Summary
We propose to adopt a new airworthiness directive (AD) for the specified ECF model 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 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.