99-10-09: Wing Front Spar Web

99-10-09 BOEING: Amendment 39-11162. Docket 97-NM-100-AD. \n\n\tApplicability: Model 747-100, 747-200, and 747-SP series airplanes and military type E-4B airplanes; as listed in Boeing Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997; certificated in any category. \n\n\tNOTE 1: This AD applies to each airplane 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 airplanes 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 (d) 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. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tNOTE 2: Inspections and modifications accomplished prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-57A2303, dated December 19, 1996, are considered acceptable for compliance with the applicable action specified in this amendment. \n\n\tTo detect and correct fatigue cracking of the wing front spar web, which could result in a fuel leak, and consequent increased risk of a fire, accomplish the following: \n\nInitial and Repetitive Inspections \n\n\t(a)\tPerform an ultrasonic inspection to detect cracking of the wing front spar web at the fastener rows behind and between the upper link fittings for the number 2 and 3 engine struts, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997, at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. \n\n\t\t(1)For airplanes identified as Group 1, 2, 3, or 5 in the alert service bulletin: Inspect prior to the accumulation of 12,500 total flight cycles, or within 15 months after the effective date of this AD, whichever occurs later. Repeat the inspection thereafter at intervals not to exceed 2,200 flight cycles. \n\n\t\t(2)\tFor airplanes identified as Group 4, 6, 7, 8, 9, or 10 in the alert service bulletin: Inspect prior to the accumulation of 18,000 total flight cycles, or within 15 months after the effective date of this AD, whichever occurs later. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. \n\nCorrective Actions \n\n\t(b)\tIf any crack is found during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD. \n\n\t\t(1)\tAccomplish the terminating action in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997.Accomplishment of this action constitutes terminating action for the repetitive inspection requirements of this AD; or \n\n\t\t(2)\tRepair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle, ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. \n\nOptional Terminating Action \n\n\t(c)\tReplacement of the affected wing front spar web with a new shot-peened wing front spar web in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997, constitutes terminating action for the repetitive inspection requirements of this AD, and, for the modified area only, for the repetitive inspection requirements of AD 98-15-21, amendment 39-10672. \n\n\tNOTE 3: The area subject to the optional terminating action specified in paragraph (c) of this AD overlaps with part of the wing front spar that is the subject of AD 98-15-21.\n\nAlternative Method of Compliance \n\n\t(d)\tAn 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, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\n\tNOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(e)\tSpecial 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 airplane to a location where the requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(f)\tThe inspections and replacement shall be done in accordance with Boeing Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997. 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. 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\nEffective Date \n\n\t(g)\tThis amendment becomes effective on June 15, 1999.