Wulfsberg Electronics Division VC-401B VHF ATC Communication Transceiver for aircraft ins User Manual pilot guide

Wulfsberg Electronics Division VHF ATC Communication Transceiver for aircraft ins pilot guide

pilot guide

Publication No. 150-040564 Rev. A January 2000Chelton Avionics Inc.A Chelton Group Company6400 Wilkinson DrivePrescott, AZ 86305U.S.A.Series III AvionicsPilot's Guide
Series III AvionicsPilot's Guide Page iiWulfsberg Electronics Division, located in Prescott, Arizona, designs and manufactures the CheltonSeries III line of products, including the VCS-40A VHF Communications System. For more than 25 years,Wulfsberg Electronics has distinguished itself by providing top quality avionics products for civil, airtransport, and military applications.Information in this manual is subject to change without notice. No part of this manual may be reproducedor transmitted in any form or by any means, electronic or mechanical, without express written permissionof Chelton Avionics, Inc.Chelton Avionics, Inc. makes no warranty, expressed or implied, with regard to this manual, including butnot limited to any implied warranties of merchantability, fitness for a particular purpose, and non-infringement. In addition, Chelton Avionics, Inc. makes no warranty with regard to the documentation ordata contained herein. Chelton Avionics, Inc. is not liable in the event of incidental, special,consequential, or any other damages in connection with or arising from furnishing, performance, or use ofthis manual. 2000 Chelton Avionics, Inc. All rights reservedVCS-40A, VC-401B, CD-402B, VNS-41A, VN-411B, CD-412B, CD-413B, TRS-42A, TR-421B, CD-422B,DFS-43A, DF-431B, CD-432B, DMS-44A, DM-441B, and SD-442B are trademarks of Chelton Avionics, Inc.
Series III AvionicsPilot's Guide Page iiiVCS-40A VHF Communications System...................................................................................................................1General Description................................................................................................................................................1CD-402B Control Display Unit..............................................................................................................................2CD-402B Controls (Fixed Channel Spacing) .........................................................................................................3CD-402B Controls (Switchable Channel Spacing).................................................................................................3CD-402B Controls (All) .........................................................................................................................................4CD-402B Display ...................................................................................................................................................5Operating the VCS-40A .........................................................................................................................................6VCS-40A Notes......................................................................................................................................................8VCS-40A System Block Diagram (Typical) ..........................................................................................................9VNS-41A VHF Navigation System...........................................................................................................................10General Description..............................................................................................................................................10CD-412B Control Display Unit............................................................................................................................11VNS-41A Controls ...............................................................................................................................................12VNS-41A Display.................................................................................................................................................13Operating the VNS-41A.......................................................................................................................................15VNS-41A Notes....................................................................................................................................................16VNS-41A System Block Diagram (Typical)........................................................................................................17TRS-42A ATC Transponder System........................................................................................................................18General Description..............................................................................................................................................18CD-422B Control Display Unit............................................................................................................................19TRS-42A Controls................................................................................................................................................20CD-422B Display .................................................................................................................................................23Operating the TRS-42A........................................................................................................................................25TRS-42A Notes ....................................................................................................................................................26TRS-42A System Block Diagram (Typical).........................................................................................................27DFS-43A Automatic Direction Finder System........................................................................................................28General Description..............................................................................................................................................28CD-432B Control Display Unit............................................................................................................................29DFS-43A Controls................................................................................................................................................30Operating the DFS-43A........................................................................................................................................34DFS-43A Notes ....................................................................................................................................................35DFS-43A System Block Diagram (Typical).........................................................................................................36DMS-44A Distance Measuring System....................................................................................................................37General Description..............................................................................................................................................37SD-442B Selector Display Unit............................................................................................................................38DMS-44A Controls...............................................................................................................................................39Operating the DMS-44A.......................................................................................................................................41DMS-44A Notes...................................................................................................................................................42DMS-44A System Block Diagram (Typical) .......................................................................................................43
Series III AvionicsPilot's Guide Page 1VCS-40A VHF Communication SystemGeneral DescriptionThe Chelton VCS-40A VHF Communications System is a fully synthesized ATC VHF transceiver. TheVCS-40A system consists of a lightweight, remote-mounted VC-401B transceiver and a panel-mountedCD-402B Control Display Unit.The VC-401B transceiver is available with fixed 25 kHz channel spacing, fixed 8.33 kHz channel spacingfor European airspace, and switchable 25 kHz - 8.33 kHz channel spacing. Operation over the frequencyrange of 118.00 – 136.975 MHz is standard. Extended operation over the frequency range of 118.00 –151.975 MHz is available as an option.The VC-401B features a coherent squelch system that permits the receiver to respond only to on-channelsignals, rejecting high-level noise. This makes it ideal for CLIMAX operations. The system also featuresbuilt-in SELCAL and ACARS capabilities for regional airlines and major fleet operators.Reliability of the VC-401B is substantially increased by a specially designed thermal protective device thatenables continuous operation at reduced power (instead of the full 20 watts rated output) withoutdamaging the transceiver. A heavy-duty heat sink accommodates continuous operation, and a uniquecooling fin design dissipates heat, decreases internal unit temperatures and increases service life.The CD-402B Control Display Unit is available in versions for use with transceivers with fixed channelspacing (25 kHz or 8.33 kHz), and for units with switchable (25 kHz and 8.33 kHz) channel spacing.The CD-402B Control Display Unit provides a simultaneous readout of two frequencies: The activefrequency in the upper display and, immediately below it, the standby frequency. Frequency switching isaccomplished by simply pressing a frequency transfer button. The Transmit Annunciator (Tx) appears inthe display when RF is present at the output of the transceiver, providing positive proof-of-operation.When the VC-401B System is turned on, a diagnosis of all critical circuits begins, and continues until theSystem is turned off. If a fault is detected at any time, a FAIL annunciation appears in the display.The VCS-40A System has a nonvolatile memory which allows it to remember the last frequenciesdisplayed, indefinitely, even when power is removed. This feature prevents momentary power interruptsfrom affecting the system, and allows the last frequencies used to appear immediately when the Systemis turned on.The VCS-40A System provides ARINC format 429 output for external use, and can also be tuned byARINC format 429 commands from external equipment such as an RMS-555 Radio ManagementSystem.
