control valve
in pump.
Replace fuel pump
Replace if
Replace worn
11-9
MODEL R172 SERIES SERVICE MANUAL
11-15.
TROUBLE SHOOTING (Cont)
HIGH CYLINDER HEAD
TEMPERATURE.
Defective cylinder head temperature indicating system.
Refer to Section 15.
Improper use of cowl flap.
Refer to Pilot's Operating Handbook.
Defective cowl flap operating
system.
Refer to paragraph 11-6.
Engine baffles loose, bent or
missing.
Check visually. Install baffles
properly. Repair or replace
if defective.
Dirt accumulated on cylinder
cooling fins.
Check visually.
thoroughly.
Incorrect grade of fuel.
Drain and refill with proper fuel.
Incorrect ignition timing.
Refer to paragraph 11-80 or 11-87.
Defective fuel injection system.
Refer to paragraph 11-51.
Improper use of mixture control.
Refer to Pilot's Operating Handbook.
Defective engine.
HIGH OR LOW OIL
TEMPERATURE
OR PRESSURE.
Clean
Repair as required.
Refer to paragraph 11-42.
11-16. 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 take-off 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 results of the RPM obtained. It
should be within 50 RPM of 2565 RPM.
d. If the average results of the RPM obtained are
lower than stated above, the following recommended
checks may be performed to determined a possible
deficiency,
1. Check governor control for proper rigging.
It should be determined that the governor control arm
travels to the high RPM stop on the governor and that
the high RPM stop screw is adjusted properly. (Refer
11-10
REMEDY
PROBABLE CAUSE
TROUBLE
to Section 13 for procedures.)
NOTE
If verification of governor operation is
necessary, the governor may be removed
from the engine and a flat plate installed
over the engine pad. Run-up engine to
determine that the governor was adjusted
properly.
2. Check operation of alternate air door spring
or magnetic lock to make sure door will remain
closed in normal operation.
3. Check magneto timing, spark plugs, and ignition harness for setting and condition.
4. Check fuel injection nozzles for restriction
and check for correct unmetered fuel flow.
5. Check condition of induction air filter. Clean
if required.
6. Perform an engine compression check.
Refer to engine Manufacturer's Manual for procedures.
MODEL R172 SERIES SERVICE MANUAL
11-17. ENGINE REMOVAL. If the engine is to be
placed in storage or returned to the manufacturer.
proper preparatory steps should be taken prior to
beginning the removal procedure. Refer to Section
2 for engine storage.
NOTE
Tag each item disconnected to aid in identifying wires, hoses, and control linkage when engine is installed. 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 and fuel shut-off valve
in the OFF position.
b. Remove the engine cowling. (Refer to paragraph
11-3.
c. Open battery circuit by disconnecting battery.
d. Disconnect ignition switch leads at the magnetos.
WARNING
These magnetos DO NOT have internal grounding springs. Ground the magneto points to prevent accidental firing when propeller is rotated.
e. Drain the engine oil.
f. Remove the propeller.
propeller removal.
Refer to Section 13 for
NOTE
During the following procedures, remove any
clamps which secure controls, wires, hoses,
or lines to the engine, engine mount, or attached brackets, so they will not interfere with
removal of the engine and mount.
g. Disconnect the throttle control, propeller
control, and mixture control at their respective
units. Pull these controls free of engine, using care
not to damage them by bending too sharply.
h. Remove oil temperature bulb located directly
above oil cooler. Work bulb aft through baffles carefully to prevent damage to capillary tube.
i. Disconnect wires and cables as follows:
1. Tachometer drive at adapter.
2. Cylinder head temperature wire at temperature bulb on lower side of cylinder,
3. Electrical wires and wire shielding ground at
alternator.
CAUTION
When disconnecting the starter cable, do not
permit starter terminal bolt to rotate. Rotation of the terminal bolt could break the conductor between terminal and field coils causing
the starter to be inoperative.
4. Starter electrical cable at starter and insulate cable as a safety precaution.
5. Remove all clamps attaching wires or cables
to the engine. Pull all wires and cables aft to clear
the engine.
j.
Disconnect lines and hoses as follows:
1. Vacuum pump hoses at vacuum pump.
2. Manifold pressure line at firewall.
3. Fuel supply hose at fuel strainer and vapor
return hose at firewall.
WARNING
Residual fuel draining from lines and hoses
is a fire hazard. Use care to prevent the
accumulation of such fuel when lines and/or
hoses are disconnected.
4. Fuel flow gage line at firewall.
5. Oil pressure hose at firewall.
6. Engine primer line at firewall.
k. Disconnect flexible ducting.
1. Attach a hoist to the hoisting lug on top of the
engine and take up engine weight on hoist.
CAUTION
Place a stand under the tail tie-down ring before removing the engine. The loss of engine
weight will allow the tail to drop.
m. Remove bolts attaching engine mount to upper
part of firewall, then remove bolts attaching engine
mount to lower part of firewall. Balance the engine
by hand as the last of these bolts is removed.
CAUTION
Hoist engine slowly and make sure all wires,
lines, and hoses have been disconnected.
n. Carefully guide disconnected components out of
engine assembly.
11-18. CLEANING. The engine and engine compartment should be cleaned thoroughly with a solventdampened cloth. Solvent may be applied with a spray
gun or brush and allowed to soften and dissolve inaccessible grease deposits before compressed air is
used to remove them.
CAUTION
Particular care should be given to electrical
components before cleaning. Solvent should
not be allowed to enter magnetos, starters,
alternators, voltage regulators, and the like.
Hence, these should be protected before saturating the engine with solvent. Any oil, fuel,
and air openings on the engine and accessories
should be covered before washing down the engine with solvent. Caustic cleaning solutions
should not be used.
11-19. 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 disassembly process, removed
items should be examined carefully. and defective
parts should be tagged for repair or replacement.
11-11
MODEL R172 SERIES SERVICE MANUAL
NOTE
Items easily confused with similar items
should be tagged to provide a means 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 hole. This
will prevent entry of foreign particles. If
suitable covers are not available, tape may
be used to cover the openings.
f.
Connect lines and hoses as follows:
1. Engine primer line at firewall.
2. Oil pressure hose at firewall.
3. Fuel flow gage line at firewall.
4. Fuel supply hose at fuel strainer and vapor
return hose at firewall
NOTE
Throughout the aircraft fuel system, from the
fuel tanks to the engine-driven fuel pump, 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 lubricant or to
seal a leaking connection. Apply sparingly to
male threads only, omitting the first two
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.
Throughout the fuel injection system, from the
engine-driven fuel pump through the discharge
nozzles, use only a fuel-soluble lubricant,
such as engine oil, on fitting threads. Do not
use any other form of thread compound on the
injection system.
11-20. INSPECTION. For specific items to be inspected refer to engine manufacturer's manual.
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 hoses 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 examining hoses for stiffness.
e. Refer to Section 2 for replacement intervals for
flexible fluid carrying hoses in the engine compartment.
f. For major engine repairs, refer to the manufacturer's overhaul and repair manual.
5. Manifold pressure line at firewall.
6. Vacuum pump hoses at firewall and separator.
g. Connect wires and cables as follows:
1. Tachometer drive shaft at adapter on engine.
Tighten drive shaft attaching nut to 100 lb-in.
2. Cylinder head temperature wire at temperature bulb. Do not exceed 4 lb-in torque.
3. Electrical wire and wire shielding ground at
alternator.
11-21. BUILD-UP. Engine build-up consists of the
installation of parts, accessories and components to
the basic engine to build up a powerplant unit ready
for installation in the aircraft. All safety wire, lockwashers. Palnuts, elastic stop nuts, gaskets and
rubber connections should be new parts.
11-22. INSTALLATION. Before installing the engine,
reinstall any items which were removed from the engine after it was removed from the aircraft.
NOTE
Remove all protective covers, plugs, caps,
and identification tags as each item is connected or installed.
a. Hoist engine and mount assembly to a point near
the firewall.
b. Route controls, lines, and hoses in place as the
engine is positioned near the firewall.
c. Install engine mount bolts. Install the upper
engine mount bolts at firewall, then install lower
bolts. When tightening, torque to 160 to 190 lb-in. l.
d. Remove hoist and stand placed under tail.
e. Route throttle, mixture, and propeller controls
to their respective units and connect. Secure controls
in position with clamps.
11-12
CAUTION
When connecting the starter cable, do not
permit starter terminal bolt to rotate. Rotation of the terminal bolt could break the
conductor between terminal and field coils
causing the starter to be inoperative.
4. Starter electrical cable at starter.
5. Install all clamps attaching wires or cables
to the engine.
h. Install oil temperature bulb.
i. Install propeller. (See Section 13.)
j. Make a magneto switch ground-out and continuity
check. Connect magneto primary wires to the magnetos. Remove temporary ground.
WARNING
Be sure magneto switch is in OFF position
when connecting primary leads to magnetos.
k.
Clean induction air filter and install.
Service engine with proper grade and quantity of
engine oil. Refer to Section 2 if engine has been in
storage.
m. Make sure all switches are in the OFF position,
and connect battery ground cable.
MODEL R172 SERIES SERVICE MANUAL
n. Rig engine controls in accordance with paragraphs 11-93 and 11-97.
o. Check engine installation for security, correct
routing of controls, lines, hoses and electrical
wiring, proper safetying, and tightness of all cornponents.
p. Install engine cowling.
q. Perform engine run-up and make final adjustments on engine controls.
11-23.
FLEXIBLE FLUID HOSES.
11-24. PRESSURE TEST.
a. After each 50 hours of engine operation, all
flexible fluid hoses in the engine compartment should
be pressure tested as follows:
1. Place mixture control in the idle cut-off positionf.
2. Operate the auxiliary fuel pump in the high
position.
o
3. Examine the exterior of hoses for evidence
of leakage or wetness.
4. Hoses found leaking should be replaced.
5. After pressure testing fuel hoses, allow sufficient time for excess fuel to drain overboard from
the engine manifold before attempting an engine start.
6. Refer to paragraph 11-20for detailed inspection procedures for flexible hoses.
11-25. 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 with sta-straps to prevent chafing,
d. Rubber hoses will take a permanent set during
extended use in service. Straightening 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, Chapter 10, for additional
installation procedures for flexible fluid hose assemblies.
11-26.
TACHOMETER DRIVE ADAPTER SEAL.
11-27. REMOVAL AND INSTALLATION. To install
a new tachometer drive seal, special tools are required. (See figures 11-3 and 11-4.)
NOTE
Tool Kit MK6-1 and tool SE909 are available
from the Cessna Service Parts Center. Tools
in the MK6-1 kit are used for installing the
seal in the adapter and installation of the
adapter on the engine. The E0 tool is used
to apply the correct torque value on the tachometer drive connector.
a. Remove engine cowling as required for access.
b. Drain oil until a maximum of eight quarts are
left in the enine
c. Remove alternator. (Refer to Section 16.)
d. Disconnect tachometer drive shaft from tachometer drive reduction adapter.
e. Remove drive reduction adapter from tachometer drive housing.
f. Remove three sets of nuts and washers and remove tachometer drive housing.
g. Engage lock tool (10) and driver tool (9) through
the housing (4) as shown in figure 11-4. Tap the
driver tool (9) with a hammer until the seal (4) is
removed from the drive housing.
h Engage bolt (5) through sleeve (6), washer (7),
drive housing (4), seal (3), and into driver tool (8)
as shown in figure 11-4.
Tighten bolt (5) until driver
tool (8) comes in conta2t with the face o, drive housing (4).
SHOP NOTES:
11-13
MODEL R172 SERIES SERVICE MANUAL
NOTE
11-28.
Seal is to be installedl with lip o' seal as
shownin figure 11-4.
i. Remove the tools and inspect seal (3) for proper seating.
j. Using the SE909 tool, remove tachometer shaft
connector from engine.
k. Inspect connector for rough or sharp edges
along groove for the tachometer cable drive,
1. If sharp or rough edges are found, use a fine
stone and smooth the edges of the connector. Rough
or sharp edges could damage the seal.
m. Install connector and using tool SE909, torque
connector to 280 to 300 lb-in.
n. Insert bullet tool (2) into end of the tachometer
drive connector as shown in figure 11-4.
NOTE
ENGINE BAFFLES.
11-29. 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 of the engine. These baffles incorporate rubber-asbestos composition seals at points of
contact with the engine cowling to help confine and
direct the airflow to the desired area. It is very
important to engine cooling that the baffles and seals
are installed correctly and maintained in good condition.
11-30. CLEANING AND INSPECTION. The engine
baffles should be cleaned with a suitable solvent to
remove oil and dirt.
NOTE
The rubber-asbestos seals are oil and grease
resistant but should not be soaked in solvent for
long periods.
The end of connector (1) has a sharp edge.
The bullet tool will protect the seal (3)
during engagement of the connector with
the housing (4).
Inspect baffles for cracks in the metal and for loose
and/or torn seals. Replace or repair defective parts.
o. Using a new gasket, install housing and remove
bullet tool.
p. Install reduction adapter and connect tachometer
drive shaft. Tighten reduction adapter and drive
shaft nuts to 100 lb-in.
,
q. Install alternator. (Refer to Section 16.)
r. Service engine with oil and install cowling removed for access.
11-31. REMOVAL AND INSTALLATION. Removal
and installation of the various baffle segments 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.
FILL WELD AND
REMOVE EXCESS
3-1/4
SIDE VIEW
END VIEW
5/8-INCH, 12-POINT, 1/2-INCH DRIVE SOCKET
SE909 TOOL
Figure 11-3.
11-14
Torque Wrench Adapter
MODEL R172 SERIES SERVICE MANUAL
LIP OF SEAL INSTALLED
IN THIS DIRECTION
INSERTING TACHOMETER
SHAFT THROUGH SEAL
PRESSING SEAL
INTO HOUSING
.4.
REMOVING SEAL
FROM HOUSING
Figure 11-4.
1. Tachometer Drive Connector
2. SE867-1 Bullet Tool
3. Seal
Tachometer Drive Housing
5 SE867-203 Bolt Tool
6. SE867-204 Sleeve Tool
7. SE867-205 Washer Tool
8. SE867-202 Driver Tool
9. SE867-4 Driver Tool
10. SE867-3 Lock Tool
Tachometer Drive Seal Installation
11-15
MODEL R172 SERIES SERVICE MANUAL
11-32. REPAIR. Baffles ordinarily should be replaced 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.
11-33.
h. Remove bolts attaching engine mount to fuselage
and work mount from aircraft.
i. To install the engine mount, reverse the preceding steps. Be sure that spacer washers are installed between engine mount and firewall.
ENGINE MOUNT.
11-34. DESCRIPTION. The engine mount is composed of sections of tubing welded together and reinforced with welded gussets. The purpose of the
mount is to support the engine and attach it to the air11-35. REMOVAL AND INSTALLATION. Removal
and installation of the engine mount may be accomplished without completely removing the engine from
the aircraft.
a. Remove cowling for acess.
b. Remove engine exhaust system as outlined in
paragraph 11-101.
c. Remove clamps attaching lines, hoses, and
wiring to engine mount.
d. Remove heat shields from right hand rear and
left hand forward engine shock mounts (if installed).
e. Attach a suitable hoist to the hoisting lug on top
of the engine and take up engine weight with the hoist.
NOTE
When tightening mount-to-firewall bolts, tighten to a torque value of 160 to 190 lb-in. When
tightening engine-to-mount bolts, tighten to a
torque value of 450 to 500 lb-in.
Refer to section 18 of this manual
11-36. REPAIR.
repair
for procedures.
11-37.
PAINTING. Refer to section 19 of this manual for painting procedures.
11-38. SHOCK MOUNT PADS. The bonded rubber
and metal shock mounts are designed to reduce
transmission of engine vibrations to the airframe.
The rubber pads should be wiped clean with a dry
cloth.
NOTE
Do not clean the rubber parts with any type
of cleaning solvent.
Place a stand under the tail tie-down ring before lifting the engine. The loss of engine
eparts
weight will allow the tail to drops.
weight
f. Remove nuts, washers, and bolts attaching engine to mount.
g. Raise hoist slightly so that no engine weight is
on the mount and remove engine shock mount pads
and spacers.
Use care when lifting engine to prevent damage
to lines, hoses, wiring, and controls.
SHOP NOTES:
11-16
Inspect metal parts for cracks and excessive wear
due to aging and deterioration. Inspect the rubber
for swelling, cracking, or a pronounced set
of the part. Replace with new parts all of the parts
11-39. ENGINE OIL SYSTEM.
11-40.
DESCRIPTION.
A wet-sump, pressure-
MODEL R172 SERIES SERVICE MANUAL
11-41. OIL SYSTEM CAPACITY. (Refer also to
Section 2. ) The oil system has an 8-quart capacity.
Engine should not be operated on less than six quarts.
To minimize loss of oil through breather, fill to seven quart level for normal flights of less than three
11-42.
hours. For extended flights, fill to eight quarts.
These quantities refer to dipstick readings only. For
engines that have the optional full-flow oil filter installed, one additional quart is required when the filter is changed.
TROUBLE SHOOTING.
TROUBLE
NO OIL PRESSURE.
LOW OIL PRESSURE.
PROBABLE CAUSE
REMEDY
No oil in sump.
Check oil with dipstick. Fill sump
with proper grade and quantity of
oil. Refer to Section 2.
Oil pressure line broken,
disconnected or pinched.
Check visually.
connect.
Oil pump defective.
Remove and inspect. Examine
engine. Metal particles from
damaged pump may have entered
engine oil passages.
Defective oil pressure gage.
Check with a known good gage.
Replace gage if defective.
Oil congealed in gage line.
Disconnect line at engine and gage;
flush with kerosene. Pre-fill with
kerosene and install.
Relief valve defective.
Remove and check for dirty or defective parts. Clean and install;
replace defective parts.
Low oil supply.
Check with dipstick. Replenish
with proper grade and quantity.
Low viscosity oil.
Check visually. Drain sump and
refill with proper grade and
quantity of oil.
Oil pressure relief valve spring
weak or broken.
Remove and inspect. Replace
weak or broken spring.
Defective oil pump.
Remove and inspect. Examine
engine. Metal particles from
damaged pump may have entered
engine oil passages.
Defective oil pressure gage.
Check with a known good gage.
Replace gage if defective.
Secondary result of high oil
temperature.
Observe oil temperature gage for
high indication. Determine and
correct reason for high oil temperature.
Replace or
11-17
MODEL R172 SERIES SERVICE MANUAL
11-42.
TROUBLE SHOOTING (Cont).
TROUBLE
HIGH OIL PRESSURE.
LOW OIL TEMPERATURE.
HIGH OIL TEMPERATURE.
11-18
PROBABLE CAUSE
REMEDY
High viscosity oil.
Check visually. 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 defective parts.
Defective oil pressure gage.
Check with a known good gage.
Replace oil pressure gage.
Defective oil temperature gage
or temperature bulb.
Check with another gage. If
reading is normal, aircraft
gage is defective. If reading
is similar temperature bulb
is defective. Replace defective part/or parts.
Oil cooler thermo-bypass
valve defective or stuck
closed,
Remove valve and check for
proper operation. Replace
valve if defective.
Defective wiring.
Check continuity.
Oil cooler air passages clogged.
Check visually.
Oil cooler oil passages clogged.
Attempt to drain cooler. Inspect
for sludge. Remove cooler and
flush thoroughly.
Low oil supply.
Replenish.
Oil viscosity too high.
Drain and fill sump with proper
grade and quantity.
Prolonged high speed operation
on ground.
Hold ground running above 1500
RPM to a minimum.
Defective oil temperature
indicating system.
Refer to Section 15.
Oil congealed in cooler.
If congealing is suspected, use
external heater or a heated
hangar to thaw the congealed
oil.
Secondary result of low
oil pressure.
Check for low oil pressure
reading. Determine cause
and correct.
Secondary result of high
cylinder head temperature.
Check for high cylinder head
temperature. Determine
cause and correct.
Repair wiring.
Clean air passages
MODEL R172 SERIES SERVICE MANUAL
NOTE
8
7
Do not substitute automotive gaskets
for any gasket used in this assembly.
Use only approved gaskets listed in
the Parts Catalog.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Oil Screen Nut
Accessory Case
Stud
O-Ring Seal
Gasket
Adapter
Safety Wire
Filter
Seal
Nut
Washer
,Figure
11-43.
11-6.
Full-Flow Oil Filter
OIL COOLER.
11-44. DESCRIPTION. The fin and plate oil cooler
is attached to a plate on the aft left side of the engine
crankcase. Oil is allowed to circulate through the
adapter plate until the oil reaches a predetermined
temperature, the Vernatherm then closes causing the
oil to be routed through the oil cooler to be cooled.
Cooling air is routed through the cooler from the top
side and is exhausted into the lower cowling.
11-45.
FULL-FLOW OIL FILTER. (See figure 11-6.)
11-46. DESCRIPTION. Beginning with Serials R1723200 & on, and FR1720656 & on, the Full-Flow oil
filter is included as standard equipment. The filter
and filter adapter replace the regular oil filter screen.
The filter adapter is a bolt on type held by three studs
installed on the engine accessory case. The filter is
a throw-away type spin-on filter which has an internal bypass valve.
11-47. REMOVAL AND INSTALLATION (FILTER).
(See figure 11-6.)
a Remove engine cowl as necessary to gain access
to the filter.
b. Remove safety wire (7) from filter, (8).
c. Unscrew filter from adapter, (6).
NOTE
Teledyne Continental Motors recommends
that the spin-on filter be inspected. Refer
to Continental Aircraft Engine Service Bulletin M74-2, dated 16 January 1974.
d. Lightly lubricate gasket (9) with engine oil only
prior to installation.
e. Install spin-on filter, (8), on the stud and torque
to 18-20 Ib-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.
11-48. REMOVAL AND INSTALLATION (ADAPTER).
(See figure 11-6. )
a. Remove spin-on filter per paragraph 11-45.
b. Remove safety wire between adapter (6) and oil
screen nut.
c. Remove nuts (10) and washers (11) and pull adapter from accessory case (2) taking care not to damage
O-ring seal (4).
d. Check O-ring seal for damage.
e. Place new adapter gasket (5) over studs.
f. Lubricate O-ring seal with engine oil and slide
adapter into place taking care not to damage O-ring
seal.
11-19
MODEL R172 SERIES SERVICE MANUAL
-
Install
h.
I. Install
11-49.
washers and nuts
in throttle position, engine speed, or a combination
Safety wire oil screen nut to adapter,
oil filter per paragraph 11-47.
ENGINE FUEL SYSTEM.
(See figure 11-7.)
11-50. DESCRIPTION. The fuel injection system is
a simple. low-pressure system of injecting metered
fuel into the intake valve ports in the cylinders. It is
a multi-nozzle. continuous-flow system which controls fuel flow to match engine airflow. Any change
SHOP NOTES:
11-20
of both. changes fuel flow in the correct relation to
engine airflow.
A manual mixture control and a fuel
flow indicator are provided for leaning at any combination of altitude and power setting. The continuousflow system uses a typical rotary-vane fuel pump,
which is the only running part in the system. Since
the fuel injection nozzles and the intake manifolds
are installed on the top side of the cylinders, drain
lines are installed in the bottom side of the intake
ports to drain any fuel which might accumulate in the
intake ports during engine shut-down.
MODEL R172 SERIES SERVICE MANUAL
TO
FUEL
TANK
VAPOR EJECTOR JET
-
FROM
FUEL
RELIEF VALVE
, METERING DISC
MIXTURE
PUMP
BYPASS VALVE
ORIFICE
THROTTLE VALVE
IDLE CUT-OFF
CHECK
VALVE
DIAPHRAGM
INDICATOR
UNIT
PLUNGER
SCREEN
VALVE
DUST
COVER
AIR
INLET PRESSURE
11-21
LEGEND:
INLET PRESSURE
PUMP PRESSURE
MIXTURE
FUEL METERED BY MIXTURE CONTROL
FUEL METERED BY THROTTLE CONTROL
Figure 11-7.
Fuel Injection Schematic
11-21
MODEL R172 SERIES SERVICE MANUAL
11-51.
TROUBLE SHOOTING.
TROUBLE
NO FUEL DELIVERED
TO ENGINE.
HIGH FUEL PRESSURE.
ENGINE RUNS ROUGH
AT IDLE.
11-22
PROBABLE CAUSE
REMEDY
Fuel tanks or bays empty.
Check visually. Service with
desired quantity of fuel.
Defective aircraft fuel system.
Refer to Section 12.
Vaporized fuel. (Most likely
to occur in hot weather with a
hot engine.)
Refer to Pilot's Operating
Handbook.
Fuel pump not permitting fuel
from electric pump to bypass.
Check fuel-flow through pump.
Replace engine-driven fuel
pump if defective.
Defective fuel control unit.
Check fuel flow through unit.
Replace fuel-air control unit
if necessary.
Defective fuel manifold valve,
or clogged screen inside valve.
Check fuel flow through valve.
Remove and clean in accordance with paragraph 11-59.
Replace if defective.
Clogged fuel injection lines or
discharge nozzles.
Check fuel flow through lines and
nozzles. Clean and replace if
defective.
Restricted discharge nozzles.
Clean or replace plugged nozzle
or nozzles.
Restriction in vapor vent return
line or check valve.
Clean vapor return line.
or replace check valve.
Improper idle mixture adjustment.
Refer to paragraph 11-55.
Restriction in aircraft fuel
system.
Refer to Section 12.
Low unmetered fuel pressure.
Refer to paragraph 11-68.
High unmetered fuel pressure.
Refer to paragraph 11-68.
Worn throttle plate shaft or
shaft O-rings.
Replace shaft and/or O-rings.
Intake manifold leaks.
Repair leaks or replace
defective parts.
Leaking intake valves.
Engine repair required.
Discharge nozzle air vent
manifolding restricted or
defective.
Check for bent or loose
connections, restrictions
or defective components.
Tighten loose connections;
replace defective components.
Clean
MODEL R172 SERIES SERVICE MANUAL
11-51.
TROUBLE SHOOTING (Cont).
TROUBLE
PROBABLE CAUSE
REMEDY
ENGINE RUNS ROUGH
AT IDLE. (Cont.)
Improper positioning of discharge nozzle dust caps.
Position dust caps to have opening
of approximately 1/16-inch between
bottom of dust cap and wrench pads
on nozzle.
POOR IDLE CUT-OFF.
Dirt in fuel pump or
defective pump.
Remove pump and fush
out thoroughly. Check
that mixture arm contacts
cut-off stop.
Dirty or defective fuel
manifold valve.
Remove and clean in
accordance with paragraphs
11-58 and 11-59. Replace
if defective.
11-52.
FUEL-AIR CONTROL UNIT.
11-53. DESCRIPTION. The fuel-air control unit,
located at the inlet to the intake manifold, contains
the air throttle and a fuel metering unit. The function
of the fuel-air control unit is to meter fuel and air in
the proper ratio. The throttle control operates the
air throttle valve. The valve shaft extends into the
fuel metering valve. Idle speed and idle mixture
adjustments are provided in the fuel-air control unit.
The main mixture control is incorporated in the fuel
pump.
NOTE
connect fuel-air control unit to intake manifolds,
and slide hoses away from connection.
e. Disconnect throttle control rod end.
f. Disconnect induction air valve return spring
from tab on mounting bolt.
g. Remove bolts attaching fuel-air control unit to
airbox. Lay microswitch and bracket to one side.
Note any other parts secured by these bolts.
h. Remove bolts attaching fuel-air control unit to
bracket on engine, and remove the unit. Cover open
ends of intake manifolds and airbox.
i. Reverse this procedure to install the fuel-air
control unit. Check rigging of throttle and throttleoperated microswitch.
Throughout the aircraft fuel system, from the
fuel tanks or bays to the engine-driven fuel
pump, 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
lubricant or to seal a leaking connection,
Apply sparingly to male threads only, omitting the first two threads, exercising extreme
11-55. ADJUSTMENT (IDLE SPEED AND IDLE
MIXTURE). (See figure 11-8.) The idle speed n y
be regulated by adjusting a spring-loaded screw located on the air throttle lever. The idling screw
should be set to provide between 575 and 625 RPM.
The idle mixture adjustment is a screw/alien screw
located on the fuel metering unit. Turning clockwise
leans the mixture and counterclockwise richens the
mixture. Adjust mixture control to obtain a slight &
end of the fitting Always ensure tat across t
pound, the residue from a previously used
compound, or any other foreign material
cannot enter the system. Throughout the fuel
injection system, from the engine-driven fuel
pump through the discharge nozzles, use only
a fuel-soluble lubricant, such as engine oil,
on fitting threads. Do not use any other form
of thread compound on the injection system.
momentary gain of 25 RPM maximum at 1000 RPM
engine speed as mixture control is moved slowly
from full RICH toward idle cutoff. If mixture is set
too LEAN, engine speed will drop immediately, thus
requiring enrichment. If mixture is set too RICH,
engine speed will increase above 25 RPM, thus requiring leaning. Return mixture control to full RICH
position as soon as leaning effect is observed, to
keep engine running.
NOTE
11-54. REMOVAL
AND INSTALLATION.
INSTALLATION.
11-54.REMOVALAD
ing unit,
c. Disconnect manifold pressure line.
d. Loosen clamps securing the two hoses which
Engine idle speed may vary among different
without excessive vibration, and the idle
idling oil pressure and to preclude any possibility of engine stoppage in flight when the
throttle is closed. When checking or setting
11-23
MODEL R172 SERIES SERVICE MANUAL
IDLE MIXTURE ADJUSTMENT
FUEL-AIR CONTROL UNIT
RIGHT SIDE
LEFT SIDE
IDLE SPEED ADJUSTMENT
-
- NOTE
When problems exist with respect to nonrepeatability or drifting of fuel pressures,
fuel flow, or idle mixtures, refer to Conttinental Aircraft Engine Service Bulletin
#76-11 and all revisions thereto. Fuel
pump pressure must be checked and adjusted ( if necessary ) before idle mixture can be set. Refer to paragraph 11-
RIGHT SIDE
68.
IDLE MIXTURE ADJUSTMENT
Figure 11-8.
11-24
Idle Speed and Idle Mixture Adjustment
MODEL R172 SERIES SERVICE MANUAL
idle speed or idle mixture, "clear" the engine between checks to prevent false indications.
11-56.
FUEL MANIFOLD VALVE.
11-57. DESCRIPTION. Metered fuel flows to the
fuel manifold valve, which provides a central point
for distributing fuel to individual cylinders. An internal diaphragm, operated by fuel pressure, raises
or lowers a plunger to open and close the individual
cylinder supply ports simultaneously. A needle valve
in the plunger ensures that the plunger fully opens the
outlet ports before fuel flow starts, and closes the
ports simultaneously for positive engine shut-down.
A fine-mesh screen is included in the fuel manifold
valve.
11-58. REMOVAL AND INSTALLATION.
a. Disconnect all lines and hoses from the fuel
manifold valve,
b. Remove the two crankcase bolts which secure
mounting bracket. After removal, bracket may be
disassembled from manifold valve if desired.
c. Reverse this procedure to install the fuel manifold valve.
11-59. CLEANING.
a. Remove fuel manifold valve from engine and remove safety wire from cover attaching screws.
b. Hold the top cover down against internal spring
until all four cover attaching screws have been removed, then gently lift off the cover. Use care not
to damage the spring-loaded diaphragm below cover.
c. Remove the upper spring and lift the diaphragm
assembly straight up.
NOTE
If the valve attached to the diaphragm is
stuck in the bore of the body, grasp the
center nut and rotate and lift at the same
time to work gently out of the body.
jCAUTION
Do not attempt to remove needle or spring
from inside plunger valve. Removal of
these items from the valve will disturb the
calibration of the valve.
d. Using clean gasoline, flush out the chamber
below the screen,
e. Flush above the screen and inside the center
bore making sure that outlet passages are open.
Use only a gentle stream of compressed air to remove dust and dirt and to dry.
CAUTIONThe filter screen is a tight fit in the body
and may be damaged if removal is attempted.
It should be removed only if a new screen is
to be installed.
f. Clean diaphragm and valve and top cover in the
same manner. Be sure the vent hole in the top cover
is open and clean.
g. Carefully replace diaphragm and valve. Check
that valve works freely in body bore.
h. Position diaphragm so that horizontal hole in
plunger valve is 90 degrees from the fuel inlet port
in the valve body.
i. Place upper spring in position on diaphragm.
j. Place cover in position so that vent hole in
cover is 90 degrees from inlet port in valve body.
Install cover attaching screws and tighten to 20±1
lb-in. Install safety wire on cover screws.
k. Install fuel manifold valve assembly on engine
and reconnect all lines and hoses to valve.
1. Inspect installation and install cowling.
11-60.
FUEL DISCHARGE NOZZLES.
11-61. DESCRIPTION. From the fuel manifold valve,
individual, identical size and length fuel lines carry
metered fuel to the fuel discharge nozzles located in
the cylinder heads. The outlet of each nozzle is directed into the intake port of each cylinder. An air
bleed, incorporated into each nozzle, aids in vaporizing the fuel by breaking the high vacuum in the intake manifold at idle RPM and keeps the fuel lines
filled. The nozzles are calibrated in several ranges
All nozzles furnished for one engine are the same
range and are identified by a number and a suffix
letter stamped on the flat portion of the nozzle body.
When replacing a fuel discharge nozzle be sure that
it is of the same calibrated range as the rest of the
nozzles in the engine. When a complete set of nozzles
is being replaced, the number must be the same as
the one removed, but the suffix letters may be different, as long as they are the same for all nozzles
being installed on a particular engine.
11-62.
REMOVAL.
NOTE
Plug or cap all disconnected lines and fittings.
a. Disconnect the fuel injection lines at the fuel
discharge nozzles. Remove the nozzles with a 1/2inch deep socket.
11-63. CLEANING AND INSPECTION. To clean
nozzles, immerse in clean solvent and use compressed
air to dry them. When cleaning the nozzle with compressed air, direct air through the nozzle in the direction opposite of normal fuel flow. Do not remove the
nozzle shield or distort it in any way. Do not use a
wire or other metal object to clean the orifice or
metering jet. After cleaning, check the shield height
from the hex portion of the nozzle. The bottom of the
shield should be approximately 1/16 inch above the
hex portion of the nozzle.
11-64. INSTALLATION.
a. Install the fuel discharge nozzles in the cylinders
using a 1/2-inch deep socket, and tighten nozzle to a
torque value of 60 to 80 lb-in.
b. Connect the fuel injection lines at the fuel discharge nozzles.
c. Check installation for crimped lines, loose fittings, etc,
11-25
MODEL R172 SERIES SERVICE MANUAL
11-65.
FUEL INJECTION PUMP.
11-66. DESCRIPTION. The fuel pump is a positivedisplacement, rotating vane type, located just forward
of number five cylinder at the propeller end of the engine. Fuel enters the pump at the swirl well of the
pump vapor separator. Here, vapor is separated by
a swirling motion so that only liquid fuel is fed to the
pump. The vapor is drawn from the top center of the
swirl well by small pressure jet of fuel and is fed into
the vapor return line, where it is returned to the aircraft fuel tank or bay. Since the pump is enginedriven, changes in engine speed affect total pump
flow proportionally. The pump supplies more fuel
than is required by the engine: therefore, a springloaded, diaphragm type relief valve is provided, with
an adjustable orifice installed in the fuel passage to
this relief valve to maintain the desired pressure at
the full throttle position. The fuel pump is equipped
with a manual mixture control to provide positive
mixture control throughout the range required by the
injection system. This control limits output of the
pump from full rich to idle cutoff. Non-adjustable
mechanical stops are located at these positions. A
check valve allows the auxiliary fuel pump pressure
to bypass the engine-driven fuel pump for starting,
or in the event of an engine-driven fuel pump failure.
11-67. REMOVAL AND INSTALLATION.
a. Place fuel shut-off valve in OFF position and remove cowling, baffles, and covers as necessary for
access.
b. Disconnect mixture control from lever on pump.
c. Tag and disconnect fuel hoses attached to pump.
d. Remove mounting nuts, and pull pump and gasket
from mounting pad.
e. The drive shaft coupling may come off with the
fuel pump, or if may remain in the engine. If it
comes off with the pump, reinstall it in the engine to
prevent dropping or losing it.
f. If a pump is not to be installed for some time,
install a cover on the engine pad.
g. Using a new gasket, reverse this procedure to
install the fuel pump. Do not force engagement of
drive. Rotate engine crankshaft and drive will engage smoothly when aligned properly. Check mixture control rigging.
11-68.
ADJUSTMENT.
NOTE
On fuel pumps requiring full throttle fuel
pressure calibration and the adjustable
orifice is sealed, Continental Aircraft
Engine Service Bulletin No. M70-10 must
be complied with before calibration can be
performed.
a.
b.
fuel
nect
tem
Remove engine cowling as required for access.
Disconnect engine-driven fuel pump hose at the
metering unit. Using test hose and fittings, contest gage pressure port into fuel injection sysin accordance with figure 11-9.
11-26
NOTE
Cessna Service Kit No. SK320-2J provides
a special indicator, lines, and instructions
for connecting the indicator into the system
to perform accurate calibration of the engine-driven fuel pump.
c. Allow engine to warm-up. Set mixture control
full rich and propeller control full forward (low pitch
high RPM).
d. Idle engine at 600 RPM and check fuel pressure
on special indicator per paragraph 11-12.
