Becker Avionics ATC3401 Aviation Trasponder User Manual TIT IO

Becker Flugfunkwerk GmbH Aviation Trasponder TIT IO

Manual

TransponderATC 3401from Serial No. 2001 upwardsINSTALLATION AND OPERATIONBecker Flugfunkwerk GmbHBaden Airpark Postfach 34 76549 HügelsheimTel. 07229 / 3050 Fax 07229 / 30521734-50-07 July 15/97
DV 63803.03© 1997 by Becker Flugfunkwerk GmbHAll rights reserved
LIST OF EFFECTIVE PAGESSUBJECT PAGE DATE SUBJECT PAGE DATETitle Page 1 July 15/97List of EffectivePage 1 July 15/97Table of Contents 1 July 15/97Introduction 1 July 15/97GeneralDescription I-I July 15/971-1 July 15/971-2 July 15/971-3 July 15/971-4 July 15/971-5 July 15/971-6 July 15/97Installation II-I July 15/972-1 July 15/972-2 July 15/972-3 July 15/972-4 July 15/972-5 July 15/972-6 July 15/972-7 July 15/972-8 July 15/972-9 July 15/972-10 July 15/972-11 July 15/972-12 July 15/972-13 July 15/972-14 July 15/97Operation III-I July 15/973-1 July 15/973-2 July 15/973-3 July 15/973-4 July 15/973-5 July 15/973-6 July 15/973-7 July 15/973-8 BlankINSTALLATION AND OPERATIONATC 3401LEP Seite 134-50-07 July 15/97
TABLE OF CONTENTSPageINTRODUCTION 1GENERAL DESCRIPTION 1-1INSTALLATION 2-1OPERATION 3-1INSTALLATION AND OPERATIONATC 3401TOC Page 134-50-07 July 15/97
INTRODUCTION1. GeneralThis component maintenance manual describes the BECKER transponderATC 3401 from serial No. 2001 upwards. 2. ManufacturingThe transponder ATC 3401 is manufactured and product supported by :Becker Flugfunkwerk GmbHBaden AirparkP.O. Box 3476549 HügelsheimGermanyTelephone: 0 72 29 - 305 - 0Telex: 78 12 71Telefax: 0 72 29 - 305 - 2173. Layout of manualThe manual is divided into three sections. Section 1 contains the general descripti-on of the transponder and gives the technical data. Section 2 describes the instal-lation instructions and Section 3 the operation of the unit. INSTALLATION AND OPERATIONATC 3401INTRO Page 134-50-07 July 15/97
Table of contentsGENERAL DESCRIPTION Page1. Application 1-12. General description 1-13. Technical data 1-24. System approvals 1-65. Available models 1-66. Accessories (not contained in the scope of delivery) 1-6INSTALLATION AND OPERATIONATC 3401Page I-I34-50-07 July 15/97
GENERAL DESCRIPTION1. ApplicationThe ATC 3401 transponder is the airborne component of the ATCRBS (Air TrafficControl Radar Beacon System). It operates on the secondary radar principle andenables the particular ground stations to locate, identify and track aircraft for thepurposes of air traffic control. The transponder can also be used to transmitspecial information to the air traffic controllers (ATC) at the same time.2. General descriptionA. The ATC 3401 transponder is constructed as a single module unit designed forinstallation in the instrument panel or control panel of an aircraft. The dimensionscorrespond to the ARINC standard for control panels and it is secured in placeby means of four DZUS fasteners.B. All controls are located on the front panel of the unit. The unit connector forconnecting the aircraft wiring and the antenna socket are fitted on the backof the transponder.C. The control panel contains the electrical modules, processor board and displayboard. D. The electronic equipment of the transceiver consists of the encoder/power supplymodule, the receiver/decoder module and the transmitter tube.The receiver/decoder module can be swung out for servicing, thus making allthe components of the transponder readily accessible. The transmitter tube isbolted to the side of the unit frame.E. The transponder is ready to operate within 30 seconds of switch on. During thisperiod the display test is performed and the transmitter tube is warmed up and stabilized.F. The following modes are possible with the transponder :(1) Standby mode (SBY)(2) ON mode (mode A) where a code set on the transponder is transmittedback in response to interrogation from a ground station.(3) ALT mode (mode C) where in addition to the facility in mode A the encoded aircraft altitude is also transmitted, provided a coding altimeter is connected to the transponder.(4) Indication of flight level (altitude/100) if a coding altimeter is connectedto the transponder.INSTALLATION AND OPERATIONATC 3401Page 1-134-50-07 July 15/97
