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TT31 Transponder Installation Manual 

8 May 2017 

00455-00 

Issue AQ 

 

 
 

______________________ 

Trig Avionics Limited 

Page 5  

3.3.1

 

Mode S Transponder Installation Approval 

Installation of the TT31 as a replacement for an existing transponder is considered a Minor Change by 
EASA and the FAA, and should be documented accordingly. 

Note:  With no GPS interface configured, the transponder does not enable any ADS-B 
functions, and will behave as a conventional Mode S transponder. 

3.3.2

 

ADS-B Installation Approval 

At the time of publishing this manual, enabling the ADS-B Out feature is considered a major change 
and will generally involve further approval. 

For installers seeking US FAA STC approval, our STC partner is Peregrine in Denver who hold a range 
of AML STCs for TT31 transponders.  Contact them at - 

peregrine.aero/contact.html

 

Installers seeking approvals for other parts of the world or for more information on our STC program, 
should contact the Trig support team – 

support@trig-avionics.com

 

For uncertified aircraft installations or for installers developing their own solution, this manual can be 
used for guidance on the ADS-B installation.  Further technical diagrams, schematics and instructions 
are contained within the STC pack which can be obtained through Peregrine. 

3.4  Non 

– TSO Functions 

The TT31 Mode S Transponder contains the following non-TSO functions: 

 

Stopwatch and Flight Timer. The transponder provides a simple stopwatch and flight timer 
function, displayed on the front panel.   

 

Altitude Monitor. The Altitude Monitor activates an audio annunciator or annunciator light 
(depending on installation) when the aircraft pressure altitude differs from the previously 
selected altitude by more than 250 feet. 

 

Altitude Repeater. This is a serial altitude output that can connect to a GPS or other device 
needing serial altitude data – this allows the transponder to act as a repeater for the altitude 
input instead of requiring a second altitude encoder. 

The operation of each of these functions is described later in this manual.   

The non-TSO functions defined in this section are not part of the TSO approval. The non-TSO function 
data included in this section is approved under 14 CFR 21.305(d).   

Summary of Contents for TT31

Page 1: ...TT31 Mode S Transponder Installation Manual 00455 00 AQ 8 May 2017 Trig Avionics Limited Heriot Watt Research Park Riccarton Currie EH14 4AP Scotland UK Copyright Trig Avionics Limited 2006 2017 ...

Page 2: ...This page intentionally left blank ...

Page 3: ...lation Approval 5 3 3 2 ADS B Installation Approval 5 3 4 NON TSO FUNCTIONS 5 4 UNIT AND ACCESSORIES SUPPLIED 6 4 1 TT31 MODE S TRANSPONDER ITEMS 6 4 2 INSTALLATION KIT 6 4 3 DOCUMENTATION KIT 6 4 4 REQUIRED ITEMS 6 5 INSTALLATION 8 5 1 UNPACKING AND INSPECTING EQUIPMENT 8 5 2 MOUNTING 8 5 3 COOLING REQUIREMENTS 8 5 4 ELECTRICAL CONNECTIONS 8 5 4 1 Primary Interface Pinout 9 5 4 2 Secondary Interf...

Page 4: ...S 18 6 1 1 Aircraft Registration VFR Flight ID 18 6 1 2 Aircraft Address Programming 18 6 1 3 VFR Squawk Code 19 6 1 4 Airspeed Category 19 6 1 5 Aircraft Category 19 6 1 6 Squat Switch Source 19 6 1 7 ARINC TIS Output 19 6 1 8 RS232 Input Output 19 6 1 9 ADS B Configuration 20 6 1 10 Audio Volume 21 6 1 11 LCD Dim Point 21 6 1 12 LCD Brightness Curve 21 6 2 TEST ITEMS 21 6 2 1 Interface Check 21 ...