WARNING
DO NOT make fuel pump pressure adjustments while engine is operating.
e. If pressure is not within prescribed tolerances,
stop engine and adjust pressure by turning the screw
on the fuel pump relief valve (turn IN to increase
pressure and OUT to decrease pressure) to attain
correct pressure and repeat steps "c" and "d".
NOTE
After adjusting fuel pressure, idle speed
and idle mixture must be readjusted (refer
to paragraph 11-55).
f. Advance throttle to obtain maximum RPM and
check fuel pressure on special indicator per paragraph 11-12.
WARNING
DO NOT make fuel pump pressure adjustments while engine is operating.
g. If pressure is not within prescribed tolerances,
(paragraph 11-12) on the adjustable orifice pump; stop
engine and adjust pressure by loosening locknut and
turning the slotheaded needle valve located just below
the fuel pump inlet fitting (turn clockwise to increase
pressure and counterclockwise to decrease pressure)
to attain the correct pressure and repeat steps "c and d".
h. After correctpressure isobtained, safetyadjustable orifice locknut and remove test equipment.
i. Install cowling.
NOTE
When a problem exists with respect to nonrepeatability or drifting of fuel pressures,
fuel flows, or idle mixtures, refer to Continental Aircraft Engine Service Bulletin
#76-11 and all revisions thereto.
11-69. AUXILIARY ELECTRI FUEL PUMP FLOW
RATE ADJUSTMENT
(Refer to Section 12
11-70.
INDUCTION AIR SYSTEM.
11-71.
DESCRIPTION.
Induction air enters the
MODEL R172 SERIES SERVICE MANUAL
cylindrical air filter and flows through the airbox,
through the air throttle body, into the intake manifolds. The complete air induction system, including
the intake manifolds, is located on the top side of the
engine. The alternate air source is automatic. If
the air filter should become clogged, suction from
the engine intake will open a spring-loaded door.
This permits the induction air to be drawn from within the engine compartment.
11-72. REMOVAL AND INSTALLATION.
a. Remove and install the air filter as follows:
Cut safety wire and loosen wing nut at outer
1.
end of filter.
2.
Remove element for cleaning or replacement.
Refer to Section 2 for servicing.
3. Do not over-tighten wing nut when installing
but be sure to resafety.
b. Remove and install the induction airbox as
follows:
1. Disconnect alternate air duct.
2.
Disconnect lever return spring.
3. Remove four bolts and nuts securing airbox
to air throttle body, and remove airbox. Lay parts
of the throttle-operated microswitch to one side.
N.,te any other parts secured by these bolts.
4. Reverse this procedure to install airbox,
using new gasket. Check rigging of throttle-operated
microswitch.
NOTE
The air throttle body is a part of the fuel-air
control unit, which is included in the fuel injection system discussed later.
c. Removal of various intake manifold sections is
accomplished by loosening hose clamps, sliding hoses
back, and removing nuts attaching.those segments
which are secured to engine cylinders. Disconnect
any lines or hoses interfering with removal. Reverse
this procedure to install the intake manifold.
11-73.
IGNITION SYSTEM.
11-74. DESCRIPTION. The ignition system is cornprised of two 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.
FUEL METERING
UNIT-
ENGINE-DRIVEN
FUEL PUMP
EXISTING FUEL PUMP
OUTLET HOSE
1I/
AN816-4D
--
PRESSURE
S1168-2-93
HOSE
TEE
AN816-2D
NIPPLE
-
S1499-4JJ-8.50
TEST HOSE
NOTE
AN816-2D
NIPPLE
WHEN ADJUSTING THE UNMETERED FUEL PRESSURE, THE TEST
EQUIPMENT MAY BE "TEED" INTO THE ENGINE-DRIVEN FUEL
PUMP OUTLET PRESSURE HOSE AT THE FUEL PUMP OR AT
THE FUEL METERING UNIT.
Figure 11-9.
Test Harness Fuel Injection Pump Adjustment
11-27
MODEL R172 SERIES SERVICE MANUAL
11-75.
TROUBLE SHOOTING.
TROUBLE
ENGINE FAILS TO START.
ENGINE WILL NOT IDLE
OR RUN PROPERLY.
11-28
PROBABLE CAUSE
REMEDY
Defective ignition switch.
Check switch continuity.
if defective.
Spark plugs defective, improperly
gapped or fouled by moisture or
deposits.
Clean, regap and test plugs.
Replace if defective.
Defective ignition harness.
If no defects are found by a
visual inspection, check
with a harness tester. Replace defective parts.
Magneto "P" lead grounded.
Check continuity. "P" lead
should not be grounded in the
ON position, but should be
grounded in OFF position.
Repair or replace "P" lead.
Failure of impulse couplings.
Impulse coupling pawls should
engage at cranking speeds.
Listen for loud clicks as impulse couplings operate. Remove magnetos and determine
cause. Replace defective parts.
Defective magneto.
Refer to paragraph 11-81 or 11-88.
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.
Spark plugs defective, improperly gapped or fouled
by moisture or deposits.
Clean, regap and test plugs.
Replace if defective.
Defective ignition harness.
If no defects are found by a
visual inspection, check with
a harness tester. Replace
defective parts.
Defective magneto.
Refer to paragraph 11-81 or 11-88.
Impulse coupling pawls
remain engaged.
Pawls should never engage
above 450 RPM. Listen for
loud clicks as impulse
coupling operates. Remove
magneto and determine cause.
Replace defective parts.
Spark plugs loose.
Check and install properly.
Replace
MODEL R172 SERIES SERVICE MANUAL
11-76.
MAGNETO'S
(THRU R1723199 & FR1720655)
11-77. DESCRIPTION. Two Bendix Scintilla, S6LN-25
magnitos, equiped with impulse couplings are used on
this engine. The magnitos contain a conventional
two-pole rotating magnet (rotor) mounted in ball
bearings. Engine-driven at one end, the rotor shaft
operates breaker contact points at the other end. A
gear on the rotor shaft drives a distributor gear
which transfers high-tension current from the coil
to the proper outlet in the distributor block. A
breaker compartment is located at the opposite end
of the drive end, and a capacitor is provided in this
breaker compartment, next to the breaker contact
points.
points.
11-78. REMOVAL. Access to the breaker compartment is gained by removing the breaker compartment
cover at the back end of the magneto. To remove the
magneto from the engine, proceed as follows:
a. Remove cowling as necessary for access.
b. Remove high-tension outlet plate, and disconnect magneto "P" lead.
c. Disconnect any noise filters used with radio installations.
d. Note the approximate angular position at which
the magneto is installed, then remove magneto
mounting clamps,
NOTE
Never remove the screws fastening the two
halves of the magneto together. Separating
the halves would disengage distributor gears,
causing loss of internal timing and necessitating complete removal and internal retiming.
d. Attach timing template to breaker compartment
as shown in figure 11-11. using 8-32 screws 1/4
inch long.
e. Turn rotating magnet in its direction of rotation
until the painted chamfered tooth on distributor gear
is approximately in the center of inspection window,
then turn rotating magnet back until it locates in its
magnetic neutral position.
NOTE
Impulse coupling pawls must be depressed to
un oaing mae
in
normal direction
o rotation.
of rotation.
f. Remove cam screw, lockwasher, and washer,
and use cam screw to install timing pointer so it
indexes with 0 ° mark on template, while rotating
magnet is still in its magnetic neutral position.
g. Turn rotating magnet in proper direction of rotation until pointer indexes with 10 ° mark ("E" gap).
Using a 11-9110 timing light or equivalent, adjust
breaker contacts to open at this point.
h. Turn rotating magnet until cam follower is on
high part of cam lobe, and measure clearance between breaker contacts. Clearance must be .018±
.006 inch. If clearance is not within these limits,
readjust breaker contacts until they are within tolerance, then recheck the 10 ° ("E" gap) position.
Tolerance on the "E" gap position is ± 4 ° . Replace
breaker assembly if "E" gap and contact clearance
will not both fall within the specified tolerances.
i. Remove timing pointer and timing template, and
install cam screw, lockwasher, and washer.
j. Install magneto and time to engine in accordance
with paragraph 11-80.
11-80.
11-79. INTERNAL TIMING. (Bendix Scintilla Mag.
netos. ) The following information gives instructions
for adjusting breaker contacts to open at the proper
position. It is assumed that the magneto has not been
disassembled, and that the distributor gear, rotor
gear and cam have been assembled for correct meshing of gears and direction of rotation. Magneto overhaul, including separating the two major sections of
the magneto, is not covered in this manual. Refer to
applicable Bendix publications for disassembly and
overhaul.
a. Fabricate a timing template as follows:
1. Cut a paper template from figure 11-12.
2.
Cement paper template to a thin piece of
metal for use as a support plate, then trim the plate
to the shape of the paper template.
3.
Drill the two mounting holes with a No. 18
dril.
b. Fabricate a timing pointer as shown in figure
11-10.
c. Remove magneto from engine per paragraph
11-78, remove breaker compartment cover, and
remove timing inspection plug from top of magneto.
INSTALLATION AND TIMING TO ENGINE.
a. Turn propeller in normal direction of rotation
until No. 1 cylinder is 20 ° BTC on compression
stroke, the correct firing position.
NOTE
A plugged hole, through which timing marks
on a crankshaft counterweight hanger are
visible, is provided to facilitate timing.
T
This hole is located under a brass, hex-head
plug on the upper left side of the engine,
above No. 2 cylinder. Marks are scribed
from 24° BTC to 16 BTC, plus a mark for
top center (TC). Reference for the marks is
the centerlneofthe hole. Determine compression stroke by placing thumb over spark
plug hole.
b. Turn magneto backwards (so impulse coupling
pawls will not engage) until painted chamfered tooth
is approximately in center of timing window. Be
11-29
MODEL R172 SERIES SERVICE MANUAL
CAUTION
sure magneto gasket is in place, then install magneto approximately at the angle noted during removal.
Tighten mounting clamps enough to hold magneto in
place, but loose enough to permit magneto to be
rotated in its clamps.
c. Using a timing light connected across the breaker contacts, rotate magneto case in normal direction
of cam rotation until contacts have just closed, then
rotate in the opposite direction until timing light indicates position at which contacts break. Secure
magneto.
d. Turn propeller back a few degrees (approximately 5° ) to close contacts.
Do not adjust contacts to compensate for incorrect magneto-to-engine timing. Breaker
contact adjustment is for internal timing only,
and any readjustment after internal timing
has been accomplished will result in a weaker
spark, with reduced engine performance.
f. After tightening magneto mounting clamps and
rechecking magneto-to-engine timing, remove timing equipment. Install and connect any spark plugs
that were removed.
g. Install timing inspection plug, breaker compartment cover, any noise filters that were removed, and
magneto "P" lead.
h. Install high-tension outlet plate.
NOTE
The No. 1 magneto outlet is identified with
the number "1."
The magneto fires at each
successive outlet in direction of rotation.
No. 1 magneto outlet routes to No. 1 cylinder, No. 2 magneto outlet to the next cylinder to fire, etc. Cylinder firing order is
CAN
11-10.
Timing Pointer
. Reinstall cowling removed for access.
11-81. MAINTENANCE. (Bendix Scintilla Magnetos.)
At the first 25-hour inspection and at each 100-hour
inspection thereafter, the breaker compartment should
be inspected. Magneto-to-engine timing should be
checked at each 100-hour inspection. If timing is 20 °
(plus zero, minus 2°), internal timing need not be
checked. If timing is out of tolerance, remove magneto and set internal timing, then reinstall and time
the engine.
-<.
,
NOTE
Figure 11-11.
If ignition trouble should develop, spark plugs
and ignition wiring should be checked first.
If the trouble appears definitely to be associated with a magneto, the following may be
used to help disclose the source of trouble
without overhauling the magneto.
Template and Pointer Attached
NOTE
Do not turn propeller back far enough to engage impulse coupling, or propeller will have
to be turned in normal direction of rotation
until impulse coupling releases, then again
backed up to a few degrees before the firing
position.
e. Slowly advance propeller (tap forward with minute movements as firing position is approached) in
normal direction of rotation until timing light indicates position at which contacts break. The contacts
should break at the advance firing position of No. 1
cylinder listed in step "a." Rotate magneto case to
make contacts break at correct position.
11-30
a.
Moisture Check.
1. Remove the high-tension outlet plate, cables,
and grommet, and inspect for moisture.
2.
Inspect distributor block high-tension outlet
side for moisture.
3.
If any moisture is evident, lightly wipe with
a soft, dry, clean, lint-free cloth.
CAT
Do not use gasoline or other solvents, as
these will remove the wax coating on some
parts and could cause electrical leakage.
b.
Breaker Compartment Check.
1. Remove breaker cover.
2. Check all parts of the breaker assembly for
security.
MODEL R172 SERIES SERVICE MANUAL
CAUTION
TO REPRODUCE THIS TEMPLATE FROM AEROFICHE TO CORRECT SCALE ON
PAPER, READER/PRINTER LENS MUST BE 42X MAGNIFICATION.
Figure 11-12.
Templates For Timing Bendix Magnetos
11-31
11-31
MODEL R172 SERIES SERVICE MANUAL
3. Check breaker contacts for excessive wear,
burning, deep pits, and carbon deposits. Contacts
may be cleaned with a hard-finish paper. Replace
defective breaker assemblies. Make no attempt to
stone or dress contacts. Clean new contacts with
clear, unleaded gasoline and hard-finish paper before
installing.
4. Check cam follower oiling felt. If it appears
dry, re-oil with 2 or 3 drops of lubricant (Scintilla
10 86527, or equivalent). Allow about 30 minutes
for the felt to absorb the oil, then blot off excess
with a clean cloth. Too much oil may result in foulicr and excessive burning of contacts.
5. Check that the condenser mounting bracket
is not cracked or loose. If equipment is available,
check condenser for a minimum capacitance of .30
microfarads. If equipment for testing is not avail.able and a defective condenser is suspected, replace
with a new one.
c. If the trouble has not been corrected after accomplishing steps "a" and "b, " check magneto-toengine timing. If timing is not within prescribed
tolerance, remove magneto and set internal timing,
tien reinstall and time to the engine.
d. If the trouble has still not been corrected, magIreto overhaul or replacement is indicated.
11-82 MAGNETO CHECK. Advanced timing setfings in some cases, is the result of the erroneous-.
practice of bumping magnetos up in timing in order
tn reduce RPM drop on single ignition. NEVER ADVANCE TIMING BEYOND SPECIFICATIONS IN ORDER TO REDUCE RPM DROP. Too much importance
is being attached to RPM drop on single ignition.
RPM drop on single ignition is a natural character,stic of dual ignition design. The purpose of the following magneto check is to determine that all cylinders are firing. If all cylinders are not firing, the
engine will run extremely rough and cause for investigation will be quite apparent. The amount of RPM
drop is not necessarily significant and will be influcniced by ambient air temperature, humidity, airport
;ltitude, etc. In fact, absence of RPM drop should
hb cause for suspicion that the magneto timing has
b'oen bumped up and is set in advance of the setting
specified. Magneto checks should be performed on a
c'onparative basis between individual right and left
m.ligneto performance.
i. Start and run engine until the oil and cylinder
head temperature is in the normal operating range.
b. Place the propeller control in the full low pitch
(high RPM) position.
c. Advance engine speed to 1800 RPM.
d. 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.
e. Turn the switch to the "L" position and note the
RPM drop, then return the switch to the "BOTH"
position.
f. The RPM drop should not exceed 150 RPM on
either magneto or show greater than 50 RPM differential between magnetos. 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
11-32
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 disconnected ground lead at magneto or possibly the magneto timing is set too
far in advance.
11-83. MAGNETO'S
& FR1720656)
(BEGINNING WITH R1723200
11-84. DESCRIPTION. Two Slick 6214 Magnitos,
equiped with impulse couplings are used on this engine.
The magnitos incorporate an integral feed-thru
capacitor and require no external noise filter in the
ground lead. The direction of rotation of the magnito
shafts, viewed from the anti-propeller end of engine, is
clockwise. Refer to Slick 4200/6200 Series Aircraft
Magnetos Maintenance and Overhaul Instructions
Bulletin. and all revisions and supplements thereto,
for a detailed description, disassembly and reassembly of the magneto.
MVAL.
WARNING
The mgneto isin
a SWITCH ON condition
whe the swtch wre s disconnected.
Therefore, ground the breaker contact
poits 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.
11-86. INTERNAL TIMING. (MAGNETO REMOVED
FROM ENGINE.) Refer to Slick 4200/6200 Series
Aircraft Magnetos Maintenance and Overhaul Instructions Bulletin, and all revisions and supplements
thereto, for internal timing instructions.
MODEL R172 SERIES SERVICE MANUAL
11-87. INSTALLATION AND TIMING TO ENGINE.
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:
a. Reverse the removal steps for reinstallation.
Magneto (primary lead nut torque range is
13-15 inch-pounds. Exceeding this torque
range could result in possible condenser
11-90. SPARK PLUGS. Two 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 service 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.
damage.
NOTE
WARNING
Be
and
insure
"OFF"
switch
position
is
"P"
lead is grounded. lead
is
grounded.
b. Turn the engine crankshaft in the normal direction of rotation until the No. 1 cylinder is in the fulladvance firing position, following the engine manufacturer's procedure for timing of magnetos.
c. 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 magneto 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 propeler is moved. TURN SWITCH "OFF".
11-88. DISASSEMBLY, INSPECTION, AND REASSEMBLY. Refer to Slick 4200/6200 Series Aircraft
Magnitos Maintenance and Overhaul Instructions.
11-89.
11-82.
MAGNETO CHECK.
Refer to Section 2 for inspection interval.
the ch inspection, remove, clean, inspect
and regap all plugs, Install lower spark
plugs in upper portion of cylinders and install upper spark plugs in lower portion of
stall upper spark plugs in lower portion of
cylinders. Since dey meoration of lower
of the upper spark plugs, rotating helps
ofthe
spark plugng
helps
prolong spark plug fe
11-91.
ENGINE CONTROLS.
11-92. DESCRIPTION. The throttle, mixture and
propeller controls are of the push-pull type. The
propeller and mixture controls are 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 propeller and mixture controls also have a vernier adjustment. Turning the
control knob in either direction will change 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. An additional "Palnut" type lockout is installed in back of the
locknut at the engine end of the throttle, mixture and
Refer to paragraph
SHOP NOTES:
Revision 1
11-33
MODEL R172 SERIES SERVICE MANUAL
propeller controls. Beginning with Serials R1722930
& on and FR17200631 & on, the throttle, mixture, and
propeller control cable ends that utilize a ball bearing
-type rod end, are secured to the engine with a predrilled AN bolt, washers, castellated nut, and a cotter
pin. (See figure 11-13.)
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.
I
11-94.
THROTTLE CONTROL.
(See figure 11-14.)
NOTE
Before rigging throttle control, check that
clamping sleeve (13) is secure. If any
indication of looseness or breakage is
apparent, replace throttle control.
a. Screw friction lock nut (2) into threads of barrel
(7).
b. Ensure washer (5) is installed, and nut (8) on
forward side of panel is secured against washer.
c. Disconnect the throttle control at the engine.
d. Push knob assembly (1) full in against friction
lock nut (2), then pull knob assembly out approximately 1/8-inch to obtain "cushion."
e. Tighten friction lock nut (2) against barrel (7),
being careful not to change the position of the throttle.
f. Move the throttle arm on the fuel-air control
unit to full open.
NOTE
Ensure palnut (17) and locknut (4) are on
threads of plunger (18) before installing
rod end (16).
g. Adjust end of control to fit, and connect to
throttle arm on fuel-air control unit.
1.
2.
3.
4.
5.
6.
7.
8.
Bolt
8
Washer
Nut
LockNut
Washer
Cotter Pin
Castellated Nut
Rod End Bearing
Figure 11-13. Control Cable End (Typical).
11-93. RIGGING. When adjusting any engine control,
it is important to check that the control slides smoothly throughout its full travel, that it locks securely and
the arm or lever which it operates moves through its
full arc of traveL Throttle and mixture control arms
at their corresponding engine components may be repositioned on ther shafts if necessary. Make sure the
countersunk side of the arm faces the serrated portion
of its shaft. If throttle arm is repositioned, check
rigging of throttle-operated cam and microswitch.
CAUTION
Whenever a fuel pump arm or fuel-air control unit arm is removed or installed,
always use a wrench at the wrench pads on
the arm when removing or installing attaching nut. This will prevent twisting the shaft
or other damage which might be caused.
.11-34
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.
h. Check clamping sleeve (13) in bracket (12) and
clamp (15).
i. Loosen friction lock nut (2).
j. Pull knob assembly full out and check that idle
stop on carburetor is contacted.
k. Push knob assembly full i and check that full
power stop on carburetor is contacted.
L Check that throttle has maintained the approximate 1/8-inch "cushion" set in step "c".
m. 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.
11-95.
MIXTURE CONTROL.
NOTE
When checking mixture control rigging see
that the arm on the fuel injection pump
contacts the mechanical stops in both directions, that the mixture control has approximately 1/8 inch cushion at the instrument
MODEL R172 SERIES SERVICE MANUAL
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Knob Assembly
Friction Lock Nut
Locking Collet
Instrument Panel
Washer
Nut
Barrel
Core
Casing
Clamping Sleeve
Firewall
Bracket
Clamping Sleeve
Packing
Clamp
Rod End
Palnut
Plunger
Plunger Seal
Plunger Guide
12
9
13
10
14
8
15
7
4
3
2
1
16
17
.--
18
19
20
Figure 11-14.
panel, and that the small retaining ring contacts the end of the control housing at the
same time that the idle cut-off stop is reached.
a. Disconnect mixture control rod end from arm
on fuel injection pump.
CAUTION
The mixture control has a small retaining ring
brazed (or attached with epoxy resin) near the
threaded end (engine end of control) of the control. The purpose of this retaining ring is to
prevent inadvertent withdrawal and possible
damage to the knob end of the control while
jam nuts and rod end are removed.
b. Pull mixture control full out until retaining ring
contacts control housing.
c. Move mixture control arm to idle cut-off. With
arm against stop, adjust rod end to align with arm,
and connect in this position.
d. Push mixture control full forward and check that
when the full rich stop is reached, there is approximately 1/8 inch cushion at the instrument panel.
Throttle Control.
After rigging is completed, be sure that the idle cutoff stop is reached at the same time that the retaining
ring contacts the mixture control housing and that the
full rich stop is reached with the proper amount of
cushion. Tighten jam nuts to secure the rod end.
Be sure the threaded end of the rod extends into the
rod end far enough. An inspection hole is provided
in the rod end for checking purposes.
NOTE
Refer to the inspection chart in Section 2
for inspection and/or replacement interval for the mixture control.
11-96. PROPELLER GOVERNOR CONTROL.
to Section 13.)
(Refer
11-97.
RIGGING THROTTLE-OPERATED MICROSWITCH. (Refer to Section 12.)
11-98.
EXHAUST SYSTEM.
11-35
MODEL R172 SERIES SERVICE MANUAL
11-109. DESCRIPTION. The exhaust system controls of two exhaust stack assemblies. one for the
and the
the for
right bank of cylinders. Each
heater
has
a riser pipe attached to the exhaust port.
risers at each bank of cylinders are joined
three
other into a collector pipe forming an exhaust
stack assembly. Each exhaust stack assembly contacts tothe mufler assembly beneath the engine.
The muffler assembly is enclosed in a shroud which
captures exhaust heat that is used to heat the airplane cabin. The tailpipe is welded to the muffler.
11-100.
ECONOMY MIXTURE INDICATOR (EGT).
tion must be replaced with new parts.
REMOVAL.
2.
Is installed. remove exhaust gas temperature
or disconnect leads. (See figure 11-15.)
disconnect ducts from heater shroud on muffler
assembly.
d. Revome
nuts, bolts, and clamps attaching stack
reassemblies to the muffler.
e. Loosen nuts attaching exhaust stacks to the cylinders and remove muffler assembly.
f. Remove nuts attaching exhaust stack assemblies
the
Where a surface is not accessible for visual
inspection or for a positive test, proceed as follows:
1. Remove exhaust pipes and muffler.
Remove engine cowling for access.
in
The 100 hour
inspection is as follows:
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.
(Refere to Section 15. )
11-101
Any time exhaust fumes are detected in the cabin.
an immediate inspection must be performed. All
components that show cracks and general deteriora-
cylinders and remove exhaust stacks and
components with compressed air.
e.
gaskets.
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
Install the exhaust system and engine cowling.
11-103.
INSTALLATION.
NOTE
..
a. Place all sections of the assembly in position
and join together loosely with attaching clamps.
b. Tighten nuts securing risers to cylinders first;
then tighten all clamps joining sections together.
c. Torque exhaust stack nuts at cylinders to 100110 pound-inches.
d. Install engine cowling.
e. Check for adequate clearance where tailpipe
emerges through the cowling.
,
1.
2.
3.
4.
5.
6.
Tailpipe
Clamp
Shroud
Stack Assembly
Muffler
(EGT) Probe
11-104.
Figure 11-15.
11-102.
Exhaust System.
INSPECTION.
NOTE
Refer to the inspection chart in Section 2
for exhaust system inspection interval.
The exhaust system must be thoroughly inspected.
especially the heat exchange section of the muffler.
11-36
Use new gaskets between riser and mounting
on cylinder, regardless of apparent condition of those removed. Install the exhaust
flange gasket with raised bead toward exhaust
port on engine.
STARTING SYSTEM.
11-105. DESCRIPTION. An electric starter motor,
mounted on a 90 degree starter adapter, is provided
as an integral part of the engine. A starter solenoid
is activated by the ignition switch on the instrument
panel. When the starter solenoid is actuated, its contacts close and electrical current energizes the
starter motor. Initial rotation of the starter motor
engages the starter through an overrunning clutch in
the starter adapter, which incorporates worm reduction gears. The starter motor is located just aft of
the right rear cylinder.
MODEL R172 SERIES SERVICE MANUAL
11-106.
TROUBLE SHOOTING.
TROUBLE
STARTER WILL NOT OPERATE.
STARTER MOTOR RUNS, BUT
DOES NOT TURN CRANKSHAFT.
STARTER MOTOR DRAGS.
STARTER EXCESSIVELY
NOISY.
PROBABLE CAUSE
REMEDY
Defective master switch or
circuit.
Check continuity.
switch or wires.
Install new
Defective starter switch or
switch circuit.
Check continuity.
switch or wires.
Install new
Defective starter motor.
Check voltage to starter. Repair
or replace starter motor.
Defective overrunning clutch
or drive.
Remove starter and inspect.
Install new starter adapter.
Starter motor shaft broken.
Install new starter motor.
Low battery.
Charge or install new battery.
Starter switch or relay contacts
burned or dirty.
Check continuity.
serviceable unit.
Defective starter motor
power cable.
Check visually.
new cable.
Loose or dirty connections.
Check visually. Remove, clean
and tighten all terminal connections.
Defective starter motor.
Check starter motor brushes,
brush spring tension, thrown
solder on brush cover. Repair
or install new starter motor.
Dirty or worn commutator.
Check visually. Clean and
turn commutator.
Worn starter pinion.
Remove starter and inspect.
Replace starter drive.
Worn or broken teeth
on crankshaft gears.
Check visually. Replace
crankshaft gear.
11-107. PRIMARY MAINTENANCE. The starter circult should be inspected at regular intervals, the
frequency of which should be determined by the
amount of 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
Install
Install
uneven wear, excessive glazing or evidence of exccssive 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 or No. 000 sandpaper around the commutator (with sanding side out) 1-1/4 to 1-1/2 timne
maximum. Drop brushes on sandpaper covered c(tr:!inutator and turn slowly in direction of normal rotation. Clean sanding dust from motor after seating
brushes.
11-37
MODEL R172 SERIES SERVICE MANUAL
11-108.
STARTER MOTOR
11-109.
REMOVAL AND INSTALLATION.
CAUTION
When disconnecting on connecting the starter
cable do not permit starter terminal bolt to
rotate. Rotation of the terminal bolt could
break the conductor between terminal bolt
and field coils causing the starter to be inoperative.
a. Disconnect electrical cable from starter motor.
Insulate cable terminal as a safety precaution.
b. Remove two sets of nuts and washers securing
motor to the starter adapter and pull motor from
mounting pad.
c. To install the starter motor, reverse the preceding steps. Install a new O-ring on the starter,
then install to starter motor, be sure that starter
motor drive engages drive in the starter adapter.
11-110.
EXTREME WEATHER MAINTENANCE.
NOTE
Refer to the appropriate Pilot's Operating
Handbook for approved starting procedures.
11-111. COLD WEATHER. Cold weather starting
is made easier by the installation of the manuallyoperated 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
forward end of each engine intake manifold. This
primes the entire length of each intake manifold
for each bank of cylinders. 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 pre-heated. 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. After pre-heating
the oil, gasoline may be mixed with the oil in a ratio
of 1 part gasoline 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. After the engine
compartment has been preheated, inspect all engine
compartment drain and vent lines for presence of
ice. After this procedure has been followed, pull
the propeller through several revolutions by hand
before starting the engine.
11-38
WARNING
Do not heat the oil above 121 0 C (2500F). 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.
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 lubrication 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.
11-112. 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.
11-113. 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.
MODEL R172 SERIES SERVICE MANUAL
SECTION 12
FUEL SYSTEM
TABLE OF CONTENTS
FUEL SYSTEM ........
Description ........
Precautions .
.......
Trouble Shooting ......
Fuel Tanks ........
Description ......
Removal and Installation.
Fuel Quantity Transmitters .
Fuel Vents .........
Description ......
Checking .......
Fuel Reservoir Tank ....
Description ......
Removal and Installation.
Fuel Selector Valve. .....
Description ......
Removal and Installation.
Disassembly ......
Cleaning, Inspection
and Repair
.....
Reassembly ......
Fuel Shutoff Valve .....
Description ......
Removal and Installation.
Disassembly
......
Cleaning, Inspection
and Repair .....
Reassembly ......
Page No.
Aerofiche/Manual
1J16/12-1
1J16/12-1
1J16/12-1
1J18/12-3
1J22/12-7
1J22/12-7
1J22/12-7
1J22/12-7
1J23/12-8
1J23/12-8
1J23/12-8
1J23/12-8
1J23/12-8
1J23/12-8
J23/12-8
1J23/12-8
1J23/12-8
1J23/12-8
1J24/12-9
1J24/12-9
1J24/12-9
1J24/12-9
1J24/12-9
1J24/12-9
1J24/12-9
1J24/12-9
12-1. FUEL SYSTEM. The fuel system as covered
in this manual includes all components up to and including the line (inlet) to the engine driven fuel pump.
The fuel pump and the fuel injection system are not
covered, because they are considered engine accessories, therefore, are covered in the Engine Section.
12-2. DESCRIPTION. These aircraft are equipped
with either a standard fuel system, an optional longrange fuel system, or beginning with Serials R1722930
and FR1720631, an optional extended range "Wet
Wing" system. The standard and long range systems
are essentially the same, differing mainly in fuel
tank capacity. 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, through a three-position fuel
selector valve, fuel reservoir tank, fuel shutoff valve,
auxiliary fuel pump, fuel strainer, engine-driven fuel
pump and mixture unit, to a fuel/air control unit,
Auxiliary Fuel Pump ....
11K2/12-11
Description ....
.1K2/12-11
Removal and Installation. 1K2/12-11
Electric Circuit ....
1K3/12-12
Rigging Microswitch . . K4/12-13
Flow Rate Adjustment .
1K5/12-14
Maximum High Boost
Check. ....
...
1K6/12-15
Fuel Strainer.......
1K6/12-15
Description ..
...
1K6/12-15
Removal and Installation. 1K6/12-15
Disassembly and
Assembly......
1K6/12-15
Priming System ......
1K6/12-15
Description ......
1K6/12-15
Removal and Installation. 1K6/12-15
EXTENDED RANGE OPTION . . 1K9/12-18
Classification of Fuel Leaks . 1K9/12-18
Fuel Bay Purging. ......
1K9/12-18
Integral Fuel Bay Sealant ..
1K9/12-18
Mixing Sealant .....
1K9/12-18
Sealing Bays ......
1K10/12-19
Sealing Leaks .....
1K13/12-22
Curing Time ......
1K13/12-22
Testing..........
1K14/12-23
Fuel Quantity Transmitter. .1K14/12-23
VENTED FUEL FILLER CAP ..
1K14/12-23
Description ......
1K14/12-23
Inspection, Cleaning
and Repair
.....
1K14/12-23
which directs the flow to the engine fuel manifold and
fuel flow indicator. Depending upon selector valve
handle position, fuel is directed from either or both
tanks or bays to the engine through other components
of the system. Positive ventilation for all three
systems is provided by a vent line and check valve
assembly located in the left wing tank/bay, a crossover vent line connecting the two tanks/bays together,
and a vented cap on the right hand tank/bay. The vent
line from the check valve assembly extends overboard
thru the lower wing skin adjacent to the left wing strut.
The reservoir tank has a vapor return line from the
engine and a vent line connected to the tank crossover
line.
general precautions should be observed when performing maintenance on the fuel and associated
systems. Some of these are as follows:
a. Always GROUND aircraft to a suitable ground
stAke to prevent electrostatic build-up.
b. Eliminate accumulation of residual fuel spills
and drainage by using proper drip pans and good
housekeeping practices.
12-1
MODEL R172 SERIES SERVICE MANUAL
c.
Prevent damage to fittings and entry of forgin
connection
materials bV covrl ing, or cappinL all crpc;i o; disclonected lines. littinis. and corlnectrs.
NOTE
Throughout the aircraft fuel system from
the fuel tanks to the engine-driven fuel
pump, 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 lubricant or to seal a leaking
12-4.
Apply sparingly to male threads
only, omitting the first two threads, exercising extreme care 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.
Throughout the fuel injection system, from
the engine-driven fuel pump through the
discharge nozzles, use only a fuel-soluble
lubricant, such as engine oil, on fitting
threads. Do not use any other form of
thread compound on the injection system.
TROUBLE SHOOTING.
NOTE
Use this trouble shooting chart in conjunction with the engine
and fuel-injection trouble shooting charts in Section 11.
TROUBLE
NO FUEL FLOW TO ENGINEDRIVEN FUEL PUMP.
FUEL STARVATION AFTER
STARTING.
NO FUEL FLOW WHEN
ELECTRIC PUMP IS
OPERATED.
12-2
PROBABLE CAUSE
REMEDY
Fuel shut-off valve control
not pushed in.
Push shut-off valve in.
Fuel tanks or bays empty.
Service with proper grade and
amount of fuel.
Fuel line disconnected or broken.
Connect or repair fuel lines.
Fuel tank or bay outlet
screen plugged.
Remove and clean screen and
flush out fuel tank or bay.
Defective fuel shut-off valve or
selector valve.
Remove and repair or replace
valves.
Plugged fuel strainer.
Clean strainer and screen.
Defective electric fuel pump.
Repair or replace fuel pump.
Fuel line plugged.
Clean out or replace fuel line.
Partial fuel flow from the preceding causes.
Use the preceding remedies.
Malfunction of engine-driven
fuel pump or fuel injection
system.
Refer to Section 11.
Fuel vent plugged.
Refer to paragraph 12-11.
Water in fuel.
Drain fuel tank or bay sumps,
fuel lines and fuel strainer.
Defective fuel pump switch.
Replace defective switch.
Defective throttle switch.
Replace defective switch.
Open or defective circuit
breaker.
Reset.
Replace if defective.
MODEL R172 SERIES SERVICE MANUAL
12-4.
TROUBLE SHOOTING. (Cont.)
TROUBLE
NO FUEL FLOW WHEN
ELECTRIC PUMP IS
OPERATED. (CONT.)
PRESSURIZED FUEL TANKS
OR BAYS.
NO FUEL QUANTITY
INDICATION.
REMEDY
PROBABLE CAUSE
Loose connections or open
circuit.
Tighten connections; repair or
replace wiring.
Defective electric fuel pump
Replace defective pump.
Defective engine-driven fuel
pump by-pass or defective
fuel injection system.
Refer to Section 11.
Plugged bleed hole in vent valve.
Refer to paragraph 12-11.
Fuel tanks or bays empty.
Service with proper grade and
amount of fuel.
Circuit breaker open or defective.
Reset.
Loose connections or open circuit.
Tighten connections; repair or
replace wiring.
Defective fuel quantity indicator.
Replace if defective.
Refer to Section 15.
SHOP NOTES:
12-3
MODEL R172 SERIES SERVICE MANUAL
FUEL QUANTITY INDICATORS
FUEL QUANTITY
VENTED
TRANSMITTER
FILLER CAP
VENTED FILLER CAP
FILLER CAP
FILLER CAP
FUEL QUANTITY
TRANSMITTER
RIGHT FUEL TANK
DRAIN
SELECTOR
CONDITION:
SYSTEM SHOWN WITH
FUEL SELECTOR VALVE
IN BOTH POSITION
VALVE
DRAIN PLUG
FUEL RESERVOIR
TANK
FUEL
SHUTOFF
FUEL RESERVOIR
DRAIN VALVE
VALVE KNOB
AUXILIARY
FUEL PUMP
SWITCH
FUEL PUMP
FUEL
STRAINER
FUEL
STRAINER
CONTROL
VENT
ENGINE
ENGINE PRIMER
TO ENSURE MAXIMUM FUEL
CAPACITY WHEN REFUELING
AND MINIMIZE CROSS-FEEDING
WHEN PARKEDON A SLOPING
SURFACE, PLACE THE FUEL
SELECTOR VALVE IN EITHER
LEFT OR RIGHT POSITION.
