Trig’s TT31 transponder is the perfect retro-fit for the popular Bendix King KT76A and KT78A transponders. The TT31 is a certified Class 1 transponder which will ‘plug and play’ straight into the existing Bendix King tray. This significantly reduces both installation time and cost. It provides pilots with class leading Mode S technology that is also 1090ES ADS-B Out capable too (ADS-B functionality requires a Trig tray).
Mode A and C transponders are now being replaced by Mode S transponders, technology which is optimised for tomorrow’s airspace requirements. Around the world the introduction of ADS-B surveillance technology means the modern transponder has now become the heart of future airspace compliance requirements. Here the TT31 remains the transponder of choice. The TT31 was the world’s first transponder certified to TSO C166b. This is latest FAA standard for the U.S. 2020 ADS-B mandate and demonstrates Trig’s advanced levels of compliance.
Pilots can buy the TT31 with confidence. Not only is it the easiest upgrade path for their old BK transponder, with a Trig TT31 tray installed the same transponder is mandate ready. The TT31 uses half the electrical power of the leading competitor transponder, whilst still transmitting at a higher signal power, its efficient design reduces waste heat in the avionics stack. This reduces the load on the aircraft electrical system improving overall reliability. The flexible power input means that both 14 and 28 volt systems can be used without special configuration or dropper resistors (we recommend that any dropper resistor fitted for a previous transponder should always be removed). The TT31 is compatible with both parallel and serial altitude encoders; it can even act as a serial altitude repeater to provide a convenient altitude source for your GPS.
The TT31 is popular in the U.S. where a certified WAAS GPS, and a ground air determination device are also required forming the ideal 2020 ADS-B solution. It’s worth remembering that to receive all ADS-B In transmissions in the U.S. the FAA requires a functioning certified ADS-B Out device, so don’t miss out on airspace information - fit a Trig TT31.
All Trig products come with a two year warranty, supported by our global network of Approved Trig Dealers and Approved Trig Service Centers in the U.S. and Australia.
I encountered problems installing this Slide-in replacement for my KT76A. Although the unit did slide into the tray, it did not seat all the way in. The avionics guy eventually figured out that the two guide pins at the back of the tray were thicker than the guide holes in the TT31 that they slide into. Once he increased the diameter of the holes, the unit went in all the way. For a unit touted as being a 15 second slide-in replacement, my 1.5 hour technician bill was not welcome.
TRIG TT31 XPDR M-S C-1 SLIDE IN FOR KT 76A
Unit shipped fast, installed easily. Very happy
We had Gwinnett Aero purchase and install in our 79 Warrior. They tied it to our existing Garmin 430W (needed firmware upgrade). They wired the ADSB interface and the Mode S to the Garmin. I now get traffic on the 430 that I did not get before. The ADSB traffic shows up on Foreflight. I am very happy with the price and install.
Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.
Per the manual, you will require an encoding altimeter or a blind encoder with either parallel Gray code or RS232 serial output. For best results, and simpler installation, an encoder with a serial output is recommended.
Yes, the Trig TT 31 (11-07997) will directly interface the GNS 430W.
Yes, the TT31 with software version 3.13 which we carry is compatible with the Garmin 430/530W series for ADS-B compliance. The TT31 will fit in the same tray as the KT-76.
Yes, when coupled to a 430W the TT31 is approved for ADS-B out. For ADS-B in you will need a GDL 39. Certified Aircraft require GDL 88 which is only available at local Garmin dealer.
A logbook entry would still need to be signed off by an A&P.
No, the Garmin 296 is not an approved WAAS GPS source.
The TT31 does not include a WAAS GPS. The TN70, pn 11-13061, is available to provide WAAS GPS position data to the TT31. It is FAA Approved for installation in certificated aircraft. No adapters are included for interfacing with a KT78.
No, the 496 is not an approved WAAS GPS Source. You need an approved WAAS GPS source to ADS-B out compliant.
Yes, the Trig TT31 will transmit 1090ES (extended squitter).
Yes, per the manufacturer this is a plug and play with the KT76A, KT76C, and the KT78A