TT31 Transponder Installation Manual
8 May 2017
00455-00
Issue AQ
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Trig Avionics Limited
Page 27
9. Continued Airworthiness
9.1 Maintenance
Other than for periodic functional checks required by the regulations, the TT31 Mode S transponder
has been designed and manufactured to allow “on condition maintenance”. This means that there are
no periodic service requirements necessary to maintain continued airworthiness, and no maintenance is
required until the equipment does not properly perform its intended function. When service is required,
a complete performance test should be accomplished following any repair action. Repairs should only
be carried out in accordance with Trig Avionics Limited service procedures.
9.2 ADS-B Installations
9.2.1
GPS Receiver Maintenance
If any maintenance is required on the connected GPS receiver, it is advisable to check with the GPS
manufacturer that you have the most recent and correct version of tests to carry out after maintenance.
Check that there are no additional requirements to be considered when using the GPS as part of an
ADS-B system.
There is no requirement to test the full ADS-B system following maintenance on the GPS receiver as
long as the post maintenance checks verify the output being used by the TT31.
9.2.2
GPS Receiver Design Changes
It should be noted that if the GPS receiver has been sent away for repair, it may have additional
upgrades or design changes applied to it when it returns. The installer must check with the
manufacturer that these upgrades or design changes do not adversely affect the compatibility with the
TT31.