Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede Airworthiness Directive (AD) 2012-10- 53 for Eurocopter Deutschland GmbH (ECD) Model EC135P1, EC135P2, EC135P2+, EC135T1, EC135T2, and EC135T2+ helicopters. AD 2012-10-53 currently requires, before further flight and at specified intervals, checking and inspecting the upper and lower main rotor hub (MRH) shaft flanges for a crack, and inspecting the lower hub-shaft flange bolt attachment areas for a crack. Since we issued AD 2012-10-53, it has been determined that it is safe to increase the visual inspection intervals of the MRH shaft flanges from 10 hours time-in-service (TIS) to 50 hours TIS and remove the inspection of the lower MRH shaft flange bolt attachment areas. This proposed AD would continue to require checking and inspecting the upper and lower MRH shaft flanges for a crack. The proposed actions are intended to detect a crack on the MRH shaft flange, which if not corrected, could result in failure of the MRH and subsequent loss of control of the helicopter.