71-17-06 PRATT & WHITNEY AIRCRAFT: Amendment 39-1262. Applies to all Pratt & Whitney Aircraft JT12A-6, JT12A-6A, JT12A-8, and J60P-5B Turbojet engines.
Compliance required as indicated.
To prevent cracking and possible failure of stage 2, 3, 7 and 8 compressor rotor discs of life limits on these parts have been reduced below the figures currently approved. Unless already accomplished, remove from service stage 2, 3, 7 and 8 compressor rotor discs prior to reaching the revised life limit below or, within the next 30 cycles in service after the effective date of this airworthiness directive, whichever comes later.
Part Number
Previous Life Limit Cycles
Revised Life Limit Cycles
406302
8000
6000
541902
8000
6000
406203
7500
4000
541903
7500
4000
426107
4000
2500
541907
4000
2500
406208
8000
5000
541908
8000
5000
NOTE: (The disc hour life limit as specified in Pratt & Whitney Aircraft Overhaul Manual Part No. 435108 Table of Limits Section XI has not been revised.)
(Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, may adjust the compliance time.)
NOTE: P&WA Telegram PSE/AMG/1-7-13-1 covers this same subject.
This amendment is effective August 17, 1971.