Series III AvionicsPilot's Guide Page 2CD-402B Control Display Unit
Series III AvionicsPilot's Guide Page 3CD-402B Controls (Switchable Channel Spacing)Off/On Channel Spacing Selector and TESTPushbuttonOFF - Deactivates the VCS-40A System. Recordsthe last frequencies displayed in the system'snon-volatile memory.25 - Activates the VCS-40A System. Selects 25 kHzchannel spacing. The last frequencies displayedreappear on the display.8.33 - Selects 8.33 kHz channel spacing. The lastfrequencies displayed reappear on the display.TEST PushbuttonDisables the squelch circuits to allow audibleverification of receiver operation.CD-402B Controls (Fixed Channel Spacing)Off/On/Test Function SelectorOFF - Deactivates the VCS-40A System. Recordsthe last frequencies displayed in the system'snon-volatile memory.ON - Activates the VCS-40A System. The lastfrequencies displayed reappear on the display.TST - Disables the squelch circuits to allow audibleverification of receiver operation.
Series III AvionicsPilot's Guide Page 4CD-402B Controls (All)Frequency KnobsThe outer knob tunes the transmit/receive frequencyin whole MHz steps (118, 119, 120, etc.). The innerknob tunes in 25 or 8.33 kHz steps (refer to the tableon page 6).Volume Control (Optional) - Inner knob controlsthe receiver audio volume.Frequency Transfer ButtonPress and release to exchange active and standbyfrequencies. Press and hold 2 seconds to removethe standby frequency so that the active frequencycan be changed. Press and hold 2 seconds again torestore the standby frequency.Press and hold for 7 seconds or longer to set theactive frequency to 121.50 MHz.
Series III AvionicsPilot's Guide Page 5CD-402B DisplayActive FrequencyThe upper line of the display always shows the activefrequency…Active Annunciator…which is indicated by the Active Annunciator (the lettersACT).Standby FrequencyThe lower line of the display shows the standby frequency.When both frequencies are shown, rotating theFREQUENCY KNOBS changes the standby frequency.Transmit AnnunciatorThe Transmit Annunciator (the letters Tx) indicates an RFoutput of the transmitter. It appears when the microphoneis keyed.System NumberThe System Number indicates that this display is for COMSystem 2 (when more than one system is installed). Thenumber 1 indicates that this display is for COM System 1(when more than one system is installed).If only one COM System is installed or if this ControlDisplay Unit controls COM 3 in a three-radio system, thedisplay shows a blank instead of 1 or 2.FAIL 1 in the lower line of the display indicates a Systemfailure. Neither transmitter nor receiver is operative.FAIL 2 in the lower line of the display indicates aTransmitter only failure. This is displayed only when themicrophone is keyed. The receiver is still operative unlessFAIL 1 is displayed with the microphone not keyed.
Series III AvionicsPilot's Guide Page 6Operating the VCS-40A1. Turn the SELECTOR to ON (fixed channel spacing) or to 25 or 8.33 (switchable channel spacing).The last frequencies selected prior to System turnoff reappear in the display.2. If these are not the desired frequencies, rotate the appropriate FREQUENCY KNOB until the desiredfrequency is displayed as the standby frequency in the lower line of the display.The large frequency knob increments (clockwise rotation) or decrements (counter-clockwise rotation)the frequency being tuned by one megahertz for each detent.The small frequency knob increments (clockwise rotation) or decrements (counter-clockwise rotation)the frequency being tuned by 25 kHz or 8.33 kHz for each detent.For 8.33 kHz channel spacing, the small frequency knob sequences through a list of both 25 kHz and8.33 kHz channels (see table below).Frequency (MHz) Channel Spacing (kHz) Channel Name118.0000 25 118.000118.0000 8.33 118.005118.0083 8.33 118.010118.0167 8.33 118.015118.0250 25 118.025118.0250 8.33 118.030118.0333 8.33 118.035118.0417 8.33 118.040118.0500 25 118.050118.0500 8.33 118.055118.0583 8.33 118.060118.0667 8.33 118.065118.0750 25 118.075118.0750 8.33 118.080118.0833 8.33 118.085118.0917 8.33 118.090118.1000 25 118.100.....136.9750 25 136.975136.9750 8.33 136.980136.9833 8.33 136.985136.9917 8.33 136.990
Series III AvionicsPilot's Guide Page 73. Press and release the FREQUENCY TRANSFER button. This exchanges the two displayedfrequencies. The desired frequency is now active and may be used immediately.4. Use the VOLUME CONTROL to adjust volume if a station is broadcasting.5. To set a new standby frequency, rotate the appropriate FREQUENCY KNOB until the desiredfrequency is displayed in the lower line of the display.NOTE: To tune the active frequency only (without first tuning the standby and then "flipping" thefrequencies), press and hold the FREQUENCY TRANSFER button for two seconds, thenrelease it. This removes the standby frequency from the display.The FREQUENCY KNOBS may now be used to change the active frequency.Press and hold the FREQUENCY TRANSFER button for two seconds again to restore thestandby frequency to the display, if desired.
