Airworthiness Directives; Eurocopter France Model AS-350B, BA, B1, B2, and D, and Model AS-355E, F, F1, F2, and N Helicopters

This amendment supersedes an existing airworthiness directive (AD) that applies to Eurocopter France Model AS-350B, BA, B1, B2, and D, and Model AS-355E, F, F1, F2, and N helicopters and requires inspecting the main gearbox suspension bi-directional cross-beam (cross-beam) for cracks, and replacing the cross-beam if a crack is found. This amendment requires the same inspections as the existing AD, but adds the time intervals for performing repetitive dye-penetrant inspections on cross-beams with 5,000 or more hours time-in-service (TIS). This amendment is prompted by the discovery that time intervals for performing the required dye-penetrant inspections are not included in the existing AD. The actions specified by this AD are intended to prevent failure of the cross-beam that could lead to rotation of the main gearbox, resulting in severe vibrations and a subsequent forced landing.