Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron, Inc. (BHTI) Model 214ST helicopters. This proposal would require creation of a component history card using a Retirement Index Number (RIN) system; would establish a system for tracking increases to the accumulated RIN; and would establish a maximum accumulated RIN for the pillow block bearing bolts (bearing bolts). This proposal is prompted by fatigue analyses and tests that show certain bearing bolts fail sooner than originally anticipated because of the unanticipated high number of takeoffs and external load lifts utilizing high-power settings in addition to the time-in-service (TIS) accrued under other operating conditions. The actions specified by the proposed AD are intended to prevent fatigue failure of the bearing bolts, which could result in failure of the main rotor system and subsequent loss of control of the helicopter.