Airworthiness Directives; Bell Helicopter Textron, Inc. Model 206A, 206B, 206A-1, 206B-1, 206L, and 206L-1 Helicopters

الملخص

This document proposes to revise an existing airworthiness directive (AD) for Bell Helicopter Textron, Inc. (BHTI) Model 206A, 206B, 206A-1, 206B-1, 206L, and 206L-1 helicopters that currently establishes a retirement life for the main rotor trunnion (trunnion) based on hours time-in-service (TIS). This action would retain those requirements but would revise the AD to remove the trunnion, part number (P/N) 206-011-120-103, from the applicability. This proposal is prompted by the issuance of another AD for the BHTI Model 206L and 206L-1 helicopters that requires a different method of calculating the retirement life for the trunnions. The actions specified by this AD are intended prevent failure of the trunnion due to fatigue cracks and subsequent loss of control of the helicopter.