Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 369 (YOH-6A), 369A (OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, and 500N Helicopters

This amendment supersedes an existing airworthiness directive (AD), applicable to McDonnell Douglas Helicopter Systems (MDHS) Model 369 (YOH-6A), 369A (OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, and 369HS helicopters, that currently requires replacing overrunning clutch outer races (outer races) having certain heat treatment numbers. This amendment requires replacing all outer races with airworthy outer races, regardless of the heat treatment number, and is applicable to a particular model helicopter that was not included in the existing AD (Model 500N helicopters). This amendment is prompted by several reports of failed clutch races having heat treatment numbers other than the ones addressed in the earlier AD. The actions specified by this AD are intended to prevent failure of the overrunning clutch assembly outer race, which could result in loss of engine drive to the rotor system and a subsequent forced landing.