STC Program (EASA)

European pilots who operate EASA type approved aircraft can now upgrade their TT31 or TT22 Mode S transponder to be ADS-B Out capable, using popular Garmin GNS and GTN WAAS Navigators. Other suitable GPS units can also be used, including Trig’s TN70 GPS position source.

Our free EASA STC and ADS-B STC AML (approved model list) is available via Approved Trig Dealers. It enables numerous aircraft to be legally configured using either a Trig TT31 or TT22 transponder, with listed GPS units.

This is a practical and cost effective way to become ADS-B Out equipped, enhancing your visibility and flight safety.

The following WAAS GPS units are compatible and approved for use with TT31 and TT22 transponders.

  • Garmin GTN 600 and 700 series
  • Garmin GNS 400W and 500W series
  • Trig TN70 WAAS GPS
  • FreeFlight 1201 WAAS GPS
  • Accord NexNav Mini WAAS GPS

Please note – our TN72 GPS Position Source can be used for voluntary equipage of ADS-B. In Europe the installation of a TN72 in an EASA aircraft uses our free EASA Minor Change, an AML (approved model list).

STC Provision

Each of the following links will open the official EASA STC approval. You can check the relevant approved model list (AML) and GPS equipment within each STC.

The EASA STC is available free of charge from appropriately qualified Approved Trig Dealers. This STC can be accessed from the Trig Dealer Portal, by qualified dealers.

TT31 Transponder

EASA STC certificate

TT31 STC AML expansion

July 2018 – Aircraft models are listed on our TT31 STC.

TT22 Transponder

EASA STC certificate

TT22 STC AML expansion

July 2018 – Aircraft models are listed on our TT22 STC.

Further Information

Please bear in mind that STC requirements differ from country to country – if you wish to gain more information about any of these specific STC approvals please contact