AD 77-19-03

77-19-03 HUGHES HELICOPTERS: Amendment 39-3038. Applies to Hughes Model 369D helicopters, certificated in all categories, which have P/N 369D21200 main rotor hub serial numbers 0001 through 0178 installed.

Compliance required as indicated.

To prevent failure of the main rotor retention straps which can result in loss of a main rotor blade accomplish the following:

A. Before further flight after the effective date of the AD, visually inspect the lead leg of each main rotor retention strap pack, P/N 369D21210, at the inboard ends to determine if two adjacent metallic anti-fretting laminates P/N 369D21271-5, -51, -53 or -55, have been installed on the upper side of the lead leg of any strap pack.

(1) If two adjacent metallic anti-fretting laminates have been installed, visually inspect to determine if one or both are cracked or have been broken off where they extend from the hub.

(i) If no anti-fretting laminate is found cracked or broken, repeat the inspections in (1), above, at times in service not to exceed 25 hours. This repetitive inspection can be discontinued when the main rotor hub, P/N 369D21200, has been replaced by a serviceable hub having only one anti-fretting laminate on the upper side of the lead leg of each main rotor strap pack.

(ii) If any anti-fretting laminate is found cracked or broken, further visually inspect the main rotor retention strap laminates adjacent to the anti-fretting laminates.

(a) If any strap laminate is broken or cracked, replace the main rotor hub, P/N 369D21200, before further flight.

(b) If no strap laminate is cracked or broken, replace the main rotor hub, P/N 369D21200, within ten hours time in service.

(2) If the inspection reveals that only one metallic anti-fretting laminate has been installed on the upper lead leg of each strap pack no further action is required by this AD.

This amendment becomes effective September 27, 1977, for all persons except those to whom it was made effective by telegram dated August 12, 1977, which contained this amendment.