Airworthiness Directive · Amendment 39-17195 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
This AD applies to Turbomeca S.A. Arriel 2B, 2B1, 2S2, and 2C2 turboshaft engines not modified by TU166 modification.
We are superseding an existing airworthiness directive (AD) for certain Turbomeca S.A. Arriel 2B and 2B1 turboshaft engines. That AD currently requires accomplishment of the TU166 modification. This new AD requires adding the Arriel 2S2 and 2C2 engines to the applicability of engines requiring the TU166 modification with different compliance times. This AD was prompted by reports of an accident involving a twin-engine helicopter powered by two Arriel 2S2 engines. We are issuing this AD to prevent rupture of a gas generator (GG) turbine blade, which could result in an uncommanded in-flight shutdown and a forced landing or accident.
(1) For Arriel 2B and 2B1 turboshaft engines, accomplish the TU166 modification in accordance with the instructions specified within Turbomeca Alert Mandatory Service Bulletin (MSB) No. A292 72 3166 Version B, dated September 20, 2010, when the GG Turbine is replaced or when the engine or Module M03 is going through overhaul or repair, or within 676 cycles-in-service (CIS) after the effective date of this AD, whichever occurs first.
(2) For Arriel 2S2 turboshaft engines, accomplish the TU166 modification in accordance with the instructions specified within Turbomeca Alert MSB No. A292 72 4166 Version A, dated March 23, 2012, when the GG Turbine is replaced or when the engine or Module M03 is going through overhaul or repair, or within 500 CIS after the effective date of this AD, whichever occurs first.
(3) For Arriel 2C2 turboshaft engines, accomplish the TU166 modification in accordance with the instructions specified within Turbomeca Alert MSB No. A292 72 5166 Version A, dated June 18, 2012, when the GG Turbine is replaced or when the engine or Module M03 is going through overhaul or repair or within 650 engine hours after the effective date of this AD, whichever occurs first.
(1) For Arriel 2B and 2B1 turboshaft engines, if you performed the TU166 modification before the effective date of this AD using Turbomeca Alert MSB No. A292 72 3166 Version A, dated August 17, 2010, you met the requirements of paragraph (e)(1) of this AD.
(2) For Arriel 2C2 and 2S2 turboshaft engines, if you performed the TU166 modification before the effective date of this AD using Turbomeca Alert MSB No. A292 72 2166 Version A, dated March 30, 2009, Version B, dated September 4, 2009, Version C, dated June 15, 2010, Version D, dated July 28, 2010, Version E, dated October 4, 2010, Version F, dated May 13, 2011, or Version G, dated March 26, 2012, you met the requirements of paragraph (e)(2) or (e)(3) as applicable, of this AD.
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.
