76-12-02 BELL: Amendment 39-2638. Applies to Bell Models 47B, 47B-3, 47D, 47D-1, 47E, 47G, 47G-2, and 47H-1 helicopters certificated in all categories.
Compliance required as indicated.
To prevent possible fatigue failure of the tail rotor yoke, Part Number 47-641-057-9, remove and replace tail rotor yokes having Serial Numbers SR29-50501 through SR29-50507, SR-29-50509 through SR29-50528, SR29-50530 through SR29-50533, SR29-50535 through SR29-50537, SR29-50539 through SR29-50544, and SR29-50546 through SR29-50554, as specified below.
(a) Replace those yokes with 390 or more hours' total time in service on the effective date of this AD, within 10 hours' time in service.
(b) Replace those yokes with less than 390 hours' total time in service on the effective date of this AD, prior to accumulating 400 hours' total time in service.
(c) Compliance with Bell Helicopter Company Service Bulletin Number 47-05-73-1, Revision A, dated November 18, 1975, fulfills compliance with this AD.
(d) The requirements of this AD do not affect other Model 47 series helicopter tail rotor yokes.
This amendment becomes effective July 14, 1976.