55-05-01 BELL: Applies to All Models 47B, 47B3, 47D, 47D1, 47G Helicopters.
Compliance required at the expiration of 50 flying hours total time. Twenty-five additional flying hours may be acceptable provided the inspection called for in Bell's Mandatory Service Bulletin No. 97, Revision A, is complied with.
In order to prevent seizing, binding or brinelling of pitch control link bearings in the tail rotor pitch control links, P/N 47-641-032-1, it is necessary that these links be replaced with a newly designed tail rotor control link, P/N 47-641-070-1. This new control link incorporates a spherical type bearing in place of the self-aligning ball type bearing.
(Bell Mandatory Service Bulletin No. 97, Revision "A" dated December 3, 1954, covers this same subject and outlines the details for the installation.)