(5) Additional identification information whereby the ident button of the trans-ponder is pressed on instructions from the air traffic controller. The iden-tification pulse (SPI pulse) transmitted in this case enables immediateidentification of the aircraft on the controller’s radar screen, by means ofan additional marking on the object display.(6) Test function by pressing the TEST push-button in which all digits flash in the displays and the reply lamp comes on.3. Technical dataA. General dataSupply voltage 10.0 V - 32.2 V DCCurrent consumption 1.5 A at 14 V(without panel lighting) 0.8 A at 28 V- in standby mode 0.5 A at 14 V0.3 A at 28 VPanel lighting typ. 480 mA at 14 Vtyp. 240 mA at 28 Vtyp. 1.5 A at 5 VWarm-up time approx. 30 sFuse protection 2 A medium-blowOperating temperature range - 20° C bis + 55° C (short-time + 70° C)Altitude max. 35 000 ft.EUROCAE/RTCA ED-14C/DO-160C Cat. A1 C1(no altitude limitation in pressurizedaircrafts)Vibration EUROCAE/RTCA ED-14C/DO-160C Cat. M+N(rigid mounted in all aircraftswithout limitations)Environmental conditions EUROCAE/RTCA ED-14C/DO-160CEnv. Cat. [A1C1]-BA(MN)XXXXXXZBABATAXXXWeight 1.2 kgMechanical dimensionsFront panel 47.5 x 146 mm (H x W)Case depth 217 mm above antenna socketTest and assembly standards JTSO-C74c Class 1ARTCA DO-150 Cat. B.(cat. A conversion possible)INSTALLATION AND OPERATIONATC 3401Page 1-234-50-07 July 15/97
B. Receiver dataModes mode Amode A+CReceive frequency 1030 MHz ± 0.2 MHzSensitivity - 72 dBm (on 90 % reply rate)Selectivity ± 15 MHz > 40 dB± 25 MHz > 60 dBDynamic range ≥ 50 dBBandwidth ± 3 MHz < 3 dBSide lobe suppression 3-pulse methodC. Transmitter dataTransmit frequency 1090 MHz ± 3 MHzPower output 250 W min. at the antenna socketReply limitation effective as from 1200 replies/sOutput impedance 50 ΩReply code (mode A) ICAO coding system with 4096 replycapacityAltitude code (mode C) ICAO coding system in 100 ft stepsof -1000 to 62700 ftTransmit pulse shape pulse width 0.45 µs ± 0.1 µsrise time 0.05 - 0.1 µsfall time 0.05 - 0.2 µsD. Transponder antenna DMNI 70-1Frequency range 950 MHz - 1220 MHzStanding wave ratio (VSWR) < 1.5 : 1Impedance 50 ΩType corresponds to λ / 4 rodPolarization verticalType of radiation omnidirectionalPeak power output max. 2 KWWeight approx. 113 gINSTALLATION AND OPERATIONATC 3401Page 1-334-50-07 July 15/97
Connection C socketDC resistance Idle (∞)E. Transponder antenna ANT 2000Frequency range 1030 MHz - 1090 MHzStanding wave ratio (VSWR) < 1.25 : 1Impedance 50 ΩType corresponds to λ / 4 rodPolarization verticalRadiation omnidirectionalConnection BNC socketInsulation resistance min. 1000 MΩPeak power output max. 2 KWWeight approx. 20 gF. Transponder antenna CI 100-2Frequency range 960 MHz - 1220 MHzStanding wave ratio (VSWR)at 1030 to 1090 MHz < 1.4 : 1Standing wave ratio (VSWR)at 960 MHz to 1220 MHz < 1.6 : 1Impedance 50 ΩType corresponds to λ / 4-rodPolarization verticalType of radiation omnidirectionalNominally designed for 2.5 machHeight 66 mmWeight approx. 136 gConnection TNC connectorApprovals TSO C66a, C74c, Class A, DO-138Environmental condition Env. Cat. AASXXXXXXXXXINSTALLATION AND OPERATIONATC 3401Page 1-434-50-07 July 15/97
