AD 93-14-20

93-14-20 PRATT & WHITNEY: Amendment 39-8645. Docket No. 91-ANE-05. Applicability: Pratt & Whitney (PW) JT9D-59A, -70A, -7Q, and -7Q3 turbofan engines installed on, but not limited to Boeing 747, McDonnell Douglas DC-10, and Airbus A300 aircraft, in which the following high pressure turbine (HPT) stage 2 vane assemblies, identified by vane cluster assembly part numbers, are installed: 743772, 774872, 806272, 807372, 807772, 807072, and 808372. Compliance: Required as indicated, unless previously accomplished. To prevent uncontained HPT stage 2 blade fractures or lenticular airseal failures, accomplish the following: (a) For engines that have not incorporated the requirements of PW Service Bulletin (SB) 5566, Revision 5, dated August 10, 1990, and the requirements of PW SB 5428, Revision 3, dated March 12, 1984, borescope inspect the HPT stage 2 vanes in accordance with the Accomplishment Instructions of PW SB 5667, Revision 2, dated June 11, 1992, and in accordance withthe criteria identified in the applicable PW Maintenance Manual (MM) listed in paragraph (c) of this AD, prior to accumulating 1,000 hours time in service (TIS) since vane installation, or within the next 125 hours TIS after the effective date of this AD, whichever occurs later, and remove from service, prior to further flight, second stage turbine vanes exhibiting distress beyond serviceable limits. (b) For engines that have incorporated the requirements of PW SB 5566, Revision 5, dated August 10, 1990, and PW SB 5428, Revision 3, dated March 12, 1984, borescope inspect the HPT stage 2 vanes in accordance with the Accomplishment Instructions of PW SB 5667, Revision 2, dated June 11, 1992, and in accordance with the criteria identified in the applicable PW MM listed in paragraph (c) of this AD, prior to accumulating 2,000 hours total part TIS since new on the entire set of vanes, or within 1,000 hours TIS since vane installation, or within the next 125 hours TIS after the effectivedate of this AD, whichever occurs later, and remove from service, prior to further flight, second stage turbine vanes exhibiting distress beyond serviceable limits. (c) Thereafter, inspect the HPT stage 2 vanes in accordance with the criteria identified in the following PW MMs, and remove from service, prior to further flight, HPT stage 2 vanes exhibiting distress beyond serviceable limits.

Engine Models MM Part Number/ Revision Date Section/Table JT9D-7Q/7Q3 783777/December 25, 1989 72-00-00/604A JT9D-59A/-70A 783778/April 25, 1990 72-00-00/605A JT9D-59A 783779/September 15, 1989 72-00-00/605

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from Engine Certification Office. (e) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. (f) The inspections shall be done in accordance with the following service document:

Document No. Pages Issue Date PW SB No. 5667 1-6 Revision 2 June 11, 1992 Total pages: 6

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Pratt & Whitney, Publications Department, 400 Main Street, East Hartford, CT 06108. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (g) This amendment becomes effective on August 27, 1993.