Action
Final rule.
Summary
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.