TT31 Minor Change Library

The TT31 is designed to be a "plug-and-play" upgrade from the popular KT76A, KT76C and KT78A transponders. We have developed a set of universal upgrade instructions that document the process of changing from a KT76A or other existing transponder to a TT31 in a wide range of light aircraft, and we have obtained EASA approval for these instructions. Trig installers can use these instructions to achieve airworthiness compliance without needing to seek further approval from EASA.

There is NO CHARGE for these Minor Change Approvals.

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 set of minor changes has grown, and as we have responded to questions from our installers, we have made improvements to these master instructions. The accomplishment instructions and compliance information in the latest revision are still applicable to all the Minor Changes listed below, and 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: Issue 1.4, Issue 1.5.

Minor Change Approval Sheets

Each approved aircraft type has a corresponding approval certificate available for download here. Note that some of these 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.

Finally, for space reasons, both the EASA approval sheets and this web page have abbreviated some sub-type information where a series approval applies. The following master documents are the actual lists approved by EASA 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 on 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.

Alenia Aermacchi

F260, S205, SF260TP

Alpha

HR200, R2100, R2112, R2120, R2160

American Champion

8KCAB

AMS

Carat A

Apex Aircraft

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

Aquila

AT01

Aviat

A-1A, A-1B, Pup

Beagle

B121 Pup

Beechcraft

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

Bölkow

BO208, BO209

Cessna

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.