ENGINE-DRIVEN
FUEL PUMP
AND
MIXTURE
CONTROL
MIXTURE UNIT
FUEL/AIR
CONTROL UNIT
THROTTLE
CONTROL
FUEL
MANIFOLD
CODE
,
FUEL SUPPLY
EXCESS FUEL AND
VAPOR RETURN
VENT
ENGINE
---
MECHANICAL
LINKAGE
ELECTRICAL
FUEL FLOW INDICATOR
(Right Half of Dual Instrument)
Figure 12-1.
12-4
Fuel System Schematic
CONNECTION
MODEL R172 SERIES SERVICE MANUAL
-.
-SEE
FIGURE 12-7.
,
Detail
B
1. Strainer Drain Line
2. Shut-Off Valve Control
3. Reservoir Tank.
4. Primer Line
5.
Vapor Return Line
6.
7.
8.
9.
Fuel Tank
Vent Crossover Line
Vent Line
Selector Valve
11.
Shut-Off Valve
-,,
SEE FIGURE 12-5
15
12. Drain Valve
13. Check Valve
14. Stop Block
15. Shaft
16. Bracket
17. Placard
18.
19.
20.
21.
22.
23.
Hacade
Screw
Washer
Cap
Tee
Primer
-,
BEGINNING WITH R1723400
R1722653 THRU R1723399
SEE FIGURE 12-5
Detail A
Figure 12-2. Fuel System Installation
12-5
MODEL R172 SERIES SERVICE MANUAL
TRANSMITTER
GROUNDING
NOTES
* Hinge for vent valve (22) must be at top.
* Remove shims (16) when required to
increase tension of leaf spring (17).
8 * Serials R1722000 thru R1722751
and FR17200591 thru FR17200630.
a Beginning with Serial R1 722752 and On.
and FR17200631 and On, the left hand cap
Detail A
Detail
2.
DetailD
B
'
* Airplanes R1722000 and On and FR1720591
and On incorporating SK172-116 have one
additional drain valve. Airplanes incorporating SK172-135 have four additional
drain valves.
Fuel Tank
5---
Washer
3. Drain Valve
4. Fuel Sampler Cup
Fuel Quantity Transmitter
6. Gasket
7. Top Wing Skin
Ground Strap
9. Pad
10. Strap
*
Plate
14. Gasket
15. Spacer
Shim
DetailC
17. Leaf Spring
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
12-6
Revision 1
MODEL R172 SERIES SERVICE MANUAL
1.
2.
3.
4.
5.
Wing
Vent
Strut
Fairing
Tie-Down Ring
Figure 12-4.
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. Airplanes R 1722000 and On and FR1720591
and On incorporating SK172-116 have an additional
quick drain valve installed in the lower, outboard corner
of the tank for draining trapped water and sediment. Airplanes R1722000 and On and FR1720591 and On incorporating SK172-135 have four additional quick drain
valves in each tank for draining trapped water and sediment.
12-7. REMOVAL AND INSTALLATION. (See figure
12-3.)
a. Remove sump drain valves 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
Fuel Vent Location
from tank. Remove fittings as necessary 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.
g. Reverse the preceding steps for installation. Ensure
transmitter is grounded in accordance 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 is contained in Section 15.
NOTE
Ensure transmitter is properly grounded
in accordance with figure 12-3.
Revision 1 12-7
MODEL R172 SERIES SERVICE MANUAL
12-9.
FUEL VENTS.
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 downward. A vent valve is installed on the inboard end of the vent line inside the
fuel tank, and a crossover vent line connects the two
tanks for positive ventilation. In addition, the right
hand fuel tank cap incorporates a small vent safety
valve to ensure positive fuel tank ventilation.
a. Completely drain all fuel from wing tanks, fuel
strainer, lines, reservoir tanks and selector valve.
b. Remove copilot's seat and carpeting as necessary to gain access to tank cover plate.
c. Remove access plate from floorboard.
d. Disconnect and cap or plug all fuel lines at tank.
e. Remove tank mounting bolt and screws and lift
out tank.
f. Reverse the preceding steps for installation.
Prior to reinstalling access plate, service fuel tanks
and check for leaks.
12-15.
12-11. CHECKING. Field experience has demonstrated that the fuel vent can become plugged, with
possible fuel flow interruption. Also, the bleed hole
in the vent valve assembly could possibly become
phlugged, allowing pressure from expanding fuel to
pressurize the tanks/bays. The following procedure
may be used to check the vent and bleed hQle in the
valve assembly.
a. Attach a rubber tube to the end of vent line beneath the wing.
b. Blow into tube to slightly pressurize tank. If
air 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
again to 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 flow interruption
or the pressurizing of the tanks/bays by fuel
expansion.
e. Any fuel vent found plugged or restricted must
be corrected prior to returning aircraft to service.
NOTE
The fuel vent line protruding beneath the wing
near the wing strut must be correctly aligned
toavoid possible icing of the vent tube. Dimensions are shown in figure 12-4.
12-12. FUEL RESERVOIR TANK.
12-13. DESCRIPTION. A reservoir tank is installed
in the lower fuselage area beneath the floor immediately forward of the copilot position. The tank has
four fuel line connections; a fuel supply line from the
selector valve, a supply line to the shut-off valve, a
vapor return line from the engine and a vent line teed
into the tank crossover vent line. A drain plug or
valve is installed in the bottom of the tank for draining trapped water and sediment from the fuel system.
12-14.
12-8
REMOVAL AND INSTALLATION.
(See figure
FUEL SELECTOR VALVE.
12-16. DESCRIPTION. A three position fuel selector
valve is located between the pilot and copilot positions
on the pedestal. The positions on the valve are labeled "LEFT, BOTH ON and RIGHT." Valve repair consists of replacement of seals, springs, balls and other
detail parts. Figure 12-5 illustrates the proper relationship of parts and may be used as a guide during
disassembly and assembly.
12-17. REMOVAL AND INSTALLATION. (See figure
12-2.)
a. Completely drain all fuel from wing tanks, fuel
strainer, lines, reservoir tank and selector valve.
(Observe precautions in paragraph 12-3.)
b. Remove fuel selector valve handle.
c. Remove pedestal cover.
d. Remove carpeting as necessary to gain access to
plates aft of pedestal and inboard of right front doorpost.
e. Disconnect handle drive shaft from valve.
f. Disconnect and cap or plug all fuel lines at valve.
g. Remove screws attaching valve to bracket and
remove valve.
h. Reverse the preceding steps for installation.
Prior to installing access plates, service fuel tanks
and check for leaks.
12-18. DISASSEMBLY. (See figure 12-5.)
a. Remove fuel selector valve in accordance
with paragraph 12-17.
b. Remove nipples (10) from the two fuel inlet
ports.
NOTE
Removal of inlet nipples will allow
spring (9). ball (4). O-ring (8). retainer (7) and ball (4) to pop free of
valve body. Use care to avoid loss
of these parts during disassembly.
c. Remove nipple (10) from fuel outlet port.
d. Remove roll pin (3) and lift housing (1)
from cam. Retain ball (4) and detent spring'
(18) for reinstallation.
e. Remove two screws holding stop (2) to cover.
Remove four screws attaching cover (15) to valve
body (6) and carefully remove cover.
f. Remove gasket (12) and withdraw cam (13)
with washer (14) and O-ring (8).
g. Remove bushing (5).
MODEL R172 SERIES SERVICE MANUAL
NOTE
Repair of damaged or worn parts of the selector valve 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.
b. Inspect all parts for obvious wear or damage as
follows:
1. Check detent holes in cover (15) for excessive wear.
2. Inspect shaft and bearing surfaces of cam
(13) for removal of black anodized surface indicating
wear.
3. Examine valve body (6) for wear, cracks,
distortion and internal corrosion. Any damage to
thread surfaces at inlet and outlet ports or cover
attach holes is cause for rejection.
O'
12-20. REASSEMBLY. (See figure 12-5.)
a. Ensure that all component parts are clean,
then coat sparingly with lightweight engine oil.
b. Insert bushing (5) into place in valve body.
c. Fit washer and a new O-ring in place on cam
(13) and insert cam into valve body.
d. Install new gasket (12) and cover (15).
e. Install ball (4), retainer (7), O-ring (8), ball
(4), spring (9), O-ring (8) and nipple (10) in each
inlet port.
f. Install nipple (10) and O-ring (8) in outlet port.
g. Lubricate detent spring (16) and ball (4) with
lubricant conforming to Military Specification
VV-P-236 (USP Petrolatum or equivalent).
h. Insert spring (16) in hole in housing (1).
i. Rotate cam as necessary so that ball (4) will
align with one of the detent holes on cover when in
position on cam.
j. With ball (4) on spring (16), slide housing (1)
onto cam and install roll pin.
k. Install stop (2) and check rotation of cam for
ease of operation and positive detent engagement.
1. Reinstall selector valve in accordance with
paragraph 12-17
12-21.
FUEL SHUTOFF VALVE.
12-22. DESCRIPTION. The fuel shutoff valve is a
two position ON-OFF valve mounted directly on the
reservoir tank using an adapter. The valve control
knob is located on the left lower instrument panel.
Valve repair consists of replacement of seals,
springs, balls and other detail parts. Figure 12-6
illustrates the proper relationship of parts and may
be used as a guide during disassembly and reassembly.
12-2.)
a. Completely drain all fuel from wing tanks, fuel
strainer, lines, reservoir tank and selector valve.
b. Remove copilot's seat and carpeting as necessary to gain access to reservoir tank access plate.
c. Remove access plate from floorboard.
d. Disconnect shutoff valve control.
e. Disconnect and cap or plug all fuel lines at valve.
f. Remove valve mounting bolts.
g. Reverse the preceding steps for installation.
Prior to reinstalling access plate, rig valve control,
service fuel tanks and check for leaks.
12-24. DISASSEMBLY. (See figure 12-6.)
a. Remove fuel shutoff valve in accordance with
paragraph 12-23.
b. Remove two screws securing cover (2) to valve
body (1) and carefully remove cover. Discard O-ring
(8) but retain ball (5) and detent spring (4) for reinstallation.
c. Slowly withdraw rotor (3) from valve body.
NOTE
Removal of rotor (3) will allow seal (9),
O-ring (10), washer (11) and spring (12)
to pop free.
12-25.
CLEANING, INSPECTION AND REPAIR.
NOTE
Repair of damaged or worn parts of the
fuel shutoff valve is NOT authorized, and
therefore is limited to the replacement of
component parts only.
a. Clean disassembled parts by washing in Stoddard
solvent or equivalent. Blow parts dry using clean
compressed air.
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 on rotor (3).
2. Inspect shaft and bearing surfaces of rotor
(3) for removal of black anodized finish indicating
wear. Check for internal corrosion of drilled passages.
3. Examine valve body (1) 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.
12-26.
REASSEMBLY.
(See figure 12-6.)
12-9
MODEL R172 SERIES SERVICE MANUAL
NOTE
Be sure to install stop (2). The selector valve
contains an OFF position that is not used. The
stop prevents the selector valve handle from
being turned to this unused position.
.
SELECTOR VALVE
1.
2.
3.
4.
5.
6.
Housing
Stop
Roll Pin
Ball
Bushing
Body
7.
8.
9.
10.
11.
12.
Figure 12-5.
NOTE
Reassembly of fuel shutoff valve is facilitated by mounting in a bench vise or equivalent bench support, making sure valve
body (1) is protected from damage. Fabrication of a spring compressor (13) is
recommended before reassembly.
a. Ensure all components are clean, then coat
sparingly with lightweight engine oil.
b. Insert new O-ring (8) into recess in valve
body (1).
c. Insert spring (12) into body (1).
d. With spring compressor in place as shown in
Section A-A on figure 12-6, compress spring (12)
and install washer (11), new O-ring (10) and seal (6)
into inlet port.
12-10
Retainer
0-Ring
Spring
Nipple
Plug
Gasket
13.
14.
15.
16.
Cam
Washer
Cover
Detent Spring
Fuel Selector Valve
e. Holding spring compressed, carefully insert
rotor (3) into valve body (1).
Release spring compressor and check for proper seating of seal to
rotor.
f. Lubricate detent spring (4) and ball (5) with
lubricant conforming to Military Specification VVP-236 (USP Petrolatum or equivalent), inserting
spring into hole in rotor.
g. Place ball (5) on spring and turn rotor as required to index one of the detent holes in cover (2).
h. Attach cover (2) and test rotation of rotor shaft
for ease of operation and positive detent engagement.
i. Reinstall shutoff valve in accordance with paragraph 12-23.
MODEL R172 SERIES SERVICE MANUAL
Detail
B
Cross Section
1.
2.
3.
4.
5.
6.
7.
Valve Body
Cover
Rotor
Detent Spring
Steel Ball
Screw
Roll Pin
Figure 12-6.
12-27. AUXILIARY FUEL PUMP.
12-28, DESCRIPTION. The auxiliary fuel pump is
located beneath the floorboard just to the left of the
selector valve handle. An integral bypass and check
valve permits fuel flow through the pump even when
inoperative but prevents reverse flow. A separate
overboard drain line from the pump prevents entry
offuel into the electric motor, in the event of an internal leak. The auxiliary pump is used in starting
and in the event of engine-driven pump malfunction.
12-29. REMOVAL AND INSTALLATION.
12-7.)
(See figure
A-A
8. O-Ring
9. Seal
10. O-Ring
11. Washer
12. Spring
13. Spring Compressor
Fuel Shutoff Valve
a. Remove pilot and copilot seats in accordance
with Section 3.
b. Peel back carpet as required to expose pump
access cover.
c. Place fuel shut-off valve in "OFF" position and
drain as much fuel as possible from strainer bowl
and associated lines using strainer drain control.
(Observe precautions in paragraph 12-3. )
d. Disconnect and cap fuel lines to pump and remove electrical leads.
e. Loosen clamps securing pump and remove.
f. Reverse preceding steps for installation. With
fuel shut-off valve in "ON" position check for leaks
and proper auxiliary pump operation.
12-11
MODEL R172 SERIES SERVICE MANUAL
.
FROM FUEL
SHUT-OFF
VALVE
2.
"B"
Nut
2
3. "O" Ring
4. Auxiliary Fuel Pump
5. Elbow
6.
Primer Line
7. Strainer Drain Control
TO ENGINE-DRIVEN
FUEL PUMP
11
Figure 12-7.
Auxiliary Fuel Pump and Strainer Drain Installation
12-30. ELECTRIC AUXILIARY FUEL PUMP CIRCUIT. The electric auxiliary fuel pump circuit used
on these aircraft supplies fuel flow for start priming
and engine operation if the engine driven pump should
fail. The auxiliary pump on aircraft serial R1722724
and earlier is controlled by a three position toggle
switch, located on the lower left switch/circuit breaker panel. Aircraft beginning serial R1722725 and subsequent have a dual/split rocker type switch installed.
a. Aircraft employing the toggle type switch operate as follows: With the switch in the up position,
labeled "HI", the auxiliary fuel pump operates at maximum output.
NOTE
The switch is spring loaded to OFF from the
HI position, and must, therefore, be held in
"HI" to obtain maximum output.
The HI position is used for engine starting, for vapor
purging in very hot weather, and for engine operation
with a failed engine-driven pump during takeoff, or
other very high power operations.
12-12
The down position of the auxiliary fuel pump switch,
labeled LOW, operates the pump at one of two speeds,
depending on the throttle position. With the throttle
at cruise setting, and the auxiliary fuel pump switch
is the "LOW" position, sufficient fuel is provided for
cruise flight operation, with a failed engine-driven
fuel pump. When the throttle is moved toward the
closed position, the auxiliary fuel pump flow rate is
automatically reduced, preventing an excessively rich
mixture during periods of low engine power operation.
With the switch in the "LOW" position, the pump will
supply sufficient flow for vapor suppression during
taxi and flight operations in hot climates.
CAUTION
If the auxiliary fuel pump switch is turned on
when the master switch is on, but the engine
is stopped, the intake manifolds will be flooded
unless the mixture control is in "IDLE CUTOFF."
b. Beginning with 1978 model aircraft, the red and
yellow split-rocker auxiliary fuel pump switch oper-
MODEL R172 SERIES SERVICE MANUAL
MICROSWITCH
ADJUSTING
SLOTS
* BETWEEN
CENTERLINE OF
IDLE STOP AND CAM PEAK
IDLE STOP-
SWITCH ROLLER
1/16 INCH
*,
With switch actuated
on high cam, clearance
must exist between
arm and switch body.
CAM
/--IDLE SCREW
(Against Stop)
DETAIL A
Figure 12-8.
THROTTLE ARM
(Full Retard)
DETAIL B
Rigging Throttle Operated Microswitch
ates as follows: The YELLOW right half of the switch
is labeled LOW, and is used to prime the engine for
normal starting and minor vapor purging during taxi.
The RED left half of the switch is labeled HIGH, and
is used in the event an engine-driven pump failure
during takeoff or high power operation. The HIGH
position may also be used for extreme vapor purging.
With the YELLOW half of the switch in the LOW posi-DLE
tion, the pump operates at one of two speeds, that
are dependent upon the throttle setting. If the throttie is open to cruise settings the pump operates at
high flow capacity, to supply sufficient fuel flow to
maintain flight. When the throttle is moved toward
the closed position, as during letdown, landing or
taxiing, the fuel pump flow is automatically reduced
to prevent an excessively rich mixture during these
low engine speed conditions. Maximum fuel flow is
produced when the RED portion of the split rocker is
held in the spring loaded HIGH position. In the HIGH
position, an interlock in the switch also moves the
YELLOW portion of the switch to the LOW position.
When the spring-loaded HIGH portion is released,
the LOW will remain ON until manually turned OFF.
When the engine driven fuel pump is operating, a
fuel air ratio considerably richer than best-power
is produced unless the mixture is leaned. A throttle
operated microswitch adds resistance to the circuit
to lower pump output as the throttle is retarded.
CAUTION
tally selected with the master switch ON and
tally selected wth the mster switch ON and
the engine stopped, the intake anifolds will
befloodedunless the mixture contr is in
12-31. RIGGING THROTTLE OPERATED MICRO
SWITCH. (See figure 12-8.) The aircraft electirn
auxiliary fuel pump circuit is equipped with a nicr, switch which operates on a cam attached to the
tle arm of the fuel-air control unit. The cam on thei
throttle arm actuates the microswitch as the thrutile
is retarded to a manifold pressure of approximatelv
16" Hg, thus reduces the speed of the auxiliary fui1l
pump by introducing a resistance into the circuil
Rig the microswitch as follows:
a. Perform an initial adjustment of cant and
switch as follows:
1. Close throttle and adjust cam as shown i.
detail "A" of figure 12-8.
2. Refer to detail "B" of figure 12-8 to set
microswitch to actuate on the peak of the cam. and
to de-actuate on the flat portion of the cam. Be sure
that roller arm of switch actuator clears switch l^,dv
in actuated position.
b. Start engine, and set throttle to obtain approximately 15 - 17" Hg manifold pressure. Mark this
position on throttle control rod, and stop engine.
12-1.
MODEL R172 SERIES SERVICE MANUAL
,
Detail
1.
2.
Rotated 90 °
Upward.
No 1 Resistor (Hi Boost)
No 2 Resistor (Low Boost)
Figure 12-9.
c.
Auxiliary Fuel Pump Resistors.
Set controls as follows:A
1.
Mixture Control - IDLE CUT-OFF.
2.
3.
Auxiliary Fuel Pump Switch:
(a) Toggle - LOW.
(b) Split-Rocker - ON.
Throttle - FULL OPEN.
WARNING
Be sure the propeller area is clear, because
certain malfunctions
malfunctions can
cause the
engine to
to
certain
aen cause
the engine
turn when external 0ower is aoolied.
mast when urn
external power .s applied, or
or the
master switch is turned on.
4.
Master Switch - ON.
d. Close throttle until mark made in step "b" appears. At this position the microswitch should actuate. and the auxiliary fuel pump should slow down
enough to be audibly detectable.
e. Adjust microswitch as required to cause auxiliary
fuel pump to slow down as throttle is closed to marked
position.
f. Return all controls to "OFF" position.
12-32. AUXILIARY FUEL PUMP FLOW RATE ADJUSTMENT. (See figure 12-9.) Conduct these tests
with engine stopped and external power on bus.
12-14
A
WARNING
During this test raw fuel may drain from the
engine compartment, therefore, proper safety
precautions should be taken. Conduct test in
a well ventilated area, use drip pans, insure
aircraft is properly grounded, and keep ignition source, (cigarettes, lighters, matches,
) away from area.
a. Serials THRU R1722929
R1722929 and
and FR1720630
FR1720630 apply
apply an
an
external source of 27. 75 ± .25 VDC to airplane bus.
BEGINNING WITH serials R1722930 and FR1720631
apply an external source of 28. 8 VDC to airplane bus.
b. Set mixture control at FULL RICH
c. Turn Master Switch - ON, and Aux Fuel to either:
1. Toggle - LOW.
2. Split-Rocker - LOW.
d. Advance throttle to FULL OPEN.
e. Check metered fuel pressure/flow on airplane
gage for a flow of 6 to 6.5 gal/hr fuel flow.
f. Adjust number one(l) if required. (See figure
12-9.)
g. Retard throttle slowly, as previously marked
position is passed, speed of auxiliary pump should
slow enough to be audible.
h. Wait momentarily for pressure/flow meter to
MODEL R172 SERIES SERVICE MANUAL
stabilize. The pressure/flow gage should read 2
galihr.
i. Adjust number (2) two resistor if required.
12-33.
MAXIMUM HIGH BOOST CHECK. To verify
high position function momentarily depress springloaded rocker, with master switch "ON." and verify
noticeable increase in fuel flow on the fuel flow gage.
12-34.
9
FUEL STRAINER,.
12-35. DESCRIPTION. The fuel stainer is mounted
on the firewall in the engine compartment. 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. Access to the
drain control is made through the oil dipstick cowling
NOTE
The fuel strainer can be disassembled, cleaned
and reassembled without removing the assembly
from the aircraft. (Refer to paragraph 12-37.)
12-36.
REMOVAL AND INSTALLATION.
(See figure
a.
Remove cowling as necessary to gain access to
*primer.
strainer.~
b. With shut-off valve in "OFF" position, drain fuel
from strainer and lines with strainer quick-drain
~~~~~~~~control.
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 shut-off valve in "ON" position check for leaks
and proper operation of quick-drain valve.
12-37. DISASSEMBLY AND ASSEMBLY
a. With shut-off 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 removt.
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. Tig;l.ici
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 shut-off valve in "ON" position, check f.,r
leaks and proper operation of quick-drain valve.
h. Safety wire bottom nut to top assembly. Wir
must have right hand wrap, at least 45 degrees.
12-38.
PRIMING SYSTEM
12-39. DESCRIPTION. The priming system is
.
prised of a plunger-type manually-operated prilit
which draws fuel from the strainer and forces it
through a tee fitting to the front end of each intakemanifold. Injecting the fuel into each manifold
manifold Injecting the fuel into each manifold
prlmes both banks of cylinders.
12-40. REMOVAL AND INSTALLATION.
a. With shut-off valve in "OFF" position, drain
fuel from strainer and lines with quick-drain cunti.J!.
b. Disconnect and cap or plug all fuel lines at
pimer. (bsere pcap or plug all ful lines at
(Observe precautions in paragraph 12-3.'
d.
screw
d ut and remove plunger fro
pump
bod
Remove pump body from instrument panel.
NOTE
Visually inspect primer lines for crushed,
Visually inspect primer lines for crushed,
kinked, or broken condition. Ensure proper
clamping to prevent fatigue due to vibration
and chafing.
e. Prior to installing a primer, check for proper
pumping action and positive fuel shut-off in the
locked position.
f. Reverse the preceding steps for installation.
With shut-off valve in"ON" position, check for
leaks and proper pumping action.
SHOP NOTES:
12-15
MODEL R172 SERIES SERVICE MANUAL
NOTE
The strainer drain control is located in
the engine compartment adjacent to the
oil dipstick. Access is gained through
the oil dipstick door in the upper left
hand engine cowl.
,
.- ,
.
·SAFETY WIRE HOLE
,
-
SAFETY WIRE HOLE
NOTE
Torque nut (15) to 25-30 lb in.
1.
2.
3.
4.
Spring
Washer
Plunger
Top
5.
6.
7.
8.
Drain Control
Plate
O-Ring
Gasket
Figure 12-10.
12-16
9.
10.
11.
12.
Filter
Collar
Standpipe
O-Ring
Fuel Strainer
13.
14.
15.
16.
Bowl
O-Ring
Nut
Drain Line
MODEL R172 SERIES SERVICE MANUAL
NOTE
NOTE
After performing maintenance
inside the fuel bay areas. seal
according to paragraph 12-47.
B
*Airplanes R 722930 thru
R1723454 incorporating
SK182-100.
2
4
*
LH Fuel Cell Non-Vented
Detail
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Inspection Cover
Upper Trailing Edge Skin
Fuel Vent Valve Assembly
Tube Weld Assembly
Gasket
LH Rib
Gasket
Washer
Fuel Cap Assembly
Upper Forward LH Skin
Fuel Filler Neck Assembly
12.
13.
14.
15.
16.
17.
18.
19.
20.
Figure 12-11.
Fuel Indicator Assembly
Fuel Transmitter Nut Ring
Gasket
Wing Root (LH) Rib Assembly
Transmitter
Fuel
(LH
Cell)
Inspection Doubler Assembly
Gusset
Lower Forward (LH) Skin
Fuel Drain Valve
21.
22.
23.
24
25.
26.
27.
28.
29.
30.
C
Trailing Edge Skin Stiffener
Rib
Fuel (LH) Spar Assembly
Baffle
Screen
Stiffener
Flap Track Rib Assembly
LH Channel
Gusset
Quick Drain Valve*
Intergral Fuel Cell Structure Assembly.
Revision 1 12-17
MODEL R172 SERIES SERVICE MANUAL
12-41. EXTENDED RANGE FUEL SYSTEM
(OPTIONALi.
12-42. DESCRIPTION. Beginning with Serials
R1722930 and FR17200631, an extended range fuel systern 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
bav, non-vented fuel cap for left wing fuel bay, fuel quantitv transmitters mounted on the side of the left and right
wing root rib assemblies, fuel vent valve assembly mounted on the inboard 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.
12-43. 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 repaired 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 area, 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 12-12.
NOTE
Stains and seeps that are not considered a
flight hazard must be inspected after each
flight to ensure that they have not growL 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 available 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 aircraft can then be flown to a base where
the fuel leak can be repaired.
12-44. FUEL BAY PURGING.
WARNING
Purge fuel bavs with an inert gas prior
to repairing fuel leaks, to preclude the
possibility of explosions.
12-18
Revision 1
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 shut-off valve control knob
and pull control to "OFF" position. (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.)
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.
12-45. INTEGRAL FUEL BAY SEALANT. Two kinds of
sealant 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 damage to them. 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
hydroperoxide. 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.
12-46. MIXING SEALANT. Use all the accelerator and
sealant in the container when mixing, to insure 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.
MODEL R172 SERIES SERVICE MANUAL
STAIN
3/4" Max.
RUNNING
LEAK
-
Size will vary
with location
and intensity.
3/4" to 11/2"
Fuel will usually flow in
this area along skin contour after it is wiped dry.
HEAVY
1 1/2' to 4"
at this point.
WARNINGS
REFER TO PARAGRAPH 12-44 FOR FUEL BAY PURGING WHICH
SHOULD BE ACCOMPLISHED BEFORE REPAIRING FUEL BAYS.
Figure 12-12. Classification of Fuel Leaks
12-47. SEALING DURING AND AFTER STRUCTURAL
REPAIR.
CAUTION
Protect drain holes and fuel outlet screens
when applying sealants.
Any repair that breaks
sitate resealing of that
that need sealing must
the sealing operation.
the fuel bay seal will necesarea of the bay. Repair parts
be installed and riveted during
All joints within the boundary
bay, but which do not provide a direct fuel path
the bay, such as stringers and rib flanges withbay, must be fay surface sealed only. Joints
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
of the
out of
in the
which
SHOP NOTES:
12-19
MODEL R172 SERIES SERVICE MANUAL
KEEP DRAIN HOLES
FREE FROM SEALING
AND LOWER)
Types of sealing shown in this figure
are used during manufacture of the
fuel area. The same types should
SEAL
SURFACE
a structural
when making
be usedFAYING
must be
free of
dirt and
fillet
sealant Fillets
is applied,
joints
shall
be
tamination.
Figure
12-1.
TpconFILLET fuel
SEALlaid on intersecting
being sealed and positioned for final
before
installation.
RIVET AND FASTENER SEAL
Figure 12-13.
Typical Fuel Bay Sealing (Sheet 1 of 2).
after the
the joint
joint is
is fay
surface sealed
sealed and
and riveted
riveted or
or
fay surface
fastened together.
sealing is
is applying
applying sealant
together. Fillet sealing
to
the edge
of all
bend reliefs,
tovoids,
riveted joints,
the
or faes
rs joggles,
the
rivets
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
is
out sealant, to which the
applied, but the squeezed
CODE
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 seal12-20
ant
is with
with an
an extrusion
Then work
work the
sealant
ant is
extrusion gun.
gun. Then
the sealant
into the joint
to
with a small paddle,
paddle, being careful to
joint with
eliminate all air bubbles.
NOTE
During structural
structural repair,
repair, parts
parts must
must be
be prepreor dimpled
dimpled and
countersunk or
drilled, countersunk
and cleaned
cleaned
^^
installation.
positioned for final
Remove all existing sealant from area to be
MODEL R172 SERIES SERVICE MANUAL
SEALANT MUST SQUEEZE OUT CONTINUOUSLY
.030 (Max)
.005 (Min and preferred)
FAY SURFACE SEALING
SEALANT MUST SQUEEZE OUT CONTINUOUSLY
/
------
FUEL SIDE
(Min)
FILLET SEALING (With fay surfaces sealed)
.
(Min)
FASTENER SEALING
Figure 12-13.
Typical Fuel Bay Sealing (Sheet 2 of 2).
12-21
MODEL R172 SERIES SERVICE MANUAL
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-like 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.
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.
be found by testing the complete bay as described in
paragraph 12-50. 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 12-47, 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 12-50.
12-49. CURING TIME. Service Kit SK210-56 contains SP654890B2 Fuel Tank Area Sealant Kit and
SP654706B2 Access Door Sealant Kit. Normal curing time for SP654890B2 Sealant Kit is 72 hours.
Normal curing time for SP654706B2 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.
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 lifo. 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
12-49 for curing time.
h. Clean stains from outside of bay area.
i. Test fuel bay for leaks as described in paragraph
12-50.
12-48. 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
12-22
160
140
120
Time in Hours
3
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 condition of 77 ° Fahrenheit and
50% relative humidity. Harmful vapors are
released if sealant is heated above 90°F.
12-50. 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.
MODEL R172 SERIES SERVICE MANUAL
cap incorporates a vent and safety valve that provides
CAUTION
both vacuum and positive pressure relief.
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,
12-51. 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, operation, and maintenance
is covered in Section 15.
12-52. VENTED FUEL FILLER CAP.
12-14.)
12-53.
1.
2.
3.
4.
5.
(See figure
DESCRIPTION. The RIGHT-HAND fuel filler
12-54. 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 cottom 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 cottom 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.
Umbrella Rubber
Check Valve (Vent)
Gasket
Frictionless Washer
Fuel Cap Body
Figure 12-14. Vented Fuel Filler Cap
12-23/(12-24 blank)
MODEL R172 SERIES SERVICE MANUAL
SECTION 13
PROPELLER AND GOVERNOR
OR
INSPECTION
ANY
PERFORMING
WHEN
MAINTENANCE THAT REQUIRE TURNING ON THE
MASTER SWITCH, INSTALLING A BATTERY, OR TURNING
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.
TABLE OF CONTENTS
PROPELLER
.....................
Description .....................
Repair ..........
..............
Trouble Shooting ............
Removal .
......................
Installation ....................
Time Between Overhaul (TBO) ...
NA/13-1
NA/13-1
NA/13-1
NA/13-2
NA/13-3
NA/13-3
NA/13-7
13-1. PROPELLER. (See figure 13-1.)
13-2. DESCRIPTION. The airplane is equipped with an
all metal, constant-speed, governor-regulated
propeller. The constant-speed propeller is single
acting, in which engine oil pressure, boosted and
regulated by the governor is used to obtain the
correct blade pitch for the engine load. Engine
lubrication oil is supplied to the power piston in the
propeller hub through the crankshaft. The amount
and pressure of the oil supplied is controlled by the
engine driven governor. An increase or decrease in
throttle setting or a change in aircraft attitude will
affect the balance which maintains a given RPM. If
the throttle is opened further or if the aircraft speed
is increased, engine RPM will try to increase. The
governor senses this and directs oil pressure to the
forward side of the piston in the propeller hub. The
blades will be moved to a higher pitch and engine
speed will remain constant. Conversely, if the
throttle opening or the aircraft speed is decreased,
the engine RPM will try to decrease. The governor
senses this and allows oil to drain from the forward
side of the piston. Spring tension and centrifugal
twisting moment will move the blades to a lower
pitch to maintain the selected engine speed.
Temporary Revision Number 2
April 3,1998
Page No.
Aerofiche/Manual
Page No.
Aerofiche/Manual
GOVERNOR ........................
Description .....................
Trouble Shooting ...............
Removal..
Installation ....................
High RPM Stop Adjustment ......
Rigging Governor Control .......
Time Between Overhaul (TBO) ...
NA/13-7
NA/13-7
NA/13-7
NA/13-7
NA/13-7
NA/13-8
NA/13-8
NA/13-8
NOTE:
For information not covered in this section, refer
to the applicable McCauley Service Manual and
applicable supplements.
13-3. REPAIR. Metal propeller repair first involves
evaluating the damage and determining whether
the repair will 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 repairs or alterations to a propeller
FAR 43, FAA AC No. 43.13 and the propeller
manufacturer's instructions must be observed.
13-1
MODEL R172 SERIES SERVICE MANUAL
13-4. TROUBLE SHOOTING
PROBABLE CAUSE
TROUBLE
FAILURE TO CHANGE PITCH
FAILURE TO CHANGE PITCH
FULLY
REMEDY
Governor control disconnected or
broken.
Check visual. Connect or replace
control.
not correct
Governor
propeller (Sensing wrong).
Check that correct governor is
installed. Replace governor.
for
Inoperative governor.
Refer to paragraph 13-10.
Inoperative
pitch
changing
mechanism inside propeller or
blade
propeller
excessive
friction.
Improper rigging of governor
Propeller repair or replacement
is required.
RESPONSE
TO
Excessive
friction
and control have full travel. Rig
control and arm as required.
Refer to paragraph 13-10.
Inoperative governor.
SLUGGISH
Check that governor control arm
in
pitch
Propeller repair or replacement
inside
changing mechanism
propeller or excessive blade
is required.
Governor high RPM stop set too
Refer to paragraph 13-13.
Inoperative governor.
Refer to paragraph 13-10.
See
Overspeed
Limitations
Contained in Section 11.
Incorrect propeller or incorrect
low pitch blade angle.
Check aircraft specification and
install correct propeller with
correct blade angle.
STATIC RPM TOO LOW
Governor high RPM stop set too
low.
Refer to paragraph 13-13.
Inoperative governor.
Refer to paragraph 13-10.
Incorrect propeller or incorrect
low pitch blade angle.
Check aircraft specification and
install correct propeller with
correct blade angle.
Sludge in governor
Refer to paragraph 13-10.
PROPELLER CONTROL
friction.
STATIC RPM TOO HIGH
ENGINE SPEED WILL NOT
STABILIZE
13-2
high.
Air
trapped
in
actuating cylinder.
propeller
Trapped air should be purged by
exercising the propeller several
times prior to take-off after
propeller has been reinstalled or
has been idle for an extended
period of time.
Excessive friction in pitch
changing mechanism inside
propeller or excessive blade
friction.
Propeller repair or replacement
is required.
Inoperative governor.
Refer to paragraph 13-10.
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
TROUBLE
PROBABLE CAUSE
OIL LEAKAGE AT PROPELLER
MOUNTING FLANGE.
Damaged O-ring and seal between
engine crankshaft flange and
REMEDY
Check visual. Remove propeller and
install O-ring seal.
propeller.
OIL LEAKAGE AT ANY OTHER
PLACE
Foreign material between engine
crankshaft flange and propeller
mating surface or mounting nuts are
not tight.
Failed seals, gaskets, threads etc., or
incorrect assembly.
Remove propeller and clean mating
surfaces; install new O-ring and
tighten mounting nuts evenly to
torque value in figure 13-1.
Propeller repair or replacement is
required.
WARNING
EXERCISE CARE WHEN WORKING WITH THE
PROPELLER.
ALWAYS
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. ENSURE MAGNETO SWITCH
IS IN THE OFF POSITION BEFORE TURNING
THE PROPELLER.
ENSURE MAGNETOS ARE GROUNDED BEFORE
TURNING PROPELLER.
AVOID SCRAPING METAL FROM BORE OF
SPINNER
BULKHEAD
AND
WEDGING
SCRAPINGS BETWEEN ENGINE FLANGE AND
PROPELLER. TRIM THE INSIDE DIAMETER
OF THE BULKHEAD AS NECESSARY WHEN
INSTALLING A NEW SPINNER BULKHEAD.
b. Clean propeller hub cavity and mating surfaces of
propeller and crankshaft.
c. Lightly lubricate new O-ring and the crankshaft pilot
with clean engine oil and install the O-ring in the
propeller hub.
