99-14-08: Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

99-14-08 Pratt & Whitney: Amendment 39-11219. Docket No. 92-ANE-23. Supersedes AD 94-10-09, Amendment 39-8916. Applicability: Pratt & Whitney (PW) Model JT9D-59A, -70A, -7Q, and -7Q3 turbofan engines, installed on but not limited to Boeing 747 series, McDonnell Douglas DC-10 series, and Airbus A300 series aircraft. Note 1: This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. Compliance: Required as indicated, unless accomplished previously. To prevent an uncontained failure of the sixth stage low pressure turbine (LPT) inner airseal, accomplish the following: (a) Prior to further flight, rework the sixth stage LPT inner airseal knife edge diameters in accordance with the Accomplishment Instructions of PW Service Bulletin (SB) 5847, Revision 2, dated October 31, 1990. (b) Prior to further flight, rework the sixth stage LPT inner airseal rear retaining wing in accordance with the Accomplishment Instructions of PW SB 5745, Revision 2, dated October 24, 1990. Note 2: Rework of the sixth stage LPT inner airseal rear retaining wing in accordance with paragraph (b) of this AD does not exempt sixth stage LPT inner airseals from initial and repetitive inspections in accordance with paragraphs (c)(1), (c)(2), (c)(3), and (c)(4) of this AD. (c) Eddy current inspect(ECI) or borescope inspect sixth stage LPT inner airseal rear retaining wings for cracks, as follows: (1) For sixth stage LPT inner airseals identified by part number (P/N) in PW SB No. 5978, Revision 4, dated May 6, 1998, or Revision 3, dated May 20, 1992, with greater than 500 cycles since new (CSN) on the effective date of this AD, accomplish an initial ECI or borescope inspection prior to accumulating more than 250 cycles in service (CIS) after the effective date of this AD, or 500 CIS since the last in-shop fluorescent penetrant inspection (FPI), whichever occurs later, in accordance with the Accomplishment Instructions of PW SB No. 5978, Revision 4, dated May 6, 1998, or Revision 3, dated May 20, 1992. (2) For sixth stage LPT inner airseals identified by P/N in PW SB No. 5978, Revision 4, dated May 6, 1998, or Revision 3, dated May 20, 1992, with less than or equal to 500 CSN on the effective date of this AD, accomplish an initial ECI or borescope inspection prior to accumulating 750 CSN, or 500 CIS since the last in-shop FPI, whichever occurs later, in accordance with the Accomplishment Instructions of PW SB No. 5978, Revision 4, dated May 6, 1998, or Revision 3, dated May 20, 1992. (3) For sixth stage LPT inner airseals that meet the continue in service criteria described in PW SB No. 5978, Revision 4, dated May 6, 1998, thereafter, ECI or borescope inspect the sixth stage LPT inner airseal retaining wing for cracks at intervals specified in accordance with the Accomplishment Instructions of PW SB No. 5978, Revision 4, dated May 6, 1998. (4) Remove cracked sixth stage LPT inner airseals that do not meet the continue in service criteria described in PW SB No. 5978, Revision 4, dated May 6, 1998, and replace with a new, or serviceable sixth stage LPT inner airseal that has been reworked in accordance with paragraph (c) of this AD. (5) Thereafter, inspect initially, reinspect, and remove from service, if necessary, the replacement sixth stage LPT inner airseals in accordance with paragraphs (c)(1), (c)(2), (c)(3), and (c)(4) of this AD. (d) Installation of a new, improved 6th stage LPT inner airseal, in accordance with PW SB No. 6054, Revision 1, dated April 24, 1992, constitutes terminating action to the inspections and rework required by this AD. (e) 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. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. Note 3: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (f) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished. (g) The actions required by this AD shall be done in accordance with the following PW SBs: Document No. Pages Revision Date 5847 1-4 2 October 31, 1990 5 Original April 11, 1989 6 2 October 31, 1990 7 Original April 11, 1989 8 2 October 31, 1990 9 Original April 11, 1989 10 2 October 31, 1990 Total pages: 10 5978 1 4 May 6, 1998 2 Original December 19, 1990 3,4 4 May 6, 1998 5 1 October 10, 1991 6 4 May 6, 1998 7-11 1 October 10, 1991 12 4 May 6, 1998 13-18 1 October 10, 1991 19 4 May 6, 1998 20-33 1 October 10, 1991 34 2 April 28, 1992 Total pages: 34 5978 1 3 May 20, 1992 2 Original December 19, 1990 3,4 2 April 28, 1992 5-11 1 October 10, 1991 12 3 May20, 1992 3-18 1 October 10, 1991 19 3 May 20, 1992 20-33 1 October 10, 1991 34 2 April 28, 1992 Total pages: 34 5745 1-9 2 October 24, 1990 Total pages: 9 6054 1-4 1 April 24, 1992 5-7 Original November 6, 1991 8 1 April 24, 1992 9-16 Original November 6, 1991 Total pages: 16 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, 400 Main St., East Hartford, CT 06108; telephone (860) 565-8770, fax (860) 565-4503. Copies may be inspected at the FAA, New England Region, Office of the Regional 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. (h) This amendment becomes effective on September 13, 1999.