98-22-06: Fan Disks

98-22-06 General Electric Company: Amendment 39-10853. Docket 98-ANE-52 -AD. Applicability: General Electric Company (GE) CF6-6, -45, -50, -80A, and -80C2 series turbofan engines, with stage 1 fan disks installed, identified by serial numbers (S/Ns) in the following GE Alert Service Bulletins (ASBs): CF6-6 ASB 72-A996, Revision 4, dated June 9, 1998; CF6-50 ASB 72-A988, Revision 6, dated August 25, 1998; CF6-80A ASB 72-A565, Revision 5, dated June 9, 1998; and CF6-80C2 ASB 72-A478, Revision 4, dated June 9, 1998. These engines are installed on but not limited to Boeing 747 and 767, Airbus A300 and A310, McDonnell Douglas DC-10 and McDonnell Douglas MD-11 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 thatthe 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 (b) 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 fan disk failure due to cracks, which could result in an uncontained engine failure and damage to the aircraft, accomplish the following: (a) Prior to further flight, perform an ultrasonic immersion inspection for cracks of affected stage 1 fan disks, and, if necessary, replace with serviceable parts, as follows: (1) For GE CF6-6 series engines, in accordance with GE CF6-6 ASB 72-A996, Revision 4, dated June 9, 1998. (2) For GE CF6-45 and -50 series engines, in accordance with GE CF6-50 ASB 72-A988, Revision 6, dated August 25, 1998. (3) For GE CF6-80A series engines, in accordance with CF6-80A ASB 72-A565, Revision 5, dated June 9, 1998. (4) For GE CF6-80C2 series engines, in accordance with CF6-80C2 ASB 72-A478, Revision 4, dated June 9, 1998. (5) Remove from service cracked fan disks and replace with serviceable parts. (b) 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 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (c) Specialflight 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. (d) The actions required by this AD shall be done in accordance with the following GE ASBs: Document No. Pages Revision Date CF6-6 ASB 72-A996 1-13 4 June 9, 1998 Total pages: 13. CF6-50 ASB 72-A988 1-13 6 August 25, 1998 Total pages: 13. CF6-80A ASB 72-A565 1-13 5 June 9, 1998 Total pages: 13. CF6-80C2 ASB 72-A478 1-13 4 June 9, 1998 Total pages: 13. 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 General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, OH 45215; telephone (513) 672-8400, fax (513) 672-8422. 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. (e) This amendment becomes effective on November 23, 1998.