2002-10-10: Fuselage Internal Structure

2002-10-10 Boeing: Amendment 39-12756. Docket 2000-NM-355-AD. Supersedes AD 93-08-12, Amendment 39-8559. \n\n\tApplicability: Model 747 series airplanes, as listed in Boeing Service Bulletin 747-53-2349, dated June 27, 1991, or Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000; 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 (h)(1) 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\tTo prevent loss of the structural integrity of the fuselage, which could result in rapid depressurization of the airplane, do the following: \n\nRestatement of Requirements of AD 93-08-12 \n\nRepetitive Inspections \n\n\t(a) Prior to the accumulation of 22,000 total flight cycles, or within 1,000 flight cycles after June 11, 1993 (the effective date of AD 93-08-12, amendment 39-8559), whichever occurs later, unless accomplished previously within the last 2,000 flight cycles; and thereafter at intervals not to exceed 3,000 flight cycles: Perform a detailed internal inspection to detect cracks in the areas of the fuselage internal structure specified in paragraphs (a)(1) through (a)(7) of this AD; in accordance with Boeing Service Bulletin 747-53-2349, dated June 27, 1991. \n\n\t\t(1) Sections 41 and 42 upper deck floor beams. \n\n\t\t(2) Section 42 upper lobe frames. \n\n\t\t(3) Section 46 lower lobe frames. \n\n\t\t(4) Section 42 lower lobe frames. \n\n\t\t(5) Main entry door cutouts. \n\n\t\t(6) Section 41 body station 260, 340, and 400 bulkheads. \n\n\t\t(7) Main entry doors. \n\n\t(b) Prior to the accumulation of 25,000 total flight cycles, or within 1,000 flight cycles after June 11, 1993, whichever occurs later, unless accomplished previously within the last 2,000 flight cycles; and thereafter at intervals not to exceed 3,000 flight cycles: Perform a detailed internal inspection to detect cracks in the Section 46 upper lobe frames, in accordance with Boeing Service Bulletin 747-53-2349, dated June 27, 1991. \n\nRepair \n\n\t(c) Prior to further flight, repair any cracks detected during the inspections done per paragraph (a) or (b) of this AD, per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER) 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 approval letter must specifically reference this AD. \n\nNew Requirements of This AD \n\nRepetitive Inspections \n\n\t(d) Before the accumulation of 22,000 total flight cycles, or within 3,000 flight cycles after doing the most recent inspection required by paragraph (a) of this AD, whichever occurs later: Do a detailed inspection to find cracking in the areas specified in paragraph (d)(1) or (d)(2) of this AD, as applicable, per Figure 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000. Repeat the inspection after that every 3,000 flight cycles. Doing this inspection terminates the inspections required by paragraph (a) of this AD in the area specified in paragraph (a)(1) of this AD only. \n\n\t\t(1) For Groups1, 2, 4, and 5 airplanes: Do the inspections of Area 1 (sections 41 and 42 upper deck floor beams), including existing repairs and modifications. \n\t\n\t\t(2) For Group 3 airplanes: Do the inspections of Area 1 (sections 41, 42, and 44 upper deck floor beams from body stations 380 through 1100 inclusive), including existing repairs and modifications. \n\n\tNote 2: 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 mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required." \n\n\t(e) Before the accumulation of 28,000 total flight cycles, or within 3,000 flight cycles after doing the most recent inspection required by paragraph (a)of this AD, whichever occurs later: Do a high frequency eddy current (HFEC) inspection to find cracking of the open holes in the horizontal flanges of the upper chord of each upper deck floor beam in the areas specified in paragraph (e)(1) or (e)(2) of this AD, as applicable, per the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000. Do the inspection per "Inspection Alternatives," as specified in Sheet 7 of Figure 2 of the Accomplishment Instructions of the service bulletin. Repeat the applicable inspection according to the "Repeat Inspection Intervals," specified in Sheet 7 of Figure 2 of the Accomplishment Instructions of the service bulletin. \n\t\n\t\t(1) For Group 1, 2, 4, and 5 airplanes: Do the inspections at the applicable locations (BS 380 through BS 780 inclusive for Groups 1, 2, and 4, BS 380 through BS 860 inclusive for Group 5) as specified in Sheet 7 of Figure 2. \n\n\t\t(2) For Group 3 airplanes: Do the inspections as specified in Sheet 7 of Figure 2, at the upper deck floor beams from BS 380 through BS 1100 inclusive. \n\n\tNote 3: HFEC inspections of the left and right sides of the upper deck floor beam at body station 380, between buttock lines 40 and 76, done per AD 2000-04-17, amendment 39-11600, are considered acceptable for compliance with the applicable inspections specified in paragraph (e) of this AD. \n\nAdjustments to Compliance Time: Cabin Differential Pressure \n\n\t(f) For the purposes of calculating the compliance threshold and repetitive interval for the actions required by paragraphs (d) and (e) of this AD: For Area 1 only, the number of flight cycles in which cabin differential pressure is at 2.0 pounds per square inch (psi) or less need not be counted when determining the number of flight cycles that have occurred on the airplane, provided that flight cycles with momentary spikes in cabin differential pressure above 2.0 psi are included as full pressure cycles. For this provisionto apply, all cabin pressure records must be maintained for each airplane: NO fleet-averaging of cabin pressure is allowed. \n\nRepair \n\n\t(g) Before further flight, repair any cracking found during the inspections done per paragraphs (d) and (e) of this AD, according to Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000. Where the service bulletin specifies to contact Boeing for repair instructions, repair per a method approved by the Manager, Seattle ACO; or per data meeting the type certification basis of the airplane approved by a Boeing Company DER 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 approval letter must specifically reference this AD. \n\nAlternative Methods of Compliance \n\n\t(h)(1) 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, 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\t(2) Alternative methods of compliance and FAA-approved repairs, approved previously in accordance with AD 93-08-12, amendment 39-8559, are approved as alternative methods of compliance with this AD. \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(i) Special flight permits may be issued in accordance with §§ 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(j) Except as provided by paragraphs (c), (f), and (g) of this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-53-2349, dated June 27, 1991; and Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000; as applicable. \n\n\t\t(1) The incorporation by reference of Boeing Alert Service Bulletin 747-53A2349, Revision 1, dated October 12, 2000, as listed in the regulations, is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. \n\n\t\t(2) The incorporation by reference of Boeing Service Bulletin 747-53-2349, dated June 27, 1991, was approved previously by the Director of the Federal Register as of June 11, 1993 (58 FR 27927, May 12, 1993). \n\n\t\t(3) 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(k) This amendment becomes effectiveon June 27, 2002.