Airworthiness Directive · Amendment 39-10129 · Bell Helicopter Textron, Inc. Model 214ST Helicopters
Bell Helicopter Textron, Inc. Model 214ST Helicopters
All Model 214ST helicopters with pillow block bearing bolts (bearing bolts), part number (P/N) 20-057-12-48D or - 50D, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD), applicable to Bell Helicopter Textron, Inc. (BHTI) Model 214ST helicopters, that requires creation of a component history card or equivalent record using a Retirement Index Number (RIN) system; establishes a system for tracking increases to the accumulated RIN; and establishes a maximum accumulated RIN for the pillow block bearing bolts (bearing bolts). 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 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 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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