WARNING
13-5. REMOVAL. (Refer to figure 13-1.)
ENSURE MAGNETOS ARE
a. Remove all power from the airplane.
BEFORE
ARE GROUNDED
GROUNDED BEFORE
ENSURE
TURNING MAGNETOS
PROPELLER.
Remove
from all thepower
airplane.
b. Remove spinner attaching screws (2) and remove
spinner (1), spinner support (3) and spacers (4). Retain d. Lubricate the hub mounting studs with A-163716
grease.
MIL-T-83483)
spacers (4) if so equipped.
c. Remove cowling as required for access to mounting
nuts (9).
d. Loosen all mounting nuts (9) approximately 1/4 inch
and pull propeller (15) forward until stopped by nuts.
NOTE:
As the propeller (15) is separated from the
engine crankshaft flange, oil will drain from the
propeller and engine cavities.
e. Remove all propeller mounting nuts (9) and pull
propeller forward to remove from engine crankshaft
(12).
f. If desired, the spinner bulkhead (11) can be removed
by removing screws (10), which attach the spinner
bulkhead to the propeller.
13-6. INSTALLATION. (Refer to figure 13-1.)
a. If the spinner bulkhead was removed, position
bulkhead so the propeller blades will protrude through
the spinner with ample clearance. Install spinner
bulkhead attaching screws (10), which attach the
spinner to bulkhead.
Temporary Revision Number 2
April 3, 1998
ALL PROPELLER STUDS AND NUTS ARE REQUIRED TO BE INSTALLED WITH LUBRICATION ON THE HUB MOUNTING STUDS.
e. Align propeller mounting studs and dowel pins with
proper holes in engine crankshaft flange and slide
propeller carefully over crankshaft pilot until mating
surfaces of propeller and crankshaft flange are
approximately 1/4 inch apart.
f. Install propeller attaching washers and new nuts (9)
and work propeller aft as far as possible, then tighten
nuts evenly.
WARNING
DO NOT USE ALL STEEL LOCKNUTS. USE ONLY
NEW ELASTIC ELEMENT LOCKNUTS WHEN
INSTALLING PROPELLER.
g. Torque nuts 45 to 50 lb-ft. LUBRICATED TORQUE
ONLY. Refer to McCauley Service Bulletin 227, or
latest revision, as applicable for propeller stud and nut
torque and lubrication requirements.
13-3
MODEL R172 SERIES SERVICE MANUAL
R1722000 thru R1722834
FR1720591 thru FR1720630
13
12
For replacement refer to Cessna
Single Engine Service Letter
SE78-4.
2
1. Spinner
2. Screw
3. Grommet
4. Cylinder
6.
Torque
Cylinder
NOTE
nuts 45 to 50 lb-ft.
LUBRICATED TORQUE ONLY.
Service
Refer
to McCauley
Bulletin 227, or latest revision, as
Ring
5. Cylinder Mounting Screw
7. Cylinder Mounting Tube
8. ropeller Blade
9. Stud
10. Spinner Bulkhead
11.Crankshaft Flange
12. Lug
13. Hub Mounting Nut
14. Bolt
applicable for propeller stud and
15. Washer
nut
16. Nut
torque
and
lubrication
requirements.
17. Hub Assembly
18. Balance Weight
Figure 13-1.
13-4
Propeller Installation (Sheet 1 of 2)
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
14
Beginning with Serials:
R1722835 and FR1720631
Per Cessna Engine Service Letter
SE78-4, this propeller and spinner
bulkhead may be installed on
R1722000 thru R1722834 and
FR1720591 thru FR1720630.
13
1112
9
10
15
17
18
19
1.
2.
3.
4.
5.
6.
7.
8.
9.
NOTE
10. Stud
Torque nuts 45 to 50 lb-ft.
LUBRICATED TORQUE ONLY.
Refer
to
McCauley
Spinner
Stabilizer
Screw
Grommet
Cylinder
Cylinder Mounting Screw
Cylinder Ring
Cylinder Mounting Tube
propeller Blade
Service
Bulletin 227, or latest revision, as
applicable for propeller stud and
nut torque and
lubrication
requirements.
11.Spinner Bulkhead
12. Crankshaft Flange
13. Lug
14. Hub Mounting Nut
15. Bolt
16. Washer
17. Nut
18. Hub Assembly
19. Balance Weight
Figure 13-1.
Temporary Revision Number 2
April 3,1998
Propeller Installation (Sheet 2 of 2)
13-5
MODEL R172 SERIES SERVICE MANUAL
6
5
3. Governor Arm Extension
4. Nut
1. Propeller Governor
2. High Speed Stop Screw
Figure 13-2.
Governor and Controls Adjustments
USE OF CROW FOOT OPEN-ENDED TORQUE
WRENCHES CAN CAUSE SLIPPAGE AND
LEAVE MARKS ON THE ENGINE OUTPUT
FLANGE IF CARE IS NOT USED DURING THE
TORQUE PROCESS.
USE PROPER CALCULATIONS WHEN USING
TORQUE ADAPTERS TO ENSURE CORRECT
INSTALLATION TORQUE.
CONSISTENT
PRODUCE AND
AND ACCURATE
ACCURATE
CONSISTENT
TO PRODUCE TO
TORQUE,
INSTALLATION
MCCAULEY
RECOMMENDS AN ADJUSTABLE "CLICK"
TYPE WRENCH WITH NON RATCHETING,
INTERCHANGEABLE,
WRENCH HEADS.
12 POINT BOX-END
HOWEVER,
IN CERTAIN APPLICATIONS.
IT
THE USE OF A TORQUE WRENCH WITH ANY
FORM OF EXTENSION REQUIRES THE TORQUE
READING ON THE WRENCH TO BE CHANGED
TO OBTAIN THE CORRECT TORQUE APPLIED
AT THE NUT. TO OBTAIN CORRECT RESULTS
REFER TO THE FORMULA IN SECTION 1.
h. Install Spinner.
Install Spinner.
1. For R1722000 thru R1722834 and FR1720591 thru
FR1720630 that have not complied with Cessna
Single Engine Service Letter SE78-4:
(a.)
Install spinner stabilizer, and grommet on
(b.)
Hold spinner snug against spinner support
and align holes in spinner with holes in
propeller cylinder.
spinner bulkhead.
IT MAY BE NECESSARY TO USE VARIOUS
ADAPTERS
5. Control Rod End
6. Governor Control
IS
STRONGLY
RECOMMENDED THAT EXTREME CAUTION
THAT
BE EXERCISED TO ENSURE
ACCURATE TORQUE IS BEING APPLIED
(c.)
Install screws and washers (if required).
(d.)
Tighten all screws uniformly
spinner.
around the
2. For R1722835 and On and FR1720631 and On,
FOR MAXIMUM RETENTION.
A TORQUE WRENCH
ON MOSTAIRPLANES,
and earlier serial number airplanes that have
complied with Cessna Single Engine Service Letter
PROPELLER MOUNTING NUT BECAUSE OF
(a.)
ON MOST AIRPLANES, A TORQUE WRENCH
CANNOT BE FITTED DIRECTLY ON THE
SE78-4:
Install
spacers
and
spinner
support
on
THE LACK OF CLEARANCE BETWEEN THE
propeller cylinder. If spacers are not centered
FLANGE AND ENGINE CASE. AN ADAPTER
MUST BE USED ON THE TORQUE WRENCH.
mechanically (piloted), visually center and
hold them until spinner support is forced
firmly in place.
13-6
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
(b.)
(c.)
(d.)
Hold spinner snug against spinner support and
check alignment of holes in spinner with holes in
spinner bulkhead. Add or remove spacers from
propeller cylinder until holes are within .050 inch
forward of the true center of holes in spinner
bulkhead assembly.
bulkhead
assembly.
Push on spinner to align holes and install screws
and washers (if required) in three (3) or more
equal spacers around the spinner bulkhead (11).
Relax pressure on spinner and install remaining
screws and washers (if required) in spinner.
Tighten all screws uniformly around the spinner.
13-7. TIME BETWEEN OVERHAUL (TBO). Propeller
overhaul shall coincide with engine overhaul, but
shall not exceed limits specified in McCauley
Service Bulletin 137 and all revisions and
supplements thereto.
13-8. GOVERNOR. (See Figurer 13-2.) for
13-10. TROUBLESHOOTING. When troubleshooting the
propeller/governor
combination,
it
is
recommended that a governor known to be in good
condition be installed to check whether the
propeller or the governor has failed. Removal and
replacement, rigging high-speed stop adjustment,
de-sludging and replacement of the governor
mounting gasket are not major repairs and may be
accomplished in the field. Repairs to propeller
governors are classed as propeller major repairs in
the Federal Aviation Regulations, which also
define who may accomplish such repairs.
13-11. REMOVAL. (See Figure 13-2.)
a. Remove all electrical
airplane.
b. Remove cowling and engine baffles as required
for access to the governor.
gov
access to the
c. Disconnect
governor
control
from
governor extension arm.
WARNING
EXERCISE CARE WHEN WORKING WITH
THE PROPELLER. ALWAYS TREAT THE
PROPELLER AS IF THE IGNITION SWITCH
WERE ON. DO NOT STAND , NOR ALLOW
ANYONE ELSE TO STAND, WITHIN THE
ENSURE
ARC OF THE PROPELLER.
OFF
IN THE
IS
SWITCH
MAGNETO
POSITION
BEFORE
TURNING
THE
PROPELLER.
WARNING
WARNING
ENSURE MAGNETOS ARE GROUNDED BEFORE
TURNING THE PROPELLER.
13-9. DESCRIPTION. The propeller governor is a singleacting, centrifugal type, which boosts oil pressure
power from the
NOTE:
Note the position of all washers so that washers
may be installed in the same position on
reinstallation.
d Remove four nuts and washers securing
governor from mounting studs.
e. Remove gasket from between governor and
engine mounting pad.
13-12. INSTALLATION. (See Figurer 13-2.)
a. Clean mating surfaces of propeller governor
and engine mounting surface.
b. Install new gasket on the mounting studs.
Install gasket with the raised surface of the
gasket screen toward the governor.
from the engine and directs it to the propeller where
the oil is used to increase blade pitch. A singleacting governor uses oil pressure to effect a pitch
change in one direction only; a pitch change in the
DO
opposite direction results from a combination of
centrifugal twisting moment of rotating blades and
compressed springs. Oil pressure is boosted in the
governor by a gear type oil pump. A pilot valve,
flyweight and speeder spring act together to open
and close governor oil passages as required to
maintain a constant engine speed.
ENGAGEMENT.
ROTATE THE ENGINE
CRANKSHAFT SLIGHTLY AND SPLINES
WILL MESH SMOOTHLY WHEN PROPERLY
ALIGNED.
c. Position governor on the mounting studs
aligning governor drive splines in the engine and
install mounting nuts and washers. Do not force
spline engagement. Rotate engine crankshaft as
required to properly align the propeller drive
NOTE:
Outward physical appearance of specific
governors is the same, but internal parts
determine whether it uses oil pressure to
The
increase or decrease blade pitch.
propellers used on these aircraft require
governors which "sense" in a certain manner.
"Sensing" is determined by the type pilot
valve installed inside the governor. Since the
basic governor may be sent to"sense"
oppositely, it is important to ascertain that the
governor is correct for the propeller being
used.
Temporary Revision Number 2
April 3, 1998
NOT
FORCE
GOVERNOR
SPLINE
splines.
d. Connect governor control to governor arm
extension and rig control as outlined in
paragraph 13-14.
e. Reinstall all items removed for access.
13-7
MODEL R172 SERIES SERVICE MANUAL
13-13.
HIGH RPM STOP ADJUSTMENT.
EXERCISE CARE WHEN WORKING
ALWAYS
WITH THE PROPELLER.
TREAT THE PROPELLER AS IF THE
IGNITION SWITCH WERE ON. DO NOT
THE PROPELLER
CONTROL HAS A SMALL
RETAINING
BRAZED
RING
(OR
ATTACHED
WITH EPOXY RESIGN) NEAR THE THREADED
END (ENGINE END) OF THE CONTROL. THE
PURPOSE OF THIS RETAINING RING IS TO
PREVENT INADVERTENT WITHDRAWAL AND
POSSIBLE DAMAGE TO THE KNOB END OF THE
STAND, NOR ALLOW ANYONE ELSE TO
WHILE JAM NUTS AND ROD END IS
TCONTROL
OF
THE
THE
ARC
WITHIN
STAND,
STAND, WITHIN THE ARC OF THE
PROPELLER.
SWITCH
IS
ENSURE
IN THE
MAGNETO
OFF POSITION
BEFORE TURNING THE PROPELLER.
REMOVED.
a. Disconnect
governor
control
from
governor
extension arm.
b. Place propeller governor control, in cabin, full
forward, then pull back approximately 1/8 inch.
This will allow "cushion" to assure full contact of the
ENSURE MAGNETOS ARE GROUNDED
BEFORE TURNING THE PROPELLER.
a. Remove engine cowling and baffles as required for
access.
b. Remove safety wire and loosen the high speed screw
locknut.
c. Turn the stop screw IN (clockwise) to decrease
maximum RPM and OUT (counterclockwise) to
increase maximum RPM. One full turn of the stop
screw causes a change of approximately 25 RPM.
d. Tighten stop screw locknut, safety wire stop screw and
make propeller control linkage adjustment as
necessary to maintain full travel,
e. Install baffles and cowling.
f. Functionally test the propeller and governor.
NOTE:
It is possible for either the propeller low pitch (high
RPM) stop or the governor high RPM stop to be the
high RPM limiting factor. It is desirable for the
governor
governor stop
stop to
to limit
limit the
the high
high RPM
RPM at
at the
the
maximum rated RPM for a particular aircraft. Due
to climatic conditions, field elevation, low pitch
blade angle and other considerations, an engine
may not reach rated RPM on the ground. It may be
necessary to adjust the governor stop after test
flying to obtain maximum rated RPM when
flyingto obtain maximum rated RPM when
airborne.
13-14.
RIGGING PROPELLER CONTROL.
c. Place governor arm against the high RPM stop
screw.
d. Loosen jam nut and adjust control rod end until
attaching holes align while governor arm is against
the high RPM stop screw. Be sure to maintain
sufficient thread engagement of the control and rod
end. If necessary, shift control in the clamps to
achieve this.
e. Attach rod end to the governor arm extension.
sure all washers are installed correctly.
f. Operate the control to see that the governor arm
bottoms out against the high pitch stop on the
governor before reaching the end of control cable
travel.
NOTE:
The governor is equipped with an offset extension to
the governor arm. The offset extension has an
elongated slot to permit further adjustment. The
proceeding steps may still be used as an outline in
the rigging procedure. The result of rigging, in all
against
high and
low
pitch stops)
with some
cases, isboth
full travel
of the
governor
arm (bottom
out
against both high nd low pitch stops) with some
13-15. TIME BETWEEN OVERHAUL (TBO).
Propeller governing overhaul should, as much as
practicable, coincide with engine overhaul, but shall
not exceed 1800 hours of service. Refer to Section 11
for engine time between overhaul (TBO) periods.
The governor overhaul manual is available from
Cessna Parts Distribution.
WARNING
EXERCISE CARE WHEN WORKING
WITH THE PROPELLER.
ALWAYS
TREAT THE PROPELLER AS IF THE
IGNITION SWITCH WERE ON. DO NOT
STAND, NOR ALLOW ANYONE ELSE TO
STAND, WITHIN THE ARC OF THE
ENSURE MAGNETO
PROPELLER.
SWITCH IS IN THE OFF POSITION
BEFORE TURNING THE PROPELLER.
13-8
Be
Temporary Revision Number 2
April 3, 1998
MODEL R172 SERIES SERVICE MANUAL
SECTION 14
UTILITY SYSTEMS
TABLE OF CONTENTS
UTILITY SYSTEMS .........
Heating System ....
Description .........
Operation ..........
Trouble Shooting
Removal, Repair and
Installation ......
Defroster System .
Description ...
.
Operation ..........
Trouble Shooting.
.
...
Removal, Repair and
Installation .....
14-1.
UTILITY SYSTEMS.
14-2.
HEATING SYSTEM.
Page No.
Aerofiche/Manual
1L5/14-1
1L5/14-1
1L5/14-1
1L5/14-1
1L5/14-1
Ventilating Systems .......
Description ....
.
Operation ..........
Trouble Shooting
..
Removal, Repair and
Operation ........
Air Circulating Fan System .
.
Description
.1L8/14-4
.
Removal ..
.
Inspection and Repair ..
.
Installation.
.........
. 1L5/14-1
. L5/14-1
. 1L5/14-1
1L8/14-4
. 1L8/14-4
. L8/14-4
.L8/14-4
1L8/14-4
L8/14-4
.1L8/14-4
.1L8/14-4
1L8/14-4
L8/14-4
L8/14-4
. 1L8/14-4
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/or their controls, damaged air ducting, or defects in the exhaust muffler. In most cases, valves
or controls can be freed by proper lubrication.
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 complete 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 accomplished. Refer
to applicable paragraph in Section 11 for this inspection. 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 shut-off valves or
openings at the firewall with Pro-Seal //700 (Coast
Pro-Seal Co., Los Angeles, California) compound,
or equivalent.
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 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. 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.
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.
14-1
MODEL R172 SERIES SERVICE MANUAL
.,
-......
NOTE
.-
....
Refer to Section 2 of this
y/f
a,1\
-..
.
1.
2.
13
Detail A
Heating and Defrosting Systems
Valve Guide
14.2. Clamp.
Nozzle
16. Defros
17.
Figure 14-1.
Heater Hose
Clamp
Screw
MODEL R172 SERIES SERVICE MANUAL
.....
... ...........
.
....
.
.........
.-.....
NOTE
.
Refer to Section 15 of this
Temperature Gage instal-
.
emented
Refer to Section
5. Clamp Bolt
,
15 of
is
this
NOTE
Insert (15)
to
1
7.
Fuselage Skin
Air Vent Silencer
9. Escutcheon
10. Knob
11.
(10)
EC1300L,
Screw
.
13.
Washer
16.
Outlet Assembly
17.
Bullet Catch31
.
14.
1. Knob
Detail
A
18. Seal
19. Washer
O^
20.
Washer
23.
ut
Tube Assembly
25.
26.
27.
28.
Airscoop
Nutplate
Elbow
Element
Refer to Section 2 of this
manual for hin10nt
lubrcaton
29. Adapter
30. Bracket
31. Cap
13
Detail
D
1
Figure 14-2.
Ventilating Systems
14 -3
MODEL R172 SERIES SERVICE MANUAL
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,
coming cabin ventilating air, which greatly reduces
inlet air noise. The outlet assemblies, installed near
the upper corners of the windshield are manuallyoperated, increasing or decreasing flow of ram air
into the cabin.
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.
14-15. 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 could contaminate the air. The filters may be removed to increase
air flow. However, their removal will cause a slight
increase in noise level.
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 inthe 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.
4-12.
VENTILATING SYSTEMS.
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 provide the
conditions desired by the pilot. The heating system,
defrosting system and one ventilating system receive
air from the duct across the aft side of the firewall.
As long as the "CABIN HT" 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 silencer
assemblies, mounted in the left and right rear cabin
wing root areas. These units receive ram air from
the airscoops in the wing root fillets. Each silencer
assembly is equipped with a valve which meters in14-4
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 CIRCULATING FAN SYSTEM.
ure 14-3.)
(See fig-
14-18. DESCRIPTION. An optional cabin ventilating
fan may be located above the extended baggage compartment. This 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 fans rotate 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.
MODEL R172 SERIES SERVICE MANUAL
......
....
.
.,
...
..- ... . ..
.........
......
...... .....
K
1.
2.
3.
4.
5.
6.
7.
8.
9.
.
STATION
130.400
Switch
Circuit Breaker
Support
Bulkhead
Blower Assembly
Support
Clamp
Duct
Duct Assembly
Figure 14-3.
Circulating Fan Installation
14-5/(14-6 blank)
MODEL R172 SERIES SERVICE MANUAL
SECTION 15
INSTRUMENTS AND INSTRUMENT SYSTEMS
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
INSTRUMENTS AND INSTRUMENT
..............
.
SYSTEMS
...............
.
General
...........
Instrument Panel
.............
Description
Removal and Installation .....
..........
Shock Mounts .
Instruments .................
.
..............
Removal
.............
Installation
Pitot and Static Systems .........
................
Description .
.
.............
Maintenance
Static System Inspection
and Leakage Test ...........
Pitot System Inspection
and Leakage Test ...........
Blowing Out Lines ..........
Removal and Installation
............
of Components .
Encoding Altimeter ..........
................
Description .
Removal and Installation .....
Trouble Shooting .............
True Airspeed Indicator .......
................
Description .
Removal and Installation .....
Trouble Shooting .............
Trouble Shooting-Altimeter ..
Trouble Shooting-Vertical
Speed Indicator . ............
Trouble Shooting-Pitot
................
Tube Heater .
Vacuum System .................
Description ..................
Trouble Shooting ...........
Trouble Shooting-Gyros .......
Trouble Shooting-Pump .......
Removal and Installation .....
Cleaning ....................
Vacuum Relief
Valve Adjustment ............
Standby Vacuum System ......
Description ..................
Removal and Installation .....
..........
Engine Indicators .
2A3/15-2
2A3/15-2
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A4/15-3
2A5/15-4
2A5/15-4
2A5/15-4
2A5/15-4
2A5/15-4
2A5/15-4
2A8/15-7
2A8/15-7
2A8/15-7
2A8/15-7
2A8/15-7
2A10/15-9
2A10/15-9
2A11/15-10
2A11/15-10
2A1115-10
2A12/15-11
2A12/15-11
2A18/15-15
2A18/15-15
2A18/15-15
2A18/15-15
2A18/15-15
2A18/15-15
2A18/15-15
2A18/15-15
Page No.
Aerofiche/Manual
Tachometer ...................
Description ................
Manifold Pressure/Fuel
Flow Indicator .............
Description ................
Trouble Shooting-Manifold
Pressure Gage ..............
Trouble Shooting-Fuel Flow
Indicator ..................
Cylinder Head Temperature
Gage ......................
Description ................
Trouble Shooting ...........
Oil Pressure Gage .............
Description ................
Trouble Shooting ...........
Oil Temperature Gage .........
Description ................
Economy Mixture Indicator ....
Description ................
Calibration ................
Removal and Installation ...
Trouble Shooting ...........
Fuel Quantity Indicating
System ....................
Description ................
Removal and Installation ...
Trouble Shooting ...........
Transmitter Calibration ....
Hourmeter ...................
Description ................
Magnetic Compass ............
Description ................
Removal and Installation ...
Stall Warning System .........
Description ................
Removal and Installation ...
Turn Coordinator .............
Description ................
Trouble Shooting ...........
Turn-and-Slip Indicator ........
Description ................
Outside Air Temperature
Gage ......................
2A18/15-15
2A18/15-15
2A19/15-16
2A19/15-16
2A19/15-16
2A20/15-17
2A21/15-18
2A21/15-18
2A21/15-18
2A21/15-18
2A21/15-18
2A22/15-19
2A22/15-19
2A22/15-19
2A23/15-20
2A23/15-20
2A23/15-20
2A23/15-20
2A23/15-20
2B1/15-22
2B1/15-22
2B1/15-22
2B1/15-22
2B2/15-22A
2B4/15-23
2B4/15-23
2B4/15-23
2B4/15-23
2B4/15-23
2B4/15-23
2B4/15-23
2B4/15-23
2B6/15-25
2B6/15-25
2B6/15-25
2B7/15-26
2B7/15-26
2B7/15-26
Revision 1
15-1
MODEL R172 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 be sent
to an approved instrument overhaul and repair station
or returned to manufacturer for servicing. Our concern here is with preventive maintenance on various
instrument systems 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 technician 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 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.
-
NOTE POSITION OF GROUND
STRAP AND SEQUENCE OF
ATTACHING PARTS WHEN
REMOVING OR INSTALLING
SHOCK PANEL.
Detail A
1.
2.
3.
4.
l
Shock-Mounted Panel
Radio Panel
Heating and Ventilating Controls
Engine Controls
5.
6.
7.
8.
Switch and Circuit Breaker Panel
Engine Instruments
Shock-Mount
Ground Strap
Figure 15-1.
15-2
Typical Instrument Panel
9.
10.
11.
12.
Stud
Instrument Panel
Decorative Cover
Threaded Button
MODEL R172 SERIES SERVICE MANUAL
15-3.
INSTRUMENT PANEL.
15-4. DESCRIPTION. The instrument panel assembly consist of a stationary and shock-mounted panel.
The stationary panel contains instruments which are
NOT sensitive to vibration. The shock-mounted panel contains major flight instruments such as horizontal
and directional gyros which are affected by vibration.
Most of the instruments are screw-mounted on the
panel backs,
15-5. REMOVAL AND INSTALLATION. (Refer to
figure 15-1.) The stationary panel is secured to engine mount stringers 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. (Refer to figure 15-1.) Most instruments are secured to panel with screws inserted
through panel face. To remove an instrument, remove decorative cover, disconnect wiring or plumbing to 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, disconnect 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.
15-9. 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
Service Parts Center.
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.
figure 15-2.)
(Refer to
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 atmospheric pressure through plastic tubing connected to static ports.
A static line sump is installed at source buttons to
collect condensation in static system. A pitot tube
heater may be installed. The heating 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 Owner's Manual 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 obstructions in pitot system will result in false airspeed indications, while
static system malfunctions will affect readings of all
three instruments. Under instrument flight conditions,
these instrument errors could be hazardous. Cleanliness and security are the prinicpal 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 procedure 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 alternations 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
15-3
MODEL R172 SERIES SERVICE MANUAL
source opening, place a piece of tape over other openi"g. Figure 15-3 shows method of obtaining suction
e. Slowly apply suction until altimeter indicates a
1'. O-foot increase in altitude.
sure 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.
CAUTION
When applying or releasing suction, do not
exceed range of vertical speed indicator or
airpseed indicator.
f. Cut off suction source to maintain
:;stem for one minute. Leakage shall
feat of altitude loss as indicated on
. If leakage rate is within tolerance,
source.
a "closed"
not exceed
altimeter.
slowly re-
SAUTIO
Never blow through pitot or static lines toward
instruments.
NOTE
If leakage rate exceeds maximum allowable,
first tighten all connections, then repeat
leakage test. If leakage rate still exceeds
maximum allowable, use following procedure.
h. Disconnect static pressure lines from airspeed
indicator and vertical speed indicator. Use suitable
fillines to connect lines together so altimeter is the
i,
instrument still connected into static pressure
-. f,:omn.
Repeat leakage test to check whether static prs,iire system or the bypassed instruments are cause of
If instruments are at fault, they must be relpaired by an appropriately rated repair station" or
replaced. If static pressure system is at fault, use
'-llowing procedure to locate leakage.
Attach a source of positive pressure to static
:murce opening. Figure 15-3 shows one method of
: taining 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
t-.is altimeter indication while checking for leaks.
'
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 taps 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 pres-
15-4
15-15. BLOWING OUT LINES. Although pitot syster 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.
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 systern 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 hoses
which have cracked, hardened or show other signs of
deterioration.
15-16. REMOVAL AND INSTALLATION OF COMPONENTS. (Refer to 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. If twisting of plastic tubing is
encountered when tightening fittings, W-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.
MODEL R172 SERIES SERVICE MANUAL
4
-
.
.
.
Detail
TRUE AIRSPEED
INSTALLATION
-
-
Detail
B
HEATED
Detail
NOTE
DetailC
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Vertical Speed Indicator
Altimeter
Shock-Mounted Panel
Airspeed Indicator
Pitot Line
Static Line
Mounting Screw
Cover
Retainer
True Airspeed Ring
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
Instrument Panel
Spacer
Connector
Mast Body
Heater Element
Valve
Knob
Insert
Line (to Sump)
Static Sump
Flange
Do not overtighten screws (7)
and do not lubricate any parts.
Use spacers (12) as required
for adequate friction on ring
assembly (10).
Figure 15-2. Pitot Static Systems (Sheet 1 of 2)
15-5
MODEL R172 SERIES SERVICE MANUAL
,
.. -
,
ENCODING ALTIMETER INSTALLATION
-
Detail F
23.
24.
25.
26.
27.
28.
29.
30.
Backup Altimeter
Vertical Speed Indicator
Encoding Altimeter
Static Line
Airspeed Indicator
Pitot Line
Static Line
Cable (to Transponder)
Figure 15-2. Pitot Static Systems (Sheet 2 of 2)
15-6
MODEL R172 SERIES SERVICE MANUAL
15-20. TROUBLE SHOOTING--PITOT STATIC SYSTEM.
TROUBLE
PROBABLE CAUSE
REMEDY
LOW OR SLUGGISH AIRSPEED
INDICATION. (Normal altimeter
and vertical speed. )
Pitot tube obstructed, leak or
obstruction in pitot line.
Test pitot tube and line for leaks
or obstructions. Blow out tube
and line, repair or replace damaged line.
INCORRECT OR SLUGGISH
RESPONSE. (all three
instruments. )
Leaks or obstruction in static
line.
Test line for leaks and obstructions. Repair or replace line,
blow out obstructed line.
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.
15-24.
15-23. REMOVAL AND INSTALLATION. (Refer to
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).
TROUBLE SHOOTING--AIRSPEED INDICATOR.
TROUBLE
HAND FAILS TO RESPOND.
INCORRECT INDICATION
OR HAND OSCILLATES.
HAND VIBRATES.
PROBABLE CAUSE
REMEDY
Pitot pressure connection not
properly connected to pressure line from pitot tube.
Test line and connection for leak;.
Repair or replace damaged line.
tighten connections.
Pitot or static lines clogged.
Check line for obstructions.
out lines.
Leak in pitot or static lines.
Test lines and connections for
leaks. Repair or replace damaged lines, tighten connections.
Defective mechanism or
leaking diaphragm.
Substitute known-good indicator
and check reading. Replace
instrument.
Excessive vibration.
Check panel shock mounts. Replace defective shock mounts.
Excessive tubing vibration.
Check clamps and line connections
for security. Tighten clamps and
connections, replace tubing with
flexible hose.
Blow
15-7
MODEL R172 SERIES SERVICE MANUAL
NOTE
Air bulb with check valves may be obtained
locally from a surgical supply company. This
is the type used in measuring blood pressure.
PRESSURE
THICK-WALLED
SURGICAL HOSE
PRESSURE BLEED-OFF
SCREW (CLOSED)
AIR BULB
WITH CHECK
VALVES
CLAMP
CLAMP
THICK-WALLED
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. Continue 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.
15-8
Static Test Equipment
MODEL R172 SERIES SERVICE MANUAL
15-25.
TROUBLE SHOOTING--ALTIMETER
TROUBLE
INSTRUMENT FAILS TO
OPERATE.
INCORRECT INDICATION.
HAND OSCILLATES.
15-26.
PROBABLE CAUSE
REMEDY
Static line plugged.
Check line for obstructions.
Blow out lines.
Defective mechanism.
Substitute known-good altimeter and check reading.
Replace instrument.
Hands not carefully set.
Reset hands with knob.
Leaking diaphragm.
Substitute known-good altimeter and check reading.
Replace instrument.
Pointers out of calibration.
Compare reading with knowngood altimeter. Replace
instrument.
Static pressure irregular.
Check lines for obstruction
or leaks. Blow out lines,
tighten connections.
Leak in airspeed or vertical
speed indicator installations,
Check other instruments and
system plumbing for leaks.
Blow out lines, tighten connections.
TROUBLE SHOOTING--VERTICAL SPEED INDICATOR.
TROUBLE
INSTRUMENT FAILS TO
OPERATE.
INCORRECT INDICATION.
POINTER OSCILLATES.
PROBABLE CAUSE
REMEDY
Static line plugged.
Check line for obstructions.
Blow out lines.
Static line broken.
Check line for damage, connections for security. Repair or replace damaged line,
tighten connections.
Partially plugged static line.
Check line for obstructions.
Blow out lines.
Ruptured diaphragm.
Substitute known-good indicator
and check reading. Replace
instrument.
Pointer off zero.
Reset pointer to zero.
pointer to zero.
Partially plugged static line.
Check line for obstructions.
Blow out lines.
Reset
15-9
MODEL R172 SERIES SERVICE MANUAL
15-26.
TROUBLE SHOOTING--VERTICAL SPEED INDICATOR.
REMEDY
PROBABLE CAUSE
TROUBLE
POINTER OSCILLATES.
(Cont)
(cont).
Leak in static line.
Test lines and connections for
leaks. Repair or replace damaged lines, tighten connections.
Leak in instrument case.
Substitute known-good indicator
and check reading. Replace
instrument.
HAND VIBRATES.
15-27.
Excessive vibration.
Check shock mounts. Replace
defective shock mounts.
Defective diaphragm.
Substitute known-good indicator
and check for vibration. Replace instrument.
TROUBLE SHOOTING--PITOT TUBE HEATER.
TROUBLE
TUBE DOES NOT HEAT OR
CLEAR ICE.
PROBABLE CAUSE
REMEDY
Switch turned "OFF."
Turn switch "ON."
Open circuit breaker.
Reset circuit breaker.
Break in wiring.
Test for open circuit.
Repair
wiring.
Heating element burned out.
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 the 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
15-10
Revision 1
Check resistance of heating
element. Replace element.
differential pressure will gradually decrease as the
central air filter becomes dirty, causing a lower reading on the suction gage. In addition, airplanes
R1722000 and On and FR1720591 and On incorporating SK 72-87 have a red low-vacuum light 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 master switch. The
light illuminates when suction drops below approximately 3.0 inches of mercury.
MODEL R172 SERIES SERVICE MANUAL
15-30.
TROUBLE SHOOTING--VACUUM SYSTEM
PROBABLE CAUSE
TROUBLE
REMEDY
HIGH SUCTION GAGE READINGS.
Gyros function normally-relief
valve screen clogged, relief
valve malfunction.
Check screen, then valve. Compare gage readings with new gage.
Clean screen, reset valve. Replace gage.
NORMAL SUCTION GAGE
READING, SLUGGISH OR
ERRATIC GYRO RESPONSE.
Instrument air filters clogged.
Check Filter.
LOW SUCTION GAGE
READINGS.
Leaks or restriction between
instruments and relief valve,
relief valve out of adjustment,
defective pump.
Check lines for leaks, disconnect
and test pump. Repair or replace
lines, adjust or replace relief
valve, repair or replace pump.
Central air filter dirty.
Check Filter.
Defective gage or sticking relief
valve.
Check suction with test gage.
Replace gage. Clean sticking
valve with Stoddard solvent.
Blow dry and test. If valve
sticks after cleaning, replace
valve.
SUCTION GAGE FLUCTUATES.
15-31.
Replace if Required.
Replace if required.
TROUBLE SHOOTING--GYROS.
TROUBLE
HORIZON BAR FAILS TO
RESPOND.
HORIZON BAR DOES NOT
SETTLE.
PROBABLE CAUSE
REMEDY
Central filter dirty.
Check Filter.
Suction relief valve improperly
adjusted.
Adjust or replace relief valve.
Faulty suction gage.
Substitute known-good suction
gage and check gyro response.
Replace suction gage.
Vacuum pump failure.
Check pump.
Vacuum line kinked or leaking.
Check lines for damage and leaks.
Repair or replace damaged lines,
tighten connections.
Defective mechanism.
Substitute known-good gyro and
check indication. Replace instrument.
Insufficient vacuum.
Adjust or replace relief valve.
Excessive vibration.
Check panel shock-mounts.
Replace defective shock-mounts.
Replace if Required.
Replace pump.
15-11
MODEL R172 SERIES SERVICE MANUAL
15-31.
TROUBLE SHOOTING--GYROS.
TROUBLE
HORIZON BAR OSCILLATES
OR VIBRATES EXCESSIVELY.
EXCESSIVE DRIFT IN
EITHER DIRECTION.
DIAL SPINS IN ONE
DIRECTION CONTINUOUSLY.
SHOP NOTES:
15-12
(Cont).
PROBABLE CAUSE
REMEDY
Replace if Required.
Central filter dirty.
Check Filter.
Suction relief valve improperly adjusted.
Adjust or replace relief 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.
Central air filter dirty.
Check Filter.
Low vacuum, relief valve
improperly adjusted.
Adjust or replace relief valve.
Faulty suction gage.
Substitute known-good suction
gage and check gyro indication.
Replace suction gage.
Vacuum pump failure.
Check pump.
Vacuum line kinked or
leaking.
Check lines for damage and
leaks. Repair or replace damaged lines, tighten connections.
Operating limits have been
exceeded.
Replace instrument.
Defective mechanism.
Substitute known-good gyro
and check indication. Replace
instrument.
Replace if Required.
Replace pump.
MODEL R172 SERIES SERVICE MANUAL
R1722029 thru
R1723373
THRU R1722028
1.
2.
3.
4.
5.
6.
7.
8.
Vacuum Pump
Overboard Vent Tube
Firewall
Bracket
Filter Assembly
Gyro Horizon
Directional Gyro
Suction Gage
,
..
Detail
9. Suction Relief Valve
A
10. Firewall
Figure 15-4.
Vacuum System (Sheet 1 of 2)
15-13
15 -13
MODEL R172 SERIES SERVICE MANUAL
Detai A
BEGINNING WITH R1723374
Figure 15-4.
15-14
Vacuum System (Sheet 2 of 2)
MODEL R172 SERIES SERVICE MANUAL
..............
.
1.
2.
.
....
...........
.
Circuit Breaker Switch
Instrument Panel
.
...
