Airworthiness Directives; Eurocopter France Model SA-365C, SA-365C1, SA-365C2, SA-365N, SA-365N1, AS-365N2, AS 365 N3, and SA-366G1 Helicopters

요약

We propose to adopt a new airworthiness directive (AD) for the specified Eurocopter France (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 states that the manufacturer has received some reports of deterioration and two reports of failure of Starflex star arm ends. These deteriorations generated high-amplitude vibrations in flight requiring precautionary landings. They state these deteriorations are due to the strong effect of temperature on the strength of the bush-to- Starflex star arm end attachment. Consequently, the MCAI AD requires modification of the frequency adapters and the frequency adapter bushes to improve the ventilation in the area on the star arm end. This proposed AD is intended to require modifying the main rotor frequency adapters to reduce the temperature in the area, to prevent failure of the star arm end, severe vibration, and subsequent loss of control of the helicopter.