90-14-08 PRATT & WHITNEY: Amendment 39-6428. Docket No. 89-ANE-15.
Applicability: Pratt & Whitney (PW) JT9D-7R4D and -7R4E turbofan engines installed on Boeing B767 aircraft.
Compliance: Required as indicated, unless already accomplished.
To prevent engine overtemperature and loss of power or engine shutdown inflight, accomplish the following:
(a) Adjust the engine vane and bleed control (EVBC), Hamilton Standard, Part Number (P/N) 776555-3, to the 1.27 engine pressure ratio (EPR) bleed trim, and Hamilton Standard, P/N 776555-5, to 1.27 EPR in accordance with the instructions of Appendix 2 of this AD, (unless already adjusted to 1.32 EPR bleed trim in accordance with the instructions of Appendix 1 of this AD) as follows:
(1) Within 5 calendar days or 50 cycles in service after the effective date of this AD, whichever occurs later, for those engines with 4,000 or more cycles in service on the effective date of this AD, or since last high pressure compressor (HPC) overhaul.
(2) Within 15 calendar days or 150 cycles in service after the effective date of this AD, whichever occurs later, but not to exceed 4,050 cycles in service or since HPC overhaul, for those engines with less than 4,000 cycles in service on the effective date of this AD, or since last HPC overhaul.
(3) The 3.0 bleed trim screw may bottom out before the two clockwise turns are completed in accordance with the instructions of Appendix 2 of this AD. If the turn screw bottoms out, this is an acceptable condition.
(b) An engine which has had no 3.0 bleed or vane schedule adjustments since it was last trimmed in the test cell (P/N 776555-3 to 1.27 EPR or P/N 776555-5 to 1.32 EPR) is exempt from the requirements of paragraphs (a)(1) and (a)(2).
NOTE: For the purpose of this AD, the definition of HPC overhaul is anytime the HPC is disassembled, inspected, and repaired in accordance with PW Engine Manual P/N 785059, Section 72-35-00.
(c) Adjust the decel schedule trimof fuel control unit (FCU), P/N 797371, and reidentify the FCU, in accordance with the instructions of Appendix 3 of this AD, within the applicable schedule in paragraph (a)(1) or (a)(2) above. If cycling bleeds occur as a result of the decel schedule uptrim, downtrim the decel schedule in accordance with the instructions of Appendix 4 of this AD.
(d) Within the next 30 calendar days after the effective date of this AD accomplish the following:
(1) Adjust the EVBC, P/N 776555-3, to the 1.27 EPR bleed trim and, P/N 776555-5, to the 1.32 EPR bleed trim in accordance with the instructions of Appendix 1 of this AD.
(2) Modify the 3.0 bleed valve cylinder, P/N 806885 or 774300, in accordance with the instructions of Appendix 5 or Appendix 6 of this AD.
(3) Inspect the 3.0 bleed valve linkage for wear in accordance with the instructions of Appendix 7 of this AD and accomplish the following:
(i) Remove engines with worn 3.0 valve linkage prior to accumulating 5 cycles inservice since inspection and replace with a serviceable engine.
(ii) Reinspect linkages found serviceable in accordance with the requirement of paragraph (c)(3) above, at intervals not to exceed 3,000 hours since last inspection.
(e) Incorporate the following modifications to upgrade the EVBC to Hamilton Standard, P/N 776555-5, prior to July 31, 1990, by accomplishing the following:
(1) Incorporate the fluid drain between sensor servo piston chevron seals, in accordance with the instructions of Appendix 8 of this AD.
(2) Incorporate the pilot valve spring, P/N 801040-1, in accordance with the instructions of Appendix 9 of this AD.
(3) Incorporate the decel bleed reset piston spring, P/N 801073-1, in accordance with the instructions of Appendix 10 of this AD.
(4) Incorporate the 3.0 bleed cam, P/N 765357-11, and recalibrate the control, in accordance with the instructions of Appendix 11 of this AD.
(5) Incorporate the actuator valve, P/N 800997-1, in accordance with the instructions of Appendix 12 of this AD; or remove actuator valve, P/N 728149-3, and replace with a new or serviceable actuator valve, P/N 728149-3. Replacement actuator valves, P/N 728149-3, must be removed from service at, or prior to accumulating 10,000 hours since new.
(6) Incorporate the adjust EVBC to 1.32 EPR bleed trim, in accordance with paragraph (c)(1) above.
(f) Modify FCU, Hamilton Standard, P/N 773333-3, prior to July 31, 1990, by accomplishing the following:
(1) Incorporate the L-22 idle speed cam, P/N 774537-9, in accordance with the instructions of Appendix 13 of this AD.