Figure 15-4A. Standby Vacuum System (Sheet 1 of 2)
.
.
Detail
A
Revision 1
15-14A
MODEL R172 SERIES SERVICE MANUAL
~3
3.
4.
Filter Assembly
Relief Valve
5.
Hose (to Gyro Horizon)
Hose (to Directional Gyro)
6.
7.
8.
9.
,
-
.
'
Vent Hose
Nut
10.
Washer
11.
12.
13.
Fittings
Ground Wire
Motor
15.
16.
17.
18.
19.
20.
21.
22.
WaerBolt
23.
Firewall
16
Detail
B
Bracket
Voltage Input Wire
Washer
Nut
Vacuum Pump
Hose
Manifold
Figure 15-4A. Standby Vacuum System (Sheet 2 of 2)
15-14B
Revision 1
MODEL R172 SERIES SERVICE MANUAL
15-32.
TROUBLE SHOOTING--VACUUM PUMP.
REMEDY
PROBABLE CAUSE
TROUBLE
OIL IN DISCHARGE.
Damaged engine drive seal.
Replace gasket.
HIGH SUCTION.
Suction relief valve filter
clogged.
Check Filter.
LOW SUCTION.
Relief valve leaking.
Replace relief valve.
Vacuum pump failure.
Substitute known-good pump
and check pump suction.
Replace vacuum pump.
Safety valve leaking.
Replace safety valve.
Vacuum pump failure.
Substitute known-good pump
and check pump pressure.
Replace vacuum pump.
LOW PRESSURE.
15-33. REMOVAL AND INSTALLATION. For removal and installation of vacuum system components
refer to figure 15-4. The various components of
vacuum system are secured by conventional clamps,
mounting screws and nuts. To remove a component,
remove mounting screws and disconnect inlet and
discharge lines. When replacing a vacuum system
component, ensure connections are made correctly.
Use no thread-lube on any connections. Teflon tape
may be used on male threads. Avoid over-tightening
connections. Before re-installing a vacuum pump,
place mounting pad gasket over studs. After installing pump, before connecting plumbing, start engine
and check for evidence of oil in the discharge which
would indicate a leaking engine drive seal.
15-34. CLEANING. In general, low-pressure, dry
compressed air should be used in cleaning vacuum
system components. Suction relief valve, exposed
to engine oil and dirt, should be washed with Stoddatd solvent, then dried with a low-pressure air
blast. Check hose for collapsed inner liners as well
as external damage.
iCAUTION
Never apply compressed air to lines or components installed 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.
Replace if Required.
Do not exceed maximum engine temperature.
Be sure element is clean before installing. If reading
drops noticeably, install new filter element.
15-35A. STANDBY VACUUM SYSTEM.
15-35B. DESCRIPTION. Airplanes R1722725 and
ON and FR17200621 and On incorporating SK172-88
have an electric standby vacuum system installed. The
system consists of a vacuum pump, driven by an electric motor, mounted on the aft side of the firewall and
associated hoses. 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 cabin air control on the instrument panel, controls and protects the system.
15-35C. REMOVAL AND INSTALLATION. Refer to
figure 15-4A for removal and installation of standby
vacuum pump system.
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 driveshaft. To function properly, shaft housing must be free
ofkinks,
dents and sharp bends. There should
be no
bendkinks
on a radius shorter pbends.There
than six inchesshould
and nobeno
bend
15-35. VACUUM RELIEF VALVE ADJUSTMENT.
of mercury
mercury is
inches of
5. 33 inches
of 5.
A suction gage reading of
is
desirable for gyro instruments. However a rnge
of 4.d
esirable
for gyro instru
of mentrcury is acceptver, a range
within three inches of either terminal. If a tachometer
s acceptab.
is noisyTo
or pointer oscillates, check cable housing for
i mercury
adjust the relief valve, remove control air filter,
kinks, sharp bends and damage. Disconnect cable at
run engine to 2200 rpm on the ground and adjust retachometer and pull it out of housing. Check cable for
lief valve to 5.3 ±. 1 inches of mercury.
worn spots, breaks and kinks.
Revision 1
15-15
MODEL R172 SERIES SERVICE MANUAL
15-39. MANIFOLD PRESSURE/FUEL FLOW INDICATOR.
NOTE
Before replacing a tachometer cable in housing, coat lower two thirds with AC Type ST640 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 torque to
50 pound-inches (at instrument). Refer to
Section 11.
15-41.
TROUBLE SHOOTING -- MANIFOLD PRESSURE GAGE.
TROUBLE
EXCESSIVE ERROR AT EXISTING BAROMETRIC PRESSURE.
JERKY MOVEMENT OF
POINTER.
SLUGGISH OPERATION OF
POINTER.
15-16
15-40. DESCRIPTION. The manifold pressure and
fuel flow indicators are in one instrument case.
However, each instrument operates independently.
The manifold pressure gage is a barometric instrument which indicates absolute pressure in the intake
manifold in inches of mercury. The fuel flow indicator is a pressure instrument calibrated in gallons
per hour, indicating approximate gallons of fuel metered per hour to the engine. Pressure for operating
the indicator is obtained through a hose from the fuel
manifold valve.
PROBABLE CAUSE
REMEDY
Pointer shifted.
Replace instrument.
Leak in vacuum bellows.
Replace instrument.
Loose pointer.
Replace instrument.
Leak in pressure line.
Test line and connections for leaks
Repair or replace damaged line,
tighten connections.
Condensate or fuel in line.
Check line for obstructions.
Blow out line.
Excessive internal friction.
Replace instrument.
Rocker shaft screws tight.
Replace instrument.
Link springs too tight.
Replace instrument.
Dirty pivot bearings.
Replace instrument.
Defective mechanism.
Replace instrument.
Leak in pressure line.
Test line and connections for leaks
Repair or replace damaged line,
tighten connections.
Foreign matter in line.
Check line for obstructions.
Blow out line.
Damping needle dirty.
Replace instrument.
Leak in pressure line.
Test line and connections for leaks
Repair or replace damaged line,
tighten connections.
MODEL R172 SERIES SERVICE MANUAL
15-41.
TROUBLE SHOOTING--MANIFOLD PRESSURE GAGE (Cont.)
TROUBLE
EXCESSIVE POINTER
VIBRATION.
PROBABLE CAUSE
REMEDY
Tight rocker pivot bearings.
Replace instrument.
Excessive vibration.
Check panel shock-mounts.
Replace defective shock-mounts.
IMPROPER CALIBRATION.
Faulty mechanism.
Replace instrument.
NO POINTER MOVEMENT.
Faulty mechanism.
Replace instrument.
Broken pressure line.
Check line and connections for
breaks.
Repair or replace damaged line.
15-42.
TROUBLE SHOOTING -- FUEL FLOW INDICATOR.
TROUBLE
DOES NOT REGISTER.
POINTER FAILS TO
RETURN TO ZERO.
INCORRECT OR ERRATIC
READING.
PROBABLE CAUSE
REMEDY
Pressure line clogged.
Check line for obstructions.
Blow out line.
Pressure line broken.
Check line for damage or leaks.
Repair or replace damaged line.
Fractured bellows or
damaged mechanism.
Replace instrument.
Clogged snubber orifice.
Replace instrument.
Pointer loose on shaft
Replace instrument.
Foreign matter in line.
Check line for obstructions.
Blow out line.
Clogged snubber orifice.
Replace instrument.
Damaged bellows or
mechanism.
Replace instrument.
Damaged or dirty mechanism.
Replace instrument.
Pointer bent, rubbing
on dial or glass.
Replace instrument.
Leak or partial obstruction in pressure or vent
line.
Check line for obstructions
or leaks.
Blow out dirty line, repair
or tighten loose connections.
15-17
MODEL R172 SERIES SERVICE MANUAL
15-43. CYLINDER HEAD TEMPERATURE GAGE
15-44. 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.
15.45
Torque on lead nut at sending unit is not to exceed
4 inch-pounds. The Rochester and Stewart-Warner
gages are connected the same. but the Rochester gage
does not have a calibration pot and cannot be adjusted.
Refer to Table 1, page 15-22A, when trouble shooting
the cylinder head temperature gage
TROUBLE SHOOTING.
TROUBLE
GAGE INOPERATIVE.
REMEDY
PROBABLE CAUSE
Check circuit breaker and electrical
circuit to gage.
No current to circuit.
Repair electrical circuit.
Defective gage. bulb or circuit.
Isolate with ohmmeter check of
circuits.
Repair or replace defective items.
GAGE FLUCTUATES
RAPIDLY.
GAGE READS TOO
HIGH ON SCALE.
GAGE READS TOO
LOW ON SCALE.
GAGE READS OFF
SCALE AT HIGH END.
OBVIOUSLY INCORRECT
READING.
Loose or broken wire permitting
alternate make and break of
gage circuit.
Inspect circuit wiring.
High voltage.
Check voltage supply.
Gage off calibration.
Replace gage.
Low voltage.
Check voltage supply.
Gage off calibration
Replace gage.
Break in bulb.
Replace bulb.
Break in bulb lead.
Replace bulb.
Internal break in bulb.
Replace bulb.
Defective gage mechanism
Replace gage.
Incorrect calibration.
Replace gage.
15-46. OIL PRESSURE GAGE.
15-47. DESCRIPTION. The Bourdon tube-type oil
pressure gage is a direct-reading instrument, operated
by a pressure pickup line connected to the engine
15-18
Revision 1
Repair or replace defective items.
main oil gallery. The oil pressure line from the
instrument to the engine should be filled with
kerosene, especially during cold weather operation.
to attain an immediate oil indication.
MODEL R172 SERIES SERVICE MANUAL
15-48. TROUBLE SHOOTING.
TROUBLE
GAGE DOES NOT REGISTER.
GAGE POINTER FAILS TO
RETURN TO ZERO.
GAGE DOES NOT REGISTER
PROBABLE CAUSE
REMEDY
Pressure line clogged.
Check line for obstructions.
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 shaft.
Replace instrument.
Damaged gage movement.
Replace instrument.
Foreign matter in line.
Check line for obstructions.
Clean line.
Foreign matter in Bourdon
tube.
Replace instrument.
Bourdon tube stretched.
Replace instrument.
Faulty mechanism.
Replace instrument.
Worn or bent movement.
Replace instrument.
Foreign matter in Bourdon
tube.
Replace instrument.
Dirty or corroded movement.
Replace instrument.
Pointer bent and rubbing on
dial, dial screw or glass.
Replace instrument.
Leak in pressure line.
Check line for leaks and damage.
Repair or replace damaged line.
PROPERLY.
GAGE HAS ERRATIC
OPERATION.
15-49. OIL TEMPERATURE GAGE.
15-50. DESCRIPTION. The oil temperature gage is
an electrically operated indicator, located in the
instrument cluster. The gage is connected by a single
wire to a sending unit located in the engine oil passage
above the oil cooler. The gage and sending unit
requires little or no maintenace other than cleaning,
making sure the lead is properly supported and all
connections are clean, tight and properly insulated.
Refer to Table 2. page 15-22B, when trouble shooting
the oil temperature gage.
Revision 1
15-19
|
MODEL R172 SERIES SERVICE MANUAL
15-51.
ECONOMY MIXTURE INDICATOR (EGT)
DESCRIPTION. The economy mixture indi15-52.
cator 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 intering the engine cylinders. Refer to the Pilots
Operating Handbook for operating procedures.
CALIBRATION. A potentiometer adjustment
15-53.
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 inlevel 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).
NOTE
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 to 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.
15-54. REMOVAL AND INSTALLATION. (Refer to
figure 15-5.)
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 convenient
out of the way location.
This setting will provide selective temperature indications for normal cruise power
settings within range of the instrument.
15-55.
TROUBLE SHOOTING.
TROUBLE
PROBABLE CAUSE
REMEDY
GAGE INOPERATIVE
Defective gage, probe or circuit
Repair or replace defective part.
INCORRECT READING
Indicator needs calibrating
Calibrate indicator in accordance
with paragraph 15-53.
FLUCTUTATING READING
Loose, frayed or broken
lead, permitting alternate
make and break of circuit,
Tighten connections and repair or replace defective
leads.
15-20
MODEL R172 SERIES SERVICE MANUAL
Detail
A
5
Figure 15-5.
6
7
1.
2.
3.
4.
5.
6.
Probe
Panel Cover
Screw
Instrument Panel
Indicator
Lockwasher
7.
Nut
Economy Mixture Indicating System E.G.T.
15-21
MODEL R172 SERIES SERVICE MANUAL
15-56.
FUEL QUANTITY INDICATING SYSTEM.
c. Disconnect electrical lead and ground strap/wire
from transmitter.
d. Remove screws attaching transmitter and carefully work transmitter from tank. DO NOT BEND
FLOAT ARM.
e. Install transmitter by reversing preceding steps,
using new gaskets around opening in fuel tank and
under screw heads. Be sure to tighten screws evenly.
f. When re-installing the transmitter access plate
on the extended range fuel system the sealing procedures outlined in Section 12 should be followed.
g. Service fuel tanks. Check for leaks and correct
quantity indication.
15-57. DESCRIPTION. The magnetic type fuelquantity indicators are used in conjunction with a floatoperated 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 transmitter is increased,
producing a decreased current flow through fuel quantity indicator and a smaller pointer deflection.
15-58.
REMOVAL AND INSTALLATION OF FUEL
QUANTITY TRANSMITTERS.
a. Drain fuel from tank. (Observe precautions in
Section 12.
b. Remove access plate above fuel tank for access
to transmitter.
15-59.
Ensure transmitter is properly grounded in
accordance with Section 12.
TROUBLE SHOOTING.
TROUBLE
FAILURE TO INDICATE.
OFF CALIBRATION.
STICKY OR SLUGGISH
INDICATOR OPERATION.
ERRATIC READINGS.
15-22
NOTE
PROBABLE CAUSE
REMEDY
No power to indicator or transmitter. (Pointer stays below E.)
Check fuse and inspect for open
circuit. Replace fuse, repair
or replace defective wire.
Grounded wire.
above F.)
Check for partial ground between
transmitter and gage. Repair or
replace defective wire.
(Pointer stays
Low voltage.
Check voltage at indicator.
Correct voltage.
Defective indicator.
Substitute known-good indicator.
Replace indicator.
Defective indicator.
Substitute known-good indicator.
Replace indicator.
Defective transmitter.
Substitute known-good transmitter.
Recalibrate or replace.
Low or high voltage.
Check voltage at indicator.
Correct voltage.
Defective indicator.
Substitute known-good indicator.
Replace indicator.
Low voltage.
Check voltage at indicator.
Correct voltage
Loose or broken wiring on
indicator or transmitter.
Inspect circuit wiring.
Repair or replace defective wire.
Defective indicator or transmitter.
Substitute known-good component.
Replace indicator or transmitter.
Defective master switch.
Replace switch.
MODEL R172 SERIES SERVICE MANUAL
.
TRANSMITTER CALIBRATION.
15-60.
WARNING
Using the following fuel transmitter calibration procedure on components other
than the originally installed (Stewart Warner) components will result in a
faulty fuel quantity reading.
15-60A.
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 become 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 transmitter in accordance with paragraph 15-49.
15-60B.
ROCHESTER GAGE TRANSMITTER. Do not attempt to adjust float arm or stop. No adjustment is allowed.
Table 1
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 temperature column.
200°F
22
0
F
450°F
475°F
Part Number
Type
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
Revision 1
15-22A
MODEL R172 SERIES SERVICE MANUAL
Table 2
NOTE
Select the oil temperature sending unit part number from the left column and
the temperature from the column headings. Read the ohms value under the appropriate temperature column.
72°F
120°F
165°F
220°F
250°F
Part Number
Type
S1630-1
Oil Temp
S1630-3
Oil Temp
620.0
52.4
S1630-4
Oil Temp
620.0
52.4
S1630-5
Oil Temp
S2335-1
Oil Temp
15-22B
Revision 1
46.4
192.0
990.0
34.0
MODEL R172 SERIES SERVICE MANUAL
15-60 TRANSMITTER ADJUSTMENT.
(Refer to page 15-24A.)
15-63. MAGNETIC COMPASS.
15-64. DESCRIPTION. The magnetic compass is
liquid-filled, with expansion provisions to compensate
for temperature changes. It is equipped with compensating magnets adjustable from front of case. The compass is internally lighted, controlled by the panel
lights rheostat. No maintenance is required on compass except an occasional check on a compass rose for
adjustment of compensation and replacement of lamp.
15-61. HOURMETER. (Refer to figure 15-6.)
15-62. DESCRIPTION. The hourmeter is electrically
operated and is actuated by a pressure switch in the oil
system. Electrical power is supplied through a oneamp fuse from the electrical clock circuit and therefore, will not 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 meter is inoperative
and clock is operating, the meter or its wiring is faulty
and must be replaced.
NOTE
Hourmeters installed in some later aircraft
and later spares incorporate adiode. These
are identified only by awhite "+ " above the
positive terminal. When installing this
type hourmeter, the positive wire (red on
factory equipped aircraft) must be con-
15-65. REMOVAL AND INSTALLATION. Refer to
figure 15-6 for removal and installation.
15-66. STALL WARNING SYSTEM.
15-67. 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 approximately 5 to 10 knots above
stalling speed as a negative air pressure area at wing
leading edge causes a reverse flow of air through the
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. Approximately 3/32 inch adjustment of plate will change speed at which horn actuation occurs by 5 miles per hour. 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.
nected to the white " + " terminal. Connect-
ing wires incorrectly will damage the meter.
15-68. REMOVAL AND INSTALLATION. Refer to
figure 15-6 for removal and installation.
SHOP NOTES:
Revisiun i
15-23
MODEL R172 SERIES SERVICE MANUAL
Detail A
16
Detail D
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Doorpost Cover
Horn Assembly
Scoop
Adapter
Felt Seal
Adjustable Plate
Screen
Compass
Compass Card
Bracket
Hourmeter
Adapter
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
Pressure Switch
Positive Wire
Ground Wire
Wire from Clock
Circuit
O.A.T. Gage
Rubber Washer
Knob
Air Vent
Washer
Plastic Washer
Nut
Detail C
NOTE
Bug screen (7) should be inspected
and cleaned periodically.
Figure 15-6. Miscellaneous Instruments and Stall Warning System
15-24
MODEL R172 SERIES SERVICE MANUAL
15-60.
WARNING: USING THE FOLLOWING FUEL TRANSMITTER CALIBRATION PROCEDURES ON
COMPONENTS OTHER THAN THE ORIGINALLY INSTALLED (STEWART WARNER)
COMPONENTS WILL RESULT IN A FAULTY FUEL QUANTITY READING.
15-60A.
STEWART WARNER GAGE TRANSMITTER CALIBRATION
Chances of transmitter calibration changing in normal service is remote; however it is possible that the
float arm or the float arm stops may become bent if the transmitter is removed from the fuel cell/tank.
Transmitter calibration is obtained by adjusting float travel. Float travel is limited by the 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 the master switch in the "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 the 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
transmitter in accordance with paragraph 15-49.
15-60B.
ROCHESTER FUEL GAGE TRANSMITTER
Do not attempt to adjust float arm or stop. No adjustment is allowed.
15-60C.
FUEL QUANTITY INDICATING SYSTEM OPERATIONAL TEST
WARNING:
REMOVE ALL IGNITION SOURCES FROM THE AIRPLANE AND VAPOR HAZARD
AREA. SOME TYPICAL EXAMPLES OF IGNITION SOURCES ARE STATIC
ELECTRICITY, ELECTRICALLY POWERED EQUIPMENT (TOOLS OR ELECTRONIC
TEST EQUIPMENT - BOTH INSTALLED ON THE AIRPLANE AND GROUND
SUPPORT EQUIPMENT), SMOKING AND SPARKS FROM METAL TOOLS.
WARNING:
OBSERVE ALL STANDARD FUEL SYSTEM FIRE AND SAFETY PRACTICES.
1. Disconnect all electrical power from the airplane. Attach maintenance warning tags to the battery
connector and external power receptacle stating:
DO NOT CONNECT ELECTRICAL POWER, MAINTENANCE IN PROGRESS.
2. Electrically ground the airplane.
3.
Level the airplane and drain all fuel from wing fuel tanks.
4.
Gain access to each fuel transmitter float arm and actuate the arm through the transmitter's full
range of travel.
A. Ensure the transmitter float arm moves freely and consistently through this range of travel.
Replace any transmitter that does not move freely or consistently.
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.
Temporary Revision Number 4
7 October 2002
©2002 Cessna Aircraft Company
15-24A
MODEL R172 SERIES SERVICE MANUAL
B. While the transmitter float arm is being actuated, apply airplane battery electrical power as required
to ensure that the fuel quantity indicator follows the movement of the transmitter float arm. If this
does not occur, troubleshoot, repair and/or replace components as required until the results are
achieved as stated.
NOTE: Stewart Warner fuel quantity indicating systems can be adjusted. Refer to paragraph 1560A for instructions for adjusting Stewart Warner fuel indicating systems.
Rochester fuel quantity indicating system components are not adjustable, only component
replacement or standard electrical wiring system maintenance practices are permitted.
5. With the fuel selector valve in the "OFF" position, add unusable fuel to each fuel tank.
6. Apply electrical power as required to verify the fuel quantity indicator indicates "EMPTY".
A. If "EMPTY" is not indicated, adjust, troubleshoot, repair and/or replace fuel indicating components
as required until the "EMPTY" indication is achieved.
NOTE: Stewart Warner fuel quantity indicating systems can be adjusted. Refer to paragraph 1560A for instructions for adjusting Stewart Warner fuel indicating systems.
Rochester fuel quantity indicating system components are not adjustable, only component
replacement or standard electrical wiring system maintenance practices are permitted.
7. Fill tanks to capacity, apply electrical power as required and verify fuel quantity indicator indicates
"FULL".
A. If "FULL" is not indicated, adjust, troubleshoot, repair and/or replace fuel indicating components as
required until the "FULL" indication is achieved.
NOTE: Stewart Warner fuel quantity indicating systems can be adjusted. Refer to paragraph 1560A for instructions for adjusting Stewart Warner fuel indicating systems.
Rochester fuel quantity indicating system components are not adjustable, only component
replacement or standard electrical wiring system maintenance practices are permitted.
8. Install any items and/or equipment removed to accomplish this procedure, remove maintenance warning
tags and connect the airplane battery.
15-60D. CYLINDER HEAD TEMPERATURE INDICATING SYSTEM RESISTANCE TABLE 1
The following table is provided to assist in the troubleshooting the cylinder head temperature indicating
system components.
Select the cylinder head temperature sending unit part number that is used in your airplane from the left
column and the temperature from the column headings. Read the ohms value under the appropriate
temperature column.
Part Number
S1372-1
S1372-2
S1372-3
S1372-4
S2334-3
S2334-4
Type
CHT
CHT
CHT
CHT
CHT
CHT
200°F
220°F
310.0
310.0
450°F
34.8
34.8
113.0
113.0
745.0
745.0
475°F
38.0
38.0
Temporary Revision Number 4
15-24B
© 2002 Cessna Aircraft Companv
7 October 2002
MODEL R172 SERIES SERVICE MANUAL
15-60E.
OIL TEMPERATURE INDICATING SYSTEM RESISTANCE TABLE 2
The following table is provided to assist in the troubleshooting the oil temperature indicating system
components.
Select the oil temperature sending unit part number that is used in your airplane from the left column
and the temperature from the column headings. Read the ohms value under the appropriate
temperature column.
Part Number
S1630-1
S1630-3
S1630-4
S1630-5
S2335-1
Type
Oil Temp
Oil Temp
Oil Temp
Oil Temp
Oil Temp
Temporary Revision Number 4
7 October 2002
72°F
120°F
165°F
220°F
46.4
250°F
52.4
52.4
620.0
620.0
192.0
990.0
© 2002 Cessna Aircraft Company
34.0
15-24C
MODEL R172 SERIES SERVICE MANUAL
15-69.
TURN COORDINATOR.
15-70. DESCRIPTION. The turn coordinator is an
electrically operated, gyroscopic, roll-rate turn
indicator. Its gyro simultaneously senses rate of
15-71.
motion roll and yaw axes which is projected on a
single indicator. The gyro is a non-tumbling type
requiring no caging mechanism and incorporates an
a. e. brushless spin motor with a solid state inverter.
TROUBLE SHOOTING.
TROUBLE
INDICATOR DOES NOT
RETURN TO CENTER.
PROBABLE CAUSE
REMEDY
Friction caused by contamination
in the indicator damping.
Replace instrument.
Friction in gimbal assembly.
Replace instrument.
Low voltage.
Measure voltage at instrument.
Correct voltage.
Inverter frequency changed.
Replace instrument.
NOISY MOTOR
Faulty bearings.
Replace instrument.
ROTOR DOES NOT START.
Faulty electrical connection.
Check continuity and voltage.
Correct voltage or replace
faulty wire.
Inverter malfunctioning.
Replace instrument.
Motor shorted.
Replace instrument.
Bearings frozen.
Replace instrument.
Oil in indicator becomes
too thick.
Replace instrument.
Insufficient bearing end play.
Replace instrument.
Low voltage.
Check voltage at instrument.
Correct voltage.
High voltage.
Check voltage to instrument.
Correct voltage.
Loose or defective rotor
bearings.
Replace instrument.
DOES NOT INDICATE A
STANDARD RATE TURN
(TOO SLOW).
IN COLD TEMPERATURES,
HAND FAILS TO RESPOND
OR IS SLUGGISH.
NOISY GYRO.
15-25
MODEL R172 SERIES SERVICE MANUAL
15-72.
TURN-AND-SLIP INDICATOR.
15-73.
DESCRIPTION.
15-74.
TROUBLE SHOOTING.
The turn-and-slip indicator
TROUBLE
INDICATOR POINTER FAILS TO
RESPOND.
is an electrically operated instrument powered by the
aircraft electrical system, therefore, operating only
when the master switch is ON.
PROBABLE CAUSE
REMEDY
Internal fuse blown.
Check wiring for continuity,
check voltage at indicator.
Replace fuse, if fuse still
blows, replace instrument.
Master switch "OFF" or
switch defective.
Check switch "ON."
defective switch.
Broken or grounded lead to
indicator.
Check circuit wiring. Repair
or replace defective wiring.
Indicator not grounded.
Check ground wire. Repair
or replace defective wire.
Defective mechanism.
Replace instrument.
Defective mechanism.
Replace instrument.
Low voltage.
Check voltage at indicator.
Correct voltage.
POINTER DOES NOT INDICATE
PROPER TURN.
Defective mechanism.
Replace instrument.
HAND DOES NOT SIT
ON ZERO.
Gimbal and rotor out of balance.
Replace instrument.
Hand incorrectly sits on rod.
Replace instrument.
Sensitivity spring adjustment
pulls hand off zero.
Replace instrument.
Oil in indicator becomes too
thick.
Replace instrument.
Insufficient bearing end play.
Replace instrument.
Low voltage.
Check voltage at indicator.
Correct voltage.
High voltage.
Check voltage at indicator.
Correct voltage.
Loose or defective rotor
bearings.
Replace instrument.
HAND SLUGGISH IN
RETURNING TO ZERO.
IN COLD TEMPERATURES,
HAND FAILS TO RESPOND
OR IS SLUGGISH.
NOISY GYRO.
15-75. OUTSIDE AIR TEMPERATURE GAGE
(Refer to figure 15-6. )
15-26
Replace
MODEL R172 SERIES SERVICE MANUAL
SECTION 16
ELECTRICAL SYSTEMS
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.
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
ELECTRICAL SYSTEMS. . ....
2B9/16-2
General ........
2B9/16-2
Electrical Power Supply System . 2B9/16-2
Description ..
....
. 2B9/16-2
Split Bux Bar .
.
. 2B9/16-2
Description ......
2B9/16-2
Master Switch .......
2B9/16-2
Description ......
2B9/16-2
Ammeter .......
2B9/16-2
Description ......
2B9/16-2
Battery Power System .....
2B9/16-2
Battery ..........
2B9/16-2
Description ..
2B9/16-2
Removal and Installation. 2B9/16-2
Trouble Shooting .
2B12/16-5
Cleaning the Battery . . 2B13/16-6
Adding Electrolyte or
Water to Battery . .
2B13/16-6
Testing the Battery ..
2B13/16-6
Charging the Battery
2B16/16-9
Battery Box ...
2B18/16-11
Description ......
2B18/16-11
Removal and Installation. 2B18/16-11
Maintenance of Battery
Box ..
.....
. 2B18/16-11
Battery Contactor ...
. 2B18/16-11
Description ..
2B18/16-11
Removal and Installation. 2B18/16-11
Battery Contactor Closing
Circuit .
.
. 2B18/16-11
Description ....
2B18/16-11
Ground Service Receptacle . .
2B18/16-11
Description .......
2B18/16-11
Trouble Shooting .
.
. 2B19/16-12
Removal and Installation . . 2B20/16-13
Alternator Power System ..
..
2B20/16-13
Description ...
2B20/16-13
Alternator .....
2B20/16-13
Description .
.
2B20/16-13
Trouble Shooting the
Alternator System
(Thru 1977 Models) .
2B22/16-16
Trouble Shooting the
Alternator System
(1978 Models) ....
2C1/16-18
Trouble Shooting the
Alternator System
(Beginning With
1979 Models) ...
. 2C4/16-21
Removal and Installation. 2C7/16-24
Over-Voltage Warning System.
. 2C7/16-24
Description ...
2C7/16-24
Alternator Voltage Regulator . . 2C7/16-24
Description ...
2C7/16-24
Alternator Control Unit ....
2C7/16-24
Description ........
2C8/16-25
Removal and Installation
2C8/16-25
Rigging Throttle-Operated Micro
Switch
...........
2C8/16-25
Auxiliary Electrical Fuel Pump
Flow Rate Adjustment
....
2C8/16-25
Aircraft Lighting System ....
2C12/16-29
Description ........
2C12/16-29
Trouble Shooting ..
. 2C12/16-29
Landing and Taxi Lights (Dual). . 2C16/16-33
Description ...
.
2C16/16-33
Removal and Installation . . 2C16/16-33
Adjustment ...
2C16/16-33
Navigation Lights.
L
....
.... 2C16/16-33
Description ...
.
2C16/16-33
Removal and Installation . .2C16/16-33
Anti-Collision Strobe Light . ..
2C16/16-33
Description ...
.
2C16/16-33
Removal and Installation . .2C16/16-33
Operational Requirements .
2C16/16-33
Flashing Beacon ....
2C19/16-36
Description ........
2C19/16-36
Removal and Installation . .2C19/16-36
Instrument, and Dome Lights
.2C19/16-36
Description ...
2C19/16-36
Removal and Installation . . 2C19/16-36
Courtesy Lights ...
.
2C19/16-36
Description ...
.
2C19/16-36
Removal and Installation.. .
2C19/16-36
Compass and Radio Dial Lighting. 2C19/16-36
Description ...
.
2C19/16-36
Instrument Post Lighting ....
2C19/16-36
Description ...
2C19/16-36
Removal and Installation .
2C19/16-36
Transistorized Light Dimming .
2C19/16-36
Description ...
.
2C19/16-36
Removal and Installation . . 2C19/16-36
Map Lighting
...
.
2C19/16-36
Description ...
.
2C19/16-36
Removal and Installation .
2C19/16-36
Control Wheel Map Light ....
2C24/16-41
Description ........
2C24/16-41
Removal and Installation
.
2C24/16-41
16-1
MODEL R172 SERIES SERVICE MANUAL
...
.......
Pitot Heater
Description ...
.
Cigar Lighter .........
.
Description ...
Clock .......
.
Description ...
Emergency Locator Transmitter
(Thru R1722287) .......
.
Description .
Operation
.........
Checkout Interval
.
Removal and Installation of
.
Transmitter ....
Removal and Installation of
Antenna ........
Removal and Installation of
Lithium Four Cell
Battery Pack
......
16-1.
2C24/16-41
2C24/16-41
2C24/16-41
2C24/16-41
2C24/16/41
2C24/16-41
2D4/16-45
2D4/16-45
2D4/16-45
2D4/16-45
2D4/16-45
2D6/16-47
2D6/16-47
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.
16-3.
ELECTRICAL POWER SUPPLY SYSTEM.
16-4. DESCRIPTION. Electrical energy for the aircraft is supplied by a 14-volt, direct current, singlewire, 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 are controlled by a master
switch. This 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.
16-2
Trouble Shooting .
. . . 2D6/16-47
Emergency Locator Transmitter
(Beginning with R1722288) . . . 2D8/16-49
2D8/16-49
Description ...
..
2D8/16-49
Operation ..
. 2D8/16-49
.
Checkout Interval .
Removal and Installation of
2D8/16-49
Transmitter
Removal and Installation of
2D11/16-52
Antenna ...
.
Removal and Installation of
2D11/16-52
.
Battery Pack
2D11/16-52
Trouble Shooting ......
2D13/16-54
Electrical Load Analysis Chart.
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 speed, 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 1977 models a 12-volt
battery with an approximate 25 ampere-hour capacity
is installed. Beginning with 1979 models the battery
is 24-volt with an approximate 12.75 ampere-hour
capacity as standard and a optional battery with an
approximate 15.5 ampere hour rating. The battery
is mounted in the tailcone on the left hand side,
aft of the baggage compartment. The battery is
equipped with non-spill filler caps.
16-14. REMOVAL AND INSTALLATION. (See
figure 16-2.)
CAUTION
When installing or removing battery always
observe the proper polarity with the aircraft electrical system (negative to ground),
reversing the polarity, even momentarily,
may result in failure of semiconductor devices (alternator diodes, radio proteaction
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 aft floor of baggage compartment for
access to the battery.
2. Remove battery box cover.
3. Disconnect the ground cable from the negative
MODEL R172 SERIES SERVICE MANUAL
Detail
3.
Brake
6. Circuit
Lockwasher
9.
A
Bar
e^ s3
8
Detail
B
Figure 16-1.
4
THRU 1980 MODELS
2.
Bus
5.
Decorative Panel
7.
8.
9.
10.
Nut
Screw
Lockwasher
Jumper Wire
Circuit Breaker and Bus Bar Installation (Sheet 1 of 2)
16-3
MODEL R172 SERIES SERVICE MANUAL
TO CIGAR LIGHTER
BEGINNING WITH 1981 MODELS
Figure 16-1. Circuit Breaker and Bus Bar Installation (Sheet 2 of 2)
16-4
MODEL R172 SERIES SERVICE MANUAL
4. Disconnect the cable from the positive terinal of the battery.
5. Lift the battery out of the battery box.
6. To install battery, reverse this procedure.
b. BEGINNING WITH 1980 MODELS,
1. Remove aft floor of baggage compartment for
access to the battery.
2. Disconnect the ground strap from the negative
battery terminal.
3. Cut sta-strap and remove cover from the
positive terminal, then remove positive cable.
4. Release clamp on battery drain tube and
remove tube from battery,
5. Remove hold down bolts and cover from the
battery.
6. Remove battery from aircraft.
7. To install the battery, reverse this procedure.
16-15. TROUBLE SHOOTING THE BATTERY POWER SYSTEM.
TROUBLE
BATTERY WILL NOT SUPPLY
POWER TO BUS OR IS INCAPABLE OF CRANKING ENGINE.
PROBABLE CAUSE
REMEDY
Battery discharged.
1. Measure voltage at "BAT"
terminal of battery contactor
with master switch and a suitable 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 fliud level in cells
and charge 12-volt battery at
14 volts or 24-volt battery at
28 volts for approximately 30
minutes or until battery voltage
rises to 14 volts on 12-volt battery or 28 volts on 24-volt battery. If tester indicates a good
battery, the malfunction may be
assumed to be a discharged battery. If the tester indicates a
faulty battery, replace the
battery.
Faulty contactor or wiring
between contactor or master
switch.
3. Measure voltage at master
switch terminal (smallest) on
contactor with master switch
closed. Normal indication 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.
Normal 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.
16-5
MODEL R172 SERIES SERVICE MANUAL
16-15. TROUBLE SHOOTING THE BATTERY SYSTEM (Cont.)
TROUBLE
PROBABLE CAUSE
Faulty contactor contacts.
5. Check voltage on "bus"
side of contactor with master
switch closed. Meter normally
indicates battery voltage. If
voltage is zero or intermittant,
replace contactor. If voltage
is normal, proceed to step 6.
Faulty wiring between contactor and bus.
6. Inspect wiring between contactor and bus. Repair or replace wiring.
BATTERY WILL NOT SUPPLY
POWER TO BUS OR IS INCAPABLE OF CRANKING ENGINE.
(Cont.)
16-16. CLEANING THE BATTERY. For maximum
efficiency the battery and connections should be kept
clean at all times.
a. Remove the battery and connections 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 the 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 to the preceding
paragraph.
g. Coat the battery terminals with petroleum jelly
or an ignition spray product to reduce corrosion.
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 R1722725 thru R1722776 and FR1722725 thru FR1722776 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,
16-6
REMEDY
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 Manufacturers.
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.
BATTERY HYDROMETER READINGS
READINGS
1. 280 Specific Gravity
BATTERY
CONDITION
100% Charged
1. 250 Specific Gravity
75% Charged
1. 220 Specific Gravity
50% Charged
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 readings will be slightly higher. Some hydrometers will have a built-in temperature
compensation chart and thermometer. If
this type tester is used, disregard this
chart.
MODEL R172 SERIES SERVICE MANUAL
Detail
B
12 AND 24 VOLT
1. Nut
2. Lockwasher
3. Washer
4. Insulating Washer
5.