Page 5: ...N 26 9 CONTINUED AIRWORTHINESS 27 9 1 MAINTENANCE 27 9 2 ADS B INSTALLATIONS 27 9 2 1 GPS Receiver Maintenance 27 9 2 2 GPS Receiver Design Changes 27 10 LIMITED WARRANTY 28 11 ENVIRONMENTAL QUALIFICATION FORM 29 12 ADS B COMPLIANCE 31 12 1 ADS B PARAMETERS SUPPORTED 31 12 2 FAA 91 227 COMPLIANCE 31 12 3 CS ACNS COMPLIANCE 32 12 4 TSO C199 TABS COMPLIANCE 32 12 5 AUTOMATIC AIR GROUND DETERMINATION...

Page 6: ...TT31 Transponder Installation Manual 8 May 2017 00455 00 Issue AQ ______________________ iv Trig Avionics Limited This page intentionally left blank ...

Page 7: ...e 1 3 Changes from Previous Issue In addition to minor editorial changes the following are the changes between issue AP and issue AQ 5 7 10 Audio Mute Input Added text for the intended mute behaviour 5 7 12 GPS Position Input Added support for Trig TN72 TABS GPS protocol 6 1 6 Squat Switch Source Added GPS only automatic air ground determination 6 1 8 RS232 Input Output Added settings for TN72 TAB...

Page 8: ...located by the registration authority for the aircraft and must be set when the TT31 is installed The TT31 can be configured to transmit version 2 ADS B using the 1090ES datalink The ADS B Out capability is enabled automatically when the transponder is configured to use a GPS position source over an RS232 interface With a GPS source connected the transponder supports all required features of ADS B...

Page 9: ...r a serial altitude encoder or air data computer Using serial altitude data allows the transponder to report altitude with 25 foot resolution 2 x RS232 Outputs Connections to a TIS display and a GPS or other device needing serial altitude data this allows the transponder to act as a repeater instead of requiring a second altitude encoder ARINC TIS Output ARINC429 output for connection to traffic d...

Page 10: ...1 Approved Deviations The TT31 ADS B function is certified to ETSO C166a which references DO 260A as the applicable standard the TT31 implements DO 260B which has replaced DO 260A The TT31 ADS B function is certified to FAA TSO C166b which references DO 260B but also refers to the environmental standard DO 160F and indirectly refers to the transponder standard DO 181D The TT31 transponder certific...

Page 11: ...certified aircraft installations or for installers developing their own solution this manual can be used for guidance on the ADS B installation Further technical diagrams schematics and instructions are contained within the STC pack which can be obtained through Peregrine 3 4 Non TSO Functions The TT31 Mode S Transponder contains the following non TSO functions Stopwatch and Flight Timer The trans...

Page 12: ...42 00 Washer 7 16 Plain Stainless Steel 1 00241 00 Washer 7 16 Crinkle Beryllium Copper 1 00317 00 4 3 Documentation Kit Your TT31 documentation kit includes the following items Unit Description Qty Part Number TT31 Transponder Installation Manual 1 00455 00 TT31 Pilots Operating Manual 1 00454 00 4 4 Required Items Additional items you will require but which are not in the TT31 package include An...

Page 13: ...ics Limited Page 7 you may need to fabricate additional brackets to support the transponder tray To support the optional ADS B features a GPS receiver with an appropriate serial output is required To support the optional TIS features a display with an appropriate serial or ARINC 429 input is required ...

Page 14: ... the TT31 transponder into the mounting tray using a 3 32 Allen key taking care not to over tighten the locking screw 5 3 Cooling Requirements The TT31 Mode S transponder meets all applicable ETSO and TSO requirements without forced air cooling Attention should however be given to the incorporation of cooling provisions to limit the maximum operating temperature of each unit when the TT31 is insta...

Page 15: ... 9 Suppress In Input 10 Standby Switch Input 11 11 33V DC 12 11 33V DC A Ground B Altitude B4 Input C Altitude B2 Input D Altitude C1 Input E Altitude B1 Input F Ident Switch In Input H Altitude C4 Input J Altitude A4 Input K Altitude A2 Input L Altitude C2 Input M Altitude A1 Input N Do Not Connect These signals are different to the KT76A KT76C KT78A pinout on the KT76A KT76C and KT78A these sign...

