Airworthiness Directive · Amendment 39-17866 · Turbomeca S.A. Turboshaft Engines
Turbomeca S.A. Turboshaft Engines
This AD applies to all Turbomeca S.A. Arriel 2B, 2B1, 2C, 2C1, 2C2, 2S1, and 2S2 turboshaft engines.
We are superseding airworthiness directive (AD) 2007-10-07 for all Turbomeca S.A. Arriel 2B, 2B1, and 2B1A turboshaft engines. AD 2007-10-07 required an inspection of the splines of the coupling assembly and the hydro-mechanical metering unit (HMU) drive gear shaft for wear. This AD requires the same inspection and expands the affected population. This AD also removes Arriel 2B1A engines from the applicability. We are issuing this AD to prevent failure of the HMU drive gear shaft, which could lead to damage to the engine and damage to the airplane.
(i) If on the effective date of this AD the HMU has 500 or more operating hours since new or since last overhaul, then within 25 HMU operating hours from the effective date of this AD, inspect the high-pressure (HP) pump drive gear shaft splines and coupling shaft assembly splines. Use paragraph 2.B.(1)(b) of Turbomeca S.A. Mandatory Service Bulletin (MSB) No. 292 73 2812, Version G, dated June 24, 2013, to do your inspection.
(ii) If on the effective date of this AD the HMU has less than 500 operating hours since new or since last overhaul, then inspect the HP pump drive gear shaft splines and coupling shaft assembly splines between 500 and 525 operating hours since new or since last overhaul. Use paragraph 2.B.(1)(b) of Turbomeca S.A. MSB No. 292 73 2812, Version G, dated June 24, 2013, to do your inspection.
(i) If on the effective date of this AD the HMU has 500 or more operating hours since new, since last overhaul, or if HMU operating hours are unknown, then within 200 HMU operating hours from the effective date of this AD, inspect the HP pump drive gear shaft splines and coupling shaft assembly splines. Use paragraph 2.B.(1)(b) of Turbomeca S.A. MSB No. 292 73 2822, Version F, dated June 21, 2013, to do your inspection.
(ii) If on the effective date of this AD the HMU has more than 300 but less than 500 operating hours since new or since last overhaul, then within 225 HMU operating hours, but no earlier than 500 or later than 700 HMU operating hours from the effective date of this AD, inspect the HP pump drive gear shaft splines and coupling shaft assembly splines. Use paragraph 2.B.(1)(b) of Turbomeca S.A. MSB No. 292 73 2822 Version F, dated June 21, 2013, to do your inspection.
(iii) If on the effective date of this AD the HMU has 300 operating hours or less since new or since last overhaul, then inspect the HP pump drive gear shaft splines and coupling shaft assembly splines between 500 and 525 HMU operating hours since new or since last overhaul. Use paragraph 2.B.(1)(b) of Turbomeca S.A. MSB No. 292 73 2822, Version F, dated June 21, 2013, to do your inspection.
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.
