AD 60-10-01

60-10-01 BELL: Amdt. 146 Part 507 Federal Register May 10, 1960. Applies to All Helicopter Models: 47B, 47B3, 47D, 47D1, 47G, and 47H1, all Serial Numbers; 47G2 Serial Numbers 1327 Through 2467, 2469, 2470, 2472 Through 2477, 2556 Through 2558; 47J Serial Numbers 1420 Through 1776 (Except For Helicopters On Which Kit No. 47-3410-1 (333SI) Has Been Installed); 47E, and 47K.

Compliance required as indicated except Model 47G2, Serial Numbers 2451, 2452, 2457, 2459 through 2467, 2469, 2470, 2472 through 2477, 2556 through 2558, for which compliance date is September 2, 1960.

As the result of a number of recent failures of the scissor lever pivot bolts due to excessive wear, the following is required unless already accomplished.

(a) Prior to June 30, 1960, except 47E and 47K as to which compliance is required prior to August 15, 1960, inspect the scissor lever pivot bolts, AN 174-31, and bolt holes in the brackets of the collective pitch sleeve weld assembly, P/N 47-150-117-5 for wear. Wear limits and reinspection intervals are specified in the following items (1), (2), (3), and (4).

(1) If the diameter of the two AN 174-31 bolts is less than 0.2465 inch in any area, bolts must be replaced prior to next flight.

(2) If the diameter of the bolt holes in the brackets of the collective pitch sleeve assembly is 0.2550 inch or more, install four bushings, P/N 47-150-260-3 or equivalent, and new AN 174-31 bolts within the next 25 hours' time in service.

(3) If the diameter of the bolt holes in the brackets of the collective pitch sleeve assembly is between 0.2500 and 0.2550 inch, the bolts and bolt holes must be reinspected dimensionally every 25 hours' time in service until bushings P/N 47-150-260-3 are installed.

(4) If the diameter of the bolt holes in the brackets of the collective pitch sleeve assembly is 0.2500 inch or less, the bolts and bolt holes must be reinspected dimensionally every 100 hours' time in service until bushings P/N 47-150-260-3 are installed.

(b) Upon installation of the bushings P/N 47-150-260-3, the bolts and bushing holes must be inspected every 300 hours' time in service thereafter.

(c) Upon installation of the four bushings, P/N 47-150-260-3, designate the reworked collective pitch sleeve weld assembly as P/N 47-150-117-21.

(Bell Service Bulletin No. 129SB, dated March 18, 1960, covers this same subject.)

Revised July 15, 1960.

Revised August 19, 1960.