74-10-05 R1 PRATT & WHITNEY AIRCRAFT: Amendment 39-1834 as amended by Amendment 39-3972. Applies to all Pratt & Whitney Aircraft JT9D-7, JT9D-7A, and JT9D-20 turbofan engines.
Compliance required as follows unless already accomplished.
To preclude possible turbine blade or disc failures resulting from deflection of the second stage turbine nozzle guide vane inner support, perform a radioisotope inspection in accordance with paragraph 8 below per the following schedule:
1. Engines containing second stage vanes, P/N 708952.
a. For vanes with less than 4000 hours total time in service or less than 4000 hours since the fuel nozzles and supports were last cleaned, as of June 7, 1974, inspect prior to the accumulation of 4000 hours total time, or 4000 hours since the fuel nozzles and supports were last cleaned, or 400 hours time in service after June 7, 1974, whichever occurs later.
b. For vanes with 4000 or more hours total time in service and 4000 or more hours since the fuel nozzles and supports were last cleaned, as of June 7, 1974, inspect within the next 400 hours time in service.
c. Repeat the above inspection every 700 hours time in service thereafter.
2. Engines containing second stage vanes, P/N 708952, that were reworked per Pratt & Whitney Service Bulletin 3946 and reidentified to P/N 728752 and operated in engines prior to rework.
a. Inspect within the next 400 hours time in service after June 7, 1974.
b. Repeat the above inspection every 700 hours time in service thereafter.
3. For engines containing new production second stage vanes 719552, 728752, 731552, 735882, 740292, 747082, 746492, and 747172, not reworked in accordance with Service Bulletin 3946 and operated prior to the incorporation of Pratt & Whitney Service Bulletin 4146.
a. For vanes with less than 5000 hours total time in service or less than 4000 hours since the fuel nozzles and supports were last cleaned, as of June 7, 1974, inspect prior to the accumulation of 5000 hours total time, or 4000 hours since the fuel nozzles and supports were last cleaned, or 400 hours time in service after June 7, 1974, whichever occurs later.
b. For vanes with 5000 or more hours total time in service and 4000 or more hours since the fuel nozzles and supports were last cleaned, as of June 7, 1974, inspect within the next 400 hours time in service.
c. Repeat the above inspection every 2500 hours time in service thereafter.
4. For engines containing second stage vanes, 719552, 728752, 731552, 740292, and 747172, that have incorporated Pratt & Whitney Service Bulletin 4146 before operation.
a. For vanes with less than 5000 hours total time in service or less than 5000 hours since the fuel nozzles and supports were cleaned, as of June 7, 1974, inspect prior to the accumulation of 5000 hours total time or 5000 hours since the fuel nozzles and supports were cleaned, or 400 hours time in service after June 7, 1974, whichever occurs later.
b. For vanes with more than 5000 hours total time in service and 5000 or more hours since the fuel nozzles and supports were cleaned, as of June 7, 1974, inspect within the next 400 hours time in service.
c. Repeat the above inspection every 2500 hours time in service thereafter.
5. If any radioisotope inspection mentioned above indicates a deflection which exceeds .070 inch, remove the affected engine from service prior to further flight.
6. For engines containing a complete set of second stage vanes 735882, 746492, 747082, 772572, or 785992 that have incorporated Pratt & Whitney Service Bulletin 4146 before operation.
a. For vanes with less than 5000 hours total time in service or less than 5000 hours since the fuel nozzles and supports were cleaned, as of May 10, 1974, inspect prior to the accumulation of 5000 hours total time or 5000 hours since the fuel nozzles and supports were cleaned, or 400 hours time in service after May 10, 1974, whichever occurs later.
b. For vanes with more than 5000 hours total time in service and 5000 or more hours since the fuel nozzles and supports were cleaned, as of May 10, 1974, inspect within the next 400 hours time in service.
c. Repeat the above inspection every 2500 hours time in service thereafter.
7. If the radioisotope inspection in accordance with paragraph 6 above indicates vane deflection which exceeds 0.130 inches, remove the affected engine from service prior to further flight. Engines with vane deflection greater than 0.070 inches and up to 0.130 inches must be reinspected every 1250 hours time in service thereafter. Engines with vane deflection of 0.070 inches and less must be reinspected every 2500 hours time in service thereafter.
8. The inspections required above are radioisotope inspections conducted as follows:
a. For JT9D-7 and JT9D-7A engines, inspect in accordance with radioisotope inspection procedures specified in the Boeing Maintenance Manual, Section 72-00-00, Paragraph E(7), Pages 680N and 680P, revision dated March 1974, for those engines, or later Federal Aviation Administration approved revision.
b. For JT9D-20 engines, inspect in accordance with radioisotope inspection procedures specified in the McDonnell-Douglas Maintenance Manual, Section 72-00-00, Paragraph 2.G., Pages 631 and 633, revision dated May 1973, for this engine, or later Federal Aviation Administration approved revision.
9. Upon submittal of substantiating data through a Federal Aviation Administration Inspector, the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, New England Region, may adjust the compliance time.
10. For cases where vanes are mixed, if ten or more vanes of any one of the above part numbered categories are installed in an engine, the most restrictive category will apply.
The manufacturer's specifications and procedures identified and described in this directive areincorporated 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 Boeing Company, Post Office Box 3707, Seattle, Washington 98124 and McDonnell- Douglas Corporation, Douglas Aircraft Company, 3855 Lakewood Boulevard, Long Beach, California 90801. These documents may also be examined at the Office of the Regional Counsel, New England Region, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803 and at Federal Aviation Administration 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 Federal Aviation Administration at its headquarters in Washington, D.C., and at the New England Regional Office in Burlington, Massachusetts.
Note: Pratt & Whitney Alert Service Bulletin 4304 pertains to this subject.
Amendment 39-1834 became effective June 7, 1974.
This amendment 39-3972 becomes effective November 17, 1980.