81-19-01: Main Rotor Yoke

81-19-01 BELL HELICOPTER TEXTRON (BHT): Amendment 39-4207. Applies to Model 212 series helicopters certificated in all categories (Airworthiness Docket No. 81-ASW- 38). To prevent possible failure of main rotor yoke Part Number 204-011-102 (all dash numbers), accomplish the following: a. Unless Bell Helicopter Textron Alert Service Bulletin No. 212-81-23 has been previously complied with, within 10 days after the effective date of this Airworthiness Directive: (1) Create a component history card for yoke Part Number 204-011-102 (all dash numbers). (2) Record the operating time accumulated on the yoke as follows: a. For each flight hour of passenger or internal cargo operation, enter 1 hour on the component history card. b. For each flight hour involving external load operations where more than four lifts per hour occur, including those conducted under Federal Aviation Regulation Parts 133 and 137, enter 5 hours on the component history card.c. If operating time for the yoke is unknown, enter 2,400 hours on the component history card. (3) Yokes with more than 3,300 hours time on the compliance date of this AD must be retired prior to obtaining an additional 300 hours time. (4) Yokes with less than 3,300 hours time on the compliance date of this AD must be retired on or before attaining 3,600 recorded hours. b. The 3,600-hour life and the above method of recording flight hours on the yoke component history card shall continue in effect on all Part Number 204-011-102 yokes. c. Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, Federal Aviation Administration. d. In accordance with FAR 21.197 flight is permitted to a base where the requirements of this AD may be accomplished. This amendment becomes effective September 30, 1981.