Airworthiness Directive · Amendment 39-13911 · Boeing Model 747 Series Airplanes
Boeing Model 747 Series Airplanes
Superseded. A later AD replaced this one: AD 2005-09-02. Comply with the one in force.
All Model 747 series airplanes, certificated in any category.
This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 747 series airplanes, that requires repetitive inspections for cracking of the top and side panel webs and panel stiffeners of the nose wheel well (NWW), and corrective actions if necessary. This action is necessary to detect and correct fatigue cracks in the top and side panel webs and stiffeners of the NWW, which could compromise the structural integrity of the NWW and could lead to the rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.
To 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:
(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.
(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.
(i) Do detailed and ultrasonic inspections of the top and side panel webs of the NWW for cracks.
(ii) Do detailed and surface high frequency eddy current (HFEC) inspections of the top and side panel stiffeners of the NWW for cracks.
(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.
(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.
(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.
Note 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.”
(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.
(1) Repair web cracks.
(2) Replace cracked stiffeners with new stiffeners.
(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.
(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.
(e) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-53A2465, 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: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
