Airworthiness Directives Eurocopter France (ECF) Model SA-365N1, AS-365N2, AS 365 N3, EC 155B, and EC155B1 Helicopters

요약

We are adopting a new airworthiness directive (AD) for the specified ECF model helicopters. This AD results from a mandatory continuing airworthiness information (MCAI) AD issued by the aviation authority of the European Aviation Safety Agency (EASA). The MCAI AD reports the separation and loss of a stainless steel ring (75 millimeter (mm) in diameter) from a tail rotor blade (blade) sleeve resulting in severe, high-frequency vibrations, which can lead to damage to the fenestron blades, loss of yaw control, and subsequent loss of control of the helicopter.