Picture of product TT31

Part #:

Model: TT31


Trig Avionics


Mode S Transponder

Part Number :

  • Improved retrofit performance – ‘plug and play’ Mode S installation for KT76A, KT76C and KT78A
  • Certified Mode S and 1090ES ADS-B Out capable
  • Certified for IFR / VFR flight
  • Amongst the lowest power consumption in class
  • 240 watts nominal output
  • TIS traffic capabilities – portable and/or panel mounted avionics
  • Backlit LED display
  • No cavity tube – no warm up time required (no need for dropper resistors)
  • EASA ETSO and FAA TSO Certification – TSO C166b the latest ADS-B standard
  • Free European Minor Change approvals
  • Free FAA ADS-B STC for 650 aircraft types
  • Software provides the widest compatibility with third party avionics
  • Unbeatable value and quality – designed and manufactured in the U.K.
  • Two year worldwide warranty
Type: Transponder Class 1 Mode S Level 2 els, ADS-B Class B1S Supply Voltage: 10 - 33V
Certification: ETSO C166A, 2C112B and TSO C112, C166b Compliance: ED-73B, DO-160E, DO-178B level B, D0181C, DO-260B, DO-254 Level C
Current Consumption (@ 14V): Idle: 0.22 A; Active 0.45 A Nominal Transmitter Power: 240 W at connector
Operating temperature: -20 to +55°C temperature Cooling: No fan required
Weight: 2.8 lbs Dimensions: In tray - 1.57" H x 6.30" W x 9.4" L
Part Number Transponder Description:
00220-00 Transponder Only - for KT-76A/C, KT-78A direct replacement
00225-00 System - includes tray & install kit


- Mode S Transponder (KT-76X Replacement)

NSN: 5825-01-362-9561

Price Condition Status
- Mode S Transponder (KT-76X Replacement)
Price Condition Status
- Mode S Transponder System

NSN: 5325-12-146-3930

Price Condition Status
- Mode S Transponder System (ADS-B)
Price Condition Status

Click on a question below to see the answer. If you have a question about this model that is not answered below, please contact questions@seaerospace.com

In relation to NE (New) parts, many OEMs change their prices and availability without any notice to dealers or the industry. Therefore, through the REQUEST or RFQ indication, we ask that customers contact us for the most accurate price and availability.

In relation to SV & OH parts, the used parts aftermarket in the aviation industry is not an infinite supply. It is a dynamic, constantly changing market that is significantly affected by and susceptible to highs and lows in supply and demand. Therefore, although we attempt to, at times, we are unable to predict the exact moment when an item may be available. Once again, through the REQUEST or RFQ indication on our website, we ask that customers contact us for the most current and accurate price and availability.

Yes, anytime a transponder is removed or replaced an altitude correlation between what the transponder is reporting and what is displayed on the altimeter needs to be performed. This is outlined in FAA CFR Part 91.413. This regulation indicates that following any installation or maintenance of a transponder where data correspondence error could be introduced, the integrated system has been tested, inspected, and found to comply with paragraph (c), appendix E. Furthermore, these references indicate that an integration test between the altitude reporting equipment and transponder system must be conducted.

For complete information, please refer to these FAA regulations or contact Southeast Aerospace Tech Support team at shop@seaerospace.com.
Automatic Dependent Surveillance-Broadcast (ADS-B) is a component of the Next-Generation (Next Gen) Air Transportation System. ADS-B is an advanced surveillance technology that combines an aircraft's positioning source (GPS), aircraft avionics, and a ground infrastructure to create an accurate surveillance interface between the aircraft & aircraft traffic control. ADS-B provides consistent position accuracy regardless of the aircraft's range from the receiver.

The improved accuracy and update rate of ADS-B is a critical segment of the NextGen infrastructure.

The FAA has determined that it will be necessary for all aircraft operating in specific airspaces to be equipped with ADS-B Out by 2020. A nationwide infrastructure of ground stations is scheduled for completion during 2013.

As of June 2010, only ADS-B Out is being mandated. ADS-B Out provides the ATC with real-time position information. ADS-B In is the aircraft's ability to receive and display other aircraft broadcasted information as well as the services provided by the ground stations.

ADS-B requires the use of a Positioning Source. As of June 2010, any positioning source is allowed; however, WAAS is the only positioning service that provides the equivalent availability required.

A Broadcast Link is also required for ADS-B functionality. There are two available options: 1090 MHz Extended Squitter (ES) or Universal Access Transceiver (UAT). FL 180 (the lower boundary of Class A airspace) is the ceiling for operating an aircraft equipped with UAT only.

ADS-B will eventually provide weather services, air traffic information, terrain maps and other flight information services for all pilots through satellite based data and ground stations. In accordance with NextGen, ADS-B will provide benefits that address some shortcomings over other, existing surveillance systems.

Some of these benefits include:
  • Air-to-air surveillance capability
  • Surveillance in remote areas where radar coverage is unavailable
  • Real-time traffic information for aircraft not equipped with active traffic systems (ex. TCAS, TAS)
  • Reduced separation between aircraft due to sharing of flight information between aircraft
  • Better predictability in departure and arrival times

    Ultimately, ADS-B will allow aircraft to fly at safe distances from each another.

Click Here to View the official FAA NextGen Final Rule released on 5/28/10.

You may also View an SEA Summary of the FAA NextGen Final Rule (NOTE: this information has been altered for summary purposes and should be used as Reference Only).
Configuration and programming of the TT31 transponder is simple. Hold down the FUNC button while switching on the transponder and the setup system will run. The setup includes the following configurations items: Mode S Address, VFR Squawk Code, VFR Flight ID, Aircraft Maximum Airspeed, Aircraft Category, Squat switch source, if installed, GPS position source, if installed, ADS-B parameters, Audio Output Volume, LCD Dimming Settings.

All programming is performed using the right hand knob and the ENT, BACK, FUNC buttons.

Although some manufacturers call out specific transponder antennas in their installation manuals, almost any transponder antenna can be used with any transponder. Various models are available based on the screw hole pattern desired and the speed & drag considerations based on the aircraft type.

For smaller general aviation aircraft, Southeast Aerospace recommends the stub type AV-22 or CI-101 antenna.



For medium to larger aircraft, Southeast Aerospace recommends the blade type CI-105 or AV-74 antenna.


Ultimately, it is the responsibility of the installer or installing agency to determine what antenna is suitable for the aircraft application.




Click here to find the answer.
The right hand knob is used to set squawk codes and the Flight ID. The FLT/SQ button selects which will be updated. Turning the knob will highlight the first digit on the display, and the digit can be changed as required. Press the ENT button to advance to the next digit. When ENT is pressed on the last digit, the new squawk code or Flight ID will replace the previous value. If the code entry is not completed with 7 seconds, the changes are ignored and the previous code restored.

1200 VFR code in the USA
7000 VFR code 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 on your Flight ID. Use only letters and digits. If the Flight ID is less than 8 characters long, entering a black character will end it.
The Mode S aircraft identification code is listed on AC Form 8050-3, Certificate of Aircraft Registration, as the International Civil Aviation Organization (ICAO) Aircraft Address Code. If the aircraft registration does not contain this information, aircraft owners with a Mode S transponder can obtain an aircraft identification code from the FAA Aircraft Registry in Oklahoma City, Oklahoma. This may be accomplished by writing to the following FAA address:

Federal Aviation Administration
Aircraft Registration Branch AFS-750
P.O. Box 25504
Oklahoma City, OK 73125-0504

You may also call:
PLEASE NOTE - Publications are for Reference Only