93-13-02\tBOEING: Amendment 39-8615. Docket 92-NM-238-AD. \n\n\tApplicability: All Model 737-200C series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously.\n \n\tTo prevent a cargo door from opening while the airplane is in flight, which could result in rapid decompression of the airplane, accomplish the following: \n\n\t(a)\tPrior to the accumulation of 29,000 flight cycles or within 250 flight cycles after the effective date of this AD, whichever occurs later, accomplish an external detailed visual inspection to detect cracks of the fuselage skin between stringers 19 left and 25 left and at body stations 360 to 540, in accordance with Boeing Alert Service Bulletin 737-53A1160, dated October 24, 1991; or Boeing Service Bulletin 737-53A1160, Revision 1, dated April 29, 1993. If any crack is found, prior to further flight, accomplish the requirements of paragraph (a)(1) and (a)(2) of this AD. \n\n\t\t(1)\tPerform an internal detailed visual inspection to detect cracks of the frames between stringer 19 left and 25 left and body stations 360 to 500B, in accordance with either service bulletin.\n \n\t\t(2)\tRepair all cracks in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\t(b)\tWithin 3,000 flight cycles after completing the requirements of paragraph (a) of this AD, unless accomplished within the last 6,000 flight cycles prior to the effective date of this AD, perform an internal detailed visual inspection to detect cracks of the frames between stringers 19 left and 25 left and at body stations 360 to 500B in accordance with Boeing Alert Service Bulletin 737-53A1160, dated October 24, 1991; or Boeing Service Bulletin 737-53A1160, Revision 1, dated April 29, 1993. Thereafter, repeat the internal detailed visual inspection at intervals not to exceed 9,000 flight cycles. If any crack is found, prior to further flight, accomplish the requirements of paragraph (b)(1) or (b)(2) of this AD, as applicable. \n\n\t\t(1)\tIf any crack is found that does not exceed the limits specified in the Boeing 737 Structural Repair Manual (SRM), repair the crack in accordance with the Boeing 737 SRM. Repeat the internal detailed visual inspection at intervals not to exceed 9,000 flight cycles.\n \n\t\t(2)\tIf any crack is found that exceeds the limits specified in the Boeing 737 SRM, repair the crack in an accordance with a method approved by the Manager, Seattle ACO, FAA, Transport Airplane Directorate. Repeat the internal detailed visual inspection at intervals not to exceed 9,000 flight cycles. \n\n\t(c)\tInstallation of the preventative modification in accordance with Boeing Service Bulletin 737-53A1160, Revision 1, dated April 29, 1993, constitutes terminating action for the repetitive inspections required by paragraphs (b)(1) and (b)(2) of this AD.\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, FAA, Transport Airplane Directorate. 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: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\n\t(e)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(f)\tThe inspections and modification shall be done in accordance with Boeing Alert Service Bulletin 737-53A1160, dated October 24, 1991; or Boeing Service Bulletin 737-53A1160, Revision 1, dated April 29, 1993. 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\n\t(g)\tThis amendment becomes effective on August 9, 1993.