Series III AvionicsPilot's Guide Page 8VCS-40A Notes1. The FREQUENCY SELECTOR knobs tune the VC-401B transceiver directly. The display shows thefrequencies to which the VC-401B transceiver is actually tuned. The transceiver may also be tunedby an ARINC 429 digital bus.2. Display intensity and panel lighting are controlled by external dimmer controls.3. Pressing and holding the FREQUENCY TRANSFER button for at least 7 seconds before releasing itsets the COM frequency to 121.50 MHz. This is true even if segments of the display are faulty or alighting failure occurs. From this known reference point, any other frequency may be set by countingdetents of the FREQUENCY SELECTOR knobs as they are rotated. Each clockwise detent of theouter knob is one Megahertz difference. Each clockwise detent of the inner knob is 25 or 8.33 kHzdifference.4. The FREQUENCY SELECTOR knobs rotate continuously through all detents without end stops.After rotating the outer knob clockwise to the highest number, the next detent will be the lowestnumber (118 MHz).
Series III AvionicsPilot's Guide Page 9VCS-40A System Block Diagram (Typical)
Series III AvionicsPilot's Guide Page 10VNS-41A VHF Navigation SystemGeneral DescriptionThe Chelton VNS-41A VHF Navigation System is a lightweight 200-channel microprocessor-based VHFnavigation receiving system that combines VOR/LOC, glideslope, and marker beacon reception in thesame unit. The VNS-41A is compatible with most HSIs, CDIs, and conventional marker beacon displays.The ARINC 429 serial data bus interface is compatible with EFIS displays, radio management systems(RMU), and flight management systems (FMS).The VNS-41A system consists of a remote mounted VN-411B VHF Navigation Receiver and a panelmounted CD-412B or CD-413B Control Display Unit.In addition to processing signals for external use (Marker Beacon Lamps and audio, AFCS, CDI, HSI,EFIS, etc.), the VNS-41A can digitally display BEARING TO or RADIAL FROM any selected VOR stationon the CD-412B/CD-413B with the function selector panel control.When an ILS frequency is selected by the VNS-41A, the letters LOC appear below the frequency on thedisplay when RAD or BRG are selected.Digital circuit design of the VNS-41A incorporates microprocessor technology to achieve performance,reliability, accuracy, and features not possible in previous systems. These include advanced filteringtechniques, full-time self-diagnostics, non-volatile frequency memory and continuous calibration.Special filtering circuits virtually eliminate noise, including rotor modulation noise in helicopterinstallations. Self-testing begins when the system is turned on, and continues until turnoff. Faultsdetected result in a FAIL annunciation.Non-volatile memory means that the last frequency selected is in system memory if the system is turnedoff, if power is interrupted, or even if the system is removed from the aircraft!The VNS-41A is TSO'd. It is fully compatible with other equipment using ARINC Characteristic 429Digital Information Transfer. Frequencies may be controlled remotely by a Navigation ManagementSystem (NMS) and interfaced with an Area Navigation (RNAV) System.
Series III AvionicsPilot's Guide Page 11CD-412B Control-Display
Series III AvionicsPilot's Guide Page 12VNS-41A ControlsFunction Selector and Volume ControlOFF - Deactivates the VNS-41A System.Records the last frequencies displayedinto the system's non-volatile memory.ON - Activates the VNS-41A System. The lastfrequencies displayed reappear on thedisplay.RAD - Displays the radial the aircraft is on fromthe selected VOR. It is displayed digitallybelow the selected VOR frequency.BRG - Displays the bearing to the selectedVOR. It is displayed digitally belowselected VOR frequency.Volume Control - (Inner Knob) adjusts the audiovolume of selected the station.Frequency SelectorThe outer knob tunes the receiver in whole MHzsteps (108, 109, 110, etc., up to 117 MHz).The inner knob tunes fractional MHzfrequencies in 50 kHz steps (.00, .05, .10, .15,etc., up to .95).Frequency Transfer ButtonPress and release to exchange the active andstandby frequencies when both are displayed.Press and hold 2 seconds to remove thestandby frequency so the active frequency maybe tuned (press again and hold 2 seconds torestore the standby frequency).Press and hold 7 seconds to tune the receiver to108.00 MHz.
Series III AvionicsPilot's Guide Page 13VNS-41A DisplayWhen the VNS-41A is turned on, the last displaybefore turnoff is displayed again.The upper line of the display always shows theactive frequency (indicated by the letters ACT. Thelower display may show the standby frequency,digital radial or bearing, or LOC annunciation,depending on the FUNCTION SELECTOR setting.When two frequencies are displayed, rotating theFREQUENCY knobs changes the bottom (standby)frequency.If the FUNCTION SELECTOR switch is set to RADwhen a VOR frequency is active (shown on the topline), the bottom line displays the radial the aircraftis on FROM the VOR station.In this mode, the FREQUENCY TRANSFER buttonis disabled.If the FUNCTION SELECTOR switch is set to BRGwhen a VOR frequency is active (shown on the topline) the bottom line displays the bearing TO theVOR station.Three dashes on the bottom line indicates a flagcondition. This flag means that RAD or BRG hasbeen selected on the FUNCTION SELECTORswitch but cannot be displayed because ofinsufficient signal or during VOR station passage.