Fuse-Battery Contactor
Closing Circuit
6. Fuse-Clock
7.
Bracket-Fuse Mounting
8. Resistor
9.
10.
11.
12.
Diode
Solder Terminal
Spacer1
Screw
13.
14.
15.
16.
17.
18.
19.
Battery Box Lid
Battery
Battery Box
Nylon Cover
Wire to Fuses
Diode Wire
Positive Battery Cable
20. Master Switch Wire
21. Bolt
22. Battery
24.
25.
26.
27.
tactor Closing Circuit
External Power Cable
Battery Drain Tube
Clamp16
Negative Ground Strap
24
Detail A
THRU 1977 MODELS
Figure 16-2. Battery and Electrical Equipment Installation (Sheet 1 of 4)
16-7
MODEL R172 SERIES SERVICE MANUAL
..........
Detail
2. Mounting Bracket
9. Diode Assembly. -
.-
15. Bolt
,
6. Nylon Cover
3. Battery Box
4. Battery Box Strap
5. Battery Box Lid
6. Nylon Cover
7. Sta-strap
13.
10.
11.
12.
13.
Nut
Detail A
Battery Contactor
Washer
Lockwasher
Nut
16.
17.
18.
19.
20.
Battery
Wire (to Master Switch)
Wire (to Starter)
Starter Contactor
Wire (to Battery Contactor)
Wire (to Ignition Switch)
Figure 16-2. Battery and Electrical Equipment Installation (Sheet 2 of 4)
16-8
MODEL R172 SERIES SERVICE MANUAL
16-19. CHARGING THE BATTERY. When the battery is to be charged, the level of the 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.
,
Detail B
-
Detail
A
BEGINNING WITH 1980 MODELS
1.
2.
3.
4.
5.
6.
7.
8.
9.
Nylon Cover
Sta-strap
Nut
Lockwasher
Battery Contactor
Washer
Bolt
Cover (Battery)
Battery
10.
11.
12.
13.
14.
15.
16.
17.
Terminal Cover
Positive Cable
Clamp
Elbow
Sta-strap
Drain Tube
Ground Strap
Diode
18.
19.
20.
21.
22.
23.
24.
25.
26.
Rubber Boot
Cable (to Starter Contactor)
Wire (to Ignition Switch)
Wire (to Starter)
Wire (to Ammeter)
Wire (to Battery Contactor)
Cover
Ground Wire
Starter Contactor
Figure 16-2. Battery and Electrical Equipment Installation (Sheet 3 of 4)
16-9
MODEL R172 SERIES SERVICE MANUAL
-
C
Detail
1. Cover
2. Sta-strap
3. Diode Assembly
4. Jumper Wire
5.
6.
7.
8.
9.
Positive Battery Cable
Battery Contactor
Wire ( to Master Switch)
Wire (to Starter Contactor)
Bolt
10.
Battery Cover
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Battery
Clamp
Drain Tube
Cover Positive Terminal
Positive Cable
Elbow
Mounting Bracket
Aircraft Skin
Grommet
Ground Strap
13
Detail A
Figure 16-2. Battery and Electrical Equipment Installation (Sheet 4 of 4)
16-10
MODEL R172 SERIES SERVICE MANUAL
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.
16-21. DESCRIPTION. The battery is completely
enclosed in a box which is painted with acid proof
paint. The box has a vent tube which protrudes
through the bottom of the aircraft allowing battery
gasses and spilled electrolyte to escape. The battery
box is riveted to mounting brackets in the tailcone thru
1977 models, beginning with 1978 models the battery
box is held in place by a strap riveted to the mounting
brackets.
16-22. REMOVAL AND INSTALLATION. (Refer to
figure 16-2. ) Thru 1977 models to remove the battery
box, drill out rivets securing the box to the mounting
brackets. When a battery box is installed , all rivets
and scratches inside the box should be painted with acid
proff lacquer Part No. CES1054-381, available from
the Cessna Service Parts Center. Beginning with 1978
models the box is held in place by straps riveted to
the mounting brackets.
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 a bracket aft of the battery box beginning with 1978
models. The contactor is plunger type 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 on the contactor terminals to prevent accidental
short circuits.
16-26. REMOVAL AND INSTALLATION. (See
figure 16-2. )
a. Remove aft floor of baggage compartment
b. Remove battery box cover and disconnect ground
cable from negative battery terminal.
c. Cut sta-straps and remove nylon cover/covers
from contactor/terminals.
d. Remove nuts, washers securing battery cable
and starter contactor cable.
e. Remove nut, washer securing ignition switch
wire.
f. Remove bolt, washer and nut securing each side
of the battery contactor and remove the contactor.
g. To install battery contactor, reverse the preceding steps, be sure to install diode assembly if removed.
16-27.
BATTERY CONTACTOR CLOSING CIRCUIT.
16-28. DESCRIPTION. This circuit consists of a
5 amp fuse, a resistor and a diode located on a
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 maintenance. A reverse
polarity protection system is utilized whereby ground
power must pass through an external power contactor
to be connected 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 reverse polarity, the
external power contactor will not close. This feature
protects the diodes in the alternator, and other semiconductor devices used in the aircraft from possible
reverse polarity damage.
NOTE
Thru 1977 models application of external
power opened the relay supplying voltage to
the electronics bus. Beginning with 1978
models this relay is replaced by an avionics
master switch. The avionics master switch
must be OFF when external power is applied.
16-11
MODEL R172 SERIES SERVICE MANUAL
NOTE
battery contactor will damage the diodes in
the alternator and other semiconductor de-
On Aircraft Serials R1722000 thru R1722835
refer to Cessna Single-engine Service Letter
SE78-19, dated March 27. 1978.
vices used in the aircraft.
CAUTION
Failure to observe polarity when connecting
an external power source directly to the battery or directly to the battery side of the
16-31.
NOTE
When using ground power to start the aircraft
close the master switch before removing the
ground power plug. This will ensure closure
of the battery contactor and excitation of the
alternator field
TROUBLE SHOOTING.
TROUBLE
PROBABLE CAUSE
REMEDY
STARTER ENGAGES WHEN
GROUND POWER IS CONNECTED. (THRU 1977 MODELS)
Shorted or reversed diode in
split bus-bar system.
Check wiring to, and condition
of diode mounted on the split
bus relay bracket adjacent to
the magneto switch. Correct
wiring. Replace diode board
assembly.
GROUND POWER WILL NOT
CRANK ENGINE.
Ground service connector
wired incorrectly.
1. Check for voltage at all
three terminals of external
power contactor with ground
power connected and master
switch off. If voltage is present on input and coil terminals 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 service receptacle. If voltage is not present, check ground service plug
wiring. If voltage is present,
proceed to step 3.
16-12
Open or mis-wired diode on
ground service diode board
assembly.
3. Check polarity and continuity
of diode on diode board at rear of
ground service receptacle. If
diode is open or improperly wired,
replace diode board assembly.
Faulty external power contactor.
4. Check resistance from small
(coil) terminal of external 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 resistance indicates
an open coil, replace contactor.
If resistance is normal, proceed
MODEL R172 SERIES SERVICE MANUAL
16-31.
TROUBLE SHOOTING (Cont.)
GROUND POWER WILL NOT
CRANK ENGINE (Cont.)
Faulty contacts in external
power contactor.
16-32. REMOVAL AND INSTALLATION. (See
figure 16-3.)
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.
REMEDY
PROBABLE CAUSE
TROUBLE
ALTERNATOR POWER SYSTEM.
16-34. DESCRIPTION. The alternator system consists of a engine driven alternator, a voltage regulator/alternator control unit, mounted on the left hand
5. With master switch off and
ground power applied, check for
voltage drop between two large
terminals of external power
(turn on taxi light for a load).
Normal indication is zero volts.
If voltage is intermittently present or present all the time,
replace contactor.
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 and overvoltage 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 contained within the
alternator control unit and 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 continous output thru
1977 models and 28 volts at 38 amperes beginning
with 1978 models.
SHOP NOTES:
16-13
MODEL R172 SERIES SERVICE MANUAL
2
9
Detail A
THRU R1723154
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
16-14
Diode Board
Cable (To Contactor)
Nut
Ground Strap
Washer
Brace
Bracket Assembly
Firewall
Receptacle
Doubler
Door
Cowl Skin
Bolt
Contactor
10
--
.,
.
12
THRU 1980 MODELS
BEGINNING WITH 1981 MODELS
Figure 16-3. Ground Service Receptacle Installation (Sheet 1 of 2)
MODEL R172 SERIES SERVICE MANUAL
14
8
6
13
3
4
-
Detail A
15. Boot
16.
17.
18.
19.
20.
BEGINNING WITH R1723155
Wire(to Diode)
Wire (to Terminal Block)
Ground Wire
Cover
Sta-strap
NOTE
Refer to sheet 1 for
door installation.
Figure 16-3. Ground Service Receptacle Installation (Sheet 2 of 2)
16-15
MODEL R172 SERIES SERVICE MANUAL
16-37.
TROUBLE SHOOTING THE ALTERNATOR SYSTEM
TROUBLE
AMMETER INDICATES HEAVY
DISCHARGE WITH ENGINE
NOT RUNNING OR ALTERNATOR CIRCUIT BREAKER OPENS
WHEN MASTER SWITCH IS
TURNED ON.
(THRU 1977 MODELS)
PROBABLE CAUSE
Shorted radio noise filter
or shorted wire.
REMEDY
1. Remove cable from output
terminal of alternator. Check
resistance from end of cable
to ground (MASTER SWITCH
MUST BE OFF). If resistance
does not indicate a direct short,
proceed to step 4. If resistance
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 reading 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 connected to the radio noise
filter (or alternator is no noise
filter is installed). Normal indication does not show a direct short.
If a short exists in wires, repair
or replace wiring.
Shorted diodes in alternator.
ALTERNATOR SYSTEM
WILL NOT KEEP BATTERY CHARGED.
16-16
Regulator faulty or improperly adjusted.
4. Check resistance from output
terminal of alternator 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 infinite reading is not obtained in at least one direction,
repair or replace alternator.
1. Start engine and adjust for 1500
RPM. Ammeter should indicate a
heavy charge rate with all electrical equipment turned off. Rate
should taper off in 1-3 minutes. A
voltage check at the bus should indicate a reading consistant with the
voltage ex temperature chart in the
Cessna Alternator Charging System
Service/Parts Manual. 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 is low, proceed
to step 2.
MODEL R172 SERIES SERVICE MANUAL
16-37.
TROUBLE SHOOTING THE ALTERNATOR SYSTEM (THRU 1977 MODELS) (CONT.)
TROUBLE
ALTERNATOR SYSTEM
WILL NOT KEEP BATTERY CHARGED. (cont)
PROBABLE CAUSE
Regulator faulty or improperly adjusted. (cont)
REMEDY
2. Stop engine, remove cowl,
and remove cover from voltage
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" terminal
of regulator with master switch
closed. Meter should indicate bus
voltage. If voltage is present, replace regulator. If voltage is not
present, check wiring between
regulator and bus.
4. Remove plug from regulator
and start engine. Momentarily
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 regulator.
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 continuity, repair or
replace wiring from regulator
to alternator.
6. Check resistance from "F"
terminal of alternator to alternator case. Normal indication
is 6-7 ohms. If resistance is
high or low, repair or replace
alternator.
7. Check resistance from case
of alternator to airframe ground.
Normal indication is very low
resistance. If reading indicates
no, or poor continuity, repair or
replace alternator ground wiring.
ALTERNATOR OVERCHARGES
BATTERY - BATTERY USES
EXCESSIVE WATER.
Regulator faulty or improperly
adjusted.
Check bus voltage with engine running. Normal indication agrees with
the Cessna Alternator Charging system Service/Parts Manual. Observe
ship's ammeter, ammeter should
indicate near zero after a few minutes of engine operation. Replace
regulator.
16-17
MODEL R172 SERIES SERVICE MANUAL
16-37.
TROUBLE SHOOTING THE ALTERNATOR SYSTEM (THRU 1977 MODELS) (CONT.)
TROUBLE
OVER-VOLTAGE WARNING
LIGHT ON.
Regulator faulty or improperly
adjusted. Faulty sensor switch.
16-38. TROUBLE SHOOTING THE ALTERNATOR SYSTEM.
a. ENGINE NOT RUNNING.
TROUBLE
REMEDY
PROBABLE CAUSE
1. With engine running turn off
and on battery portion 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
voltage regulator. If voltage is
present adjust or replace regulator. If voltage is not present
check master switch and wiring
for short or open condition. If
wiring and switch are normal
replace sensor.
(1978 MODELS)
PROBABLE CAUSE
REMEDY
AMMETER INDICATES HEAVY
DISCHARGE OR ALTERNATOR
CIRCUIT BREAKER OPENS.
(Battery Switch ON,
Alternator Switch OFF,
all other electrical
switches OFF. )
Shorted diode in alternator.
Turn off Battery Switch and remove "B" Lead from alternator.
Check resistance from "B"
Terminal of alternator 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 infinite reading is not obtained in at least one direction,
repair or replace alternator.
ALTERNATOR REGULATOR
CIRCUIT BREAKER OPENS
WHEN BATTERY AND
ALTERNATOR SWITCHES
ARE TURNED ON.
Short in Over-Voltage
sensor.
Disconnect Over-Voltage Sensor
plug and recheck. If circuit
breaker stays in replace OverVoltage Sensor.
Short in alternator voltage
regulator.
Disconnect regulator plug 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.
16-18
MODEL R172 SERIES SERVICE MANUAL
16-38. TROUBLE SHOOTING THE ALTERNATOR SYSTEM. (1978 MODELS) (CONT.)
b. ENGINE RUNNING (Cont.)
REMEDY
PROBABLE CAUSE
TROUBLE
ALTERNATOR CIRCUIT
BREAKER OPENS WHEN
BATTERY AND ALTERNATOR SWITCHES ARE
TURNED ON, OVERVOLTAGE LIGHT DOES
NOT COME ON.
Defective circuit breaker.
Replace circuit breaker.
ALTERNATOR REGULATOR
CIRCUIT BREAKER OPENS
WHEN BATTERY AND
ALTERNATOR SWITCHES
ARE TURNED ON, OVERVOLTAGE LIGHT DOES
NOT COME ON.
Shorted field in alternator.
Check resistance from "F"
terminal of alternator to
alternator case, if resistance
is less than 5 ohms repair/
replace.
CAUTION
This malfunction frequently causes a shorted regulator which
will result in an over-voltage condition when system is again
operated.
ALTERNATOR MAKES
ABNORMAL WHINING
NOISE
Shorted diode in alternator.
Turn off Battery Switch and
remove "B" Lead from
alternator. Check reisitance
from "B" terminal of alternator 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
infinite reading is not obtained
in at least one direction, repair
or replace alternator.
OVER-VOLTAGE LIGHT DOES
NOT GO OUT WHEN ALTERNATOR AND BATTERY
SWITCHES ARE TURNED ON.
Shorted regulator
Replace regulator
Defective over-voltage
sensor.
Replace sensor.
AFTER ENGINE START
WITH ALL ELECTRICAL
EQUIPMENT TURNED OFF
CHARGE RATE DOES NOT
TAPER OFF IN 1-3 MINUTES
Regulator faulty or high
resistance in field circuit.
With engine not running turn
off all electrical loads and
turn on battery and alternator
switches. Measure bue voltage
to ground, then measure voltage
from terminal of alternator 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.
16-19
MODEL R172 SERIES SERVICE MANUAL
16-38. TROUBLE SHOOTING THE ALTERNATOR SYSTEM. (1978 MODELS) (CONT.)
b. ENGINE RUNNING (Cont.)
TROUBLE
ALTERNATOR SYSTEM WILL
NOT KEEP BATTERY
CHARGED.
PROBABLE CAUSE
Alternator output voltage
insufficient.
REMEDY
1. Connect coltmeter between
D.C. Bus and ground. Turn 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 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.
2. Stop engine, turn off all
switches. Connect voltmeter
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 sensor,
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
open.
16-20
1. If voltage is present turn off
alternator and battery switches.
Check resistance from "F"
terminal of alternator to alternator case, turning alternator
shaft during measurement.
Normal indication is 12-20 ohms.
If resistance is high or low,
repair or replace alternator, If
OK refer to Step 2.
MODEL R172 SERIES SERVICE MANUAL
16-38. TROUBLE SHOOTING THE ALTERNATOR SYSTEM.
b. ENGINE RUNNING (Cont.)
TROUBLE
(1978 MODELS) (CONT.)
PROBABLE CAUSE
ALTERNATOR SYSTEM WILL
NOT KEEP BATTERY
CHARGED. (Cont.)
Alternator field winding
open (cont).
REMEDY
2. Check resistance from case
of alternator to airframe ground.
Normal indication is very low
resistance. If reading indicates
no, or poor continuity, repair or
replace alternator ground wiring.
16-39. TROUBLE SHOOTING THE ALTERNATOR SYSTEM. (BEGINNING WITH 1979 MODELS).
a. ENGINE NOT RUNNING.
TROUBLE
PROBABLE CAUSE
REMEDY
AMMETER INDICATES HEAVY
DISCHARGE OR ALTERNATOR
CIRCUIT BREAKER OPENS.
(Battery Switch ON, Alternator
Switch OFF, all other electrical
switches OFF. )
Shorted diode in alternator.
Turn off Battery Switch and remove
"B" Lead from alternator. Check
resistance from "B" Termianl of
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 infinite
reading is not obtained in at least one
direction, repair or replace alternator.
ALTERNATOR REGULATOR
CIRCUIT BREAKER OPENS
WHEN BATTERY AND ALTERNATOR SWITCHES ARE
TURNED ON.
Short in alternator control unit.
Disconnect Over-Voltage Sensor plug
and recheck. If circuit breaker stays
in, replace Over-Voltage Sensor.
b.
Disconnect contol unit plug and recheck. If circuit breaker stays in,
replace alternator control unit.
Short in alternator field.
Disconnect "F" terminal wire and
recheck. If circuit breaker stays
in, replace alternator.
Defective circuit breaker.
Replace circuit breaker.
ENGINE RUNNING.
ALTERNATOR CITCUIT
BREAKER OPENS WHEN
BATTERY AND ALTERNATOR SWITCHES ARE TURNED
ON, LOW-VOLTAGE LIGHT
DOES NOT COME ON.
ALTERNATOR REGULATOR
Shorted field in alternator.
CIRCUIT BREAKER OPENS
WHEN BATTERY AND ALTERNATOR SWITCHES ARE TURNED
ON, LOW-VOLTAGE LIGHT MAY
OR MAY NOT COME ON.
Check resistance from "F" terminal
of alternator to alternator case, if resistance is less than 5 ohms repair/
replace.
This malfunction may cause a shorted alternator control unit
which will result in an over-voltage condition when system is
again operated.
16-21
MODEL R172 SERIES SERVICE MANUAL
16-39. TROUBLE SHOOTING THE ALTERNATOR SYSTEM. (BEGINNING WITH 1979 MODELS) (CONT.)
b. ENGINE RUNNING (Cont).
REMEDY
PROBABLE CAUSE
TROUBLE
ALTERNATOR MAKES
ABNORMAL WHINING
NOISE.
Shorted diode in alternator.
Turn off Battery Switch and remove
"B" Lead from alternator. Check
resistance from "B" Terminal of
alternator to alternator case. Resistance reading may show continuity
in one direction but should show an
infinite reading in the other direction.
If an infinite reading is not obtained
in one direction, repair or replace
alternator.
LOW-VOLTAGE LIGHT DOES
NOT GO OUT WHEN ALTERNATOR AND BATTERY
SWITCHES ARE TURNED ON.
Shorted alternator control unit.
Replace alternator control unit.
Defective low-voltage sensor.
Replace alternator control
unit.
Alternator control unit faulty
or high resistance in field
circuit.
With engine not running turn off all
electrical loads and turn on battery
and alternator switches. Measure
bus voltage to ground, then measure
voltage from terminal of alternator
to ground. If there is more than 2
volts difference check field circuit
wiring shown on alternator system
wiring diagram in Section 19. Clean
all contacts. Replace components
until there is less than 2 volts difference between bus voltage and
field voltage.
AFTER ENGINE START WITH
ALL ELECTRICAL EQUIPMENT TURNED OFF CHARGE
RATE DOES NOT TAPER OFF
IN 1-3 MINUTES.
NOTE
Also refer to battery power system trouble shooting chart.
ALTERNATOR SYSTEM
WILL NOT KEEP BATTERY CHARGED.
Alternator output voltage
insufficient.
1. Connect voltmeter between D. C.
Bus and ground. Turn 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 doe
not rise when alternator switch is
turned on proceed to Step 2.
2. Stop engine, turn off all switches.
Connect voltmeter 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.
16-22
MODEL R172 SERIES SERVICE MANUAL
16-39. TROUBLE SHOOTING THE ALTERNATOR SYSTEM. (BEGINNING WITH 1979 MODELS) (CONT.)
b. ENGINE RUNNING (Cont).
TROUBLE
ALTERNATOR SYSTEM
WILL NOT KEEP BATTERY CHARGED. (Cont.)
PROBABLE CAUSE
REMEDY
Alternator output voltage
insufficient. (Cont).
3. Starting at "F" terminal of alternator, trace circuit to alternator conrol unit at Pin 1 (Blue Wire). Trace
circuit 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
Section 20.
Alternator field winding open.
1. If voltage is present turn off alternator and battery switches. Check resistance from "F" terminal of alternator to alternator case, turning
shaft during 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 airframe ground.
Normal indication is very low resistance. If reading indicates no,
or poor continuity, repair or
replace alternator ground wiring.
SHOP NOTES:
16-23
MODEL R172 SERIES SERVICE MANUAL
16-40. REMOVAL AND INSTALLATION. (See
figure 16-4.)
a. Insure 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 screw and nut holding blast tube to support strap clamp, blast tube will then be free for
removal.
d. Remove nuts and washers from alternator mounting bolts,
e. Remove alternator.
f. To replace alternator, reverse this procedure.
16-41.
OVER-VOLTAGE WARNING SYSTEM.
16-42. DESCRIPTION. The over-voltage system
consists of an over-voltage sensor switch and a red
warning light labeled "HIGH VOLTAGE". The overvoltage 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 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.
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) wiring 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 24.8 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.
16-43. ALTERNATOR VOLTAGE REGULATOR.
16-44. 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 regulator to 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 regulatoris 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 regulator is solid-state.
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. 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.
16-45. ALTERNATOR CONTROL UNIT.
16-24
MODEL R172 SERIES SERVICE MANUAL
16-46. 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 (PN 9870005( is Available through the Cessna Service/Parts Center for use
in isolating failures in the 28-volt alternator control
units (C611005-0101 and C611005-0102) and the 28volt alternator.
16-47. 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 regulator and/or excessive
radio noise may result.
16-48. RIGGING THROTTLE-OPERATED MICRO
SWITCHES. (Refer to Section 12.)
16-49. AUXILIARY ELECTRICAL FUEL PUMP
FLOW RATE ADJUSTMENT. (Refer to Section 12.)
................. ...
..
'
.
...........
.
5.Support
Strap
6.
2. Alternator
Hose
3. Screw
4.
5.
6.
7.
..... ......
.
..
.
.
.
-.
Washer
Support Strap
Alternator
Nut
Figure 16-4.
Alternator Installation.
16-25
..
MODEL R172 SERIES SERVICE MANUAL
*......
.....
Detail A
THRU 1977 MODELS
1.
2.
3.
4.
Voltage Regulator
Screw
Housing
Wire Shields to Ground
5.
6.
7.
8.
Wire
Wire
Wire
Wire
to
to
to
to
Alternator "F"
Alternator "A+"
Filter
Alternator Ground
9.
10.
11.
12.
Filter - Radio Noise
Wire to Master Switch
Shield - Ground
Wire to Overvoltage Light
Figure 16-5. Voltage Regulator Installation (Sheet 1 of 3)
16-26
16-26
MODEL R172 SERIES SERVICE MANUAL
-.
.
.
Detail
Rotated
1.
2.
3.
4.
5.
6.
7.
8.
Housing Plug
Housing Cap
Ground Wire
Over-Voltage Sensor
Mounting Bracket
Screw
Voltage Regulator
Firewall
Detail A
1978 MODELS
Figure 16-5. Voltage Regulator Installation (Sheet 2 of 3)
16-27
MODEL R172 SERIES SERVICE MANUAL
-.
2.
3.
4.
5.
6.
Bolt
Housing Plug
Ground Wire
Alternator Control Unit
Firewall
BEGINNING WITH 1979 MODELS
Figure 16-5. Voltage Regulator Installation (Sheet 3 of 3)
16-28
.
MODEL R172 SERIES SERVICE MANUAL
16-50. AIRCRAFT LIGHTING SYSTEM.
16-51. 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, map
light, control wheel map light, compass and radio
dial lights.
16-52. TROUBLE SHOOTING.
TROUBLE
LANDING AND TAXI LIGHT(S)
OUT.
PROBABLE CAUSE
REMEDY
Short circuit in wiring.
1. Inspect circuit breaker. If
circuit breaker is open, proceed
to step 2. If circuit breaker is
O.K. proceed to step 3.
Defective wiring.
2. Test each circuit separately
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.
Lamp burned out.
1. Test lamp with ohmmeter or
new lamp. Replace lamp.
Open circuit in wiring.
2. Test wiring for continuity.
Repair or replace wiring.
Short circuit in wiring.
1. Inspect circuit breaker. If
circuit breaker is open, proceed
to step 2. If circuit breaker is
O.K. 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 or
a new lamp. Replace lamp. If
lamp is good, proceed to step 4.
Open circuit in wiring.
4. Test circuit from lamp to
flasher for continuity. If no
continuity is present, repair or
replace wiring. If continuity is
present, proceed to step 5.
Defective switch.
5. Check voltage at flasher with
master and beacon switch on.
Should read battery voltage.
Replace switch. If voltage is
present, proceed to step 6.
Defective flasher.
6.
Install new flasher.
FLASHING BEACON
CONSTANTLY LIT.
Defective flasher.
1.
Install new flasher.
ALL NAV LIGHTS OUT.
Short circuit in wiring.
1. Inspect circuit breaker. If
circuit breaker is open, proceed
to step 2. If circuit breaker is
O.K. proceed to step 3.
LANDING AND/OR TAXI
LIGHT OUT.
FLASHING BEACON DOES
NOT LIGHT.
16-29
MODEL R172 SERIES SERVICE MANUAL
16-52. TROUBLE SHOOTING (CONT.)
TROUBLE
PROBABLE CAUSE
ALL NAV LIGHTS OUT.
ONE NAV LIGHT OUT.
(Cont).
REMEDY
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 battery voltage. Replace switch.
Lamp burned out.
1.
Open circuit in wiring.
2. Test wiring for continuity.
Repair or replace wiring.
Inspect lamp.
Replace lamp.
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.
BOTH ANTI-COLLISION
STROBE LIGHTS WILL
NOT LIGHT.
Open circuit breaker.
1. Check, if open reset. If
circuit breaker continues to
open proceed to step 2.
2. Disconnect red wire between aircraft power supply
(battery/external power) and
strobe power supplies, one
at a time. If circuit breaker
opens on one strobe power
supply. If circuit breaker
opens on both strobe power
supplies proceed to step 3.
If circuit breaker does not
open proceed to step 4.
3. Check aircraft wiring.
Repair or replace as necessary.
4. Inspect strobe power supply ground wire for contact
with wing structure.
16-30
MODEL R172 SERIES SERVICE MANUAL
16-52. TROUBLE SHOOTING (CONT.)
TROUBLE
PROBABLE CAUSE
REMEDY
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.
ONE ANTI-COLLISION
STROBE LIGHT WILL
NOT LIGHT.
Defective Strobe Power Supply,
or flash tube.
1. Connect voltmeter to red lead
between aircraft power supply
(battery/external power) and
strobe power supply, connecting
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 wiring. If no short or
open circuit is found, proceed to
step 4.
Lamp burned out.
4. Test lamp with ohmeter or
new lamp. Replace lamp.
Defective switch.
5. Check for voltage at dome
light with master and dome light
switch on. Should read battery
voltage. Replace switch.
16-31
MODEL R172 SERIES SERVICE MANUAL
16-52.
TROUBLE SHOOTING (CONT.)
TROUBLE
INSTRUMENT LIGHTS WILL
NOT LIGHT.
PROBABLE CAUSE
REMEDY
Short circuit wiring.
1. Inspect circuit breaker. If
circuit breaker is open, proceed
to step 2. If circuit breaker is
O.K., 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 wiring. If no short or
open circuit is found, proceed to
Step 4.
INSTRUMENT LIGHTS WILL
NOT DIM.
CONTROL WHEEL MAP
LIGHT WILL NOT LIGHT.
Faulty section in
dimming potentiometer.
4. Lights will work when control
is placed in brighter position. Replace potentiometer.
Faulty light dimming
transistor.
5. Test both transistors with new
transistor. Replace faulty transistor.
Faulty selector switch.
6.
Open resistor or wiring
in minimum intensity end
of potentiometer.
1. Test for continuity. Replace
resistor or repair wiring.
Shorted transistor.
2. Test transistor by substitution.
Replace defective transistor.
Nav light switch turned off.
1. Nav light switch has to be
ON before map light will light.
Short circuit in wiring.
2. Check lamp fuse on terminal
board located on back of stationary panel with ohmmeter. If
fuse is open, proceed to step 3.
If fuse is O.K., proceed to step 4.
Defective wiring.
3. Test circuit until short is located. Repair or replace wiring.
Inspect.
Replace switch.
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 assembly.
16-32
5. Check voltage at map light
assembly with master and nav
switches on. If battery voltage
is present, replace map light
assembly.
MODEL R172 SERIES SERVICE MANUAL
16-53.
LANDING AND TAXI LIGHTS.
16-54. DESCRIPTION. Cowl mounted landing and
taxi lights are installed. The left hand light is used
for taxi and the right hand light 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.
16-55. REMOVAL AND INSTALLATION. (See
figure 16-6.
a. Remove screws (1) and pull bracket assembly (2)
from nose cap to gain access to electrical leads.
b. Disconnect electrical leads from lamps making
sure switches are off and leads do not short out.
c. Remove screws (9) from plate (7) and remove
lamp assembly from bracket (2). If left hand (taxi)
light is being removed, note position of spacers (3)
and (11) for reinstallation.
d. Remove screws (10) from bracket (4) to disassemble lamp assembly.
e. Install new lamp and reassemble.
16-56. ADJUSTMENT. 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 inches, the
center of the landing light beam (right hand) on the
wall should be 35 3/4 inches above the floor. The
center of the taxi light beam, (left hand) on the wall
should be 32 1/8 inches above the floor.
16-57. NAVIGATION LIGHTS.
16-58. 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.
16-59. REMOVAL AND INSTALLATION. For removal and installation of navigation lights see
figure 16-7.
16-60. ANTI-COLLISION STROBE LIGHTS.
16-61. 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.
16-62. REMOVAL AND INSTALLATION. For removal and installation of strobe light and power supply see figure 16-7.
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.
16-63. 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 the proper voltage, 12 volt. Connect tube
to output of 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.
SHOP NOTES:
16-33
MODEL R172 SERIES SERVICE MANUAL
5
2
A minimum of one gasket and
a maximum of two (2) gaskets
may be installed to secure lamp.
Detail
A
NOTE
A maximum of two washers
on each screw may be used
for adjustment.
Figure 16-6.
16-34
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Screw
Bracket Assembly
Spacer
Bracket
Lamp
Gasket
Plate
Nose Cap
Screw
Screw
11. Washer
Landing and Taxi Light Installation.
MODEL R172 SERIES SERVICE MANUAL
Detail B
11
BEGINNING WITH R1722141
Detail A
C
Detail
1.
2.
3.
4.
5.
6.
7.
8.
9.
Electrical Leads
Cap
Washer
Insulated Washer
Spring
Insulator
Wing Tip
Receptacle
Gasket
10.
11.
12.
13.
14.
15.
16.
17.
18.
Figure 16-7.
Flash Tube Assembly
Screw
Lens Retainer
Lens
Lamp
Seal
Mount
Wing Tip Rib
Power Supply
C
Detail B
THRU R1722140
Navigation and Anti-Collision Strobe Light Installation.
16-35
MODEL R172 SERIES SERVICE MANUAL
16-64.
FLASHING BEACON.
16-65. DESCRIPTION. The flashing beacon light is
attached to the vertical fin tip. The lamp is iodinevapor, 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 beginning with 1978 models to
eliminate a pulsing effect on the cabin lighting and
ammeter.
16-66. REMOVAL AND INSTALLATION. For removal and installation of flashing beacon see figure 16-8.
16-67.
INSTRUMENT AND DOME LIGHTS.
16-68. 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. Intensity of the lamp is controlled by a rheostat switch located on the instrument
panel.
16-75. INSTRUMENT POST LIGHTING,
16-76. DESCRIPTION. Individual post lighting may
be installed to provide nonglare 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.
16-77. 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.
16-78. TRANSISTORIZED LIGHT DIMMING.
16-79. DESCRIPTION. A remotely located, twocircuit 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
16-80. REMOVAL AND INSTALLATION. For removal and installation of transistorized dimming assembly, see figure 16-10.
16-81. MAP LIGHTING.
16-69. REMOVAL AND INSTALLATION. For removal and installation of instrument and dome light,
see figure 16-9.
16-70. COURTESY LIGHTS.
16-71. DESCRIPTION.
mounted in the underside
upper wing strut attach.
socket and a single bulb.
by the dome light switch,
The courtesy lights are m
of each wing, inboard of the
The light consists of a lens
The lights are controlled
16-72. REMOVAL AND INSTALLATION. For removal and installation of the courtesy lights see
figure 16-9.
16-73.
COMPASS AND RADIO DIAL LIGHTING.
16-74. 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.
16-36
16-82. DESCRIPTION. White map lighting and rednon-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
intensisty 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
16-83. 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.
MODEL R172 SERIES SERVICE MANUAL
* THRU R1723190
-
* BEGINNING WITH R1723191
...
Detail A
Figure 16-8.
Detail
B
,
1. Dome
10. Tip Assembly - Fin
2.
3.
4.
5.
6.
7.
8.
9.
11.
12.
13..
14.
15.
16.
17.
18.
Gasket
Lamp
Screw
Baffle
Clamp Assembly
Plate - Mounting
Socket Assembly
Nut Plate
Housing - Plug
Housing - Cap
Fin Assembly
Flasher Assembly
Bulkhead
Resistor
Spacer
Z Bracket
Flashing Beacon Light Installation (Sheet 1 of 2)
16-37
MODEL R172 SERIES SERVICE MANUAL
Detail C
BEGINNING WITH R1723333
NOTE
When installing lamp be sure
socket assembly is installed
in mounting plate so lamp may
be installed with filament perpendicular to the longitudinal
axis of the aircraft.
Figure 16-8.
16-38
Flashing Beacon Light Installation (Sheet 2 of 2)
MODEL R172 SERIES SERVICE MANUAL
Detail
A
Detail
1.
2.
3.
4.
Tinnerman Nut
Tinnerman Screw
Reflector
Lamp
6. Cover
7.
8.
9.
10.
Machine Screw
Grommet
Nut
Support
12. Adjustment Screw
B
13.
14.
15.
16.
Washer
Nut Plate
Socket
Switch
18.
19.
Plug Button
Lens Retainer
Figure 16-9. Instrument, Dome and Courtesy Light Installation.
16-39
MODEL R172 SERIES SERVICE MANUAL
Detail A
X
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
7
Rheostat
Set Screw
Knob (Compass and Instrument)
Knob (Radio)
Mounting Bracket
Screw
Insulator
Transistor
Washer
Relay
Diode Board
Diode
* THRU R1722824
AND FR1720611
Figure 16-10. Transistorized Dimming.
16-40
MODEL R172 SERIES SERVICE MANUAL
16-84.
CONTROL WHEEL MAP LIGHT.
16-89.
16-85. DESCRIPTION. The control wheel map light
is mounted on the lower side of the control wheel.
Light intensity is controlled by a thumb operated
rheostat. For dimming the rheostat should be turned
clockwise,
16-86. REMOVAL AND INSTALLATION. (See
to
figure 16-12.)
a. For easy access to the map light assembly rotate the control wheel 90 ° .
b. Label the wires connecting to the map light assembly (terminal block) and remove the screws securing the wires to the terminal block.
c. The assembly should now be free for removal.
Remove the two screws securing the map light to the
control wheel and remove the map light assembly.
d. For reassembly reverse this procedure.
16-87.
PITOT HEATER.
16-88. 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.)
CIGAR LIGHTER.
16-90. DESCRIPTION. The cigar lighter (located on
the instrument panel) is equipped with a thermal-actuated circuit breaker 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.
16-91.
CLOCK..
16-92. DESCRIPTION.. 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 read out as
well as time. Both clocks are installed in the Instrument panel in the same manner, see figure 16-14.
Also refer to Pilots Operating Hnadbook for operational
procedures.
BEGINNING WITH R1723255
AND FR1720666
,
1.
2.
3.
4.
5.
6.
7.
Nut
Washer
Grommet
Adjustment Screw
Maplight Assembly
Socket Assembly
Lamp
8. Red Lamp
11. Screw
12. Front Doorpost Shield
13. Maplight Switch
14Insulator
Figure 16-11.
Map Light Installation.
16-41
MODEL R172 SERIES SERVICE MANUAL
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
THRU R1722848 AND FR17200645
15.
16.
17.
18.
