60-10-10 VERTOL: Amdt. 140 Part 507 Federal Register May 4, 1960. Applies to all 44 series helicopters.
Compliance required as indicated.
All forward rotor blades P/N 42R1002-9, -13, -15, -19, -90, -130, -131, -132, -150, and - 152 must be retired at 800 hours of service time. All forward rotor blades P/N 42R1002-137 AND -139 and all aft rotor blades P/N 42R1002-2, -4, -20, and -40 must be retired at 1,350 hours of service time.
When the above blades are modified to 42R1002-42, -133, or -135 the provisions of this airworthiness directive no longer apply.
This supersedes AD 59-25-02.