TT31 Transponder Installation Manual
8 May 2017
00455-00
Issue AQ
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Trig Avionics Limited
Page 5
3.3.1
Mode S Transponder Installation Approval
Installation of the TT31 as a replacement for an existing transponder is considered a Minor Change by
EASA and the FAA, and should be documented accordingly.
Note: With no GPS interface configured, the transponder does not enable any ADS-B
functions, and will behave as a conventional Mode S transponder.
3.3.2
ADS-B Installation Approval
At the time of publishing this manual, enabling the ADS-B Out feature is considered a major change
and will generally involve further approval.
For installers seeking US FAA STC approval, our STC partner is Peregrine in Denver who hold a range
of AML STCs for TT31 transponders. Contact them at -
peregrine.aero/contact.html
Installers seeking approvals for other parts of the world or for more information on our STC program,
should contact the Trig support team –
support@trig-avionics.com
For uncertified aircraft installations or for installers developing their own solution, this manual can be
used for guidance on the ADS-B installation. Further technical diagrams, schematics and instructions
are contained within the STC pack which can be obtained through Peregrine.
3.4 Non
– TSO Functions
The TT31 Mode S Transponder contains the following non-TSO functions:
•
Stopwatch and Flight Timer. The transponder provides a simple stopwatch and flight timer
function, displayed on the front panel.
•
Altitude Monitor. The Altitude Monitor activates an audio annunciator or annunciator light
(depending on installation) when the aircraft pressure altitude differs from the previously
selected altitude by more than 250 feet.
•
Altitude Repeater. This is a serial altitude output that can connect to a GPS or other device
needing serial altitude data – this allows the transponder to act as a repeater for the altitude
input instead of requiring a second altitude encoder.
The operation of each of these functions is described later in this manual.
The non-TSO functions defined in this section are not part of the TSO approval. The non-TSO function
data included in this section is approved under 14 CFR 21.305(d).