1.tationary Panel
Cover
Nut
Washer
Plate
Rheostat
Socket
Control Wheel Assembly
Switch
Insulator
Lamp
Nut
Clamp
Screw
Cable Assembly
Cover
Grommet
Terminal Block
Figure 16-12. Control Wheel Map Light Installation (Sheet 1 of 2)
16-42
MODEL R172 SERIES SERVICE MANUAL
BEGINNING WITH R1722849 AND FR17200646
1.
2.
3.
4.
5.
Instrument Panel
Control Tube
Nut
Washer
Rheostat
6.
7.
8.
9.
10.
Control Wheel
Screw
Switch
Escutcheon
Placard
11. Fastener
12. Knob
13. Map Light Assembly
14. Cable
15. Terminal Block
Figure 16-12. Control Wheel Map Light Installation (Sheet 2 of 2)
16-43
MODEL R172 SERIES SERVICE MANUAL
2. Pitot Tube
3. Heating Element
Figure 16-13. Heated Pitot Installation.
1.
2.
3.
4.
Decorative Cover
Screw
Instrument Panel
Clock
Figure 16-14. Digital Clock Installation.
16-44
MODEL R172 SERIES SERVICE MANUAL
16-93, EMERGENCY LOCATOR TRANSMITTER.
THRU R17222287.
16-96. CHECKOUT INTERVAL:
100 HOURS.
16-94. DESCRIPTION. The ELT is a self-contained,
solid state unit, having its own power supply, with an
externally mounted antenna. The C589510-0209 transmitter is designed to transmit simultaneously on dual
emergency frequencies of 121. 5 and 243.0 Megahertz.
The C589510-0211 transmitter used for Canadian
registry, operates on 121.5 only. 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 recognizable distress signal for reception by search and rescue personnel and others
monitoring the emergency frequencies. Power is
supplied to the transmitter by a battery-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 four lithium "D" size batteries which are stacked
in two's (See figure 16-13). The ELT exhibits line of
sight transmission 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 transmitter will broadcast an emergency signal at rated power (75 MWminimum), for a continuous period of time as listed
in the following table.
TRANSMITTER LIFE
TO 75 MILLIWATTS OUTPUT
4 Cell
Temperature
Lithium
Battery Pack
+130°F
+ 70°F
115 hrs
115 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.
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 5 seconds or less. Immediately 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 minutes after any
hour.
CAUTION
Tests with the antenna connected should be
approved and confirmed by the nearest control tower
NOTE
Without
produce
ceiver,
ications
its antenna connected, the ELT will
sufficient signal to reach your reyet it will not disturb other communor damage output circuitry.
NOTE
After accumulated test or operation time
equals 1 hour, battery-pack replacement
is required.
f. Check calendar date for replacement of batterypack. This date is supplied on a sticker attached to
the outside of the ELT case and to each battery.
16-97. 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.
NOTE
16-95. 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.
CAUTION
Do not leave the emergency locator transmitter in the ON position longer than 5 seconds
or you may activate downed aircraft procedures by C.A. P., D. O. T. or F.A.A. personnel.
Transmitter is also attached to the mounting
bracket by velcro strips; pull transmitter to
free from mounting bracket and velcro.
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 #40 adhesive to
16-45
MODEL R172 SERIES SERVICE MANUAL
-
.
..
-
...
PLACARD
NOTE
Metal Strap (4) must be positioned so that
latch is on top of transmitter as installed
in the aircraft and not across transmitter
cover.
1. Tailcone Skin
2. Bracket
3. Fabric Fastener - Hook
4. Metal Strap
5. Fabric Fastener - Pile
6. Transmitter
7. Cover
8. Access Cover
1
9.
10.
11.
12.
13.
14.
15.
16.
Connector
Arm Switch
Co-axial Cable
Sta-strap
Rubber Washer
Rubber Boot
Antenna
Doubler
Figure 16-15. Emergency Locator Transmitter Installation.
16-46
MODEL R172 SERIES SERVICE MANUAL
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
for complete cure.
d. To reinstall transmitter, reverse preceding
steps.
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
An installation tool is required to properly
secure sta-strap. This tool may be purchased locally or ordered from the Panduit
Corporation, Tinley Park, Ill., 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.
16-98. 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.
NOTE
Before installing the new 4 cell batterypack, check to ensure that its voltage is
11.2 volts or greater.
CAUTIONJ
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.
16-99. 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 AV7831 Dated November 20, 1978.
NOTE
Transmitters equipped with the 4 cell batterypack can only be replaced with another 4 cell
battery-pack.
a. After the transmitter has been removed from
aircraft in accordance with para, 16-97, place the
transmitter switch in the OFF position.
b. Remove the nine screws attaching the cover to
the case and then remove the cover to gain access to
the battery pack.
TRANSMITTER
C589510-0209
BATTERY PACK
C589510-0210
Figure 16-16. Lithium 4 Cell
Battery Pack Installation.
16-100. 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.
16-47
MODEL R172 SERIES SERVICE MANUAL
16-100.
TROUBLE SHOOTING (Cont.)
TROUBLE
*POWER LOW
PROBABLE CAUSE
REMEDY
Low battery voltage.
1. Set toggle switch to off.
2. Remove plastic plug from the remote jack
and by means of a Switchcraft #750 jackplug,
connect a Simpson 260 model voltmeter and
measure 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 voltage meets the
specifications in step 2, the battery-pack is
O.K. If the battery is O.K., check the transmitter as follows:
a. Remove the voltmeter.
b. By means of a switchcraft 750 jackplug
and 3 inch maximum long leads, connect a
Simpson Model 1223 ammeter to the jack.
c. Set the toggle switch to ON and observe
the ammeter current drain. If the currentdrain is in the 85-100 ma range, the transmitter or the co-axial cable is faulty.
Faulty co-axial
antenna cable.
4. Check co-axial antenna 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.
16-48
MODEL R172 SERIES SERVICE MANUAL
BEGINNING WITH R1722288
CAUTION
Do not leave the emergency locator transmitter in the ON position longer than 5 seconds
or you may activate downed aircraft procedures by C.A.P., D.O.T. or F.A.A. personnel.
16-102. DESCRIPTION. The ELT is a self-contained,
solid state unit, having its own power supply, with an
externally mounted antenna. The C589511-0103 is
used thru 1978 and the C589511-0117 beginning with
1979 models. The transmiiters are designed to transmit simultaneously on dual emergency frequencies of
121. 5 and 243. 0 Megahertz. Aircraft with Canadian
registry utilize the C589511-0104 thru 1978 and the
C589511-0113 transmitters beginning with 1979
models. These transmitters operate on 121. 5 only.
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 recognizable distress
signal for reception by search and rescue personnel
and others monitoring the emergency frequencies.
Power is supplied to the transmitter by a batterypack which has the service life of the batteries placarded on the batteries and also on the outside end of
the transmitter. C589511-0104 and C589511-0103
ELT's 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
the new alkaline batteries which are installed beginning with 1979 models (see figure 16-14). The ELT
exhibits line of sight transmission 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
ELT supplied domestic aircraft thru 1978 models
transmit on both distress frequencies simultaneously
at 75 mw rated power output for 48 continuous hours
in the temperature range of -40°F to +131°F~-40°C
to 55 0 C). The ELT unit in export aircraft transmits
on 121. 5 MHz at 25 mw rated power output for 100
continuous hours in the temperature range of -40°F
to +131°F (-40°C to +55°C). Battery-packs have a
normal shelf life of five to ten (5-10) years and must
16-104.
100 HOURS.
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 5 seconds or less. Immediately 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 minutes after any
hour.
CAUTION
Tests with the antenna connected should be
approved and confirmed by the nearest control tower.
NOTE
Without
produce
ceiver,
ications
its antenna connected, the ELT will
sufficient signal to reach your reyet it will not disturb other communor damage output circuitry.
NOTE
After accumulated test or operation time
equals 1 hour, battery-pack replacement
is required.
with TSO-C91. Cessna specified 5 years replacewith
Cessna
TSO-C91.
specified 5 years replacement of lithium (4-cell) battery-packs, C589511-0105.
Beginning with 1979 models the ELT supplied domestic aircraft transmits on both distress frequencies
simultaneously at 75 mw rated power output for continuous hours in the temperature range of -4°F to
+3tinuous hours in the temperature range of -4F to
+131°F (-20°C to +55°C). The ELT unit in export
aircraft 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). Alkaline battery-packs have the service life of the batterypack stamped on the battery-pack, on the end of the
transmitter below the switch and on top of the transmitter.
16-103. OPERATION. A three position switch on the
forward end of the umt 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. Placingtowardsswitchnose
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 -Og) impact force,
for a duration of 11-16 milliseconds.
CHECKOUT INTERVAL:
f. Check calendar date for replacement of batt,;rypack. This date is supplied on a sticker attached to
the utside of the ELT case ond ticker attahed
16-105. 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.
ICAUTION
the
Ensure that the direction of fight arrows
(placarded on the transmitter) are pointing
of the aircraft.
16-49
MODEL R172 SERIES SERVICE MANUAL
.
I
,. LACARD
,
-
. .
..
. .....
....
t-v~.»tlD
.
.
.. .. ........
.....
....
....
-
1. Cabin Skin
2. Bracket
Transmitter
3. Cover
4.
6..
.....
DetailB
7. Arm Switch
8. Co-axial Cable
Rubber washer
9. Rubber
Boot
10.
13. Accessr Cover
ROTATED 180
Figure 16-17. Emergency Locator Transmitter Installation (Sheet 1 of 2)
16-50
MODEL R172 SERIES SERVICE MANUAL
...
PLACARD
..
.......
......
...
.
...
. -
Detail B
Detail A
BEGINNING WITH 1979 MODELS
*
BEGINNING WITH R1723235
.ROTATED
Detail C
180*
Figure 16-17. Emergency Locator Transmitter Installation(Sheet 2 of 2)
16-51
MODEL R172 SERIES SERVICE MANUAL
16-106. 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.
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.
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.
C589511-0103 TRANSMITTER
C589511-0104 TRANSMITTER (CANADIAN)
16-107. 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.
ICAUTIONI
Lithium battery-pack must be replaced withC589511-0106
alkaline battery-packs per SK185-20.
a. After the transmitter has been removed from
aircraft in accordance with para. 16-105, 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 fig-
C589511-0105 BATTERY PACK
BATTERY PACK
(CANADIAN)
C589511-0117 TRANSMITTER
C589511-0113 TRANSMITTER (CANADIAN)
ure 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.
IWARNING
The battery-pack has pressurized contents.
Do not recharge, short circuit or dispose
of in fire.
16-52
C589511-0114 DOMESTIC &
CANADIAN
Figure 16-18. BATTERY PACK INSTALLATION.
16-108. TROUBLE SHOOTING. Should your Emergency Locating Transmitter fail the 100 Hours per-
formance 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.
MODEL R172 SERIES SERVICE MANUAL
- 16-108.
TROUBLE SHOOTING (Cont.)
TROUBLE
*POWER LOW
REMEDY
PROBABLE CAUSE
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 measure voltage.
If the battery pack transmitters is 7. 5
volts or less, the battery pack is below
specification.
Faulty transmitter.
3. If the battery-pack voltage meets the
specifications in step 2, the battery-pack
is O.K. If the battery is O.K., check the
transmitter as follows:
a. Reconnect battery pack to the transmitter.
b. By means of E. F. Johnson 105-0303001 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
antenna cable.
4. Check co-axial antenna 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.
16-53
MODEL R172 SERIES SERVICE MANUAL
ELECTRICAL LOAD ANALYSIS CHART
STANDARD EQUIPMENT (RUNNING LOAD)
Battery Contactor ...............
Fuel Indicators. .............
Flashing Beacon Light . . . .........
Instrument Lights . ...........
. . . .........
Position Lights .
. .......
Turn Coordinator
...
.
..
.
AMPS REQD
1980
1979
1981
0.5
0.1
6.00
0.7
2.5
0.3
0.5
0.1
6.00
0. 7
2. 5
0. 3
1977
1978
0. 6
0.4
7.0
1.3
5. 6
0. 8
0.45
0.11
6.00
0.67
2.50
0.28
0.5
0.1
6. 00
0.7
2.5
0.3
0.1
3.00
1.00
1 0.11
3.0
3.0
1.0
1.0
1.00*
1.00***
1.00*
1.00***
1.00*
1.00***
1.0*
2.00
0. 50
0.10
2.50**
2.50
2.50
0.07
1.50
2.90
2.00
1.00
2.00
0. 50
0.10
2.50**
50 2.
2.50
0. 1
2.00
0. 50
2.00
2.50**
50
2. 50
0.1
0.10
2.50**
2.50
2.50
2.50
0. 1
2.90
2.00
2.90
2.00
2.90
2.00
.64
2.90
0.6
1.0
2.90
0.6
1.0
2.90
2.90
2.5
1.00
7.50
7.0
7.0
7.0
OPTIONAL EQUIPMENT (RUNNING LOAD)
. . . . . .
Altitude Blind Encoder . . ...
. .
.......
Strobe Lights. .....
Cessna 300 ADF (Type R-546E) . .......
Cessna 300 Nav/Com (100 Channel Type RT-308C) .
.
Cessna 300 Nav/Com (Type RT-385A)
.
. .
Cessna 300 HF Transceiver (PT10-A) ..
Cessna 300 Transceiver (Type RT-524A) .....
.
Cessna 300 Transponder (RT-359A). .....
Cessna 400 Glideslope (Type R-443B) (40 Channel) .
. ..
Cessna 400 Marker Beacon (Type R-402A).
Sunair SS Band HF Transceiver (Type ASB-125) . .
..
Cessna 300A Navomatic (Type AF-395A) ...
Cessna 200 Navomatic (Type AF-295B) . . . . ..
.
Cessna EA-401A Encoding Altimeter ....
Cessna 300 Nav/Com (720 Channel RT-328T) .
. .
Narco 190 DME . . . . . . . . . . . . .
Cessna 400 XPDR (ARC Type RT-459A) . .....
.
Bendix GM-247A Marker Beacon......
...................
Pitot Heat.2.0
. . . . . .
. . ...
. ..
Post Lights ....
.
.............
RNAV 511
1.0
1. 5
1.5
3.2
1.0
.4
.3
5.0
2.0
2.0
.065
1.5
3.0
1.0*
1*
0.1
3.0
1.0
ITEMS NOT CONSIDERED AS PART OF
RUNNING LOAD
Cigarette Lighter. . . . . . . . .
................
Clock .....
Control Wheel Map Light ............
. .
. .
Courtesy & Dome Lights.
Flap Motor . . . . . . . .... ..
Landing and Taxi Light (Single). . . .
Landing and Taxi Lights (Dual) ...
Map Light (Door Post) .............
...
.
Air Conditioner (High Blower)
Ventilation System Blower (High Speed)
Auxiliary Fuel Pump ............
Avionics Cooling Fan ..............
t
*
*
**
***
*
16-54
Negligible
Export Only
2.25 Transmitting
7. 50 Transmitting
9. 00 Transmitting
6.00 Transmitting
. ..
. .10.0
.
.33
. . . . . . 2.5
. ..
. .15.0
. . . . . . 20.0
. 15. 6
. .
33
.
...
..
0.08
0.68
10.00
8.93
7.14
0.17
0.1
0.1
1.2
1.2
10.0
10.00
8.9
8.9
3. 6 (Ea) 3.6 (Ea)
0.2
0.2
6.7
6.7
5.0
5.0
3.0
3.0
0.1
1.2
8.5
8. 9
3. 6 (Ea)
0.2
6.7
5.0
3.0
1.0
MODEL R172 SERIES SERVICE MANUAL
SECTION 17
STRUCTURAL REPAIR
TABLE OF CONTENTS
Page No.
Aerofiche/Manual
STRUCTURAL REPAIR .......
. 2D20/17-1
Repair Criteria ........
.2D20/17-1
Equipment and Tools .......
2D21/17-2
Support Stands ........
2D21/17-2
Fuselage Repair Jigs .....
2D21/17-2
Wing Jigs ..........
2D21/17-2
Wing Twist and Stabilizer
Incidence ........
.
2D21/17-2
Repair Materials .
. .2D21/17-2
Wing .............
2D21/17-2
Description .....
.
2D21/17-2
Wing Skin .......
.
2D21/17-2
Neglibigle Damage . . . .2D21/17-2
Repairable Damage .
. . 2D21/17-2
Damage Necessitating Replacement of Parts . .. 2D22/17-3
Wing Stringers . .....
. 2D22/17-3
Negligible Damage . ...
2D22/17-3
Repairable Damage ....
2D22/17-3
Damage Necessitating Replacement of Parts
.
2D22/17-3
Wing Auxiliary Spars .
..
.2D22/17-3
Negligible Damage .....
2D22/17-3
Repairable Damage ..
. 2D22/17-3
Damage Necessitating Replacement of Parts .
. 2D22/17-3
Wing Ribs ..........
2D22/17-3
Negligible Damage ....
2D22/17-3
Repairable Damage ..
. 2D22/17-3
Damaging Necessitating Replacement of Parts . .. 2D22/17-3
Wing Spars .........
2D22/17-3
Negligible Damage ...
. 2D22/17-3
Repairable Damage ....
2D22/17-3
Damage Necessitating Replacement of Parts . . .2D22/17-3
Ailerons. .........
.
2D22/17-3
Repairable Damage ....
Damage Necessitating Replacement of Parts
.
Aileron Balancing . . .
Wing Flaps .........
Negligible Damage . ...
Repairable Damage ....
Damage Necessitating Replacement of Parts
.
17-1.
2D22/17-3
2D22/17-3
2D22/17-3
2D22/17-3
2D22/17-3
2D22/17-3
Wing Leading Edge ...
2D23/17-4
Negligible Damage ....
2D23/17-4
Repairable Damage ...
2D23/17-4
Damage Necessitating Replacement of Parts . . .2D23/17-4
Elevators and Rudder
..
2D23/17-4
Negligible Damage ...
2D23/17-4
Repairable Damage .....
2D23/17-4
Damage Necessitating Replacement of Parts .....
2D23/17-4
Elevator and Rudder Balancing. 2D23/17-4
Fin and Stabilizer ....
2D23/17-4
Negligible Damage ...
2D23/17-4
Repairable Damage ......
2D23/17-4
Damage Necessitating Replacement of Parts ..
2D23/17-4
Fuselage .
....
23/17-4
Description ........
2D23/174
Negligible Damage ......
2D23/17-4
Repairable Damage .
.....
2D24/17-5
Damage Necessitating Re2D24/17-5
placement of Parts ..
.2D24/17-5
Bonded Doors ..........
2D24/17-5
Repairable Damage ..
. 2D24/17-5
Bulkheads ..
2D24/17-5
Landing Gear Bulkheads.
2D24/17-5
Repair After Hard Landing. 2D24/17-5
Replacement of Hi-Shear Rivets .
2D24/17-5
Firewall Damage ..
2D24/17-5
Engine Mount ...
.
2D24/17-5
Description .........
2D24/17-5
General Considerations ....
2D24/175
Engine Mount Support Cradle
Damage ..........
2D24/17-5
Damage Involving Engine
Mounting Lugs and Engine
Mount to Fuselage Attach
Baffles .............
Engine Cowling . ........
Repair of Cowling Skins .
Repair of Reinforcement
Angles ......
Repair of Glass-Fiber
Constructed Components ....
2D24/17-5
2D24/17-5
2E1/17-6
2E1/17-6
2E2/17-7
2D22/17-3
STRUCTUREAL REPAIR.
17-2. REPAIR CRITERIAL. 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 aircraft must be restored
to its airworthy condition in a limited length of time,
17-1
MODEL R172 SERIES SERVICE MANUAL
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. Consuit the factory when in doubt about a repair not
specifically mentioned here,
17-3.
EQUIPMENT AND TOOLS.
17-4. 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 17-1. 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.
17-5. 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.
17-6. 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.
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.
17-10.
17-11. DESCRIPTION. The wing assemblies are a
semicantilever type employing semimoncoque 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.
17-12.
17-7. WING TWIST AND STABILIZER ANGLE-OFINCIDENCE.
17-8. Wing twist (washout) and horizontal stabilizer
angle fo 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. Refer to
figure 18-2 for wing twist measurement,
WING
Twist (Washout)
STABILIZER
Angle of Incidence
17-9. REPAIR MATERIALS.
rial on which a repair is to be
termined by measuring with a
eral, material used in Cessna
17-2
3° 37'
-3 ° 30'
Thickness of a matemade can easily be demicrometer. In genaircraft covered in
WING
WING SKIN.
17-13. 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
areas of low stress intensity, cracks, deep scratches,
or deep, sharp dents, which after trimming or stopdrilling 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. Stop drilling
is considered a temporary repair and a permanent
repair must be made as soon as practicable.
17-14. REPAIRABLE DAMAGE. Figure 17-5 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 a onehalf 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 an area where flush rivets are used, make a flush
patch type of repair; if in an area where flush rivets
MODEL R172 SERIES SERVICE MANUAL
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.
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.
17-15. 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.
17-30 REPAIRABLE DAMAGE. Figure 17-8 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.
17-16. WING STRINGERS.
17-17.
17-13.
NEGLIGIBLE DAMAGE.
Refer to paragraph
17-18. REPAIRABLE DAMAGE. Figure 17-6 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.
.
17-19. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. If a stringer is so badly damaged that
more than one section must be spliced, replacement
is recommended.
17-20.
WING AUXILIARY SPARS.
17-21.
17-13.
NEGLIGIBLE DAMAGE.
Refer to paragraph
17-22. REPAIRABLE DAMAGE. Figure 17-9 illustrates a typical auxiliary spar repair.
17-23. 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,
17-24.
WING RIBS.
17-25. NEGLIGIBLE DAMAGE.
17-13.
Refer to paragraph
17-26. REPAIRABLE DAMAGE.
trates a typical wing rib repair.
Figure 17-7 illus-
17-27. 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 .he rib, they should be repaired if practicable. Center ribs, between the front
and rear spar should always be repaired if practicable.
17-28.
WING SPARS.
17-29.
NEGLIGIBLE DAMAGE.
Due to the stress
17-31. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. Damage so extensive that a repair is not
practicable requires replacement of a complete wing
spar. Also refer to paragraph 17-2.
17-32.
AILERONS
17-33.
17-13.
NEGLIGIBLE DAMAGE.
Refer to paragraph
17-34. REPAIRABLE DAMAGE. The repair shown
in figure 17-10 may be used as a guide to repair damage to aileron leading edge skins. Figure 17 5 may
be used to repair damage to flat surfaces between corrugations. When damaged airea includes corrugations,
soo figure 17-4. It is recommended that material for
repair be cut from spare parts of the same gage and
corrugation spacing. The aileron must be balanced after repair. Refer to paragraph 17-36 and see figure
17-3 for aileron balancing. If damage would require a
repair which could not be made between adjacent ribs,
refer to following paragraph.
17-35. 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 occured, replacement of the aileron assembly is recommended.
After repair and/or replacement, balance aileron
in accordance with paragraph 17-36 and figure 17-3.
17-36. AILERON BALANCING. Following repair,
replacement or painting, the aileron must be balanced.
Complete instructions for fabricating balancing fixtures and mandrels and their use are given in figure
17-3..
17-37.
WING FLAPS.
17-38.
17-13.
NEGLIGIBLE DAMAGE.
Refer to paragraph
17-39. REPAIRABLE DAMAGE. Flap repair should
be similar to aileron repairs discussed in paragraph
17-34. A flap leading edge repair is shown in figure
17-11. If an overlapping patch is to be used, be sure
it will not interfere with the wing during flap operation.
17-40. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. Flap repairs which require replacement
of parts should be similar to aileron repairs discussed
in paragraph 17-35. Since the flap is not considered a
moveable control surface, no balnacing is required.
17-3
MODEL R172 SERIES SERVICE MANUAL
17-41.
WING LEADING EDGE.
17-42.
17-13.
NEGLIGIBLE DAMAGE.
Refer to paragraph
17-43. REPAIRABLE DAMAGE. A typical leading
edge skin repair is shown in figure 17-10. An epoxytype 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 17-12. If the
damage would require a repair which could not be
made between adjacent ribs, refer to the following
paragraph.
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 repair would be located in an area with
compound curves, see the following paragraph.
17-44. DAMAGE NECESSITATING REPLACEMENT
OF PARTS. For extensive damage, complete leading edge skin panels must be replaced. To facilitate
replacement, extra access holes may be installed in
the locations noted in figure 17-12.
17-53. 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.
17-45.
17-54.
ELEVATORS AND RUDDER.
17-46. NEGLIGIBLE DAMAGE. Refer to paragraph
17-13. 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.
17-47. REPAIRABLE DAMAGE. Skin patches illustrated in figure 17-5 may be used to repair skin
damage between corrugations. For skin damage which
includes corrugations, see figure 17-4. Following the
repair, the elevator/rudder must be balanced. See
figure 17-3 for balancing. If damage would require a
repair which could not be made between adjacent ribs,
refer to the following paragraph,
17-48. 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 17-49 and
figure 17-3.
17-49. ELEVATOR AND RUDDER BALANCING.
Following repair, replacement or painting, the elevators and rudder must be balanced. Complete instructions for fabricating balancing fixtures and
mandrels and their use are given in figure 17-3.
17-50.
FIN AND STABILIZER.
17-51.
17-13.
NEGLIGIBLE DAMAGE.
Refer to paragraph
17-52. REPAIRABLE DAMAGE. Skin patches illustrated in figure 17-8 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
17-4
FUSELAGE.
17-55. DESCRIPTION. The fuselage is of semimonocoque construction, consisting of formed
bulkheads, longitudinal stringers, reinforcing channels, and skin panels.
17-56. NEGLIGIBLE DAMAGE. Refer to paragraph
17-13. 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 investigated.
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 17-13.
MODEL R172 SERIES SERVICE MANUAL
17-33A. CRACKS IN CORRUGATED AILERON SKINS (Continued from page 17-3)
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. Any control surface that has 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 17-33, -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.
17-38A. CRACKS IN CORRUGATED FLAP SKINS (Continued from page 17-3)
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 17-38, -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 17-38, -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 3
7 January 2000
17-4A
MODEL R172 SERIES SERVICE MANUAL
17-46A. CRACKS IN CORRUGATED ELEVATOR SKINS (Continued from page 17-4)
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 17-46, -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 17-46, -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.
17-4B
Temporary Revision Number 3
7 January 2000
MODEL R172 SERIES SERVICE MANUAL
17-57. REPAIRABLE DAMAGE. Fuselage skin repairs may be accomplished in the same manner as
wing skin repairs outlined in paragraph 17-14.
Stringers, formed skin flanges, bulkhead channels
and similar parts may be repaired as shown in figure 18-6.
without machined flat surfaces around attachment
holes.
*Dash numbers are to be determined according to the
holes and the grip lengths required. Bolt grip length
should be chosen so that no threads remain in the
bearing area.
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 17-15. Damaged fittings
must be replaced. Seat rails serve as structural
parts of the fuselage and must be replaced if damaged.
17-65. FIREWALL DAMAGE. Firewall sheet may
be repaired by removing the damaged material (MILS-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 aluminum rivets. The diagonal support angles on the lower firewall are secured with aluminum rivets.
17-59.
BONDED DOORS.
17-60. REPAIRABLE DAMAGE. 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.
17-61.
BULKHEADS.
17-62. 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. Any other damage must be repaired by
replacing the landing gear support assembly as an
aligned unit.
17-63. 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 extremely 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.
17-64. REPLACEMENT OF HI-SHEAR RIVETS. Hishear rivet replacement with close-tolerance bolts or
other commercial fasteners of equivalant strength
properties is permissible. Holes must not be elongated and the Hi-shear substitute must be a smooth
push-fit. Field replacement of main landing gear
forgings on bulkheads may be accomplished by using
the following fasteners.
a. NAS464P-* bolt. MS21042-* nut and AN960-*
washer in place of Hi-shear rivets for forgings with
machined flat surfaces around attachment holes.
b. NAS464P-* bolt. ESNA 2935-* mating base washer and ESNA RM52LH2935-* self-aligning nut for
forgings (with draft angle of up to a maximum of 8 ° )
17-66.
ENGINE MOUNT.
17-67. DESCRIPTION. The mount for the aircraft
engine is constructed of 4130 chrome-molybdenum
steel tubing. A truss structure, fastened to the firewall at four points, supports a cradle arrangement.
This cradle arrangement with its supporting lugs,
forms the base for rubber shock mounted engine supports.
17-68. 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 30degree scarf welds in place of the fishmouth welds
are considered satisfactory for engine mount repair
work.
Refer to Section 18 for engine mount painting.
17-69. ENGINE MOUNT SUPPORT CRADLE DAMAGE. Minor damage such as a crack adjacent to an
engine attaching lug may be repaired by rewelding
the cradle tube and extending a gusset past the damaged area. Extensively damaged parts must be replaced.
17-70. DAMAGE INVOLVING ENGINE MOUNTING
LUGS AND ENGINE MOUNT TO FUSELAGE ATTACHING FITTINGS. Engine mounting lugs and engine
mount-to-fuselage attaching fittings should not be repaired but must be replaced.
17-71. BAFFLES. Baffles ordinarily require replacement if damaged for cracked. However, small
plate reinforcements riveted to the baffle will often
prove satisfactory both to the strength and cooling
requirements of the unit.
17-72.
ENGINE COWLING.
17-5
MODEL R172 SERIES SERVICE MANUAL
WING
12 INCH WIDE
HEAVY CANVAS
1 X12
X 30-3/4
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
1-1/2
42
34
----- 3/8 INCH DIAMETER
2
NOTE
BOLTS
X4
30
ALL DIMENSIONS ARE IN INCHES
Figure 17-1.
Wing and Fuselage Support Stands
17-73. 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
17-6
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. 131 are also applicable to cowling.
17-74. 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.
MODEL R172 SERIES SERVICE MANUAL
-
----------------
A
WING STATION
2.00
2.00
.45
1.00
1.00
1.00
29.50
29.50
24.00
39.00
100.50
208.00
ALL WING TWIST OCCURS BETWEEN STA. 100.50
*AND STA, 208. 00.
(Refer to paragraph 17-7 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).
may be lowered from wing . 10 inch maximum to attain parallelism.
Figure 17-2.
17-75. REPAIR OF GLASS-FIBER CONSTRUCTED
COMPONENTS. Glass-fiber constructed components
on the aircraft may be repaired as stipulated in instructions furnished in Service Kit SK182-12. Observe the resin manufacturer's recommendations
Forward or aft bolt
Checking Wing Twist
concerning mixing and application of the resin.
Epoxy resins are preferable for making repairs,
since epoxy compounds are usually more stable and
predictable than polyester and, in addition, give
better adhesion.
17-7
MODEL R172 SERIES SERVICE MANUAL
BALANCING PROCEDURES
1.
Balance control surfaces in an enclosed draft free area.
2.
Control surface to be balanced must be in the final flight configuration, painted (if applicable)
trim tabs installed, and all foreign matter removed from inside control surface.
3.
Make sure all control surfaces are in their approved flight configuration: 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 (detail B) on a table or other suitable FLAT, LEVELED surface.
Mandrels must be placed at 90 ° to the hinge line of the control surface.
5.
On control surfaces with the piano type hinges, insert inboard and outboard hinges into slotted
ends of the balancing mandrels, making sure that balancing mandrels are 90 ° to the hinge line.
On control surfaces with the bearing type hinge point, bolts or pins are inserted through the
attaching brackets, then placed on the knife edges of the mandrels as illustrated in (detail H).
6.
AILERONS.
a.
(1) Block up the trailing edge of the aileron until a spirit-level protractor placed on the front
face of the aileron.spar at W.S. 154.00 (± 6.00), (detail E), indicates 57 ° 10', (detail D).
(2)
ALTERNATE METHOD:
Measure the vertical distance from the aileron hinge point to the leveled surface.
1. 80 inches, then block up trailing edge of the aileron to this measurement.
Subtract
b. With the aileron blocked in position place the balancing beam (detail A) at W. S. 154.00, (90 ° to
the hinge line), and adjust the trailing edge support on the balancing beam (detail D) until the
beam is level. If the aileron has not been disturbed during this operation, the beam is now
parallel to the aileron chord line at W. S. 154.00 (detail D).
NOTE
The above procedure must be performed with care. Small angular
discrepancies will produce large balancing errors.
c. Remove balancing beam and balance the beam by itself at the knife edges by adding washers
as shown, (detail C).
d. Place the balancing beam on the aileron in its original position, then remove the blocks from
beneath the trailing edge.
e. Place the sliding weight (detail D) on the forward end of the balancing beam, moving it along
the beam until the beam is again level. A small, lightweight, spirit-level may be used for
this purpose provided it is symmetrical about its bubble reference and this reference is
placed on the beam directly over the aileron hinge line (detail D).
f.
If aileron is correctly balanced, the position of the sliding weight with respect to the aileron
hinge line, will produce a moment about the hinge line somewhere within the underbalance
tolerance listed in the chart on (Sheet 5 of 5).
g. If modification of the aileron balance weight is necessary to correct an out-of-tolerance
condition, the balance weight can be lightened by drilling out part of the weight on the inboard end. The weight can be increased by a reasonable amount by ordering additional
weight and gang channel listed in the applicable Parts Catalog, and installing next to the
inboard weight the minimum amount necessary for correct balance. The minimum amount
that must be installed, however, must contain at least two attaching rivets. If this minimum
amount results in an over-balanced condition, the new weight and/or old weights can be
lightened.
Figure 17-3.
17-8
Control Surface Balancing (Sheet 1 of 5)
MODEL R172 SERIES SERVICE MANUAL
7.
RUDDER AND ELEVATORS.
a. With the rudder/elevator set upon a FLAT, LEVELED surface, block up the trailing edge
until a center line through the attaching bolt and the trailing edge is equal distance from the
leveling surface (detail H).
b. Place the balancing beam (detail A) on the rudder/elevator near the center attaching bracket,
(90 ° to the hinge line). Adjust the trailing edge support on the balancing beam (detail H) until
the beam is level. If the rudder/elevator has not been disturbed during this operation, the
beam is now parallel to the chord line of the rudder/elevator.
NOTE
The above procedure must be performed with care. Small angular
discrepancies will produce large balancing errors.
c.
Mark position of the balancing beam, then remove and balance the beam by itself at the knife
edges by adding washers as shown in (detail C).
d. Place the balancing beam on the rudder/elevator in its original position, then remove the block
from beneath the trailing edge.
e.
Place the sliding weight (detail H) on the forward end of the balance beam, move it along the
beam until the beam is again level. A small, lightweight, spirit-level may be used for this
purpose provided it is symmetrical about its bubble reference and this reference is placed
on the beam directly over the rudder/elevator hinge line (detail H).
f.
If the rudder/elevator is correctly balanced, the position of the sliding weight with respect to
the rudder/elevator hinge line, will produce a moment about the hinge line somewhere within
the underbalance tolerance listed in the chart on (Sheet 5 of 5).
g.
If modification of the rudder/elevator balance weight is necessary to correct an out-of-balance.
condition, the balance weight can be lightened by drilling out part of the weight. The weight
can be increased by fusing bar stock solder to the weight after removal from rudder/elevator.
BALANCING BEAM
Mark graduations in inches
Four-foot length of extruded channel
Grind weight to slide along beam, grind
ends to obtain exactly one pound, and
mark center of weight.\
Fabricate vertically adjustable
trailing edge support that will
slide along beam.
Attach knife edges and
mark at mid-point.
*
Figure 17-3.
Detail A
Control Surface Balancing (Sheet 2 of 5)
17-9
MODEL R172 SERIES SERVICE MANUAL
1/16" SLOT: 3/4" DEEP
(To fit aileron hinge)
KNIFE EDGE
After locating trailing
edge support, balance
by adding washers and/
or nuts.
BALANCING
MANDREL
6-1/2
Detail C
Detail
SPIRIT-LEVEL
B
PROTRACTOR
SLIDING WEIGHT
\
R-KNIFE EDGES
TRAILING EDGE
SUPPORT
BALANCING
MANDREL
..
"d"
HINGE POINT
-
-
-AILERON
LEVELED SURFACE
* ALTERNATE METHOD
Before making trailing
edge measurement, make
sure trailing edge of
BALANCING
MANDREL
aileron is straight
in this
area.
Detail
D
AT AILERON
MIDSPAN
(W.S.154.00)
*
WING STATION 1005
17-3.
CHORD LINE
INCHES
Control Surface Balancing (Sheet 3 of 5)
AILERON-N
.
.
.
.
Detail E
Figure 17-3.
17-10
Control Surface Balancing (Sheet 3 of 5)
-WING
STATION 154.00
MODEL R172 SERIES SERVICE MANUAL
A balance in this range is "overbalance".
A balance in this range is "underbalance".--
BALANCING MANDREL
RUDDER
Detail
F
SPIRIT-LEVEL
Detail
G
PROTRACTOR
TRAILING EDGE
SUPPORT
SLIDING WEIGHT
KNIFE EDGES
BALANCING
MANDREL
CHORD LINE
HINGE POINT
LEVELED SURFACE
Detail
Figure 17-3.
-
ELEVATOR
H
Control Surface Balancing (Sheet 4 of 5)
17-11
MODEL R172 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 the control surface is trailing
edge heavy, and is symbolized by a plus (+).
OVERBALANCE is defined as the condition that exists when the control surface is leading
edge heavy, and is symbolized by a minus (-).
APPROVED FLIGHT CONFIGURATION
BALANCE LIMITS (Inch-Pounds)
AILERON
RUDDER
0.0 to + 6.7
RIGHT ELEVATOR
0. 0 to + 24. 5
LEFT ELEVATOR
0.0 to + 18.5
Figure 17-3.
