Summary
This document proposes the supersedure of an existing airworthiness directive (AD) that applies to Eurocopter France Model AS-350B, BA, B1, B2, C, D, and D1, and AS-355E, F, F1, and F2 helicopters. That AD currently requires inspections of the main rotor head components, the main gearbox (MGB) suspension bars, and the ground resonance prevention system components. This action would require those same inspections, but would also apply to Model AS-350B3 and AS-355N helicopters. This proposal is prompted by the inadvertent omission of those model helicopters from the previous AD. The actions specified by the proposed AD are intended to prevent ground resonance due to reduced structural stiffness, which could lead to failure of a main rotor head or MGB suspension component and subsequent loss of control of the helicopter.