AD 74-10-04

74-10-04 PRATT & WHITNEY: Amendment 39-1831. Applies to all Pratt & Whitney Model JT9D-3A and JT9D-7 turbofan engines.

Compliance required not later than February 1, 1975.

1. To prevent the possibility of internal main gearbox fires in the event of an internal gearbox failure, rework the main gearbox in accordance with Pratt & Whitney Service Bulletin No. 4043, dated February 5, 1973, or later Federal Aviation Administration approved revisions.

2. To prevent leakage of oil around carbon face seals, replace present seal assemblies with the redesigned carbon face seal assemblies per Pratt & Whitney Service Bulletin No. 3902, dated August 8, 1972, or later Federal Aviation Administration approved revisions or Federal Aviation Administration approved equivalent.

3. Equivalent methods of compliance to the requirements of paragraph 2 above must be approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, New England Region.

Themanufacturer'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 the Chief Engineer, Pratt and Whitney Aircraft, Division of United Aircraft Corporation, 400 Main Street, East Hartford, Connecticut 06108. These documents may also be examined at the Office of the Regional Counsel, New England Region, FAA, 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 the New England Regional Office in Burlington, Massachusetts.

This amendment becomes effective May 14, 1974.