G. Environmental conditionsThe following performance standards under environmental test conditionswere verified in accordance with EUROCAE/RTCA ED-14C/DO-160C.Environmental condition ED - 14CDO - 160C Category PerformanceTemp. and altitude 4.0 A1C1Low operating temp. 4.5.1 - 20° CLow storage temp. - 55° CHigh short-time temp. 4.5.2 + 70° CHigh operating temp. 4.5.3 + 55° CHigh storage temp. + 85° CAltitude 4.6.1 35 000 ft.Decompression 4.6.2Pressure aboveatmospheric 4.6.3Temp. change 5.0 BHumidity 6.0 A48 hrs at 50° C and≥ 95% air humidityShock under: 7.0Operating conditions 7.2 6 G/11 ms for thethree axesCrash landingconditions 7.3 Shock :15 G/11 ms for thethree axesAcceleration :12 GVibration 8.0 MNMagnetic influence 15.0 ZDeflection of acompass by 1° at adistance of ≥ 30 cmChanged supplyvoltage 16.0 BVoltage pulses on thesupply voltage 17.0 ALow frequency inter-ference voltages 18.0 BInduced magnetic andelectrical fields 19.0 AINSTALLATION AND OPERATIONATC 3401Page 1-534-50-07 July 15/97
Environmental condition ED - 14CDO - 160C Category PerformanceHigh frequency inter-ference voltages andinterference field20.0 TUnwanted radiation 21.0 A4. System approvalsJTS0-2C74c No. 10.930/49JTSOBZT approval A107416D LB5. Available modelsTransponder ATC 3401 from serial Serial No. 2001 upwards :ATC 3401-110, black panel, illumination 14/28V P/N.: 511.129-915ATC 3401-010, black panel, illumination 5V P/N.: 511.137-915ATC 3401-111, grey panel, illumination 14/28V P/N.: 511.145-915ATC 3401-011, grey panel, illumination 5V P/N.: 511.153-9156. Accessories (not contained in the scope of delivery)Cable socket 25 pol. (crimp version) P/N.: 501.786-954Cable socket 25 pol. (soldering version) P/N.: 501.824-954BNC connector for RG 58 C/U P/N.: 725.706-277BNC connector for RG 213/U P/N.: 709.425-277Transponder Antenna ANT 2000 (BNC) P/N.: 707.007-952Transponder Antenna DMNI 70-1 (C) P/N.: 706.991-952Transponder Antenna CI 100-2 (TNC) P/N.: 501.816-952BNC antenna connector for RG 58 C/U P/N.: 725.706-277BNC antenna connector for RG 213/U P/N.: 709.425-277C antenna connector for RG 58 C/U P/N.: 710.830-277C antenna connector for RG 213/U P/N.: 710.849-277TNC antenna connector for RG 58 C/U P/N.: 725.900-277TNC antenna connector for RG 213/U P/N.: 344.370-277INSTALLATION AND OPERATIONATC 3401Page 1-634-50-07 July 15/97
Table of contentsINSTALLATON Page1. General 2-12. Inspection before installation 2-13. Mechanical configuration 2-34. Aircraft wiring 2-35. Installing the transponder antenna 2-66. Checking after installation 2-6Fig. 2-1 Test setup 2-8Fig. 2-2 Dimensions ATC 3401 2-9Fig. 2-3 Installation of fastener strips 2-10Fig. 2-4 Dimensions DMNI 70-1 2-11Fig. 2-5 Dimensions ANT 2000 2-12Fig. 2-6 Dimensions CI 100-2 2-13Fig. 2-7 Installation wiring ATC 3401 2-14INSTALLATION AND OPERATIONATC 3401Page II-I34-50-07 July 15/97
INSTALLATION1. GeneralInstallation of the transponder ATC 3401 depends on the aircraft type and itsequipment. Therefore, only general information can be provided in this Section.2. Inspection before installationBefore the transponder is installed in an aircraft, a visual inspection for possibletransport damages shall be performed.A. Visual inspectionPlease look out for the following defects:(1) Dirt, dents, scratches, corrosion, broken fastening elements on housingand housing parts.(2) Dirt and scratches on nameplate, front plate and inscriptions.(3) Dirt, bent or broken pins, cracked insert of unit connector and antennasocket.(4) Dirt, stiffness and mechanical damage to the pushbuttons, rotary switchesand LC displays.