Airworthiness Directives; Eurocopter France Model AS355N Helicopters

This amendment supersedes an existing airworthiness directive (AD) for the specified Eurocopter France (ECF) helicopters. The existing AD requires visually inspecting the four engine exhaust pipe ejector (ejector) attachment lugs (lugs), the starter-generator (S-G) attachment flange (flange) and attachment half-clamps (half-clamps) for cracks, and the S-G shaft for radial play. This amendment will retain the current requirements except will not require measuring the radial play. This amendment will also require measuring each S-G engine clamp torque and vibration level and recording the S-G vibration level on a component history card or equivalent record. If the S-G vibration level is equal to or higher than 0.5 inches per second (IPS), this superseding AD requires repairing or replacing the S-G, as necessary. This amendment is prompted by additional cases of S-G damage and the need for additional corrective actions. The actions specified by this AD are intended to prevent excessive S-G vibration, which could lead to separation of an ejector, impact with the main or tail rotor, and subsequent loss of control of the helicopter.