Summary
We propose to adopt a new airworthiness directive (AD) for Eurocopter France (Eurocopter) Model AS355E, AS355F, AS355F1, AS355F2, and AS355N helicopters. This proposed 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 a metallurgical non-conformity was discovered on a flange of the forward shaft section of the tail rotor drive shaft (drive shaft). The MCAI AD also states that stress analysis has shown that this non-conformity can significantly reduce the strength of the drive shaft and thereby its service life. The proposed actions are intended to remove non- conforming drive shafts from service and prevent failure of the drive shaft and subsequent loss of control of the helicopter.