Page 16: ...utput F ARINC Traffic A Output 5 4 3 Orientation Diagram To assist in connector orientation the following example shows a typical set of connections This diagram shows the expected connector positions when viewed from the transponder side of the tray looking into the tray from the front In the example shown the aircraft uses a 14 volt lighting bus a parallel altitude encoder a DME with simple supp...

Page 17: ...e well removed from landing gear doors access doors or others openings which will break the ground plane for the antenna The antenna should be mounted on the bottom surface of the aircraft and in a vertical position when the aircraft is in level flight Avoid mounting the antenna within 3 feet of the ADF sense antenna or any COMM antenna and 6 feet from the transponder to the DME antenna Where prac...

Page 18: ...Carlisle Type 2 54 8 4 0 59 M17 128 RG400 3 16 10 4 0 47 3C142B 3 81 12 6 0 39 M17 112 RG304 5 25 17 3 0 29 M17 127 RG393 311601 6 42 21 1 0 23 311501 8 22 26 11 0 18 311201 12 59 41 3 0 12 310801 Contact Carlisle Interconnect Technologies on 1 414 421 5300 or www carlisleit com for their data sheets When routing the cable ensure that you Route the cable away from sources of heat Route the cable a...

Page 19: ...e contact aligning the conductor with the slot in the contact Avoid excess solder heat on the centre BNC conductor pin Solder the inner shield to the inside of the connector body by applying a soldering iron to the body and running solder into the gap Try to avoid excess solder heat on the connector body Solder the outer shield to the outside of the connector body Avoid excess solder heat on the c...

Page 20: ...31 mounting tray and attach the washer combination in the following order Wave washer p n 00317 00 Plain washer p n 00241 00 Circlip washer p n 00242 00 The Circlip washer should be fitted with a set of Circlip pliers The two Molex connectors should be passed through the openings in the rear of the tray and then mounted firmly to the tray from the inside using the four M3 screws supplied 00239 00 ...

Page 21: ...on requirements It is an input only and is active whenever the input is greater than approximately 5 Volts The Suppress I O on contact 4 is an ARINC compatible suppression bus interface which acts as both an input and an output The TT31 will assert this signal when it is transmitting and can be suppressed by other equipment that asserts the signal The TT31 will drive approximately 24 Volts on the ...

Page 22: ...nd stop the flight timer The input will be asserted when the voltage to ground is pulled below approximately 4 Volts The operating mode of the squat switch can be programmed during setup to allow for active low or active high logical behaviour For aircraft with no squat switch this input should be left open circuit and the setup mode programmed for Not Connected 5 7 7 Ident Switch Input The Ident ...

Page 23: ...ol Trig TN72 TSO C199 TABS GPS with NMEA protocol Some of the protocols listed above may not contain all the required data for a compliant ADS B message depending on the intended airspace regulations For further information refer to Section 12 ADS B Compliance of this manual With the Garmin ADS B protocol selected the TT31 is compatible with both the Garmin ADSB and Garmin ADSB Plus protocols NOTE...

Page 24: ...CK and FUNC buttons Make all input selections using the rotary knob Pressing the ENT button accepts the current input and advances to the next input item Pressing the BACK button accepts the current input and then returns to the previous input item Pressing the FUNC button moves directly to the next screen 6 1 Configuration Items 6 1 1 Aircraft Registration VFR Flight ID The default Flight ID for ...

Page 25: ...ch by using GPS data either alone or in combination with an Air Data Computer Note The preferred choice where available is to use a real squat switch If the squat switch input is not used the Not Connected option should be selected 6 1 7 ARINC TIS Output If the aircraft has a Traffic Information Service TIS compatible display connected to the ARINC 429 output select the appropriate interface proto...

