AD 2020-16-09 Airworthiness Directives; Airbus Helicopters (Type Certificate Previously Held by Eurocopter France) Helicopters

This AD replaces AD 2009-25-09, Amendment 39-16128 (74 FR 66045, December 14, 2009).

(1) For MGB input flexible coupling flange assemblies with less than 50 hours time-in-service (TIS) since new or since a complete overhaul of the MGB, re-adjust the tightening torque load of the 6 nuts on the flexible coupling-to-flange attachment bolts. Accomplish this re-adjustment between 50 hours TIS and 75 hours TIS since new or since a complete overhaul of the MGB in accordance with paragraph 2.B.2.a. of Eurocopter Emergency Alert Service Bulletin No. 05.95, dated March 3, 2008 (EASB 05.95) or Airbus Helicopters Emergency Alert Service Bulletin No. 05.95, Revision 1, dated October 22, 2015 (EASB 05.95 Rev 1). (2) For MGB input flexible coupling flange assemblies with 50 hours TIS and 75 or less hours TIS since new or since a complete overhaul of the MGB, either: (i) Upon or before reaching 75 hours TIS since new or since a complete overhaul of the MGB, re-adjust the tightening torque load of the 6 nuts on the flexible coupling-to-flange attachment bolts in accordance with paragraph 2.B.2.a. of EASB 05.95 or EASB 05.95 Rev 1; or (ii) Upon or before reaching 125 hours TIS since new or since a complete overhaul of the MGB, inspect the tightening torque load of the 6 nuts on the flexible coupling-to-flange attachment bolts in accordance with paragraph 2.B.2.b. of EASB 05.95 or EASB 05.95 Rev 1, except you are not required to contact the manufacturer. (3) For MGB input flexible coupling flange assemblies that have more than 75 hours TIS since new or since a complete overhaul of the MGB, within the next 50 hours TIS, inspect the tightening torque load of the 6 nuts on the flexible coupling-to-flange attachment bolts, in accordance with paragraph 2.B.2.b. of EASB 05.95 Rev 1, except you are not required to contact the manufacturer. (4) Prior to installing an MGB that contains an input flexible coupling flange assembly that has been modified per MOD 0752416 and MOD 0752419, you must comply with the provisions of this AD.

(1) The Manager, Rotorcraft Standards Branch, FAA, may approve AMOCs for this AD. Send your proposal to: James Blyn, Aviation Safety Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-5110; email 9-ASW-FTW-AMOC-Requests@faa.gov. (2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part 91, subpart K, the FAA suggests that you notify your principal inspector, or lacking a principal inspector, the manager of the local flight standards district office or certificate holding district office before operating any aircraft complying with this AD through an AMOC.

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.

This AD defines the unsafe condition as progressive fatigue failure of the coupling discs, caused by excessive fretting on the faces and in the bolt holes of the coupling discs. This condition, if not corrected, could result in loss of the MGB input, loss of the drive transmission, and subsequent loss of control of the helicopter.