Airworthiness Directives; Eurocopter France (Eurocopter) Model AS350B, BA, B1, B2, B3, D, AS355E, F, F1, F2, and N Helicopters

概要

We are adopting a new airworthiness directive (AD) for the specified Eurocopter model helicopters. This AD results from a mandatory continuing airworthiness information (MCAI) AD issued by the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community. The MCAI AD states that the AD is issued following a report of a crack discovered in the area of the center cross-member at station X 2325, at the attachment point of the yaw channel ball-type control sheath stop, of a Model AS355N helicopter fitted with the collective-to-yaw control coupling. Investigations revealed that the helicopter did not have the structural doublers, which are combined with the collective-to-yaw control coupling installation. Repetitive loads on the non-modified cross- member may cause it to crack. A crack can reduce the yaw control travel. This AD requires actions that are intended to prevent reduced yaw control and subsequent loss of control of the helicopter.