Airworthiness Directives; McDonnell Douglas Helicopter Systems and Hughes Helicopters, Inc. Model 369D, E, F, and FF Series Helicopters

Abstract

This amendment adopts a new airworthiness directive (AD) that is applicable to McDonnell Douglas Helicopter Systems and Hughes Helicopters, Inc. Model 369D, E, F, and FF series helicopters. This action requires an initial inspection of the pitch control assembly lockwasher (lockwasher) for dents at the inner tang inside radius, application of a torque stripe on the tail rotor swashplate and locknut, and repetitive inspections of the torque stripe to detect any locknut slippage. This amendment is prompted by a report that a lockwasher failed in service and allowed a locknut to loosen. The actions specified in this AD are intended to prevent failure of the inner tang of the lockwasher, loss of the locknut, disengagement of the pitch control assembly, loss of tail rotor control, and subsequent loss of control of the helicopter.