92-27-13 BOEING: Amendment 39-8448. Docket 92-NM-123-AD. Supersedes AD 92-05-01, Amendment 39-8180. \n\n\tApplicability: Model 747-400 series airplanes; having line numbers 696 to 843, 845 to 850, 852 to 870, 872 to 875, 877, 880 to 884, and 887; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent fire within the engine strut, accomplish the following: \n\n\t(a)\tFor airplanes having line numbers 696 through 734, inclusive: Within 10 days after February 18, 1992 (the effective date of AD 91-20-51, amendment 39-8152), inspect the electrical power feeder cables and the engine fuel supply tube in engine struts two and three for damage or chafing and minimum clearance of 0.375 inch, in accordance with Boeing Alert Service Bulletin 747-24A2168, dated September 24, 1991, or Revision 1, dated December 5, 1991. If damage is found or if clearance is not within the specified limits, prior to further flight, repair any damage in accordance with that service bulletin, and relocate the electrical power feeder cables so that the clearance is more than 0.375 inch. Repeat this inspection at the intervals specified in either paragraph (a)(1) or (a)(2) of this AD, as applicable: \n\n\t\t(1)\tIf the clearance is less than 0.75 inch, repeat the inspection at intervals not to exceed 500 flight hours. \n\n\t\t(2)\tIf the clearance is 0.75 inch or greater, repeat the inspection at intervals not to exceed 1,000 flight hours. \n\n\t(b)\tFor airplanes having line numbers 735 to 843, 845 to 850, 852 to 870, 872 to 875, 877, 880 to 884, and 887: Within 30 days after March 13, 1992 (the effective date of AD 92-05-01, amendment 39-8180), inspect the electrical power feeder cables and engine fuel supply tube in engine strut number three for damage or chafing and minimum clearance of 0.375 inch, in accordance with Boeing Alert Service Bulletin 747-24A2168, Revision 1, dated December 5, 1991. If damage is detected or if clearance is not greater than the specified limits, prior to further flight, repair any damage in accordance with that service bulletin, and relocate the electrical power feeder cables so that the clearance is more than 0.375 inch. Repeat this inspection at the intervals specified in either paragraph (b)(1) or (b)(2) of this AD, as applicable: \n\n\t\t(1)\tIf the clearance is less than 0.75 inch, repeat the inspection at intervals not to exceed 500 flight hours. \n\n\t\t(2)\tIf the clearance is 0.75 inch or greater, repeat the inspection at intervals not to exceed 1,000 flight hours. \n\n\t(c)\tWithin 12 months after the effective date of this AD, modify the electrical power feeder cable installation in engine struts two and three, in accordance with Phase II of Boeing Alert Service Bulletin 747-24A2168, Revision 1, dated December 5, 1991, or Revision 2, dated September 24, 1992. Once this modification is accomplished, ensure that a minimum clearance of 0.75 inch exists between the bridge bracket (installed as part of the modification) and the adjacent bleed duct. Accomplishment of this modification constitutes terminating action for the inspections required by paragraphs (a) and (b) of this AD. \n\n\t(d)\tAn alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO. \n\n\tNOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\tNOTE: Any previously approved alternative method of compliance with AD 92-05-01 continues to be considered as an approved alternative method of compliance with this AD. \n\n\t(e)\tSpecial flight permits may be issued in accordancewith FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(f)\tThe inspections and modifications shall be done in accordance with Boeing Alert Service Bulletin 747-24A2168, dated September 24, 1991; Boeing Alert Service Bulletin 747- 24A2168, Revision 1, dated December 5, 1991; or Boeing Alert Service Bulletin 747-24A2168, Revision 2, dated September 24, 1992; as applicable. Boeing Alert Service Bulletin 747- 24A2168, Revision 2, dated September 24, 1992, contains the following list of effective pages: \n\n\nPage Number\nRevision Level\nShown on Page \nDate \nShown on Page \n1-3, 5, 10-12, \n 14-18,\t\n\n1\n\nSeptember 5, 1991* \n4, 6-7, 13, 19\n2\nSeptember 24, 1992 \n8-9\t\n(None)\t\nDecember 5, 1991 \n\n\t(*The dates shown on pages indicating "REV 1" do not match the date of issuance of Revision 1 of this service bulletin.) \n\nThis incorporation by reference of Boeing Alert Service Bulletin 747-24A2168,Revision 2, dated September 24, 1992, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. The incorporation by reference of Boeing Alert Service Bulletin 747-24A2168, dated September 24, 1991, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51 as of February 18, 1992 (57 FR 3928, February 3, 1992). The incorporation by reference of Boeing Alert Service Bulletin 747-24A2168, Revision 1, dated December 5, 1991, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51 as of March 13, 1992 (57 FR 6665, February 27, 1992). Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\tThis amendment 39-8448, AD 92-27-13, supersedes AD 92-05-01, amendment 39-8180, which superseded AD 91-20-51, amendment 39-8152. \n\n\t(g)\tThis amendment becomes effective on March 1, 1993.