Page 26: ...cordance with the standards DO 178B and DO 254 for example DO 178B level C If both standards are reported but at different levels use the lower standard higher letter The following table shows example certification data current at the time of publication Equipment Certification Level Trig TN70 Level C Accord NexNav Mini Level C FreeFlight 1201 Level C Garmin 4x0W 5x0W Level C Garmin GTN series Lev...

Page 27: ... ADS B channels 1090ES and UAT and there is an ADS B based traffic information service called TIS B The ADS B ground stations relay this information between the two channels so that suitably equipped aircraft can receive traffic information To limit channel congestion these services are only provided to aircraft equipped to receive them The transponder reports what receivers are installed in a per...

Page 28: ...us to assist in verifying the correct operation of the lighting bus 6 2 4 Temperature The internal temperature of the transponder can be displayed The display is in degrees Celsius 6 2 5 RS232 Input Check The RS232 interface check provides a diagnostic that the RS232 input lines are configured correctly It will display on screen the data each RS232 line is set up to receive If valid data of the co...

Page 29: ...th the aircraft outside the hangar for good GPS reception the aircraft position should be displayed on the transponder If the position indications are all dashes then either the GPS position is not valid or the GPS interface is not correctly configured Whenever a valid position is received by the transponder and the transponder is in any mode other than Standby ADS B Extended Squitters should be o...

Page 30: ...t match the altimeter indicated altitude but will be correctly displayed by the ATC radar 8 3 Mode Selector Knob The left hand knob controls the power to the transponder and the operating mode OFF Power is removed from the transponder SBY The transponder is on but will not reply to any interrogations GND The transponder will respond to Mode S ground interrogations from surface movement radar ON Th...

Page 31: ...e commonly used in Europe 7500 Hijack code 7600 Loss of communications 7700 Emergency code The Flight ID should correspond to the aircraft call sign entered on your flight plan If no flight plan is active the aircraft registration should be used as your Flight ID Use only letters and digits If the Flight ID is less than 8 characters long entering a blank character will end it 8 6 Flight Timer The ...

Page 32: ...mally If there is a problem with the antenna installation a warning message may be displayed Depending on whether this is an intermittent problem the message may recur when cleared The transponder may still be replying to interrogations but there can be no assurance that ATC is receiving those replies 8 11 Fault Annunciation If the transponder detects an internal failure or a hard fault with the a...

Page 33: ...cs Limited service procedures 9 2 ADS B Installations 9 2 1 GPS Receiver Maintenance If any maintenance is required on the connected GPS receiver it is advisable to check with the GPS manufacturer that you have the most recent and correct version of tests to carry out after maintenance Check that there are no additional requirements to be considered when using the GPS as part of an ADS B system Th...

Page 34: ...mal wear All warranties are F O B Trig Avionics Limited Heriot Watt Research Park Riccarton Edinburgh EH14 4AP Trig Avionics will not accept or pay for any charges for warranty work performed outside our factory without prior written consent This warranty applies only to products in normal use It does not apply to units or circuit boards defective due to improper installation physical damage tampe...

Page 35: ... Aircraft zone 2 type 3 4 5 to category S level M Equipment at strike off level 3 also tested for aircraft zone 2 type 1 Helicopters to category U level G Explosion 9 0 Equipment identified as Category X no test required Waterproofness 10 0 Equipment identified as Category X no test required Fluids Susceptibility 11 0 Equipment identified as Category X no test required Sand and Dust 12 0 Equipment...

Page 36: ...ment tested to Category B and extended to use test levels for Helicopters Vibration 8 0 Aircraft zone 2 type 3 4 5 to category S level M Equipment at strike off level 3 also tested for aircraft zone 2 type 1 Helicopters to category U level G Explosion 9 0 Equipment identified as Category X no test required Waterproofness 10 0 Equipment identified as Category X no test required Fluids Susceptibilit...