(5) Missing screws.B. Checking procedureConnect the transponder to the test setup as shown in Fig. 2-1 and carry outthe following tests in the given sequence. Instead of the transponder test setSQUAWK/NAUT I an equivalent test set or a ramp test set can be used.(1) Checking receiver sensitivity(a) Set SQUAWK/NAUT I to mode A on and 400 interrogations persecond. Note that the amplitude of pulse P 2 is ≤ - 9 dB of pulseP 1.(b) Note that pulses P 1 and P 3 have equal amplitudes. Set the RFinput level to - 72 dB and observe that the transponder replies toat least 90 % of the interrogations.(c) Set SQUAWK/NAUT I to mode C and repeat test.INSTALLATION AND OPERATIONATC 3401Page 2-134-50-07 July 15/97
(2) Checking side lobe suppression (SLS)(a) Set SQUAWK/NAUT I to mode A on and 400 interrogations persecond.(b) Set pulses P 1 and P 2 to same amplitude.(c) Alter the HF input level from - 69 dBm to - 24 dBm, whereby thetransponder must reply to not more than 1 % of the interrogationpulses.(3) Checking reply pulses(a) Set SQUAWK/NAUT I to mode A at and 400 interrogations persecond. Set pulses P 1 and P 3 to - 60 dBm.(b) Transmit frequency must be 1090 MHz ± 3 MHz.(c) The output power shall be ≥ 250 W of the antenna terminal.CAUTION : If RG 58 C/U is used as indicated in the testsetup Fig. 2-1, the cable attenuation of app. 1 dBwill reduce the output power by app. 50 W.(d) Pulse spacing between the frame pulses F 1 and F 2 must be20.3 µs ± 0.1 µs.(e) The width of a reply pulse must be 0.45 µs ± 0.1 µs.(f) The necessary spacing between the reply pulses is 1.45 µs± 0.1 µs.(4) Checking reply limiting (AOC)Set SQUAWK/NAUT I to max. interrogation rate at which the transpon-der must respond with min. 1200 replies/s.(5) Checking the SPI hold time(a) Briefly press the IDENT button on the transponder.(b) For approx. 15 - 30 seconds, the SPI pulse must appear after thelast frame pulse F 2 at a spacing of 4.35 µs.INSTALLATION AND OPERATIONATC 3401Page 2-234-50-07 July 15/97
(6) Checking mode A coding(a) Set code 0000 on the transponder, resulting in only the frame pulsesF 1 and F 2 being visible on the oscilloscope.(b) Set code 7777, this must produce all 12 reply pulses including theframe pulses on the oscilloscope.(7) Checking mode C codingIf a coding altimeter is connected to the transponder, check with theaid of the MoA Gilham code whether the coded pulse sequence agreeswith the measured altitude. If the coding altimeter is not connected tothe transponder it transmits in mode C operation the frame pulses only.3. Mechanical configurationA. The transponder ATC 3401 is designed for installation aircraft instrument panelor control panel. The dimensions for installation of the transponder are shownin Fig. 2-2.B. Fitting the fastener strips e.g. on the instrument panel is shown in Fig. 2-3. Thetransponder is mounted after fitting the fastener strips with the aid of four DZUSfasteners.4. Aircraft wiringA. The aircraft wiring of the transponder together with the connection to the enco-ding altimeter is shown in Fig. 2-7.CAUTION : The transponder supply lines must not be loomed together withother equipment looms. In addition care must be taken to avoidrunning all transponder wiring in the close vicinity of ADF or otherpulse equipment looms.INSTALLATION AND OPERATIONATC 3401Page 2-334-50-07 July 15/97
B. Pin connections of the unit connectorConnector : P 8Pin :1Ident button external2TX-B (RS 422)3Illumination + 14 V (5 V)4Illumination + 28 V (5 V)5TX-A (RS422)6Switched output +10 . . . 32 V (encoding altimeter)7RX-B (RS 422)8TX-A (RS 422)9FUNCTION ON external10 DME/transponder suppression11 Supply voltage GND12 Supply voltage GND13 Supply voltage +10 . . . 32 V DC14 Altitude pulse A 415 Altitude pulse A 216 Altitude pulse A 117 Altitude pulse B 118 Altitude pulse B 4INSTALLATION AND OPERATIONATC 3401Page 2-434-50-07 July 15/97
