Summary
This document proposes the adoption of a new airworthiness directive (AD) applicable to Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2; and SA-366G1 helicopters. This proposal would require inspecting the tightening torque of the main rotor hub blade attach beam spherical thrust bearing bolts (bolts). The proposal would then require either applying the specified torque or, if necessary, conducting a dye penetrant inspection for cracks in the metal components. If a crack is found, the proposal would require replacing the spherical thrust bearing (bearing) with an airworthy bearing. This proposal is prompted by reports of cracks in the metal components of the bearing attachment joint. The actions specified by the proposed AD are intended to prevent loosening of bearing bolts in flight, which may cause cracks in the metal components, failure of the bearing, and subsequent loss of control of the helicopter.