70-26-05 PRATT & WHITNEY AIRCRAFT: Amdt. 39-1131. Applies to all model JT8D series turbofan engines.
Compliance required as indicated.
To prevent failure of the first stage compressor rotor blades as the result of improperly machined blade roots, accomplish the following:
(a) Within the next 900 hours in service after the effective date of this AD, unless already accomplished, visually inspect all P/N 487801, 511901 change letter L or earlier, 594601 and 616601 change letter B or earlier first stage compressor rotor blades, for tool marks within the radius of the Z plane platform on both sides of the blade root area. If tool marks are observed, replace the blade.
(b) Upon submission of substantiating data through an FAA Maintenance Inspector by an owner or operator to the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, compliance time may be adjusted.
(Pratt & Whitney letter PSE:HHB:0-4-6-1-33 dated April 6, 1970, pertains to this subject.)
This amendment is effective December 29, 1970.