Airworthiness Directives; Bell Helicopter Textron, Inc.-Manufactured Model OH-13E, OH-13H, and OH-13S Helicopters

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2000-18-52 which was sent previously to all known U.S. owners and operators of Bell Helicopter Textron, Inc. (BHTI)-manufactured Model OH-13E, OH-13H, and OH-13S helicopters by individual letters. This AD requires a liquid penetrant or eddy current inspection of the threads on each main rotor blade grip (grip) for a crack. The inspections must be accomplished within 100 hours time-in-service (TIS) since initial installation on any helicopter or within 10 hours TIS for grips with 100 or more hours TIS and thereafter at intervals not to exceed 200 hours TIS. This AD also establishes a retirement life of 1200 hours TIS for affected grips. This amendment is prompted by the results of an investigation of an August 1998 accident in which a grip failed on a BHTI Model 47G-2 helicopter due to a fatigue crack. The OH-13E, OH-13H, and OH-13S helicopters use the same grips as the Model 47G-2 helicopters. The actions specified by this AD are intended to prevent failure of a grip, loss of a main rotor blade, and subsequent loss of control of the helicopter.