Summary
This document proposes superseding an existing airworthiness directive (AD) for Eurocopter France (ECF) Model AS355N helicopters. The current 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 superseding AD would retain the current requirements, except would not require measuring the radial play but would 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 would require repairing or replacing the S-G, as necessary. This proposal is prompted by additional cases of S-G damage and the need for additional corrective actions. The actions specified by this proposed AD are intended toprevent 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.