TT31 Minor Change Library

At Trig we have developed a set of EASA approved upgrade instructions that document the process of installing the TT31 transponder in a range of aircraft. Trig installers can use these instructions to achieve airworthiness compliance without needing to seek further approval from EASA.

These Minor Change Approvals are free.

First – we suggest that you look at the Aircraft Approved Type List within the Minor Change Approval Summary Sheets (below). Use this to verify that your specific aircraft model is featured within the Minor Change Approval.

Next – find your specific aircraft model from the individual aircraft links (at the foot of this page). Clicking on each link takes you to the EASA Minor Change Approval Certificate.

Finally – The Minor Change Approval Certificate for your aircraft will indicate the relevant ‘Associated Technical Document’ that must be followed as part of the installation. Please see the relevant technical document in the Minor Change Master Instructions  section below.

Minor Change Approval Summary Sheets

Certain approval certificates include standard text inserted by EASA which says “The installation of this modification by third persons is subject to written permission of the approval holder”.  For the avoidance of doubt, we hereby grant that permission, and this web page may be referred to as evidence of that permission.

For space reasons, both the EASA Approval Sheets and this web page have abbreviated some sub-type information, where aircraft model variant approvals still apply.  The following master documents show the complete list of all approved EASA models and variants for those types.

Fixed Wing (CS-23) Aircraft Approved Type List (revision 2.0)

Powered Sailplane (CS-22) Aircraft Approved Type List (revision 1.0)

If you are installing a TT31 transponder in an aircraft type NOT shown here, but for which the minor change instructions would apply, Trig Avionics grant you permission to use the published minor change instructions as the basis for your own application.

Minor Change Master Instructions

The Minor Change Master Instructions are available for download here.

Fixed Wing (CS-23) TT31 Minor Change Instructions (latest revision, issue 1.6).

Fixed Wing (CS-VLA) TT31 Minor Change Instructions (latest revision, issue 2.0).

Powered Sailplane (CS-22) TT31 Minor Change Instructions (latest revision, issue 2.0).

Small Rotorcraft TT31 Minor Change Instructions (latest revision, issue 4.0).

As our library of Minor Changes has expanded we have responded to questions from our installers. As a result we have made improvements to these Master Instructions. The information in the latest revisions are still applicable to all the Minor Changes listed below. Because there is information in the latest document that is not included in the earlier revisions we recommend that installers refer to the latest document. For completeness however the previous versions of the Fixed Wing instructions are still available for download: (Fixed Wing Issue 1.4) or (Fixed Wing Issue 1.5)

Alenia Aermacchi

F260, S205, SF260TP


HR200, R2100, R2112, R2120, R2160

American Champion



Carat A

Apex Aircraft

ATL, CAP10, CAP20, CAP21, CAP230, CAP231, CAP232, DR220, DR221, DR250, DR253




A-1A, A-1B, Pup


B121 Pup


19A, 19B, 19M, 23, A23, C23 E33, E33C, J35, K35, N35, P35, S35, V35, V35A, V35B, 35-33,35-B33, 35-C33, 35-C33A, 36, A36, A36AT, A36TC, B36TC, 77

Bell Helicopters

206 series, 407




C120, C140, C150, C152, C170, C172, C175, C177, C180, C182, C188, C206, C207, C210,

Individual subtype letters have been omitted for space reasons. All these Cessna approvals cover the complete series and where appropriate apply to aircraft manufactured in either France or the USA.



Constuctii Aeronautice



DA20-A1, DA20-C1, DV20, DA40, H-36 Dimona, HK36, HK 36 Super Dimona

EADS Deutschland GmbH

SIAT 223

E.I.S. Aircraft GmbH

RF5, RF5 B, RF4 D, SFS 31


AS350B, AS350 B1, AS350 B2, AS350 B3, AS350 BA, AS350 BB, AS350 D, EC130 B4


L 13


EA300, EA300/L, EA300/S, EA300/200

FLS Aerospace Ltd

Club Sprint


RF 10, RF 3, RF 4


FA200-160, FA200-180, FA200-180AO


GY80-150, GY80-160, GY80-180

General Avia

F20, F22A, F22B, F22C, F22R


G109, G115, G120


AA-1, AA-1A, AA-1B, AA-1C, AA-5, AA-5A, AA-5B, AG-5B

HB Flugtechnik

HB 21, HB 21/2400, HB 21/2400 B, HB 23/2400, HB 23/2400SD, HB 23/2400 Scanliner, HB 23/2400 V2


M-4, M-4-210C, M-5-210C, M-5-235C, M-6-235, M-7-235, MX-7-180, MX-7-235, MXT-7-180,MX-7-180A, MXT-7-180A

M&D Flugzeugbau

AVO 68 Samburo


M20 Series


MS880, MS883, MS892, MS893, MS894 (Rallye)

Moravan (Zlin)

Z142, Z42, Z43, Z143, Z50, Z242, Z126, Z226, Z326, Z526, Z726




J3, PA-12, PA-18, PA-22, PA-24, PA-28, PA-32, PA-38-112

Individual subtype letters have been omitted for space reasons. All these Piper approvals cover the complete series.


M18, M26, M28, PZL-101, PZL-102, PZL-104 Wilga, PZL-106, PZL-Kruk, Koliber 110, 150


DR300, DR315, DR340, DR360, DR380, DR400, DR500, HR100 and HR200, R1180, R2100,R2100A, R2160D, R3000


R22, R44

Rockwell Commander

112, 112TC, 114, 114TC


SF 25SF 36

Siai Marchetti

260, 260B, 260C, 260D, 260E, 260F


T67A, T67B, T67C, T67M


TB9, TB10, TB20, TB21, TB200, Rallye 100, 110, 150


S 10






P2002JF, P2002JR


WA4, WA40, WA41

Come on board for exclusive email updates

Stay in the loop

At Trig Avionics we are passionate about aviation and aim to provide the best avionics for GA pilots. By providing us with your details below we can keep you up to date with product developments, industry information and Trig news.

Trig Avionics will not share your details with any other parties.

Country of Residence

What type of aircraft do you fly?

What category of aircraft is it?

What Trig products are you interested in?