Airworthiness Directive · Amendment 39-18739 · Safran Helicopter Engines, S.A. (Formerly Turbomeca S.A.) Turboshaft Engines
Safran Helicopter Engines, S.A. (Formerly Turbomeca S.A.) Turboshaft Engines
This AD applies to Safran Helicopter Engines, S.A. Arriel 2B, 2B1, 2C, 2C1, 2C2, 2D, 2E, 2S1, and 2S2 turboshaft engines with an engine accessory gearbox (AGB), part number 0292120650, with a machined front casing.
We are superseding airworthiness directive (AD) 2016-04-12, that applies to certain Safran Helicopter Engines, S.A. (formerly Turbomeca S.A.) Arriel 2B, 2B1, 2C, 2C1, 2C2, 2D, 2E, 2S1, and 2S2 turboshaft engines. AD 2016-04-12 required spectrometric oil analysis (SOA) inspection of the engine accessory gearbox (AGB), and, depending on the results, removal of the engine AGB. This AD requires initial and repetitive wear inspections of the engine AGB cover. This AD was prompted by a report of an uncommanded in-flight shutdown (IFSD) of an Arriel 2S2 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 correct the unsafe condition on these products.
(1) Initial Wear Inspection
(i) For all affected engines, perform a wear inspection of the engine AGB cover before the engine AGB, module M01, exceeds 850 engine hours (EH) since new or since last overhaul (SLO), or within 50 EHs after April 14, 2016, or before the next flight after the effective date of this AD, whichever occurs latest.
(ii) Reserved.
(2) Repetitive Wear Inspection Intervals
(i) For Arriel 2E engines, repeat the engine AGB cover wear inspection within every 800 EH since last inspection (SLI).
(ii) For all affected engines, except for Arriel 2E engines, repeat the engine AGB cover wear inspection within every 600 EH SLI.
(3) Inspection Criteria
(i) Use paragraph 2.4.2 of Safran Helicopter Engines, S.A. Mandatory Service Bulletin (MSB) No. 292 72 2861, Version D, dated September 23, 2016, to do the inspections required by paragraphs (e)(1) and (e)(2) of this AD.
(ii) Reserved.
(4) Corrective Actions Based on the Results of the Most Recent Wear Inspection
(i) If the wear measured from the most recent wear inspection is 0.15 mm or less, no further action is required. However, you must still comply with the repetitive inspection requirements of paragraph (e)(2) of this AD.
(ii) If the most recent wear inspection was performed while the engine was in service, and the wear is greater than 0.15 mm, do the following:
(A) If the wear measured from the most recent wear inspection is greater than 0.15 mm, but 0.30 mm or less, remove the engine AGB from service within 200 EH SLI and replace with a part eligible for installation.
(B) If the wear measured from the most recent wear inspection is greater than 0.30 mm, but 0.40 mm or less, remove the engine AGB from service within 25 EH SLI and replace with a part eligible for installation.
(C) If the wear measured from the most recent wear inspection is greater than 0.40 mm, remove the engine AGB from service before further flight and replace with a part eligible for installation.
(iii) If the most recent wear inspection was performed on the engine during an engine shop visit, and the wear is greater than 0.15 mm, remove the engine AGB before further flight and replace with a part eligible for installation.
If you have previously performed a wear inspection of the engine AGB cover prior to the effective date of this AD in accordance with the instructions given in Turbomeca MSB No. 292 72 2861, Version C, dated March 9, 2016, or Turbomeca MSB No. 292 72 2861, Version B, dated February 2, 2016, then you may take credit for that wear inspection as the “most recent” wear inspection for the purposes of paragraph (e)(4) of this AD.
For the purpose of this AD, an engine shop visit is defined as the induction of an engine into the shop for maintenance involving the separation of any major mating engine flanges, except that the separation of engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit.
