Airworthiness Directive · Amendment 39-19676 · Atc transponder system
Trig Avionics Limited Transponders
This AD applies to:
(1) Trig Avionics Limited TT31 Mode S transponders, part number (P/N) 00220-00-01 and P/N 00225-00-01, with a serial number (S/N) from 05767 to S/N 09715 inclusive, and Modification (Mod) Level 6 or below, installed.
(2) Avidyne Corporation AXP340 Mode S transponders, P/N 200-00247-0000, also marked with Trig Avionics P/N 01155-00-01, with a S/N from 00801 to S/N 01377 inclusive, and Mod Level 0, installed.
(3) BendixKing/Honeywell International KT74 Mode S transponders, P/N 89000007-002001, also marked with Trig Avionics P/N 01157-00-01, with a S/N from 01143 to S/N 02955 inclusive, and Mod Level 0, installed.
The FAA is adopting a new airworthiness directive (AD) for certain Trig Avionics Limited TT31, Avidyne Corporation AXP340, and BendixKing/Honeywell International KT74 Mode S transponders. This AD was prompted by the discovery that the retaining cam that engages in the mounting tray may not withstand g-forces experienced during an emergency landing. This AD requires one-time inspection of the transponder installation and, depending on the findings, removal of the affected transponder for modification. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 90 days after the effective date of this AD, inspect the transponder installation to determine if the transponder is installed in a conventional aft-facing avionics rack.
(2) If the transponder is installed in a conventional aft-facing avionics rack, no further action is required.
(3) If the transponder is not installed in a conventional aft-facing avionics rack, remove the transponder before further flight.
(4) Use the Accomplishment Instructions, paragraphs 4-8, to determine if the part is eligible for repair and re-installation, for the appropriate transponder, per Trig Avionics Limited Service Bulletin (SB) SUP/TT31/027, Issue 1.0, dated October 1, 2018; Trig Avionics Limited SB SUP/AXP340/002, Issue 1.0, dated October 1, 2018; or Trig Avionics Limited SB SUP/KT74/005, Issue 1.0, dated October 1, 2018.
After the effective date of this AD, do not install an affected transponder on any aircraft, unless the transponder is installed in a conventional aft-facing avionics rack as defined in this AD.
No reporting requirement contained within the SBs referenced in paragraph (g)(4) of this AD is required by this AD.
For the purpose of this AD, a conventional aft-facing avionics rack is defined as an installation with the control panel oriented in opposition to the direction of flight (aft facing).
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
