76-12-01 BELL: Amendment 39-2636. Applies to Bell Models 47B, 47B-3, 47D, 47D-1, 47G, 47G-2, and 47H-1 helicopters certificated in all categories.
Compliance required within 300 hours' time in service after the effective date of this AD unless already accomplished.
To prevent possible fatigue failure of tail rotor hub bolt, Part Numbers 47-641-052-3 or - 5, accomplish the following:
(a) Remove and disassemble the tail rotor hub and blade assembly.
(b) Remove the metal grease seal from each tail rotor blade grip and install the seal, Part Number 47-641-042-3, in each blade grip to clear the head of the hub bolt.
(c) Remove the hub assembly bolts, Part Numbers 47-641-052-3 or -5, from the tail rotor hub assembly. Install hub bolts, Part Number 47-641-194-1, in the tail rotor hub as specified in paragraph 6-16.e., Section IV, Models 47D-1, 47G, and 47G-2 Maintenance and Overhaul Instruction Manual, as revised August 15, 1961, or as specified by equivalent FAAapproved procedures.
(d) Assemble and track and balance the tail rotor hub and blade assembly as specified in the pertinent Model Maintenance and Overhaul Instruction Manual or as specified in FAA approved equivalent procedures.
(e) Compliance with Bell Helicopter Company Service Bulletin No. 47-76-1 dated January 5, 1976, or later approved revision fulfills compliance with this AD.
This amendment becomes effective July 14, 1976.