Airworthiness Directives; Airbus Helicopters (Previously Eurocopter France) Helicopters

摘要

We are superseding Airworthiness Directive (AD) 2007-25-08 for Eurocopter France (now Airbus Helicopters) Model SA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters. AD 2007-25-08 required checking the tail rotor gearbox (TGB) oil, inspecting the magnetic plug, and either replacing the TGB or performing additional inspections. This AD was prompted by reports of new occurrences of loss of yaw control due to failure of the control rod bearing. This AD requires checking the TGB oil level and replacing the bearing with a new part-numbered bearing. These actions are intended to detect and prevent damage to the bearing resulting in end play, loss of tail rotor pitch control, and subsequent loss of control of the helicopter.