Pin :19 Altitude pulse B 220 Altitude pulse C 421 Altitude pulse C 222 Altitude pulse C 123 Altitude pulse D 424 Altitude encoding GND25 Supply voltage +10 . . . 32 V DCC. External IDENT push-buttonIf this input (Pin 1 of unit connector P8) is briefly connected to GND (e.g. byan external push-button, the IDENT function is started in the same way aswith the IDENT push-button on the front panel.D. DME suppressionIf required, connnect the suppression in/out of transponder (pin 10 of unit con-nector P8) with the corresponding pin of the DME unit with type RG 178 B/U cable.INSTALLATION AND OPERATIONATC 3401Page 2-534-50-07 July 15/97
5. Installing the transponder antennaA. The transponder antenna is fitted to the underside of the aircraft fuselage at ahorizontal, flat location in the longitudinal direction. This location should not bein the "shadow" of aircraft structure items. The highest range is achievied whenthe antenna is located at the low point on the aircraft fuselage.B. The installation dimensions of the transponder antennas are shown in Fig. 2-4to Fig. 2-6.CAUTION :•Tranponder antenna DMNI 70-1 is provided with a cork gasket whichmust be interposed between the skin of the aircraft and the anten-na. To mount the antenna use only stainless screws in conjunctionwith lock washers.•The transponder antenna ANT 2000 is provided with a silicone rub-ber gasket which must also be interposed between the skin of theaircraft and the antenna.•In aircraft having a wooden or plastic airframe an electric counter-weight plate or panel must be located within the fuselage at the an-tenna location with minimum dimension 40 x 40 cm.(1) Antenna cableUse type RG 58 C/U coaxial cable when a length of 3 m or less is requi-red. Use type RG 213/U when the length exceeds 3 m.CAUTION : Keep the antenna cable as short as possible so that as litt- le power is dissipated in the cable as possible.6. Checking after installationA. GeneralAfter the installation, check the transponder to ensure satisfactory operationof the unit. The transmit frequency is to be checked and to be adjusted ifnecessary.B. Checking procedureCarry out post installation check following the description of section 2./B. uti-lizing a ramp test set.INSTALLATION AND OPERATIONATC 3401Page 2-634-50-07 July 15/97
C. Test and adjustment of transmit frequencySet code 0000 on the transponder and mode A interrogation on the ramp testset. Check transmit frequency by means of the ramp test set. Transmit fre-quency must be 1090 ± 3 MHz. If necessary use special wrench (1/4") loo-sen trimmnut through the hole in the top cover and adjust transmit frequencyby means of the tuning screw.CAUTION : After adjustment carefully tighten the trimmnut.D. Pre-flight check using self test(1) Activate the self test by pressing the TEST push-button (K). All digits in the displays flash and the reply lamp (J) comes on.(2) The EEPROM will be automatic tested with every write access. A failure is indicated by "EE" in the left display and by "FAIL" in the right display.INSTALLATION AND OPERATIONATC 3401Page 2-734-50-07 July 15/97
Fig. 2-1 Test setupINSTALLATION AND OPERATIONATC 3401Page 2-834-50-07 July 15/97
Fig. 2-2 Dimensions ATC 3401INSTALLATION AND OPERATIONATC 3401Page 2-934-50-07 July 15/97
Fig. 2-3 Installation of fastener stripsINSTALLATION AND OPERATIONATC 3401Page 2-1034-50-07 July 15/97
Fig. 2-4 Dimensions DMNI 70-1INSTALLATION AND OPERATIONATC 3401Page 2-1134-50-07 July 15/97
Fig. 2-5 Dimensions ANT 2000INSTALLATION AND OPERATIONATC 3401Page 2-1234-50-07 July 15/97
Fig. 2-6 Dimensions CI-100-2INSTALLATION AND OPERATIONATC 3401Page 2-1334-50-07 July 15/97
