Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to Eurocopter France Model AS- 350B, BA, B1, B2, and D, and Model AS-355E, F, F1, F2, and N helicopters, that currently 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 action would require the same inspections as the existing AD but would add the time intervals for performing repetitive dye-penetrant inspections on cross- beams with 5,000 or more hours time-in-service (TIS). This proposal 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 the proposed AD are intended to prevent failure of the cross-beam that could cause the main gearbox to pivot resulting in severe vibrations and a subsequent forced landing.