Series III AvionicsPilot's Guide Page 14When the top (active) frequency is a localizerstation, bearing or radial cannot be displayed.Setting the FUNCTION SELECTOR switch to BRGor RAD will cause the letters LOC to appear on thebottom line instead of the standby frequency. Thisis a reminder that this display cannot be used forbearing or radial data while on an ILS approach.NOTE: When LOC is displayed, return theFUNCTION SELECTOR to the ONposition so that the standby frequency isdisplayed instead.The number 1 below the letters ACT represent NavSystem 1 when more than one NAV System isinstalled. This number is fixed at the time ofinstallation.The number 2 below the letters ACT represent NavSystem 2 when more than one Nav System isinstalled. This number is fixed at the time ofinstallation. A blank below the letters ACTrepresent either Nav System 3 (when more than 2Nav Systems are installed) or that only one NavSystem is installed.A FAIL annunciation appears in the lower display toindicate failure of the VNS-41A System. Failmessages and their meanings are:• FAIL 1: NAV synthesizer out of lock.• FAIL 2: G/S synthesizer out of lock.• FAIL 3: NAV converter A/D check fail.• FAIL 4: Non-volatile memory fail.These annunciations are the result of a continualsystem self-test, and indicate that maintenance isrequired before the system may be used.
Series III AvionicsPilot's Guide Page 15Operating the VNS-41A1. Set the FUNCTION SELECTOR to ON.2. If these are not the desired frequencies, rotate the FREQUENCY KNOBS until the desired frequencyis displayed on the bottom portion of the display3. Press and release the FREQUENCY TRANSFER button. This exchanges the two displayedfrequencies. The desired frequency is now active and may be used immediately.4. Adjust the VOLUME CONTROL for the desired audio level.5. Rotate the FREQUENCY KNOBS until the desired standby frequency appears on the bottom portionof the display.NOTE: To tune the active frequency only (without first tuning the standby and then "flipping" thefrequencies), press and hold the FREQUENCY TRANSFER button for two seconds, thenrelease it. This temporarily removes the standby frequency from the display.Now the FREQUENCY KNOBS may be used to change the active frequency. The activefrequency may be used immediately.To restore the standby frequency to the display, press and hold the FREQUENCYTRANSFER button two seconds.
Series III AvionicsPilot's Guide Page 16VNS-41A Notes1. The FREQUENCY SELECTOR KNOBS tune the VNS-41A receiver directly. The display is directlycontrolled by the receiver, so the frequency display shows the actual frequency to which the receiveris tuned. The transceiver may also be tuned by an external ARINC 429 digital data bus.2. The VOLUME control on the CD-412B control/display does not adjust the volume of the MarkerBeacon receiver in the VNS-41A receiver. This volume is preset. Typically, Marker Beacon volumeis adjusted by a control on an audio control panel.3. Display intensity and panel lighting are controlled by external dimmer controls.4. Pressing and holding the FREQUENCY TRANSFER button for at least 7 seconds before releasing itsets the active frequency to 108.00 MHZ. Because the display is controlled by the receiver (see Note1 above), the receiver will tune to this frequency even if the display is defective. From the knownreference of 108.00 MHz as a starting point, any other frequency may be selected by countingdetents. Each clockwise detent of the outer knob is one MHz difference (108, 109, 110, etc.). Eachclockwise detent of the inner knob is .05 MHz difference (.00, .05, .10, .15, etc.). For example,rotating the outer knob clockwise three detents would put the frequency at 111.00 MHz. Thenrotating the inner knob clockwise three detents would then put the frequency at 111.15 MHz.5. The FREQUENCY SELECTOR knobs rotate continuously through all detents without end stops. Forexample, the next clockwise detent of the outer knob after 117 is 108; the next clockwise detent of theinner knob after .95 is 00.
Series III AvionicsPilot's Guide Page 17VNS-41A System Block Diagram (Typical)
Series III AvionicsPilot's Guide Page 18TRS-42A ATC Transponder SystemGeneral DescriptionThe Chelton TRS-42A ATC Transponder System is a digital, microprocessor-controlled 325 Watttransponder that allows positive identification in the Air Traffic Control environment. Features include:Dual transmitter output devicesEncoding altimeter readoutDual transponder control from a single Control Display Unit.Full-time automatic and pilot-selected self-test"Quick-select" VFR modeThe TRS-42A system consists of a TR-421B Transmitter/Receiver and a CD-422B Control Display Unit.The TR-421B Transmitter-Receiver unit assures accurate and dependable service. The unit provides4,096 discrete response codes plus modes A and B, as well as mode C - altitude reporting (whenconnected to an encoding altimeter). The unit uses a single-chip microprocessor to assure code datavalidity and condition of all critical circuits.The CD-422B Control-Display Unit has the unique capability to control a dual transponder installation witha single control head. Selection is made by simply pressing a selector button on the front panel.The CD-422B also provides an annunciation of the letters "ID" whenever the transponder replies to aninterrogation. When the mode selector is in the VFR position, the active transponder is channeled to the1200 code (VFR). This code may be programmed to other international VFR codes.To aid in channel selection, the code selection knobs of the CD-422B provide variable-rate tuning forgreater speed and accuracy. Rapid rotation of a knob causes large changes in the code, while slowrotation changes code digits slowly, one digit at a time. Also, there is no need to change to standby modebefore changing channels, because the new code will not be transmitted until the selector knobs haveremained stationary for 3 seconds. Whenever an emergency code from 7500 to 7700 is selected, thedisplay will blink on and off for 3 seconds before transmission.
