AD 62-02-02

62-02-02 BOEING AND DOUGLAS: Amdt. 385 Part 507 Federal Register January 16, 1962. Applies to All 707/720 Series and DC-8 Series Aircraft Equipped With Pratt and Whitney JT3D-3 Turbofan Engines.

Compliance required as indicated.

(a) For engines previously inspected by the procedure described in paragraph (c), reinspect in accordance with paragraph (c) every 225 hours' time in service thereafter.

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

(1) Inspect engines with 200 or more hours' time in service within the next 25 hours' time in service and every 225 hours time in service thereafter.

(2) Inspect engines with less than 200 hours' time in service by the time 225 hours' time in service have been accumulated and every 225 hours' time in service thereafter.

(c) Due to recent failures of P/N 393504 fourth stage compressor rotor disc, inspect the disc for cracks adjacent to the inside edge of the tie bolt circular rib in the disc web. Such cracks may progress along the inside of the rib and then toward the disc bore through the bore stiffening section.

To accomplish the inspection, remove the front accessory drive support assembly (N1 gearcase) and the front accessory drive main spur gear (N1 gearcase coupling). Using a strong light and borescope or similar optical device, visually inspect the fourth stage compressor rotor disc in the area noted above. If any cracking is found, the engine must be removed for disc replacement prior to further flight.

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

(Pratt and Whitney Aircraft telegraphic message of December 19, 1961, covers the same subject.)

This directive effective upon publication in the Federal Register for all persons except those to whom it was made effective immediately by telegram dated December 22, 1961.

Revised October 12, 1962.