2000-23-14: No. 4 Bearing Area

2000-23-14 Pratt & Whitney: Amendment 39-11986. Docket No. 99-NE-25-AD. Applicability Pratt & Whitney (PW) JT9D-3A, -7, -7A, -7AH, -7H, -7F, -7J, -7Q, -7Q3, -20, -20J, -59A, -70A, and -7R4D(BG 700) series turbofan engines, installed on but not limited to Boeing 747 and 767, Airbus A300, and McDonnell Douglas DC-10 series airplanes. 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 (c) 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 unsafecondition has not been eliminated, the request should include specific proposed actions to address it. Compliance Required as indicated, unless accomplished previously. To prevent oil fires in and around the No. 4 bearing area, which could result in excessive growth of the sixth stage low pressure turbine (LPT) disk, liberation of the sixth stage LPT disk, uncontained engine failure, and damage to the airplane, accomplish the following: Installation of Improved Hardware (a) At the next disassembly of the turbine exhaust case (TEC) when all hardware is stripped from the case after the effective date of this AD, install an improved No. 4 bearing internal oil pressure tube in accordance with PW Service Bulletin (SB) No. 5707, dated September 17, 1986, and SB JT9D-7R4-72- 289, dated March 26, 1986. Inspections (b) Perform initial and repetitive inspections of the No. 4 bearing oil pressure tube and TEC strut for clearance and alignment, and, if necessary, replacewith serviceable parts, in accordance with the applicable PW JT9D Engine Manuals, part numbers (P/Ns) 646028, 770407, 770408, and 777210, Section 72-53-01, Turbine Exhaust Case Assembly - Inspection 01; P/N 785059, Section 72-53-05, Turbine Exhaust Case Assembly - Inspection/Check-01-Config-2; and P/N 754459, Turbine Exhaust Section - Heavy Maintenance, Section 72-53-01, Turbine Exhaust Case Assembly - Check, as follows: (1) Initially inspect at the next disassembly of the TEC when all hardware is stripped from the case after the effective date of this AD. (2) Thereafter, inspect at every disassembly of the TEC when all hardware is stripped from the case. Alternative Methods of Compliance (c) 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 (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO. Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO. Special Flight Permits (d) Special flight permits may be issued in accordance with 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Incorporation By Reference (e) The replacement of the oil pressure tube shall be done in accordance with PW Service Bulletin No. 5707, pages 1-7, dated September 17, 1986, and PW Service Bulletin No. JT9D-7R4-72-289, pages 1-6, dated March 26, 1986. The initial and repetitive inspections shall be done in accordance with the specified sections of the appropriate PW JT9D Engine Manual: P/N Section Pages Date 646028 72-53-01 805-809 March 1, 1999 754459 72-53-01 508 October15, 1999 754459 72-53-01 508A-508D April 15, 1999 770407 72-53-01 805 March 1, 1999 770408 72-53-01 805 March 1, 1999 777210 72-53-01 805-806 October 15, 1998 777210 72-53-01 807 April 15, 1999 777210 72-53-01 815-818 October 15, 1998 785059 72-53-05 803 March 15, 1999 785059 72-53-05 807-810 March 15, 1999 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 Street, East Hartford, CT 06108; telephone: (860) 565-6600, 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. Effective Date (f) This amendment becomes effective on January 19, 2001.