AD 97-16-02 62 FR 41260

This amendment adopts a new airworthiness directive (AD) that is applicable to Robinson Helicopter Company (Robinson) Model R44 helicopters. This action requires inspections of the belt tension actuator switches (up-limit switches) for proper operation, and replacement if necessary; and replacement of a certain part-numbered clutch assembly. This amendment is prompted by six occurrences of prematurely worn sprag clutches. The actions specified in this AD are intended to prevent failure of the sprag clutch to lock in the driving direction, which would result in loss of power to the main rotor system and a subsequent forced landing; or failure of the sprag clutch to unlock in the overrunning direction, which, if combined with engine failure, would result in an inability to autorotate and a subsequent loss of control of the helicopter.