AD 62-16-05

62-16-05 PRATT & WHITNEY: Amdt. 464 Part 507 Federal Register July 17, 1962. Applies to All Pratt & Whitney Aircraft JT3D-1-MC7 Turbofan Engines.

Compliance required as indicated.

To preclude failure of the fourth stage compressor rotor disc, P/N 426504, accomplish the following:

(a) For engines previously inspected by the procedure described in paragraph (c), reinspect in accordance with paragraph (c) every 365 hours' time in service from the last inspection.

(b) For engines not previously inspected by the procedure described by paragraph (c), inspect in accordance with paragraph (c) as follows:

(1) Inspect engine with 300 or more hours' time in service since last engine overhaul within the next 365 hours' time in service and each 365 hours' time in service thereafter.

(2) Inspect engines with less than 300 hours' time in service since last overhaul prior to the accumulation of 675 hours' time in service and each 365 hours' time in service thereafter.

(c) Remove the front accessory drive support assembly (NI gearcase) and the front accessory drive main spur gear (NI gearcase coupling). Using a strong light, visually inspect the fourth stage compressor rotor disc in the area between the disc bore and the spacer shoulder on the disc. If cracking is found, remove the engine for disc replacement prior to further flight.

(d) When fourth stage compressor disc, P/N 471904 is installed in place of P/N 426504 disc, the repetitive inspections required by this AD are no longer required.

(e) The requirement for main oil screen inspections per AD 61-24-01 does not apply when the No. 1 bearing compartment is exposed for this disc inspection.

(f) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator.

(Pratt & Whitney Aircraft telegraphic message of June 6, 1962, to American Airlines, covers the same subject.)

This directive effective July 17, 1962.