Airworthiness Directives; Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2 and N3; and SA-366G1 Helicopters

This amendment supersedes an existing airworthiness directive (AD) that applies to Eurocopter France Model SA-365C, C1, C2, N, and N1; AS-365N2, and SA-366G1 helicopters. That AD currently requires 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. That AD also requires replacing the spherical thrust bearing (bearing) with an airworthy bearing if a crack is found. This amendment requires the same actions as the existing AD, but adds the Eurocopter France Model AS-365N3 helicopter to the applicability. This amendment 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-365N3 helicopter to the applicability. The actions specified by this 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.