Series III AvionicsPilot's Guide Page 19CD-422B Control Display Unit
Series III AvionicsPilot's Guide Page 20TRS-42A ControlsFunction SelectorOFF - Deactivates the TRS-42A System.Records the last data displayed into thesystem's non-volatile memory.TST - Displays barometric altitude from anencoding altimeter in the lower line of thedisplay. An unsuccessful test displaysFAIL in upper line of the display.Pressing the IDENT button in the TSTmode causes upper line of the display toread 8888 and lower line to read 88888.
Series III AvionicsPilot's Guide Page 21SBY - Applies power to the TRS-42A systemcircuits without activating the transmitter.The last displayed code appears in theupper line of the display and may bechanged with CODE SELECT knobs.Lower line of the display is blank.ON - Enables the TRS-42A to respond to ATCradar interrogations. Altitude is notencoded into the TRS-42A response.ALT - Same as ON except altitude is encodedinto the response when the TRS-42A isinterrogated by ATC radar. Altitude is notdisplayed.VFR - Automatically selects and displays 1200as the transponder code (other codesmay be programmed for non-U.S.A.operation). Altitude is still encoded intoresponses in this mode, but is notdisplayed.
Series III AvionicsPilot's Guide Page 22CODE SELECT Knobs - The outer knob selects theleft two digits of the transponder code. the innerknob selects the right two digits.The range for each knob is 00 through 77.When the FUNCTION SELECTOR is in VFRposition, the CODE SELECT knobs are disabledbecause the VFR code (1200 in the U.S.A.) isautomatically selected.IDENT Pushbutton - During normal operation, thispushbutton is pressed and released only when ATCrequests "squawk ident". The identification modewill then remain active for 15 to 30 seconds,causing the transponder to transmit a specialidentification code each time it is interrogated byATC radar. The ID annunciation will appear on thedisplay each time an interrogation occurs. Afterthis, the TRS-42A will revert to its selected mode(ON, ALT, or VFR).TRANSPONDER SYSTEM 1 or 2 SELECTPushbutton - Selects either System 1 or System 2when more than one transponder system isinstalled. The selected system number is displayedbelow the letters ACT on the display. If only onesystem is installed, the number 1 is alwaysdisplayed.
Series III AvionicsPilot's Guide Page 23CD-422B DisplayIn normal operation, the upper display is thetransponder code. It is selected either by theCODE SELECT knobs or by setting the FUNCTIONSELECTOR to VFR.The displayed code is active only when theannunciation ACT is present in the display.When a displayed code is changed, the new codewill appear on the display for 3 seconds before theannunciation ACT appears. This allows the code tobe manually changed before it becomes active if itis in error, or while "tuning through" one code onthe way to another one. It is not necessary to go toSBY to change codes.In addition to a 3-second delay before becomingactive, emergency codes (7500, 7600, or 7700) willblink on and off during the 3-second delay, alertingthe pilot that transmission of an emergencytransponder code is imminent.If the IDENT pushbutton is pressed while theFUNCTION SELECTOR is in TST mode, the topline of the display indicates 8888 while the bottomline indicates 88888.
Series III AvionicsPilot's Guide Page 24If a system failure occurs in any mode, theannunciation FAIL appears in either the upper orlower line of the display. The system is not usablein this condition.Barometric altitude is indicated in lower line ofdisplay when the MODE SELECTOR is in TSTmode. This is the altitude that will be encoded intothe transponder output when operating in analtitude-reporting mode (ALT or VFR positions ofFUNCTION SELECTOR).
Series III AvionicsPilot's Guide Page 25Operating the TRS-42APreflight1. Set the FUNCTION SELECTOR to TST.2. Select System 1 or System 2 (if more than one transponder system is installed).3. Note the encoding barometric altitude in lower display.4. Press the IDENT pushbutton. Note that the numbers 8888 are present in upper line of the display,and that 88888 is displayed in lower line.5. Set the FUNCTION SELECTOR to SBY. The system is now ready for operation.Flight Operation1. Use the CODE SELECT knobs to set the requested ATC transponder code into the display.– OR –If the flight is VFR and 1200 with altitude reporting is the appropriate code and mode, set theFUNCTION SELECTOR to VFR.2. For non-altitude reporting mode, set the FUNCTION SELECTOR to ON.3. For altitude reporting mode, set the FUNCTION SELECTOR to ALT.4. If ATC requests "stop altitude squawk", set the FUNCTION SELECTOR to ON.5. If ATC requests "squawk standby," set the FUNCTION SELECTOR to SBY.The TRS-42A is programmed to automatically select code 1200 when the FUNCTION SELECTOR is setto VFR. To program another code for the VFR position, perform the following steps:1. Set the FUNCTION SELECTOR to SBY position.2. Press and release the IDENT pushbutton.3. Select the new code with the CODE SELECT knobs.4. Press and release the IDENT pushbutton again.These steps enter the newly selected VFR code into TRS-42A system memory. The new code is ineffect any time the FUNCTION SELECTOR is in the VFR position.
