70-08-02 BELL: Amendment 39-968 as amended by Amendment 39-1137 Applies to all Bell Model 47 Series Helicopters and all other helicopters incorporating any of the following tail rotor drive shaft assemblies:
47-644-172-3
47-644-180-1
47-644-186-1
47-644-180-5
47-644-187-5
47-644-214-1
47-644-187-11
Compliance required no later than March 1, 1971; however, replacement is recommended at the next 1200-hour overhaul.
To prevent failure from internal corrosion, remove and replace all tail rotor drive shaft assemblies installed on applicable helicopters as indicated below in accordance with the applicable maintenance and overhaul manual:
Remove
Replace With
47-644-172-3
47-644-172-9
47-644-180-1
47-644-180-9
47-644-180-5
47-644-180-11
47-644-214-1
47-644-214-9
47-644-186-1
47-644-186-5
47-644-187-5
47-644-187-17
47-644-187-11
47-644-187-19
(Bell Service Bulletin No. 47-145, Rev. B, dated March 26, 1970, pertains to this matter) Amendment 39-968 effective May 9, 1970.
This amendment, 39-1137, becomes effective January 1, 1971.