Airworthiness Directive · Amendment 39-17973 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
Superseded. A later AD replaced this one: AD 2015-13-04. Comply with the one in force.
This AD applies to all Turbomeca S.A. Arriel 1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K1, 1S, 1S1, 2B, 2B1, 2C, 2C1, 2C2, 2S1, and 2S2 turboshaft engines.
We are adopting a new airworthiness directive (AD) for all Turbomeca S.A. Arriel 1A1, 1A2, 1B, 1C, 1C1, 1C2, 1D, 1D1, 1E2, 1K1, 1S, 1S1, 2B, 2B1, 2C, 2C1, 2C2, 2S1, and 2S2 turboshaft engines. This AD requires an initial one-time vibration check of the engine accessory gearbox (AGB) on certain higher risk Arriel 1 and Arriel 2 model engines. This AD also requires repetitive vibration checks of the engine AGB for all Arriel 1 and Arriel 2 engines at every engine shop visit. This AD was prompted by reports of uncommanded in-flight shutdowns on Turbomeca S.A. Arriel 1 and Arriel 2 engines following rupture of the 41-tooth gear forming part of the 41/23-tooth bevel gear located in the engine AGB. We are issuing this AD to prevent failure of the engine AGB, which could lead to in-flight shutdown and damage to the engine, which may result in damage to the aircraft.
Unless already done, do the following.
(1) For all Turbomeca S.A. Arriel 1B, 1D, 1D1, 2B, and 2B1 turboshaft engines, perform a one-time vibration check of the AGB 41/23-tooth bevel gear meshing within 32 months of the effective date of this AD, as follows:
(i) For all Turbomeca S.A. Arriel 1B, 1D, and 1D1 engines, except those engines with an AGB installed with a serial number (S/N) listed in Figure 1 of Turbomeca S.A. Mandatory Service Bulletin (MSB) No. 292 72 0839, Version B, dated November 25, 2013, use paragraphs 6.A. through 6.C. of Turbomeca S.A. MSB No. 292 72 0839, Version B, dated November 25, 2013, to perform the vibration check. Turbomeca S.A. MSB No. 292 72 0839 refers to Turbomeca S.A. Arriel 1 Technical Instruction (TI) No. 292 72 0839, Version E, dated February 20, 2014, and Turbomeca S.A. Arriel 1 TI No. 292 72 8, Version A, dated November 29, 2013, which you must also use to do the vibration check.
(ii) The reporting requirements in paragraphs 6.A.(1)(c), 6.A.(2)(b), and 6.B.(1)(c) and the requirement to return module M01 in paragraph 6.B.(2)(b) 2 of Turbomeca S.A. MSB No. 292 72 0839, Version B, dated November 25, 2013, are not required by this AD.
(iii) For all Turbomeca S.A. Arriel 2B and 2B1 engines, except those engines with an AGB installed with an S/N listed in Figure 1 of Turbomeca MSB No. 292 72 2849, Version B, dated November 25, 2013, use paragraphs 6.A. through 6.C. of Turbomeca S.A. MSB No. 292 72 2849, Version B, dated November 25, 2013, to perform the vibration check. Turbomeca S.A. MSB No. 292 72 2849 refers to Turbomeca S.A. Arriel 2 TI No. 292 72 2849, Version E, dated February 20, 2014, and Turbomeca S.A. Arriel 2 TI No. 292 72 2850, Version A, dated November 29, 2013, which you must also use to do the vibration check.
(iv) The reporting requirements in paragraphs 6.A.(1)(c), 6.A.(2)(b), and 6.B.(1)(c), and the requirement to return module M01 in paragraph 6.B.(2)(b) 2 of Turbomeca S.A. MSB No. 292 72 2849, Version B, dated November 25, 2013, are not required by this AD.
(2) For all affected Turbomeca S.A. engines, during each engine shop visit after the effective date of this AD, perform a vibration check of the AGB 41/23-tooth bevel gear meshing. Guidance on performing the vibration check during an engine shop visit can be found in the service information listed in paragraph (i)(3) in the Related Information section.
(3) If the AGB does not pass the vibration check required by paragraphs (e)(1) or (e)(2) of this AD, replace the AGB with a part eligible for installation.
If you performed a vibration check of the AGB before the effective date of this AD using Turbomeca S.A. MSB No. 292 72 0839, Version A, dated September 9, 2013; or MSB No. 292 72 2849, Version A, dated September 9, 2013, or during an engine shop visit per paragraph (e)(2) of this AD, you met the initial inspection requirement of paragraph (e)(1) of this AD.
For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges. The separation of engine flanges solely for the purpose of transportation without subsequent engine maintenance does not constitute an engine shop visit.
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.
