Airworthiness Directives; Bell Helicopter Textron, Inc. Model 214B and 214B-1 Helicopters

This amendment adopts a new airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI) Model 214B and 214B- 1 helicopters, that requires creation of a component history card or an equivalent record using the Retirement Index Number (RIN) system, establishing a system for tracking increases to the accumulated RIN, and establishing a maximum accumulated RIN for the pillow block bearing bolts (bearing bolts) of 17,000 before they must be removed from service. This amendment is prompted by fatigue analyses and tests that show certain bearing bolts fail sooner than originally anticipated because of the unanticipated high number of lifts and takeoffs (torque events) performed with those bearing bolts in addition to the time-in- service (TIS) accrued under other operating conditions. The actions specified by this 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.