73-19-02 BELL: Amdt. 39-1717. 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, P/N 47-641-057-9, remove and replace tail rotor yokes having S/N N29-1246 through N29-1266, N29-1298 through N29-1452, N29-10453 through N29-10488, and N29-10501 through N29-10525, 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.
The requirements of this AD do not affect other Model 47 series helicopter tail rotor yokes.
(Bell Helicopter Co. Service Bulletin No. 47-05-73-1 dated August 22, 1973 pertains to this subject.)
This amendment becomes effective to owners and operators on receipt of the mailed amendment and becomes effective to all other persons on September 14, 1973.