AD 75-05-06

75-05-06 PRATT & WHITNEY AIRCRAFT: Amendment 39-2099 as amended by Amendment 39-2604 is further amended by Amendment 39-2814. Applies to all Pratt & Whitney Aircraft JT8D model engines containing P/Ns 629141, 629148, 629154, 699155, 735780, and 735781 fuel manifolds with fuel manifold "B" nuts which have not been retorqued in service.

To preclude possible fuel manifold leakage accomplish the following:

1. Retorque the fuel manifold "B" nuts in accordance with Pratt and Whitney Aircraft Service Bulletin 4389, Revision 7, or later FAA approved revision or Section 72-37 of Pratt and Whitney Aircraft JT8D Engine Manual No. 481672, Revision 78, or later FAA approved revision within the next 1500 hours time in service after March 12, 1976, for fuel manifolds with "B" nuts which were single or double torqued at original manufacture and within the next 1500 hours time in service after the effective date of this amendment for fuel manifolds with "B" nuts which were quadruple torqued at original manufacture, unless already accomplished.

2. Until the fuel manifold "B" nuts are retorqued in accordance with Paragraph 1, accomplish the following inspection once a day on engines with over 1000 hours total time in service since new:

a. Within 20 minutes after engine shutdown, inspect the inside diameter of the diffuser fan duct, combustion chamber fan duct, exhaust fan duct, and exhaust nozzle for evidence of residual fuel wetness or staining, using a six volt light source or equivalent. Direct the light source into the engine tailpipe to illuminate the fan duct as far forward as the diffuser case. If residual fuel is not evident, inspect within 30 minutes after engine shutdown for the presence of dripping fuel at the diffuser fan duct and combustion chamber fan duct flanges and for the presence of fuel in the cowl bottom quadrant under these flanges.

b. Remove from service before further flight those engines that have evidence of fuel leakage.3. Equivalent methods approved by the Chief, Engineering and Manufacturing Branch, FAA, New England Region, may be substituted for torquing the fuel manifold "B" nuts and for compliance with the requirements of Paragraph 1 and 2.

NOTE: Pratt & Whitney Aircraft Alert Service Bulletin No. 4389, dated January 16, 1975, pertains to this subject.

The manufacturer's engine manual 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 & Whitney Aircraft, 400 Main Street, East Hartford, Connecticut 06108. These documents may also be examined at the Office of the Regional Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, and at Federal Aviation Administration Headquarters, 800 Independence Avenue, S.W., Washington, D.C. 20591. A historical file on this AD which includes the incorporated material in full is maintained by the Federal Aviation Administration at its headquarters in Washington, D.C., and at the New England Regional office in Burlington, Massachusetts.

Upon submission of substantiating data through an FAA maintenance inspector by an owner or operator, the Chief, Engineering and Manufacturing Branch, FAA, New England Region, may adjust the compliance time.

Amendment 39-2099 became effective March 12, 1975.

Amendment 39-2604 became effective May 20, 1976.

This amendment 39-2814 becomes effective February 24, 1977.