(2) Incorporate the decel cam, P/N 774538-13, in accordance with the instructions of Appendix 14 of this AD.
(g) Incorporate the revised test procedure for the fuel control decel bleed override, in accordance with the instructions of Appendix 15 of this AD, prior to July 31, 1990.
(h) Install 3.0 bleed dampers at the next shop visit, in accordance with PW Service Bulletin (SB) JT9D- 7R4-72-336, Revision 5, dated June 23, 1988. Installation of 3.0 bleed dampers terminates the reinspection requirements of paragraph (c)(3)(ii) above.
NOTE: For the purpose of this AD, the definition of shop visit is any time the engine or module is in a maintenance shop capable of complying with the SB instructions regardless of the planned maintenance action or the reason for engine removal.
(i) Restore the leading edge of the first stage compressor blades in accordance with PW SB JT9D-7R4- 72-117, Revision 4, dated June 30, 1989, at the next fan module overhaul after the effective date of this AD and thereafter at every fan module overhaul.
NOTE: For the purpose of this AD, the definition of fan module overhaul is anytime the fan module is disassembled, inspected, and repaired, in accordance with PW Engine Manual P/N 785058.
(j) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.(k) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance with the requirements of this AD or adjustments to the compliance times specified in this AD may be approved by the Manager, Engine Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, Federal Aviation Administration, 12 New England Executive Park, Burlington, Massachusetts 01803.
The installation and restoration procedures shall be done in accordance with the following PW documents:
Document No.
Page No.
Issue/Revision
Date
JT9D-7R4-72-117
1,2,4,5,6,
4
June 30, 1989
7,8,9,10,11
JT9D-7R4-72-117
3
3
Dec. 21, 1987
JT9D-7R4-72-336
1,3,4,8,9,10
5
June 23, 1988
11,12,13,14,15,
4
Aug. 28, 1987
16,17,18,19,20
2
3
June 8, 1987
JT9D-7R4-72-336
5,6,7
Original
March 2, 1987
This incorporation by reference was approved by the Director of the Federal Registerin accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Pratt & Whitney Publications Department, P.O. Box 611, Middletown, Connecticut 06457. Copies may be inspected at the Regional Rules Docket, Office of the Assistant Chief Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Room 311, Burlington, Massachusetts 01803, or at the Office of the Federal Register, 1100 L Street, NW, Room 8301, Washington, DC 20591.
This AD supersedes telegraphic airworthiness directive No. T89-11-51, dated May 23, 1989.
This amendment (39-6428, AD 90-14-08) becomes effective on July 2, 1990.
Appendix 1
NOTE: This appendix consists of material from:
Boeing 767 Maintenance Manual, JT9D engines, Chapter/Section 71-01-00, Test No. 10, dated February 10, 1989.
Appendix 2
NOTE: This appendix consists of material from:
Pratt & Whitney (PW) Special Instruction (SI) 55F-89, dated May 19,1989.
Appendix 3
NOTE: This appendix consists of material from:
PW SI 42F-88, Revision A, dated May 19, 1989.
Appendix 4
NOTE: This appendix consists of material from:
PW SI 53F-89, dated May 23, 1989.
Appendix 5
NOTE: This appendix consists of material from:
PW SB JT9D-7R4-75-98, Revision 1, dated August 17, 1989.
Appendix 6
NOTE: This appendix consists of material from:
PW SI 54F-89, dated May 19, 1989.
Appendix 7
NOTE: This appendix consists of material from:
PW Maintenance Manual, P/N 785050, Chapter/Section 72-00-00, Inspection/Check -06, dated November 1, 1986.
Appendix 8
NOTE: This appendix consists of material from:
Hamilton Standard Bulletin (HSB) GTA9 No. 9, Revision 1, dated October 15, 1984.
Appendix 9
NOTE: This appendix consists of material from:
HSB GTA9 No. 16, dated March 20, 1988.
Appendix 10
NOTE: This appendix consists of material from:
HSB GTS9 No. 17, dated March 31, 1988.
Appendix 11
NOTE: This appendix consists of material from:
HSB GTS9 No. 18, Revision 1, dated January 15, 1989.
Appendix 12
NOTE: This appendix consists of material from:
HSB GTA9 No. 19, dated August 12, 1988.
Appendix 13
NOTE: This appendix consists of material from:
HSB JFC68-7 No. 10, Revision 1, dated October 31, 1989.
Appendix 14
NOTE: This appendix consists of material from:
HSB JFC68-7 No. 14, Revision 1, dated October 31, 1989.
Appendix 15
NOTE: This appendix consists of material from:
HSB JFC68-7 No. 12, dated March 31, 1988.