Fig. 2-7 Installation wiring ATC 3401INSTALLATION AND OPERATIONATC 3401Page 2-1434-50-07 July 15/97
TABLE OF CONTENTSOPERATION Page1. Controls and indicators 3-12. Funtion of controls and indicators 3-13. Transponder operating instructions 3-2Fig. 3-1 Front panel of ATC 3401 3-1INSTALLATION AND OPERATIONATC 3401Seite III-I34-50-07 July 15/97
OPERATION1. Controls and indicatorsFig. 3-1 Front panel of ATC 34012. Function of controls and indicatorsA. OFF/SBY/ON/ALT OFF position : Transponder is switched offrotary mode switch (exept panel ligthing).with 4 lock positions SBY position : Standby is switched on.ON position : ON mode (Mode A) is switched on.ALT position : ALT mode (Modes A+C) is switched on.B. Rotary coding switch Control of the cursor in one of the 4 code digitswith 8 lock positions, or from the display field.continuously rotableC. Rotary coding switch Setting the code digits from 0 to 7.with 8 lock positions,continuously rotableD. Identification push-button In the ON and ALT modes this triggers the trans-IDT mission of an identification impulse additional to theMode A reply code for approximately 25 seconds.INSTALLATION AND OPERATIONATC 3401Page 3-134-50-07 July 15/97
E. Left LC display Code indication :Codes from 0000 to 7777 are possible.F. Right LC display Mode indication and flight level indication :SBY mode :"SBY" is displayed. This display flashes during thewarm up phase, i.e. for 30 seconds after power on.ON mode :"On" appears in the display.ALT mode :If a valid altitude code is present, the flight level(height in steps of 100 ft) preceded by F (e.g. "F241"= 24100 ft) appears. If no valid altitude code is pre-sent, "F " is displayed."Idt" is displayed for the duration of the identificationfunction.G. Code push-button Activates a user-specific VFR code.VFRH. Code push-button Activates a user-specific transponder reply code.CODEJ. Reply lamp The green LED signals a transponder reply and/orREPLY activation of the identification function.K. Test push-button Activates the test function.TEST3. Transponder operating instructionsA. Switch on the unit (preflight check)(1) Check that the circuit breaker is set and switch on the aircraft powersupply.WARNING : Do not switch on the transponder if the motors or engines are being started or shut down.(2) Using the mode switch (A), switch the transponder from OFF to SBY.A display test then follows for 3 seconds.(3) The transponder is in the warm up phase for 30 seconds after power on.After the display test (3 seconds) has elapsed, "SBY" flashes for 27 secondsin the mode display. The transponder cannot transmit during this time.(4) After the warm up phase has elapsed, the transponder switches to themode set on the mode switch (A).INSTALLATION AND OPERATIONATC 3401Page 3-234-50-07 July 15/97
B. Flight operation in the ON mode (transponder reply code only)(1) The transponder remains switched in the standby mode until requestedfrom the ground station (ATC) to send a code, e.g. "squawk alpha 6426".(2) Check the code display. Do not set a code with 75XX/76XX/77XX. Thesecodes are reserved for emergencies.(3) Using the double rotary switch (B,C), set the 4-digit code requested byATC as follows.(a) Using switch (B) move the cursor to the particular digit. Digits 0 to 7can then be set using switch (C).NOTE : If switch (B) is turned clockwise or counterclockwise,the cursor is moved one position to the left or the right. The cursor appears only in the code display andis indicated by the flashing digit. If no cursor is visible,the first digit flashes after a clockwise rotation and thelast digit after a counterclockwise rotation. When thecode is being changed in the ON or ALT position, thetransponder replies not of incoming interrogations. The active time of the cursor and the rate of flashing can be changed in the configuration mode.