AD 63-04-02

63-04-02 HILLER: Amdt. 535 Part 507 Federal Register February 12, 1963. Applies to All UH-12, UH-12A, UH-12B, and UH-12C Helicopters with P/N's 55008 and 55012 Tail Rotor Blades.

Compliance required as indicated.

To prevent failures of P/N's 55008 and 55012 tail rotor blades the following shall be accomplished:

(a) Within the next 50 hours' time in service, unless already accomplished:

(1) Replace all P/N's 55008 and 55012 tail rotor blades with P/N 55064 tail rotor blades in accordance with Hiller Service Bulletin No. 80.

(2) On all helicopters equipped with the large diameter (1.375 inch) spar stabilizer, P/N 37003, install the stabilizer strut in accordance with Hiller Service Bulletin No. 75B.

(3) On all helicopters equipped with the small diameter (1 inch) spar stabilizer, P/N 37001, install the stabilizer strut in accordance with Hiller Service Bulletin No. 83.

(b) Until replacement with the P/N 55064 blade is accomplished, visually inspect the P/N's 55008 and 55012 tail rotor blades prior to each flight and refueling. The outer surface of the skin on both sides of the blade shall be inspected for cracks in the area of the outer tension torsion bar retention bolt and the adjacent rivet pattern through the outer end of the root fitting. Paint must be removed from the areas to facilitate inspection. Any blades found to be cracked must be removed and replaced with P/N 55064 blades prior to further flight.

(Hiller Service Bulletins Nos. 75B, 80, and 83 pertain to this subject.)

This supersedes AD 58-24-02. This directive effective February 12, 1963.