AD 76-12-03

76-12-03 PRATT & WHITNEY: Amendment 39-2634. Applies to all Pratt and Whitney JT9D Turbofan Engines containing turbine exhaust cases, part numbers 701877, 728301 thru 728309, 731370 thru 731373, 731377, 731565, 738438, 739431, 746128, 746272 thru 746274, 749510, 752872 thru 752876, 754763, 756838 and 761943.

Compliance required once each day the engine is operated.

In order to preclude failure of the sixth stage turbine disk resulting from an oil fire in the No. 4 bearing area, visually inspect the engine tailpipe/exhaust case area, to determine if there is oil leakage from the No. 4 bearing area.

If oil leakage is found in the No. 4 bearing compartment area, either of the following corrective actions must be taken prior to further flight:

1. Inspect the No. 4 bearing oil pressure and scavenge tubes. Replace cracked or blocked tubes with new or serviceable parts.

2. Drill a drain hole in the turbine exhaust case inner flow path wall in accordance with Prattand Whitney Alert Service Bulletin 4552 dated March 29, 1976, or later FAA approved revision.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Pratt and Whitney Aircraft, Division of United Technologies Corporation, 400 Main Street, East Hartford, Connecticut 06108. These documents may also be examined at Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. A historical file on this AD which includes the incorporated material in full is maintained by the FAA at its headquarters in Washington, D.C., and at New England Region.

This amendment becomes effective June 22, 1976.