Page 37: ...nd Track 0 6 Aircraft Identification 0 8 Airborne Ground Velocity 0 9 Geometric to Barometric Altitude Difference 0 9 Geometric Vertical Speed 0 9 Squawk Code 6 1 Emergency Status 6 1 Quality Indicator NACp NACv and GVA 6 5 Quality Indicator SIL and SDA 6 5 Version Indicator 6 5 Surface Length Width 6 5 Surface Antenna Offset 6 5 In all cases uncompensated latency due to the transponder is less th...

Page 38: ...t GPS Output Setting TT31 Input Setting Trig TN70 n a FreeFlight NexNav FreeFlight 1201 n a FreeFlight NexNav Aspen NexNav Mini n a FreeFlight NexNav Avidyne IFD 4xx ADS B Avi Trig ADSB Avidyne IFD 5xx ADS B Avi Trig ADSB Garmin GNS4x0W ADS B or ADS B Garmin ADSB Garmin GNS5x0W ADS B or ADS B Garmin ADSB Garmin GTN6xx ADS B Garmin ADSB Garmin GTN7xx ADS B Garmin ADSB Garmin GPS 20A n a Garmin ADSB...

Page 39: ...the TT31 will set SIL 1 and SILSUPP 0 For all other GPS units the TT31 will set SIL 0 The TT31 will always limit the NIC value to not greater than 8 The NACp value is set using HFOM data from the GPS The NACv is a fixed setting determined from the setup menu NOTE If using the Garmin ADS B Plus protocol the NACv is set dynamically from the GPS data In this instance the NACv setting from the setup m...

Page 40: ...TT31 Transponder Installation Manual 8 May 2017 00455 00 Issue AQ ______________________ Page 34 Trig Avionics Limited 13 Installation Drawings All dimensions in millimetres ...

Page 41: ...00455 00 Issue AQ ______________________ Trig Avionics Limited Page 35 14 Connection Diagrams 14 1 Master Drawing List Figure 14 A Typical TT31 Interconnect 36 Figure 14 B Typical TT31 ADS B Out Interconnect 36 Figure 14 C RS 232 GPS Interconnect 36 ...

Page 42: ...wer 1 OTHERTRANSPONDER 1A Circuit Breaker 3 LAMP 4 11 33V Primary TRIG TT31 Secondary SERIAL ALTITUDE ENCODER or ADC Altitude Out 2 1 DME Suppression Out AUDIO PANEL Audio Audio ALL WIRES SHOULD BE 18 24 AWG NOTES 1 CONNECT ONLY ONE INPUT TO THE LIGHTING BUS DEPENDING ON LINE VOLTAGE 1 2 ONLY CONNECT ONE ALTITUDE DATA SOURCE EITHER A SERIAL ENCODER PARALLEL ENCODER OR ADC WHEN USING DATA FROM AN A...

Page 43: ... MANUFACTURERS REQUIREMENTS FOR CABLE SIZES 2 THESE INPUTS ARE USED FOR AUTOMATIC AIR GROUND DETERMINATION ONLY ONE OF THESE METHODS IS REQUIRED TO BE CONNECTED ADC SQUAT SWITCH OR AIRSPEED SWITCH NOTES 1 3 REFER TO MANUFACTURERS INSTALLATION DOCUMENTS FOR SUPPLY CONNECTIONS Coax TRIG TT31 ADC Pitot Line Airspeed Switch Static Line Aircraft Squat Switch 1 1 1 Primary 3 A Secondary REFER TO RS 232 ...

Page 44: ... PAIR TO MIL C 27500 OR EQUIVALENT 2 TERMINATE THE SHIELD GROUNDS TO A SPARE GROUND PIN ON EITHER UNIT IF NO GROUND PIN IS SPARE THEN CONNECT THE SHIELD GROUNDS TO THE AIRCRAFT CHASSIS OR CONNECTOR BACKSHELL IF APPLICABLE NOTES 1 2 1 REFER TO SECTION 6 FOR CORRECT CONFIGURATION OF TRANSPONDER 2 REFER TO APPROPRIATE GPS INSTALLATION MANUAL FOR CORRECT CONFIGURATION OF GPS POSITION SOURCE TT31 24 Wa...

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