17-12
0.0 to +11.31
Control Surface Balancing (Sheet 5 of 5)
MODEL R172 SERIES SERVICE MANUAL
1/4" MINIMUM EDGE MARGIN
AND RIVET SIZE
CUT OUT DAMAGED AREA
AILERON
-PATCH MAY OVERLAP
OR BE INSERTED UNDER
ORIGINAL PART
REPAIR PATCH IN CROSS SECTION
,-,-
A-A
Figure 17-4.
Corrugated Skin Repair
MODEL R172 SERIES SERVICE MANUAL
PATCHES AND DOUBLERS 2024-T3 ALCLAD
MS20470AD4 RIVETS
24 REQD
DOUBLER
EXISTING
SKIN
SECTION THRU PATCH
3.00 DIA. HOLE
PATCH REPAIR FOR 3 INCH DIAMETER HOLE
MS20470AD4 RIVETS
16 REQD
EXISTING
SKIN
,-4.00
DOUBLER
DIA.-
5.00 DIA.7--
SECTION THRU PATCH
PATCH REPAIR FOR 2 INCH DIAMETER HOLE
2.50 DIA.
MS20470AD4 RIVETS
EXISTING
8 REQD
SKIN
PATCH
(NO DOUBLER
REQD)
1.75
C.
DIA.
1.00 DIA. HOLE
SECTION THRU PATCH
PATCH REPAIR FOR 1 INCH DIAMETER HOLE
.ORIGINAL PARTS
REPAIR PARTS
OVERLAPPING
REPAIR PARTS IN CROSS SECTION
CIR C U L AR PATCH
Figure 17-5.
17-14
Skin Repair (Sheet 1 of 6)
MODEL R172 SERIES SERVICE MANUAL
1/2 B
SECTION THRU ASSEMBLED PATCH
A-A
EDGE MARGIN = 2 X RIVET DIA.
PATCH -
2024-T3 ALCLAD
-
DAMAGED AREA
EDGE
MARGIN = 2 X RIVET
,
RADIUS
1/2"
1/2" RADIUS- ,
..-...
,-........
. .... -
.,---DIAMETER
---
l .-
EDGE MARGIN =2 X RIVET DIA.
PARTS
DOUBLER
- 2024-T3PATCH
TANGULAR
ALCLAD
..
.............
.ORIGINAL
......... ...
.
025
.032
1/8
RIVET TABLE
OVERLAPPNG
REC-SKIN
REPAIR PARTS
PARTS IN CROSS
SECTION
Figure
15. REPAIR
Skn
Repair (Sheet 2 of 6)
Figure 17-5.
Skin Repair (Sheet 2 of 6)
GAGE
051
RIVET DIA.
5/32
RIVET
MODEL R172 SERIES SERVICE MANUAL
-
B
.
or optimum appearance and
airflow, use flush rivets, dimpled skin and patch, and countersunk doubler.
-SECTION THRU ASSEMBLED PATCH
A-A
EDGE MARGIN = 2 X RIVET DIA.
PATCH - 2024-T3 ALCLAD
2 X RIVET DIA.
,,,,
CLEAN OUT
^
RIVET SPACING =
6 X RIVET DIA.
-
DOUBLER -
.
2024-T3 "
"EDGE MARGIN =
2 X RIVET DIA.
.
1
^
RIVET
(CIRCULAR FLUSH PATCH IS
ORIGINAL PARTS
SMILAR)
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-5.
17-16
Skin Repair (Sheet 3 of 6)
020
2H
.032
.040
.051
1/8
1/8
1/8
1/8
5/32
MODEL R172 SERIES SERVICE MANUAL
NOTE
DOUBLER
Countersink doublers, and
dimple skin and patch.
DOUBLER EXISTING
SKIN
PATCH
DOUBLER -
RIVET PATTERNL
THRU PATCH
2D MIN.
TYPICAL
.50 R. MIN.
RIVET TABLE
SKIN GAGE
RIVET DIA.
.020
.025
.032
.040
.051
1/8
1/8
1/8
1/8
5/32
-PATCH
2024-T3 ALCLAD
FLUSH PATCH AT
STRINGER/BULKHEAD
INTERSECTION
ORIGINAL PARTS
REPAIR PARTS
NOTE
REPAIR PARTS IN CROSS SECTION
Figure 17-5.
This procedure is not recommended in areas where
stringers are riveted to
bulkheads.
Skin Repair (Sheet 4 of 6)
17-17
MODEL R172 SERIES SERVICE MANUAL
DOUBLERS
1/4 B (BUT NOT LESS THAN 4D)
EXISTING
SKIN
O-DOUBLER
-
.....
2024-T4 ALCLAD
*
PATCH
A-A
SECTION THRU ASSEMBLED PATCH
...
RIVET PATTERN
PITCH TYPICAL FOR
PATCH SKIN & DOUBLERU
.
EXISTING SKIN
0. 5" MIN. RADIUS
TYPICAL
- EDGE DISTANCE
RIVET TABLE
SKIN GAGE
RIVET DIA.
--------
.020
.025
· 032
.040
.051
--------
-
1/8
1/8
1/8
1/8
5/32
2024-T3 ALCLAD
OVERLAPPING PATCH AT
STRINGER/BULKHEAD
INTERSECTION
.
ORIGINAL PARTS
/
PATCH
2024-T3 ALCLAD
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-5.
17-18
Skin Repair (Sheet 5 of 6)
MODEL R172 SERIES SERVICE MANUAL
FUSELAGE SKIN
--
CLEAN OUT DAMAGED AREA
A-A
-
PICK UP EXISTING
SKIN RIVET PATTERN
10 RIVETS
EACH SIDE OF
DAMAGED AREA
FILLER-
2024-T4 ALCLAD
1/4" EDGE MARGIN-
DOUBLER ALCLAD
2024-T4
MS20470AD4 RIVETS
ORIGINAL PARTS
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-5.
Skin Repair (Sheet 6 of 6)
17-19
MODEL R172 SERIES SERVICE MANUAL
DOUBLER -
2024-T4 ALCLAD
1/4" EDGE MARGIN
RIVET SPACING TO MATCH
PATTERN IN SKIN
.-
6 RIVETS EACH SIDE
OF DAMAGED AREA
STRINGER
CLEAN OUT DAMAGED AREA
FILLER
2024-T4 ALCLAD
MS20470AD4 RIVETS
SKIN
ORIGINAL PARTS
*
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-6.
17-20
Stringer and Channel Repair (Sheet 1 of 4)
MODEL R172 SERIES SERVICE MANUAL
FILLER -
2024-T4 ALCLAD
A-A
STRIP-
2024-T3 ALCLAD
1/4" EDGE MARGIN
CLEAN OUT
'
DAMAGED AREA
.
5 RIVETS EACH SIDE
OF DAMAGED AREA
ANGLE -2024-T4
ALCLAD
RIVET
3/4" RIVET
SPACING
STRINGER
PICK UP EXISTING SKIN RIVETS
MS20470AD4 RIVETS
ORIGINAL PARTS
A
REPAIR PARTS
s
REPAIR PARTS IN CROSS SECTION
Figure 17-6.
Stringer and Channel Repair (Sheet 2 of 4)
17-21
MODEL R172 SERIES SERVICE MANUAL
STOP DRILL CRACK
^
CHANNEL
-DOUBLER
-
2024-T3 ALCLAD
1/4" EDGE MARGIN
SKIN --
-
MS20470AD4 RIVETS
ORIGINAL PARTS
.. REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-6.
17-22
Stringer and Channel Repair (Sheet 3 of 4)
MODEL R172 SERIES SERVICE MANUAL
FILLER - 2024-T4 ALCLAD
A-\
DOUBLER - 2024-T3 ALCLAD
CLEAN OUT DAMAGED AREA
SPACING
1/4" RADIUS
-2
ROWS RIVETS OUTBOARD
OF LIGHTENING HOLE
1/4" MARGIN
CHANNEL
DOUBLER - 2024-T4 ALCLAD
AN470AD4 RIVETS·
W
ORIGINAL PARTS
REPAIR PARTS
REPAIR IN CROSS SECTION
Figure 17-6.
Stringer and Channel Repair (Sheet 4 of 4)
17-23
MODEL R172 SERIES SERVICE MANUAL
STOPDRILL CRACK IF CRACK
DOES NOT EXTEND TO EDGE
OF PART
DOUBLER-
2024-T3A\
1/4" EDGE MARGIN
MS20470AD4 RIVETS-
ORIGINAL PARTS
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-7.
17-24
Rib Repair (Sheet 1 of 2)
MODEL R172 SERIES SERVICE MANUAL
FILLER - 2024-T4 ALCLAD
DOUBLER - 2024-T3 ALCLAD
3/'4" RIVET
SPACING
CLEAN OUT DAMAGED AREA
1/4" EDGE MARGIN-
ANGLE-
.
.
.
.
-
2024-T4 ALCLAD
ONE ROW RIVETS
AROUND DAMAGED
AREA
--- MS20470AD4 RIVETS
ORIGINAL PARTS
A-A
REPAIR PARTS
REPAIR PARTS IN
CROSS SECTION
Figure 17-7.
Rib Repair (Sheet 2 of 2)
17-25
MODEL R172 SERIES SERVICE MANUAL
FILLER -
FILLER -
2024-T4 ALCLAD
2024-T4 ALCLAD
DOUBLER-
CLEAN OUT DAMAGED AREA
SPAR
3/8" EDGE MARGIN
(TYPICAL)
ORIGINAL PARTS
.REPAIR
PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-8.
17-26
Wing Spar Repair (Sheet 1 of 3)
A-A
MODEL R172 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
3/4" RIVET SPACING
1/4'
MINIMUM
EACH SIDE OF
DOUBLER -
ANGLE
7/8 x
x
1/4" MINIMUM
1/4" EDGE
MARGIN
(TYP.)
MS20470AD4
RIVETS
-
EACH SIDE OF
ORIGINAL PARTS
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-8.
Wing Spar Repair (Sheet 2 of 3)
17-27
MODEL R172 SERIES SERVICE MANUAL
FILLER ALCLAD
3/4" RIVET
SPACING
2024-T4
CLEAN OUT
DAMAGED AREA
1/4" EDGE MARGIN
-- 2024-T4 ALCLAD
MS20470AD4 RIVETS
ORIGINAL PARTS
REPAMI PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-8.
17-28
Wing Spar Repair (Sheet 3 of 3)
MODEL R172 SERIES SERVICE MANUAL
DOUBLER -2024-T4
ALCLAD
DAMAGED AREA
A-A
/
1/4"
20 RIVETS EACH SIDE OF
DAMAGED AREA
FILLER
WING SKIN
RIVETS
ORIGINAL PARTS
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-9.
Auxiliary Spar Repair
17-29
MODEL R172 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.
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.
Use CR162-4
1" MAXIMUM RIVET
SPACING (TYPICAL)
DOUBLER NEED NOT
BE CUT OUT IF ALL
RIVETS ARE ACCESSIBLE
FOR BUCKING
5/16" MINIMUM EDGE
MARGIN (TYPICAL)
TRIM OUT DAMAGED AREA
.....
...
.........
....
FILLER MATERIAL
ORIGINAL PART
REPAIR PARTS
SAME THICKNESS
AS SKIN
Figure 17-10.
17-30
Leading Edge Repair
2024-T3 ALCLAD
.040" THICKNESS
MODEL R172 SERIES SERVICE MANUAL
1" MAXIMUM RIVET SPACING
1/4" MINIMUM EDGE MARGIN
RIM OUT DAMAGED AREA
*
.. '.~'.,,,,,.,-'
-
FLAP LEADING EDGE SKIN
*REPAIR DOUBLER TO BUTT
AGAINST CORRUGATED SKIN
AT TOP AND BOTTOM OF FLAP
1/4" MINIMUM EDGE MARGIN
DOUBLER ALCLAD. 020
2024-T3
FLUSH PATCH SIMILAR
TO THIS MAY BE USED
IF NEEDED.
1/8" DIA. RIVETS
ORIGINAL PARTS
REPAIR PARTS
Figure 17-11.
Flap Leading Edge Repair
17-31
MODEL R172 SERIES SERVICE MANUAL
S-1443-1 DOUBLER
-
~AT
,
-#40
~
VIEWED FROM INSIDE
WING LOOKING DOWN
TOP OF LOWER
WING SKIN.
(.098) HOLE
(10 REOD)
LOWER WING SKIN (REF)
5.062 DIA-,
^,
S-225-4F COVER
MS20426AD3
RIVETS
NOTE
PARTS ARE AVAILABLE
FROM THE CESSNA
SERVICE PARTS CENTER.
S-1022Z-8-6 SCREWS
PRECAUTIONS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Add the minimum number of access holes necessary.
Any circular or rectangular access hole which is used with approved optional equipment installations may be added in lieu of the access hole illustrated.
Do not add access holes at outboard end of wing; remove wing tip instead.
Do not add an access hole in the same bay where one is already located.
Locate new access holes near the center of a bay (spanwise).
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.
Alternate bays, with new access holes staggered forward and aft of the front spar, are preferable.
A maximum of five new access holes in each wing is permissible; if more are required, contact
the Cessna Service Department.
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.
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 17-12.
17-32
Access Hole Installation
Mark the ten rivet
MODEL R172 SERIES SERVICE MANUAL
MARGIN
CLEAN OUT DAMAGED AREA
ANGLE
-2024-T4
ALCLAD
10 RIVETS EACH SIDE
OF DAMAGED AREA
FIREWALL ANGLE
FILLER -
2024-T4 ALCLAD
MS20470AD4 RIVETS
--
FUSELAGE SKIN
ORIGINAL PARTS
:
REPAIR PARTS
REPAIR PARTS IN CROSS SECTION
Figure 17-13.
Firewall Angle Repair
17-33/(17-34 blank)
MODEL R172 SERIES SERVICE MANUAL
SECTION 18
PAINTING
NOTE
A listing of standard factory materials and area of application is contained in this section. To determine
paint color number, refer to Aircraft Trim Plate and Parts Catalog. In all cases determine the type of
paint on the aircraft, because some paints are not compatible. These materials can be obtained from
Cessna Service Parts Center.
Page No.
Aerofiche/Manual
TABLE OF CONTENTS
ACRYLIC LACQUER MATERIALS . . . 2F11/18-1
Painting ABS Parts
........
2F12/18-2
Interior ...........
2F12/18-2
Exterior
..........
2F12/18-2
Refinishing Engine Mounts. .....
2F12/18-2
MODIFIED URETHANE MATERIALS . . 2F13/18-3
Facility ............
2F13/18-3
Clean-up ..
........
2F14/18-4
MATERIAL
PAINT
NO/TYPE
Prepriming ..
......
Priming
............
Prepainting ..........
Painting
Overall .......
Masking. .........
Touch-up ......
Repair of Dents ......
DOMESTIC
*ACRYLIC LACQUER
X
LACQUER
THINNER
SOLVENT
2F14/18-4
2F14/18-4
2F14/18-4
.
2F14/18-4
2F14/18-4
. 2F15/18-5
.2F15/18-5
AREA OF APPLICATION
See note number 1.
X
See note number 1.
X
X
See note number 6.
* CES-1054-812
VHT White Enamel
X
X
See note number 7.
P60G2 With R7K44
Reducer
X
Ex-Er-7 With T-Er-4
Reducer
X
T-8402A
X
T-6094A
X
X
See note number 3.
Toluene
X
X
See note number 8.
Methyl Ethyl Keytone
(MEK)
X
X
See note number 5.
CES-1054-215
Heat Resistant Enamel
PRIMER
FRENCH
.
See note number 2.
X
See note number 2.
See note number 4.
NOTES
1.
2.
3.
4.
5.
6.
7.
8.
Used on aircraft exterior.
Used with lacquer or acrylic lacquer on aircraft exterior.
Used to thin lacquer, for burndown, and to thin VHT enamel.
Used to thin acrylic lacquer and for burndown.
Used to clean aircraft exterior prior to priming.
Used on engine mount allover.
Used on designated areas of engine mount.
Used to thin VHT enamel.
*
Beginning Serial R1722891 and FR1720631.
THRU R1722776.
NOTE
Control surfaces, except Tor
wing flaps, must be balanced
after painting. Refer to Section 17, figure 17-3 for balancing procedures.
18-1
MODEL R172 SERIES SERVICE MANUAL
18-1. PAINTING OF FORMED ABS PLASTIC PARTS.
The following procedures outline some basic steps
which are useful during touchup or painting of formed ABS plastic parts.
18-2. INTERIOR PARTS (Finish Coat of Lacquer)
a. Painting of Spare Parts.
1. Ensure a clean surface by wiping with Naphtha
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.
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 Naphtha
to remove surface contamination.
CAUTION
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 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 adhesion.
2. Ensure a clean surface by wiping with Naphtha
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. 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.
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.
18-3. EXTERIOR PARTS (Acrylic Topcoat)
a. Painting of Spare Parts.
1. Lightly scuff sand to remove scratches and
improve adhesion.
2. Ensure a clean surface by wiping with Naphtha
18-4. REFINISHING ENGINE MOUNTS. (See
figure 18-1.) After completing engine mount repairs
as outlined in Section 17 of this manual, refinish with
Part Number EX2219 (Ameron-Enmar Finishes,
16116 East 13th St., 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-inch to
0.0013-inch, and cure at 250 F for 15 minutes. Part
can be handled as soon as cool to touch. For areas
which are in close proximity to the engine exhaust
stacks, paint with Sperex SP101 VHT White (Sperex
Corp., 16131 So. Maple Ave., Gardena, Calif.,
90248) (213) 323-6162. Refer to Cessna Single-Engine
Service Letter No. SE 78-27 for surface preparation
and painting procedures.
Detail
A
Sperex SP101 VHT White
Figure 18-1.
18-2
Refinishing Engine Mount.
MODEL R172 SERIES SERVICE MANUAL
BEGINNING R1722777.
IMRON MODIFIED URETHANE
AREA OF APPLICATION
NO/TYPE
MATERIAL
IMRON ENAMEL
Used as corrosion proof topcoat
IMRON 192S Activator
Catalyst for Imron Enamel
THINNER
IMRON Y8485S Reducer
Used to thin Imron Enamel
PRIMER
WASH PRIMER P60G2
Used to prime aircraft for Imron Enamel
PAINT
REDUCER
Catalyst Reducer R7K44
Used to reduce P60G2
NOTE
Also
Do not paint pitot tube, gas caps, or aileron gap seals.
do not paint antenna covers which were not painted at the factory.
REQUIRED MATERIALS
NO/TYPE
MATERIAL
STRIPPER
CLEANER
Strypeeze Stripper
DX 440 Wax and Grease Remover
AREA OF APPLICATION
Used to strip primer overspray
Used to clean aircraft exterior
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
(MEK) Methyl Ethyl Ketone
Used to clean aircraft prior to topcoat
CLOTH
HEX Wiping Cloth
Used with solvent to clean aircraft exterior
FILLER
MASKING
White Streak
Used to fill small dents
Class A Solvent Proof Paper
Used to mask areas not to be painted
Tape Y218
Used for masking small areas
Tape Y231
Used for masking small areas
18-5. FACILITY. Painting facilities must include
the ability to maintain environmental control; terperature at 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 buildup. 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 900F. Storage at 90 0 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 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.
18-3
MODEL R172 SERIES SERVICE MANUAL
WARNING
18-6. CLEAN UP.
a. Inspect airplane for any surface defects, such as
dents or unsatisfactory previous repairs, and correct
according to paragraph 18-13.
b. Wipe excess sealer from around windows and skin
laps. Mask windows, ABS parts, and any other areas
not to be primed, with 3M tape and Class A Solvent
Proof Paper. Care must be exercised 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.
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.
18-7. 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.
18-4
AIRCRAFT SHOULD BE GROUNDED PRIOR
TO PAINTING TO PREVENT STATIC ELECTRICITY BUILD-UP AND DISCHARGE.
18-8. 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.
18-9
a.
PREPAINTING
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 shoud 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.
18-10. 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
approximately 2.0 mils. Films in excess of 3.0
mils are not desirable.
18-11. 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.
MODEL R172 SERIES SERVICE MANUAL
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 sand paper. Course paper
will leave sand marks which will decrease gloss and
depth of gloss of the finish. The use of power sander s
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
e.
Stripe colors on Imron base coat will be Imron
Enamel.
Mix as outlined in paragraph 18-9.
wet-even coats.
Dry coats will not reflow,
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 Removal. All traces of stripper must be removed before
refinishing.
18-13. REPAIR OF DENTS.
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.
and will
All
be removed in the repair area and the alu-
leave a grainy appearance. Stripes may be force
dried or air dried. Film thickness of a stripe is ap-
paint shallbe removed in
minum the White Steak to
paint has dried to a "dry to touch" condition. Care
should be exercised in removal of the masking to prvent damage to the finish.
h. Modified urethane finishes are sensitive to moisture, therefore, should be stored out of rain until
cured.
sand the filler flush with the skin surface, using care
to eater e ees
NOTE
proximately 1.5 to 2.0 mils
g. Do not remove masking tape and paper until the
askintapeandpperutsand
Donotremove
therepair area
increas
and the aluadesion.
Apply the White Streak to a level slightly above the
surrounding skin. After drying for I0 - 15 minutes,
surrounding
skin. After the skinfor
10 - 15 using
minutes,
care
surface,
the filler flush with drying
Refer to paragraph 18-4, for engine mount
refinishing procedures and paint application.
18-12. 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 panel as much as possible. Since urethane finishes cannot be "spotted in"
repairs should be in sections extending to skin laps or
stripe lines.
NOTE
Refer to Section 17 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.
NOTE
Application of a top coat thickness in excess of 5. 0
mils, requires a control surface balance check.
SHOP NOTES:
18-5/(18-6 blank)
MODEL R172 SERIES SERVICE MANUAL
TABLE OF CONTENTS
SECTION 20
WIRING DIAGRAMS
12 VOLT
Page No.
Aerofiche/Manual
Circuit Function and Specific
Circuit Code Letters .......
Cross Reference Listing ....
D.C. POWER
Battery Circuit ....
...
Bus Bar, Primary, Alternator
and Electronic ........
Alternator System, 60 Amp . ..
Alternator System, 60 Amp
.
Ammeter ...........
Ground Service Receptacle .. .
IGNITION
Magneto
.....
......
FUEL AND OIL
Fuel Pump ..........
Oil Temperature ........
ENGINE INSTRUMENTS
Fuel Gage and Transmitter . .
Cylinder Head Temperature .
Hour Meter ..........
Carburetor Air Temperature
Gage ............
FLIGHT INSTRUMENTS
Turn Coordinator . .......
Turn and Bank Indicator
.....
Encoding Altimeter . ......
2F23/19-2
. 2F24/19-3
. 2G1/19-4
2G2/19-5
2G4/19-7
. 2G5/19-8
2G6/19-9
2G7/19-10
2G8/19-11
2G9/19-12
2G10/19-13
2G11/19-14
2G12/19-15
2G13/19=16
. 2G14/19-17
2G15/19-18
2G16/19-19
2G17/19-20
D. C. POWER
Battery Circuit ........
2H13/19-40
Ground Service Receptacle . .
2H14/19-41
Bus and Avionics
Master Switch ........
2H15/19-42
Alternator System .......
2H16/19-43
Alternator System .......
217/19-44
Ammeter .
..........
2H18/19-45
Alternator System ......
. 2H19/19-46
Bus Bar & Avionics Master Switch 2H21/19-48
Battery Circuit. ........
2H23/19-50
Ammeter .
..........
2I1/19-52
Ground Service Receptacle . .
2I2/19-53
Ground Service Receptacle .
. 2I3/19-54
Alternator System .......
2I4/19-55
IGNITION
Magneto.
...........
2I5/19-56
Magneto .....
.......
2I6/19-57
FUEL AND OIL
Fuel Pump. ..........
2I7/19-58
Oil Temperature ........
2I8/19-59
Oil Temperature ........
2I9/19-60
ENGINE INSTRUMENTS
Fuel Gage and Transmitter . .
2I10/19-61
Hourmeter .
.........
2I11/19-62
Hourmeter .
..........
2I12/19-63
Hourmeter .............
2I13/19-64
Cylinder Head Temp ......
2I14/19-65
Carburetor Air Temperature
Gage ............
2I15/19-66
Instrument Clusters & Transmitter2I16/19-67
Instrument Clusters & Transmitter2I17/19-68
Hourmeter ..........
2I18/19-69
Hourmeter
2I19/20-70
Blind Encoder .......
..
2G18/19-21
OTHER INSTRUMENTS
Clock .............
2G19/19-22
LIGHTING
Map and Auxiliary Instrument
Light ............
2G20/19-23
Compass and Instrument
Light ............
2G21/19-24
Compass and Instrument
Light
............
2G22/19-25
Instrument Panel Post Lighting . 2G23/19-26
Instrument Panel Post Lighting. .2G24/19-27
Dome and Courtesy Lights. . ..
2H1/19-28
Landing and Taxi Light .....
22/19-29
Landing and Taxi Light .
.
2H3/19-30
Landing and Taxi Light .....
2H4/19-31
Navigation Lights .......
2H5/19-32
Flashing Beacon Light .....
2H6/19-33
Map Light - Control Wheel .. .
2H7/19-34
Wing Tip Strobe Light .....
2H8/19-35
HEATING, VENTING AND DE-ICING
Cigar Lighter ........
. 2H9/19-36
Pitot Heater ..........
2H10/19-37
CONTROL SURFACE SECTION
Wing Flaps - Electric
......
2H11/19-38
Wing Flaps - Electric. ......
2H12/19-39
24 VOLT
Carburetor Air Temperature
Gage ............
FLIGHT INSTRUMENTS
Turn Coordinator
Turn and Bank Insicator . ...
OTHER INSTRUMENTS
Clock .
...........
Digital Clock. .........
Clock .
............
LIGHTING
Map and Auxiliary Instrument
Light .
...........
Compass and Instrument Light
Compass and Instrument Light .
Instrument Panel Post Lighting.
Instrument Panel Post Lighting.
Dome and Courtesy Lights. . ..
Landing and Taxi Light ....
Landing and Taxi Light .....
Navigation Lights .......
Navigation Lights. ........
Flashing Beacon Light .....
Map Light - Control Wheel . .
Wing Tip Strobe Light. .....
HEATING, VENTING AND DE-ICING
Cigar Lighter .........
Pitot Heater ..........
Air Conditioner
.......
Circulation Fan ........
CONTROL SURFACE SECTION
Wing Flaps - Electric. ....
Wing Flaps - Electric
.....
Wing Flaps - Electric. .....
2I20/19-71
2I21/19-72
. 2I22/19-73
2I23/19-74
2I24/19-75
2J1/19-76
. 2J2/19-77
2J3/19-78
2J4/19-79
. 2J5/19-80
2J6/19-81
. 2J7/19-82
2J8/19-83
2J9/19-84
2J10/19-85
2J11/19-86
. 2J12/19-87
. 2J13/19-88
2J14/19-89
2J15/19-90
. 2J16/19-91
2J17/19-92
. 2J18/19-93
2J19/19-94
2J20/19-95
19-1
MODEL R172 SERIES SERVICE MANUAL
CIRCUIT FUNCTION AND SPECIFIC CIRCUIT CODE LETTERS
A - Armament
B - Photographic
C - Control Surface
CA - Automatic Pilot
CC - Wing Flaps
CD - Elevator Trim
D - Instrument (Other Than Flight or Engine
Instrument)
DA - Ammeter
DB - Flap Position Indicator
DC - Clock
DD - Voltmeter
DE - Outside Air Temperature
DF - Flight Hour Meter
E - Engine Instrument
EA - Carburetor Air Temperature
EB - Fuel Quantity Gage and Transmitter
EC - Cylinder Head Temperature
ED - Oil Pressure
EE - Oil Temperature
EF - Fuel Pressure
EG - Tachometer
EH - Torque Indicator
EJ - Instrument Cluster
F - Flight Instrument
FA - Bank and Turn
FB - Pitot Static Tube Heater and Stall Warning
Heater
FC - Stall Warning
FD - Speed Control System
FE - Indicator Lights
G - Landing Gear
GA - Actuator
GB - Retraction
GC - Warning Device (Horn)
GD - Light Switches
GE - Indicator Lights
H - Heating, Ventilating and De-Icing
HA - Anti-icing
HB - Cabin Heater
HC - Cigar Lighter
HD - De-ice
HE - Air Conditioners
J - Ignition
JA - Magneto
K - Engine Control
KA - Starter Control
KB - Propeller Synchronizer
L - Lighting
LA - Cabin
19-2
LB - Instrument
LC - Landing
LD - Navigation
LE - Taxi
LF - Rotating Beacon
LG - Radio
LH - De-ice
LJ - Fuel Selector
M - Miscellaneous
MA - Cowl Flaps
MB - Electrically Operated Seats
MC - Smoke Generator
MD - Spray Equipment
ME - Cabin Pressurization Equipment
MF - Chem 0 2 - Indicator
P - D. C. Power
PA - Battery Circuit
PB - Generator Circuits
PC - External Power Source
Q - Fuel and Oil
QA - Auxilliary Fuel Pump
QB - Oil Dilution
QC - Engine Primer
QD - Main Fuel Pumps
QE - Fuel Valves
R - Radio (Navigation and Communication)
RA - Instrument Landing
RB - Command
RC - Radio Direction Finding
RD - VHF
RE - Homing
RF - Marker Beacon
RG - Navigation
RH - High Frequency
RJ - Interphone
RK - UHF
RL - Low Frequency
RM- Frequency Modulation
RP - Audio System and Audio Amplifier
RR - Distance Measuring Equipment (DME)
RS - Airborne Public Address System
S - Radar
U - Miscellaneous Electronic
UA - Identification - Friend or Foe
W - Warning and Emergency
WA - Flare Release
WB - Chip Detector
WC - Fire Detection System
X - A. C. Power
MODEL R172 SERIES SERVICE MANUAL
FUNCTION
CIRCUITS
BASE
COLOR
(or solid)
GAUGE
STRIPE
COLOR
16
Red
None
18
Red
Black
Red
White
20
Red
Green
22
Red
Yellow
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
A+ Power
Ground
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.
SR7692
17263459
SR8454
R1722825 & FR17200621
SR7903
17265685 & F17201385
SR8490
17267585, F17201515, R1722000 &
FR17200591
SR7904
FR17200562
SR8552
17268213 & R1722141
SR8133
17267585 & F17201515
SR8596
17269310 & R1722825
SR8134
FR17200591
SR8773
17271235 & F17201750
SR8146
R1722000
SR8774
R1722910 & FR17200631
SR8259
17265782 & F17201445
SR8453
17269310 & F17201640
19-3
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
Bus Bar. Primary. Alternator & Electronic (Sheet 1 of 2)
19-5
19-5
MODEL R172 SERIES SERVICE MANUAL
--
MODEL R172 SERIES SERVICE MANUAL
II
5-lbo3 7-
HOU
N
____
P84 es \ 5*i-S-9
_
:
19-7
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
NOTES.
1
GA
22
GA JUMPER
I(
EQUIPMENT
19-10
ORCc
0
TABLE
P 4.1.0)
A
DATE
DESCRIPTION
LET
PA5 WIRE IS DELETED
WHEN
GROUND
IS INSTALLED (EF
RECEPTACLE
SEVICE
BY REV
ADD NOTE
2 WAS
PA3
GA 4
(SR7904)
BLA
APPD
MODEL R172 SERIES SERVICE MANUAL
19-11
MODEL R172 SERIES SERVICE MANUAL
NOTES:
REVISION
LET
1 ENGINE
NOT RUNNING. ASSURE THATTHROTTLEOPERATEDSWITCH IS
DESCRIPTION
---
DATE
APPD
--
.
--
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
MODEL R172 SERIES SERVICE MANUAL
REVISION
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
DATE
LET
DESCRIPTION
APPO
NOTES
HOUSING
TRANSPONDER CONNECTOR
1
OF TRANSPONDER
CABLE
DIAGRAM OF
FOR WIRING
REFER TO
TRANSPONDER
2
3
ATTACH
THE
PART
300 & 400
3920166
TRANSPONDER
BOTH
ALTIMETER TO
IS
ASSY
NO. .4
AND
ENCODING
CIRCUITBREAKER
DIGITIZER
TRANSPONDER
C4
5
RADIO
TAN/BLU 22
22-1O- 6
TAN/ YEL
22-10-4
22-10-2
TAN/RED
5-2190-1
GRY/TAN
22-8-10
GRY/BLU
22-8- 6
GRY
SOLOER
22-8-4
/YEL
4
7
0470404
------------
CABLE
ASSy
6
C744001-O101
ALT
5
RT-459A
TRANSPONOER
RT-359A
5-21P9-1
COTNECTOR
DA-155
CONNECTOR
S-1360-5l
CIRCUIT BREAKER
RT-359A
4
4
3
PART
NO
IENT
AEOUIPM
DIGITIZER
-
TABLE
-WIRE
TRANSPONDER
CONTRACT NO :
-
DESCRIPTION
E
NAME
SSIa.
DATE
DESION G. STAMM 4.23.76.
GROUP
----
4.
DRAWN
R. KLEN
CHECK
"(OAPENL
4-22-7f
AIICIAFT (0.
COMMERCIAL AIRCRAFT DIV.
500 C PAWNEE
WICHITA. KANSAS
TITLE
-
WIRING
BLIND
DIAGRAM-
ENCODER
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
19-23
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
A
1
THESE
2
19-24
WIRES
OPTIONAL
WITH
VENDOR
FURNISHED
POST LIGHTS INSTL
DESCRIPTION
BY REV
DELETE
34003-55-3410
18 GA JUMPER
DATE
WAS 34-003-55 TMS
APPD
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
19-26
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
A
8
S-16 3 7
HOIN-
PLUG
_
LC\I
,7
DATE
DESCRIPTION
BY REV: EXCHANGE
50R.U*-7_
TAXI
s-I7
LT
DTFIR
APPD
LDG LT,
SE R(S R859C)
19-29
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
Li3
-
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
KA8 <
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
DESCRIPTION
1 APPLIES
2 APPLIES
3
7
TO F172 172
TO FR172
R172
DATE
APPD
ONLY
ONLY
WIRE MUST
CONNECTED
TO "BATT" TERMINAL OF CLOCK, OTHERWISE
INTERNAL
DAMAGE TO UNIT WILL RESULT
CAUTION -
C(460So&
POWER
-0102 CLOCK.
__
GA
MATERIAL
LG
TERINALS
SERIALS
19-73
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
DESCRIPTION
DATE
A
_________________
19-76
LA I
22
______
__
S I5c.1
-I 1
-v.35
-I
APPD
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
A
DESCRIPTION
BY REV:
S-2000B271J
S 2000C201J
(SR8968)
DATE
WAS
APPD
CRS
10-3-77
19-77
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
D
19-78
DESCRIPTION
FOR
REVISION
SEE
PACE
DATE
11.2.0
APPD
MODEL R172 SERIES SERVICE MANUAL
>
T^\5 LAMP \S NOT UbEO 0M FRnZZ 0% R
A\1
BL_
Z-2-2Z -
_O
5OLOER :OLDGR
19-79
MODEL R172 SERIES SERVICE MANUAL
19-80
MODEL R172 SERIES SERVICE MANUAL
LET
DESCRIPTION
DATE
APPD
19-81
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
DESCRIPTION
DATE
APPO
MODEL R172 SERIES SERVICE MANUAL
REVISION
LE
T
DESCRIPTION
DATE
APPD
19-83
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
DESCRIPTION
DATE
APPO
MODEL R172 SERIES SERVICE MANUAL
LD I
-G-T
--
19-85
MODEL R172 SERIES SERVICE MANUAL
REVISION
DESCRIPTION
LET
1
S-
19-86
o(0
-I
SWITC.-%'
TM
I
a
A
MATERIAL
LO
TERMINALS
DATE
SERIALS
APPD
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
BY REV
A
C622006 0107 WAS
0101
DLP
DELETE
"PIGTAIL" /C62200B CIOZ
(SR8453)(REF)(SR8454)(REF)
BYREV ADD DETAIL "A",
4
SER
IN LD1
S-1235-5;
(Sk9624)
(SK9625)
T
19-88
DATE
DESCRIPTION
LET
RAO
APPD
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
BY REV: ADD DETAIL "A",HEII,HEIZ
(ADV
BY REV: RELEASED
FOR
RAD
SER
(SR9624)
REL)
REVSION
DESCRIPTION
LET
(SR9624)
A
NOTES:
1
DATE
PRODUCTION
REMOVE
DISCARD VENDOR FURNISHED
TERMINATE WITH 5-1636-1 TERMINALS
TERMINALS,
NOW
B
BY REV:
DELETE
NOTE
5-1367-2,
SHOP
PRACTICE)
(9 EIE8
13
-|
5-1c56
HOuSING
V&
IR
1-35
-193-1
19-91
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
A
BY REV: ADD 0570451
SER IN DETAIL A
T
19-92
DATE
DESCRIPTION
SER
OUT DETAIL A
RAO
APPD
MODEL R172 SERIES SERVICE MANUAL
MODEL R172 SERIES SERVICE MANUAL
REVISION
LET
DESCRIPTION
DATE
APPD
MODEL R172 SERIES SERVICE MANUAL
API
1
THESE. SWITLHES ARE PART OF
C301002-0108 ACTUATOR ASSY.
Source Exif Data:
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