AD 57-07-02

57-07-02 BELL: Applies to Model 47 Helicopters Except the Following: Model 47G 1529, 1689 and Up; 47G2 1506, 1957 and Up; Model 47H1 1361, 1534 and Up; Model 47J 1420, 1421, 1423, 1424, 1428 and Up; Model 47K.

Compliance required as indicated.

1. In order to insure that rotor hub equalizer link assembly, P/N 47-120-025-1, is assembled with sufficient threads engaged to meet safety requirements, the following inspection must be conducted and part reworked as necessary by April 15, 1957, unless item 2 has been accomplished.

(a) Inspect rod end, P/N 47-120-025-7, for adequate distance between end of shank to safety inspection hole, 0.230 to 0.270 inch required.

(b) Inspect for adequate distance between shank end of P/N 47-120-025-5 rod end shank end of P/N 47-120-025-7 rod end. Maximum of 15/32 (0.468) inch is allowed. NOTE: If dimension between rod ends exceeds 15/32 (0.468) inch, hub assembly must be rerigged and link assemblies must be adjusted until this dimension is below this valve.

2. Rework on, or before, next overhaul of main rotor hub assembly. Rework link assemblies, P/N 47-120-025-1, which do not meet conditions described in above inspection, item 1(a) as follows:

(a) Remove link assembly, P/N 47-120-025-1 from main rotor hub assembly and remove rod end, P/N 47-120-025-7 from link assembly.

(b) Drill a No. 50 (0.070) inch diameter hole through shank at a point 0.230- 0.270 inch from shank end and 90 degrees from existing inspection hole.

(c) Reassemble link assembly, install on hub assembly, and rerig hub assembly. Use new safety inspection hole to determine that rod end has sufficient threads engaged.

(Bell Service Bulletin No. 118SB dated February 1, 1957, covers this same subject.)