(b) If the cursor is not moved again within 3 seconds (can be changed in the configuration mode) or if the cursor is moved so far that it can nolonger be seen in the display field or if the ident push-button (D) ispressed (in the ON or ALT modes only), the code currently set is switched active.NOTE : Whilst settings are taking place, the transmission branch of the transponder is inhibited to prevent unintentional transmission. If only two digits were named by ATC, e.g. "squawk alpha 64", then a zero is to be used for positions three and four, i.e. "6400".(4) Set mode switch (A) from SBY to ON. The transponder immediately replieswith the set code. The green LED signals the transponder replies.(5) After a "squawk ident" request from ATC, press ident push-button (D) briefly. This transmits an additional, special impulse (SPI) for approxima-tely 25 seconds, which enables the aircraft to be clearly identified on the radar screen of the controller. Idt appears in the right LC display (F) duringthis time.(6) The last used code is stored in each case and is also activated when the transponder is switched on.INSTALLATION AND OPERATIONATC 3401Page 3-334-50-07 July 15/97
(7) During the approach, ATC normally gives the instruction "squawk standby".The transponder must then be immediately switched to SBY using modeswitch (A), because the high transmission power of the unit can cause disturbance on the radar screen. The transponder remains in the standbymode until a new instruction to transmit is received.C. Flight operation in the ALT mode (reply code and altitude code)(1) If ATC requests the transmission "alpha/charlie" or "charlie", switch thetransponder to ALT using mode switch (A).NOTE : This only makes sense if the transponder is connected to a coding altimeter. If not, tell ATC that you do not have a mode C("mode charlie not available").(2) The transponder replies using the code set under Section B and in res-ponse to mode C requests it transmits the flight level of the aircraft to ATC.The green LED (J) signals the transponder replies.(3) After "squawk ident" request from ATC, press the ident push-button (D)briefly. This transmits an additional special impulse (SPI) for approxima-tely 25 seconds which enables the aircraft to be clearly identified on theradar screen of ATC. Idt appears in the right LC display (F) during this time.(4) During the approach, ATC normally gives the instruction "squawk standby".The transponder must then be switched to SBY using mode switch (A), because the high transmission power of the unit can cause disturbance on the radar screen. The Transponder remains in the standby mode until a new request to send is received.D. Special codings(1) Two user-specific transponder codes can be stored on the transponder andactivated :Push-button (G) : User-defined VFR code.Push-button (H) : User-defined transponder code.(2) Storing a new code.(a) Set the code to be stored in accordance with Section B.(b) Press VFR button (G) or CODE button (H) and hold for at least three seconds. The old stored code first appears in the left display (E) and this is followed after three seconds by the new code, which is storedat the same time.INSTALLATION AND OPERATIONATC 3401Page 3-434-50-07 July 15/97
