Airworthiness Directives; Westland Helicopters Ltd. 30 Series 100 and 100-60 Helicopters

요약

This amendment adopts a new airworthiness directive (AD) that is applicable to Westland Helicopters Ltd. (Westland) 30 Series 100 and 100-60 helicopters. This action requires the removal and replacement of conformal pinion quill shafts installed in certain main rotor gearboxes that fail to pass a magnetic drain plug inspection. This amendment is prompted by a report of a forced landing that occurred when a single conformal pinion quill shaft failed in a main rotor gearbox (MRGB). This condition, if not corrected, could result in the failure of a MRGB, and a subsequent forced landing or loss of control of the helicopter.