Series III AvionicsPilot's Guide Page 26TRS-42A Notes1. Airborne ATC transponders are designed to operate in the Air Traffic Control Radar Beacon System(ATCRBS) environment to support inflight aircraft identification and traffic control.2. Airborne ATC transponders respond to signals from ATC secondary radar that scans the samevolume of airspace as, and in synchronization with, ATC primary radar. The ATC secondary radaroperates on 1030 MHz. On detecting a signal at this frequency, the airborne transponder respondson a frequency of 1090 MHz.3. Airborne ATC transponder responses consist of a combination of pulses determined by the position ofthe CODE SELECT switches to the CD-422B Control Display Unit. Eight possible digits (0 through 7)for each digit of the code allow a total of 4096 (8 x 8 x 8 x 8) code combinations.4. An airborne ATC transponder transmits only when "swept" by the special ATC secondary radar. Atransmission lasts for a few millionths of a second. During this transmission, and for about a halfsecond afterwards, the letters ID are annunciated on the CD-422B. This informs the pilot that he is inthe ATCRBS environment and that his transponder is functioning normally.5. Distance Measuring Equipment (DME) and airborne ATC transponders operate in the samefrequency band. To prevent interference, each system generates a special pulse during the time it istransmitting. This pulse is called a suppression pulse and is wired between units to automaticallyprevent simultaneous transmissions that might damage circuits of the receiving system that is"listening" for very weak signals. This has no effect on DME or ATC Transponder instrumentation inthe cockpit.
Series III AvionicsPilot's Guide Page 27TRS-42A System Block Diagram (Typical)
Series III AvionicsPilot's Guide Page 28DFS-43A Automatic Direction Finder SystemGeneral DescriptionThe DFS-43A Direction Finder System provides reception of low-frequency navigational aids and AMbroadcast stations in the 190.0 – 1860 kHz frequency range.The DFS-43A System consists of the DF-431B Receiver, the CD-432B Control Display Unit, and the AT-434 Loop/Sense Antenna. This system provides accurate, dependable reception of enroutenondirectional beacons (NDB), Locator Outer Markers (LOM), and commercial AM broadcast stations.Microprocessor circuitry controls operation, processes signals, performs self -calibration, and providesfull-time self -diagnostics. This all digital, solid-state design includes a unique signal filter that provides anextremely stable needle position even in areas of high RF noise.Special digital circuitry provides a unique steering command that may be used directly by Electronic FlightInstrument Systems (EFIS) or in conjunction with the Chelton Avionics VNS-41A VHF Navigation Systemfor electromechanical HSI course deviation display. Analog outputs for standard ADF indicators and RMIpointers are included.The DFS-43A certified frequency range is 190 to 1860 kHz, and the international marine HF distressfrequency of 2182 kHz. Frequency tuning may be done by the CD-432B Control Display Unitor byexternal equipment such as an RMS-555 Radio Management System.The active and standby frequency are displayed on the CD-432B simultaneously and stored in nonvolatilememory. Switching between the two is done by simply pressing a frequency transfer button below thedisplayed frequencies.Advanced heat sink and cooling fin design efficiently collect and dissipate internal heat of the receiver,providing cooler operating temperatures and longer unit life.The AT-434 Antenna unit contains a loop antenna, sense antenna, and a solid-state amplifier. The "frontend" of the receiver is actually in the antenna unit, where received signals are processed, converted to anintermediate frequency and cabled to the receiver. This minimizes effects of electrical noise, andeliminates the requirement for critical cable lengths between antenna and receiver.
Series III AvionicsPilot's Guide Page 29CD-432B Control Display Unit
Series III AvionicsPilot's Guide Page 30DFS-43A ControlsFunction Selector and Volume ControlOFF - Deactivates the DFS-43A System.Records the last frequencies displayed inthe system's non-volatile memory.ANT - Enables the DFS-43A System and thenon-directional sense antenna. The lastfrequencies displayed reappear on thedisplay. Frequency tuning is enabled,but no direction-finding capability existsin this mode. External pointers park at90°.ADF - Standard direction finding mode. Externalindicators point to station.BRG - Digitally displays the magnetic bearing toselected station. The FREQUENCYTRANSFER pushbutton is disabled.External equipment continues to functionin standard ADF mode.NOTE: BRG mode is not used fornavigation.BFO - (Beat Frequency Oscillator) Identical toADF mode, but adds a 1,000-Hz tone toaudio.Used only to identify interrupted-carriersignals (also known as cw).
Series III AvionicsPilot's Guide Page 31TST - Test Mode1. Sends a park-at-90° command to externalindicators.2. Displays the letter L along with a number inStandby Frequency window, used formaintenance purposes.3. Pressing the WHOLE/HALF KHZ button in thismode interrupts the park-at-90° command andprovides station relative bearing to externalindicators. Simultaneously, the lower line of thedisplay will indicate the same relative bearingdigitally to the nearest tenth of a degree.VOLUME - (inner knob of FUNCTIONSELECTOR). Controls audio level of receiver.Frequency KnobsLarge (outer) knob tunes the receive frequencyin hundreds of kHz from 1 through 21, skipping19 and 20.Small (inner) knob tunes tens and half kHz (seethe WHOLE/HALF KHZ pushbutton switchdescription).