(3) Activation of a stored code(a) Press the VFR button (G) or CODE button (H). The selected code is then displayed. After 3 seconds, the displayed code becomes activeand overwrites the previously-set reply code.(b) Pressing button (G) or (H) again within 3 seconds reactivates the previously-set reply code (changeable in the configuration mode).NOTE : When the unit is delivered, the store keys are not assigned a code. This means that if these keys are pressed for 0.5 seconds, "----" is shown in the codedisplay and the transponder then switches back to thepreviously-active code.E. Test(1) The test is activated by pressing the TEST button (K). All digits in the dis-plays flash and the reply lamp (J) comes on.(2) The EEPROM will be automatic tested with every write access. A failureis indicated by "EE" in the left display and by "FAIL" in the right display.F. Special codes for air emergencies(1) Special codes, which depend on the type of emergency, are laid downfor certain air emergencies:7500 Hijacking of the aircraft7600 Failure of the radio communications7700 Emergency on the aircraft which poses an immediatedanger to the aircraft.(2) The code evaluation equipment of the radar systems automatically alertsthe controller through the radar screen as soon as one of these specialcodes is received.(3) An unintentional transmission of an emergency code is prevented in thatthe transponder responses are inhibited whilst the code is being set.Thisapplies particularly where the new code is being set in the ON or ALT mode. Also if a special code is called up, no transponder reply takes placeduring the period in which the previous code can be reactivated (approx.3 seconds).INSTALLATION AND OPERATIONATC 3401Page 3-534-50-07 July 15/97
G. Configuration mode(1) The configuration mode is used set the unit on the ground by qualified personnel and must not be called up in flight.(2) The configuration mode is activated as follows.(a) Press and hold the CODE button (H) and the same time switch mode(A) from OFF to SBY. Await the display test (all digits flashing).(b) The parameter number can be set in the left display using rotaryswitch (B) and the parameter value in the right display using rotaryswitch (C).(c) The following settings are possible :P number Description Parameter (value) ProcedureP 01 Reset to factorysetting 12No changeAll parametersto standard(memory blank = "----")P 02 Delay time foractivation of code 2 (standard)1 (min.)4 (max.)P 03 Cursor active time 3 s (standard)1 s (min.)5 s (max.)P 04 Delay time for return to previouscode3 s (standard)0 s (min.)5 s (max.)(3) The reset to the factoring setting (parameter 2) is only active if changednot further parameters (P02 - P04) before storing.(4) Press TEST button (K) to leave the configuration mode and store the set values. This stores the new parameters and the transponder changes to the mode set by mode switch (A).(5) To leave the configuration mode without storing, set mode switch (A) toOFF. This switches off the transponder and changes in the configurationmode are not stored.Example of a unit configuration :INSTALLATION AND OPERATIONATC 3401Page 3-634-50-07 July 15/97
H. SafetyDo not connect the control unit to an a.c. voltage source of more than32.2 V.d.c. Do not connect the control unit to a power source with the polarities incor-rect.Avoid installing and using the control unit in environmental temperaturesbelow -20°C and over +55°C.Switch off the unit when starting or shutting down motors or engines.The control unit should be protected from the aircraft system by its own1 A circuit breaker.Do not set a code with 75XX / 76XX / 77XX. These special codes are re-served for emergencies.In the ON and ALT modes, the identifcation impulse is transmitted in addi-tion to the reply code for approximately 25 seconds only in response toMode A requests.INSTALLATION AND OPERATIONATC 3401Page 3-734-50-07 July 15/97
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