Airworthiness Directive · Amendment 39-21451 · Engine bmep/torque indicating
Safran Helicopter Engines, S.A. (Type Certificate Previously Held by Turbomeca, S.A.) Turboshaft Engines
This AD applies to all Safran Helicopter Engines, S.A. (Type Certificate previously held by Turbomeca, S.A.) Arriel 2C, 2C1, 2S1, and 2S2 model turboshaft engines.
The FAA is adopting a new airworthiness directive (AD) for all Safran Helicopter Engines, S.A. Arriel 2C, 2C1, 2S1, and 2S2 model turboshaft engines. This AD was prompted by investigations by the manufacturer following level 1 failures in flight (minor anomalies) and level 2 failures on the ground (minor failures), where cracks were found on the soldered joints of torque conformation boxes. This AD requires performing initial and repetitive inspections of the resistance values of the torque conformation box and, depending on the results of the inspections, replacement of the torque conformation box. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For engines with the torque conformation box in pre-modification TU 34 configuration, installed on Arriel 2C and 2C1 model turboshaft engines; pre-modification TU 34 or post-modification TU 188 configuration, installed on Arriel 2S1 model turboshaft engines; or post-modification TU 188 configuration, installed on Arriel 2S2 model turboshaft engines:
(i) Within 600 engine hours (EHs) or 180 days after the effective date of this AD, whichever occurs first, perform an initial inspection of the resistance values of the torque conformation box.
Note 1 to paragraph (g)(1)(i): You may delay the initial inspection by up to 60 EHs to align with other scheduled maintenance tasks.
(ii) Thereafter, perform repetitive inspections of the resistance values of the torque conformation box before exceeding 600 EHs since the last inspection of the resistance values of the torque conformation box.
(2) Use the Accomplishment Instructions, paragraph 2.3.2 or 4.3.2, of Safran Helicopter Engines Mandatory Service Bulletin No. 292 72 2868, Version A, dated December 2018, to perform the inspections of the resistance values of the torque conformation box required by paragraph (g)(1) of this AD.
(3) If, during any inspection required by paragraph (g)(1) of this AD, a non-conforming resistance value is found, before further flight, remove the torque conformation box from service and replace it with a part eligible for installation.
For the purpose of this AD, a “part eligible for installation” is a zero hour torque conformation box or a torque conformation box that has been inspected as required by paragraph (g)(1) of this AD.
