Airworthiness Directives; Eurocopter France Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, and AS355N Helicopters

摘要

This document proposes the supersedure of an existing airworthiness directive (AD) for Societe Nationale Industrielle Aerospatiale (currently Eurocopter France) Model AS350 and AS355 series helicopters. That AD requires inspecting the fuselage frame (frame) for a crack at the fuselage-to-tailboom interface and replacing or repairing, as necessary. That AD also requires a fastener torque check and retorquing, as necessary. This action would retain the requirements of the existing AD but would increase the inspection interval from 1,200 hours time-in-service (TIS) to 2,500 hours or 6 years TIS, whichever occurs first. This proposal would revise the time interval for inspecting the frame at the fuselage-to-tailboom interface to coincide with the inspection interval specified in the maintenance manual. The actions specified by the proposed AD are intended to eliminate confusion and unnecessary costs and to prevent a cracked frame, tailboom failure, and subsequent loss of control of the helicopter.