Airworthiness Directive · Amendment 39-18406 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
Superseded. A later AD replaced this one: AD 2016-25-13. Comply with the one in force.
This AD applies to Turbomeca S.A. Arriel 2B, 2B1, 2C, 2C1, 2C2, 2D, 2E, 2S1, and 2S2 turboshaft engines with an engine accessory gearbox (AGB), part number (P/N) 0292120650, with a machined front casing.
We are adopting a new airworthiness directive (AD) for certain Turbomeca S.A. Arriel 2B, 2B1, 2C, 2C1, 2C2, 2D, 2E, 2S1, and 2S2 turboshaft engines. This AD requires inspection, and, depending on the results, removal of the engine accessory gearbox (AGB). This AD was prompted by a report of an uncommanded in-flight shutdown (IFSD) of an Arriel 2 engine caused by rupture of the 41-tooth gear, which forms part of the bevel gear in the engine AGB. We are issuing this AD to prevent failure of the engine AGB, which could lead to in-flight shutdown, damage to the engine, and damage to the aircraft.
(i) Perform an initial SOA within the compliance times given in paragraph (e)(1)(i)(A) or (e)(1)(i)(B) of this AD:
(A) If the engine AGB has less than 800 engine hours (EHs) since new or since last overhaul, do an initial SOA before exceeding 850 EHs since new or since last overhaul.
(B) If the engine AGB has 800 EHs or more since new or since last overhaul, or if the EHs are unknown, do an initial SOA within 50 EHs after the effective date of this AD.
(C) Use paragraphs 2.4.2.1 and 2.4.2.2 of Turbomeca S.A. Mandatory Service Bulletin (MSB) No. 292 72 2861, Version A, dated April 24, 2015, to perform the SOA required by paragraph (e) of this AD.
(ii) Reserved.
(i) If the aluminum concentration determined from the most recent SOA is less than 0.8 parts per million (PPM), repeat the SOA required by paragraph (e) of this AD within 100 EHs time since last analysis (TSLA).
(ii) If the aluminum concentration determined from the most recent SOA is between 0.8 PPM and 1.4 PPM, inclusive, repeat the SOA required by paragraph (e) of this AD within 50 EHs TSLA. Do not perform draining before doing the next SOA.
(iii) If the aluminum concentration determined from the most recent SOA is greater than 1.4 PPM, remove the engine AGB from service within 50 EHs TSLA.
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.
