2004-25-23: Nose wheel well (NWW)

2004-25-23 Boeing: Amendment 39-13911. Docket 2001-NM-179-AD. \n\n\tApplicability: All Model 747 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo detect and correct fatigue cracks in the top and side panel webs and stiffeners of the nose wheel well (NWW), which could compromise the structural integrity of the NWW and could lead to the rapid depressurization of the airplane, accomplish the following: \n\nInitial and Repetitive Inspections \n\n\t(a) Prior to the accumulation of 16,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later, do the inspections specified in either paragraph (a)(1) or (a)(2) of this AD. \n\n\t(1) Do the inspections specified in paragraphs (a)(1)(i) and (a)(1)(ii) of this AD in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003. Repeat the inspections thereafter at intervals not to exceed 1,000 flight cycles. \n\n\t(i) Do detailed and ultrasonic inspections of the top and side panel webs of the NWW for cracks. \n\n\t(ii) Do detailed and surface high frequency eddy current (HFEC) inspections of the top and side panel stiffeners of the NWW for cracks. \n\n\t(2) Do the inspections specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004. Repeat the inspections thereafter at the intervals specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.\n\n\t(i) Do external detailed inspections of the top and side panel webs of the NWW (specified as Area 1 and Area 2 in the service bulletin), as applicable, for cracks. Repeat the inspections thereafter at intervals not to exceed 1,000 flight cycles. \n\n\t(ii) Do internal detailed and surface HFEC inspections of the top and side panel stiffeners of the NWW (specified as Area 3 in the service bulletin) for cracks. Repeat the inspections thereafter at intervals not to exceed 6,000 flight cycles. \n\n\tNote 1: For the purposes of this AD, a detailed inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required." \n\nCorrective Actions \n\n\t(b) If any crack is found during any inspection required by paragraph (a) of this AD: Prior to further flight, do the applicable corrective actions specified in paragraphs (b)(1) and (b)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003; or Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004; as applicable. Thereafter, repeat the inspections required by paragraph (a) of this AD at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. \n\n\t(1) Repair web cracks. \n\n\t(2) Replace cracked stiffeners with new stiffeners. \n\nInspections Accomplished per Previous Issue of Service Bulletin \n\n\t(c) Inspections accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2465, dated April 5, 2001, are considered acceptable for compliance with the corresponding inspections specified in paragraph (a) of this AD. \n\nAlternative Methods of Compliance \n\n\t(d) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD. \n\nIncorporation by Reference \n\n\t(e) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin747-53A2465, Revision 1, dated October 16, 2003; or Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004. 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 Airplanes, 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 National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to:\nhttp://www.archives.gov/ federal--register/code_of_federal_regulations/ibr_locations.html. \n\nEffective Date \n\n\t(f) This amendment becomes effective on January 27, 2005.