Series III AvionicsPilot's Guide Page 32When the large knob is rotated clockwise from 18to the next detent, 2100 will appear in the display.Next, rotating the small knob one detent clockwisewill cause 2182 to appear in the display. The smallknob may then be used to tune from 2181 through2183 about the maritime emergency frequency of2182 kHz.WHOLE/HALF KHZ Pushbutton switch. Alternatesbetween one-half kHz tuning and whole (units)tuning by the small FREQUENCY KNOB. When inthe one-half kHz tuning mode, a decimal point willappear in the display.In the TST position of the FUNCTION SELECTOR,pressing the WHOLE/HALF KHZ pushbuttondisplays relative station bearing in the lower line ofthe display to the nearest tenth of a degree.FREQUENCY TRANSFERMomentary pushbutton switch. Pressing andimmediately releasing exchanges the active andstandby frequencies when both are displayed.Pressing and holding for two seconds beforereleasing temporarily removes the standbyfrequency. This allows the active frequency to bechanged. Pressing again for two seconds restoresthe standby frequency.Pressing and holding for seven seconds or longerbefore releasing sets the receiver to its lowesttunable frequency (100 kHz).
Series III AvionicsPilot's Guide Page 33The top line of the display is always the activefrequency, indicated by the letters ACT. Thenumber 1 or 2 below the letters ACT indicate theADF System Number when more than one systemis installed.Data in the lower line of the display depends onposition of FUNCTION SELECTOR.In ANT, ADF, or BFO mode, the bottom line of thedisplay indicates the standby frequency.In BRG mode, the bottom line of the displayindicates the magnetic bearing of active station. Inthis mode the active frequency can be tuneddirectly.Dashes indicate a flag condition.NOTE: FAIL 1, FAIL 2 or FAIL 3, 4, 5, 6,Annunciation indicates a System fault; thesystem is not usable in these conditions.
Series III AvionicsPilot's Guide Page 34Operating the DFS-43A1. Set the FUNCTION SELECTOR to ANT. Note that the external ADF pointer moves to 90° and stops.2. If frequencies displayed are not the ones desired, rotate the FREQUENCY KNOBS until the desiredfrequency is displayed on the bottom line of the display.3. Press and release the FREQUENCY TRANSFER button. This exchanges the two displayedfrequencies. The desired frequency is now active.NOTE: An alternate tuning method is to press and hold the FREQUENCY TRANSFER button fortwo seconds before releasing. This removes the standby frequency from the display and theactive frequency may be tuned by rotating FREQUENCY KNOBS. The system is ready forimmediate operation. If desired, press the FREQUENCY TRANSFER button for twoseconds again to restore standby frequency.4. Adjust the VOLUME control to the desired audio level and identify the station represented by theactive frequency displayed.5. Rotate the FUNCTION SELECTOR to ADF. Note that the external ADF pointers leave the 90°parked position and move to indicate the direction to the active station.6. Rotate the FUNCTION SELECTOR to BRG and read the magnetic bearing shown digitally on thelower line of the display. Compare this reading with the other ADF displays to assure correct systemoperation.7. Return the FUNCTION SELECTOR to ADF for normal ADF operation.
Series III AvionicsPilot's Guide Page 35DFS-43A Notes1. The FREQUENCY SELECTOR knobs tune the DF-431B receiver directly. The display actuallyshows the frequencies to which the receiver is tuned. In addition to rotation of the FREQUENCYSELECTOR KNOBS, the receiver may be tuned by an external ARINC 429 digital bus.2. Display intensity and panel lighting are controlled by external dimmer controls.3. If the signal to which the receiver is tuned is lost for longer than 5 seconds, the electromechanicaldisplay pointers will park at 90°.4. The FREQUENCY SELECTOR KNOBS rotate continuously through all detents without end stops.After the highest number is displayed, the next detent clockwise will cause the lowest number to bedisplayed.5. If the display is not functioning, the system frequency can be established as follows: Press thetransfer button for 7 seconds. The system will then be at 100 kHz. Rotating the large frequencyselector clockwise will increase the frequency in 100 kHz steps. Rotating the small knob clockwisewill increase the frequency in 1 kHz steps.6. Frequencies selected between 100 kHz to 189 kHz and 1861 kHz to 1899 kHz are invalid and willcause the display to blink off and on.
Series III AvionicsPilot's Guide Page 36DFS-43A System Block Diagram (Typical)
Series III AvionicsPilot's Guide Page 37DMS-44A Distance Measuring SystemGeneral DescriptionThe DMS-44A is a digital, solid-state distance measuring system that can provide data from three DMEstations simultaneously. A system consists of a DM-441B transceiver and one or two SD-442BSelector-Displays. The transceiver unit may be front or rear antenna connector mounted. An efficient,advanced-design heat sink and cooling fin dissipate internal heat and keep the unit cool even at its full325 Watt output.Two DME stations are selectable during routine navigation frequency management - when the pilotselects VOR/DME's, VORTAC's, MLS/DME's, ILS/DME's, or LOC/DME's. The third DME station isselectable by an RNAV system for calculating distance to a waypoint, time to a waypoint, andgroundspeed. This third DME channel is selected automatically, independent of any pilot action, and sois said to be "transparent" to the pilot.Simultaneous three-channel operation is achieved by high-speed scanning of three different DMEstations. Lock-on to valid data takes less than 200 milliseconds with least-significant-bit accuracy of lessthan 0.01 nautical mile. Range is up to 300 nautical miles and ground speed capability is from 0 to 999knots.The DMS-44A incorporates the latest microprocessor technology to achieve superior accuracy andreliability. As soon as power is applied, the DMS-44A begins a continuous self-test of its circuitry. Whencircuits do not function within specific parameters, no data is presented, and the word FAIL isannunciated on the display. The DMS-44A also continuously monitors and analyzes the channelselection commands being supplied by NAV Receivers and the RNAV System. Invalid commandstructure or loss of command continuity results in a FAIL annunciation.If an active DME signal is temporarily lost or becomes unintelligible, the DMS-44A will continue tocompute and display data based on the last valid signal for up to 12 seconds. This feature provides anuninterrupted display during manual or automatic channel changes and during aircraft maneuvers thatblock the aircraft antenna from line-of-sight to the DME station. If power to the DMS-44A is interrupted,the last channel and mode used are retained in system memory. When power is reapplied, channel andmode are restored without external adjustment.
