Airworthiness Directive · Amendment 39-21164 · Attitude and direction data system
Airbus Helicopters
This AD applies to Airbus Helicopters Model EC 155B and EC155B1 helicopters, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for Airbus Helicopters Model EC 155B and EC155B1 helicopters. This AD requires modifying the wiring of the attitude and heading reference system (AHRS) connector. This AD was prompted by a report of wiring of the AHRS contrary to approved design specifications. The actions of this AD are intended to address an unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Before further flight in IMC or within 660 hours time-in-service, whichever occurs first:
(1) For helicopters with wiring change modification (MOD) 0722B51 installed, modify the wiring of connector 11 ALPHA as depicted in Figure 1 of Airbus Helicopters Alert Service Bulletin (ASB) No. EC155-34A033, Revision 2, dated January 30, 2018 (ASB EC155-34A033). If a combined voice and flight data recording system (MOD 0731B89) is installed, also modify the wiring to connector 11 ALPHA as depicted in Figure 2 of ASB EC155-34A033.
(2) For helicopters without wiring change MOD 0722B51 installed, modify the wiring of connector 11 ALPHA as depicted in Figure 1 and Figure 2 of Airbus Helicopters ASB No. EC155-34A037, Revision 0, dated February 19, 2018.
