Summary
This document proposes the supersedure of an existing airworthiness directive (AD) applicable to Eurocopter France Model SA- 365C, C1, C2, N, and N1; AS-365N2, and SA-366G1 helicopters. This proposal contains the same requirements as the existing AD but would add the Model AS-365N3 helicopter to the applicability. This proposal would require inspecting the tightening torque of the main rotor hub blade attach beam spherical thrust bearing bolts (bolts) and either applying a specified torque or, if necessary, inspecting for a crack in the metal components. This proposal would also require replacing the spherical thrust bearing (bearing) with an airworthy bearing if a crack is found. This proposal is prompted by reports of cracks in the metal components of the bearing attachment joint and the need to add the Eurocopter France Model AS 365 N3 helicopter to the applicability. 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.