Series III AvionicsPilot's Guide Page 38SD-442B Selector Display Unit
Series III AvionicsPilot's Guide Page 39DMS-44A ControlsThe DMS-44A has only three controls, all located onthe SD-442B Selector-Display Unit. Each is amomentary, spring-loaded type that releases whenfinger pressure is removed. On-off power is throughan external switch such as a radio or avionicsmaster switch, or a dedicated DME switch. Volumecontrol of DME station identification audio is alsoexternal, typically located on an audio panel.NAV - Alternately places annunciator 1, 2, or RNVin display.1 - Selects NAV System 1 as the controller ofthe DME channel.2 - Selects NAV System 2 as the controller ofthe DME channel.RNV - Allows the SD-442B Selector Display tobe used as a "repeater" display orRNAV-computed distance to a waypointand ground speed. This allows RNAVdata to be available during times it mightnot be displayed by the RNAV System (forexample, when other data is selected fordisplay on some types of RNAV's).HOLD - Pressing and releasing this switch does thefollowing:A. Locks the appropriate channel of theDMS-44A to the current DME frequency inuse. Aircraft wiring will effect the way inwhich the hold feature works. In someinstallations, pin 58 ground, the hold switchwill only place the corresponding channel inhold. In others, pin 58 open, the hold switchwill place the displayed channel into hold.B. Displays the current NAV frequency thatdetermines the DME channel.C. Disconnects control of the DMS-44A from theNAV Receiver.D. Displays annunciation HLD.The purpose of this switch is to allow theNAV Receiver to be set to other frequencieswithout affecting DME operations. The DMEcontinues to function on its "holding" channel.Pressing and releasing this switch while inthe HLD mode will return control back to theindicated NAV System (1 or 2).
Series III AvionicsPilot's Guide Page 40TTS - (Time-To-Station) While this switch is heldpressed, time-to-station will be shown on thedisplay above the switch. When the switch isreleased, the display returns to its previous readoutof ground speed. If in hold when the TTS switch ispressed, the HLD FREQ on the display will blinktwice to alert the pilot.NOTE: When DME is being tuned by an MLS,receive DME hold is inhibited.
Series III AvionicsPilot's Guide Page 41Operating the DMS-44A1. Apply power to the DMS-44A (depending on installation, the power-on switch may be an avionicsmaster switch, radio switch, or a dedicated DME switch). The SD-442B display(s) will come onimmediately, displaying either data, dashes (flag condition) or the word FAIL.2. Select a NAV Receiver to control the DM-441B by pressing the NAV pushbutton to display a 1, 2, orRNAV.3. To operate the DMS-44A, set the NAV Receiver controlling the DMS-44A to any VHF navaid stationwithin line-of-sight range that has a DME (VOR/ DME, VORTAC, ILS/DME, LOC/DME, MLS/DME).4. To use the SD-442B Selector Display as a repeater of RNAV-computed ground speed and distanceto the next RNAV-designated waypoint, press the NAV pushbutton to display RNV.
Series III AvionicsPilot's Guide Page 42DMS-44A Notes1. DME operates within a band of 252 internationally assigned frequency channels from 962 Megahertzto 1213 Megahertz. All channels are not currently in use, but the DMS-44A is tunable to all 252.2. DME equipment aboard the aircraft measures the delay between interrogation pulses transmitted andreply responses received. This delay is converted to distance, and, as distance changes with time, toground speed. The distance is "slant range," not horizontal, over-the-ground distance.3. If a single DMS-44A System is installed with two SD-442B Selector Displays, NAV System 1 may beselected on one display and NAV System 2 on the other. Each NAV System may then selectseparate DME stations.4. When RNV is selected, the displayed distance is horizontal, not slant, range, distance to thewaypoint. Also, no DME station identification will be present.5. When turned on, the DMS-44A will remember and display the last mode(s) used, and will be tuned tothe last channels selected before power was removed. On the ground, the display will probably beflagged because of signal distortions.6. Because of assigned "pairing" of VHF and MLS navigation facility frequencies with DME channels,airborne DME equipment is designed to be tuned to the correct DME channel/ frequenciesautomatically when a VHF navigation frequency or MLS channel is selected by the pilot. It is notnecessary to know actual DME channel and frequency assignments.7. When the DMS-44A transmits its interrogation pulses and receives invalid responses or none, theSD-422 Selector Display indicates this condition by flagging the display with dashes. This is a normalcondition when the ground DME station is out of range, the reply pulses are too weak or unreliable toprocess, the ground DME station is out of service, or there is no DME station assigned to the VHFnavigation facility to which the NAV Receiver is tuned.
Series III AvionicsPilot's Guide Page 43DMS-44A System Block Diagram (Typical)

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