97-22-07: Fuselage Lap Joints

97-22-07 BOEING: Amendment 39-10179. Docket 97-NM-229-AD. Supersedes AD 94-25-05, Amendment 39-9089. \n\n\tApplicability: Model Boeing 737 series airplanes having line numbers 292 through 2565 inclusive, 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 otherwise 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 (i) 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 sudden decompression of the airplane, accomplish the following: \n\n\t(a)\tPerform a low frequency eddy current inspection to detect cracking of the lower skin at the lower row of fasteners in the lap joints of the fuselage at the time specified in paragraph (b) or (c) of this AD, as applicable, in accordance with Part I ("Inspection") of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1177, dated November 8, 1994; Revision 1, dated September 19, 1996; Revision 2, dated July 24, 1997; or Revision 3, dated September 18, 1997. \n\n\t(b)\tFor airplanes that have accumulated 70,000 total flight cycles or more as of the effective date of this AD: Perform the inspection required by paragraph (a) of this AD at the later of the times specified in paragraphs (b)(1) and (b)(2) of this AD. \n\n\t\t(1)\tWithin 100 flight cycles after the effective date of this AD. \n\t\t(2)\tWithin 300 flight cycles afterthe last inspection accomplished in accordance with AD 94-25-05, amendment 39-9089. \n\n\t(c)\tFor airplanes that have accumulated less than 70,000 total flight cycles as of the effective date of this AD: Perform the inspection required by paragraph (a) of this AD at the later of the times specified in paragraphs (c)(1) and (c)(2) of this AD. \n\n\t\t(1)\tPrior to the accumulation of 60,000 total flight cycles. \n\t\t(2)\tAt the earliest of the times specified in paragraph (c)(2)(i), (c)(2)(ii), \t\t\tand (c)(2)(iii) of this AD. \n\t\t\t(i)\tWithin 3,500 flight cycles after the last inspection \t\t\t\t\taccomplished in accordance with AD 94-25-05, amendment \t\t\t\t39-9089. \n\t\t\t(ii)\tWithin 1,200 flight cycles after the effective date of this AD.\n\t\t\t(iii)\tPrior to the accumulation of 70,300 total flight cycles. \n\n\t(d)\tIf any cracking is detected during the inspection required by paragraph (a) of this AD, prior to further flight, repair it in accordance with Part II ("Crack Repair") of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1177, dated November 8, 1994; Revision 1, dated September 19, 1996; Revision 2, dated July 24, 1997; or Revision 3, dated September 18, 1997. \n\n\t(e)\tRepeat the inspection required by paragraph (a) of this AD at the time specified in paragraph (e)(1) or (e)(2) of this AD, as applicable, until the modification required by paragraph (f) or (g) of this AD, as applicable, is accomplished. \n\n\t\t(1)\tIf the airplane had accumulated less than 70,000 total flight cycles at the time of the immediately preceding inspection, perform the next inspection within 1,200 flight cycles or prior to the accumulation of 70,300 total flight cycles, whichever occurs first. \n\n\t\t(2)\tIf the airplane had accumulated 70,000 or more total flight cycles at the time of the immediately preceding inspection, perform the next inspection within 300 flight cycles.\n\n\t(f)\tExcept as provided by paragraph (g) of this AD, modify the fuselage lap joints at the lower rowof fasteners at stringer locations right/left stringer 4 between body station (BS) 360 and BS 1016; and right/left stringers 10 and 14 between BS 360 and BS 540, and between BS 727 and BS 1016; in accordance with Part III ("Preventive Change") of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1177, Revision 1, dated September 19, 1996; Revision 2, dated July 24, 1997; or Revision 3, dated September 18, 1997; at the time specified in paragraph (h) of this AD. Accomplishment of this modification constitutes terminating action for the repetitive inspections only for the areas that have been modified in accordance with this AD. \n\n\t(g)\tFor Boeing Model 737-200 series airplanes only: \n\n\t\t(1)\tExcept as provided in paragraphs (g)(2) and (g)(3) of this AD, in lieu of accomplishing the modification ("Preventive Change") specified in paragraph (f) of this AD, installation of the lap joint repair in accordance with Part IV ("Lap Joint Repair") of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1177, Revision 3, dated September 18, 1997, at the locations specified in Part IV of the alert service bulletin, may be accomplished. Accomplishment of the repair constitutes terminating action for the repetitive inspections only for the areas that have been modified in accordance with this AD. \n\n\t\t(2)\tPrior to conducting the repair, support the airplane in the jig position, including support (removal) of the engine weight, in accordance with Boeing Document D6-15565, "737 Structural Repair Manual (SRM)," Chapter 51, Subject 51-50-1, Revision 70, dated July 5, 1997. \n\n\tNOTE 2: Chapter 51, Subject 51-50-1 of the referenced SRM references Subjects 51-50-2, 51-50-3, and 51-60 of the referenced SRM as additional sources of service information.\n\n\t\t(3)\tNotwithstanding the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1177, Revision 3, dated September 18, 1997, the repair described in paragraph (g)(1) of this ADmay be accomplished without installing a support cradle at station 540. \n\n\t(h)\tAccomplish the modification required by paragraph (f) or (g) of this AD, as applicable, at the latest of the times specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD. \n\t\t(1)\tPrior to the accumulation of 70,000 total flight cycles. \n\t\t(2)\tWithin 600 flight cycles after the effective date of this AD. \n\t\t(3)\tWithin 80 days after the effective date of this AD. \n\n\t(i)\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\tNOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\t(j)\tSpecial flight permits may be issuedin 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\n\t(k)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 737- 53A1177, dated November 8, 1994; Boeing Alert Service Bulletin 737-53A1177, Revision 1, dated September 19, 1996; Boeing Alert Service Bulletin 737-53A1177, Revision 2, dated July 24, 1997; Boeing Alert Service Bulletin 737-53A1177, Revision 3, dated September 18, 1997; and Boeing Document D6-15565, "737 Structural Repair Manual (SRM)," Chapter 51, Subject 51-50-1, Revision 70, dated July 5, 1997, which contains the following list of effective pages (NOTE: The issue date and revision level of the SRM are indicated only on the Title Page; no other page of the document contains this information.): \n\n\nPage Number\nRevision Level\nShown on Page \nDate\nShown on Page \nTitle Page\n70\nJuly 5, 1997 \n1Not Shown\nFebruary 5, 1989 \n2, 3, 11, 12\nNot Shown\nAugust 5, 1988 \n4\nNot Shown\nFebruary 1, 1978 \n5, 6, 8-10\nNot Shown\nAugust 1, 1968 \n7\nNot Shown\nFebruary 1, 1975 \n\n\t\t(1)\tThe incorporation by reference of Boeing Alert Service Bulletin 737-53A1177, Revision 1, dated September 19, 1996; Boeing Alert Service Bulletin 737-53A1177, Revision 2, dated July 24, 1997; Boeing Alert Service Bulletin 737-53A1177, Revision 3, dated September 18, 1997; and Boeing Document D6-15565, "737 Structural Repair Manual (SRM)," Chapter 51, Subject 51-50-1, Revision 70, dated July 5, 1997; is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. \n\t\t(2)\tThe incorporation by reference of Boeing Alert Service Bulletin 737-53A1177, dated November 8, 1994, was approved previously by the Director of the Federal Register as of December 27, 1994 (59 FR 63716, December 9, 1994). \n\n\t\t(3)\tCopies 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\n\t(l)\tThis amendment becomes effective on November 12, 1997.