AD 60-13-04

60-13-04 SIKORSKY: Amdt. 171 Part 507 Federal Register June 24, 1960. Applies to All Models S-51 and S-55 Helicopters.

Compliance required by August 15, 1960.

A fatigue failure of the RE5M7 shank rod end bearing has occurred in the S-55 main rotor upper controls. This rod had a hollow shank rather than a solid shank and is not an approved part. Preliminary investigation indicates that the hollow shank part has been installed in S-51 and S-55 helicopters because of improper identification. To ensure removal of this part from service, the following must be accomplished:

Unless already accomplished, remove the following rod assemblies and inspect for RE5M7 rod end bearings with hollow shanks and S510085 pivots with hollow shanks, as noted (S510085 pivots are altered RE5M7 rod ends.)

(a) Model S-51 main rotor assembly, P/N S510000.

(1) P/N S510333 (Alternate P/N S510140) rod assembly contains one RE5M7 rod end.

(2) P/N S510082 rod assembly contains one RE5M7 rod end and one P/N S510085 pivot.

(b) Model S-51 main rotor assembly, P/N S10-10-1100.

(1) P/N S510333 rod assembly contains one RE5M7 rod end.

(c) Model S-55 servo unit assembly, P/N S14-40-5000.

(1) P/N S14-40-5024 control arm contains one RE5M7 rod end.

Remove all hollow shank units and replace with solid shank units.