Summary
This document proposes adopting a new airworthiness directive (AD) for the specified Eurocopter France (Eurocopter) model helicopters. This proposal would require installing a tail rotor blade (blade)-to-torsion bar attachment bushing (bushing) with a tuning weight assembly on each blade of the Quiet Fenestron tail rotor, and replacing each blade attachment bushing. This proposal is prompted by a discovery of tail rotor induced vibration during flight tests. The actions specified by this proposed AD are intended to prevent vibrations in the tail rotor and the pilot's anti-torque pedals, blade pitch control failure, and subsequent loss of control of the helicopter.