AD 98-25-06

Final rule

98-25-06 BOEING: Amendment 39-10931. Docket 98-NM-291-AD.\n\n\tApplicability: The following airplane models, certificated in any category:\n\n\t--\tModel 737-200 and -200C series airplanes, line numbers 6 through 873 inclusive;\n\n\t--\tModel 737-200, -200C, -300, and -400 series airplanes; line numbers 874 through 1642 inclusive; equipped with an aft cargo door having Boeing part number (P/N) 65-47952-1 or P/N 65-47952-524; except:\n\n\t1.\tThose airplanes on which that door has been modified in accordance with Boeing Service Bulletin 737-52-1079; or,\n\n\t2.\tThose airplanes on which the door assembly having P/N 65-47952-524 includes four straps (P/N's 65-47952-139, 65-47952-140, 65-47952-141, and 65-47952-142) and a thicker lower cross beam web (P/N 65-47952-157).\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 (d) 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 fatigue cracking of the corners of the door frame and the cross beams of the aft cargo door, which could result in rapid depressurization of the airplane, accomplish the following:\n\n\t(a)\tWithin 90 days or 700 flight cycles after the effective date of this AD, whichever occurs later, perform an internal detailed visual inspection to detect cracking of the corners of the door frame and the cross beams of the aft cargo door, in accordance with Boeing Service Bulletin 737-52-1079, Revision 5, dated May 16, 1996.\n\n\t\t(1)\tIf no cracking is detected, accomplish the requirements of either paragraph (a)(1)(i) or (a)(1)(ii) of this AD.\n\n\t\t\t(i)\tRepeat the internal visual inspection thereafter at intervals not to exceed 4,500 flight cycles. Or,\n\n\t\t\t(ii)\tPrior to further flight, modify the corners of the door frame and the cross beams of the aft cargo door in accordance with the service bulletin. Accomplishment of such modification constitutes terminating action for the repetitive inspection requirements of this AD.\n\n\t\t(2)\tIf any cracking is detected in the upper or lower cross beams, prior to further flight, modify the cracked beam in accordance with paragraph III.C. of Part I of the Accomplishment Instructions of the service bulletin. Accomplishment of such modification constitutes terminating action for the repetitive inspection requirements of this AD for the repaired beam.\n\n\t\t(3)\tIf any cracking is detected in the forward or aft upper door frame, prior to further flight, repair the frame and modify the corners of the door frame of the aft cargo door, in accordance with paragraph III.E. of Part I of the Accomplishment Instructions of the service bulletin, except as provided by paragraph (b) of this AD. Accomplishment of such modification constitutes terminating action for the repetitive inspection requirements of this AD for the upper door frame.\n\n\tNOTE 2: Cracks of the forward or aft upper door frame, regardless of length, must be repaired prior to further flight in accordance with paragraph III.E. of Part I of the Accomplishment Instructions of the service bulletin.\n\n\t\t(4)\tIf any cracking is detected in the forward or aft lower door frame, prior to further flight, replace the damaged frame with a new frame, and modify the corners of the door frame of the aft cargo door, in accordance with paragraph III.F. of Part I of the Accomplishment Instructions of the service bulletin. Accomplishment of such modification constitutes terminating action for the repetitive inspection requirements of this AD for the lower door frame.\n\n\t(b)\tWhere Boeing Service Bulletin 737-52-1079, Revision 5, dated May 16, 1996, specifies that certain repairs are to be accomplished in accordance with instructions received from Boeing, this AD requires that, prior to further flight, such repairs be accomplished in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.\n\n\t(c)\tModification of the corners of the door frame and the cross beams of the aft cargo door in accordance with Boeing Service Bulletin 737-52-1079, Revision 5, dated May 16, 1996, or in accordance with the requirements of AD 90-06-02, amendment 39-6489, constitutes terminating action for the repetitive inspection requirements of this AD.\n\n\tNOTE 3: Modification of the corners of the door frame and the cross beams of the aft cargo door accomplished prior to the effective date of this AD in accordance with Boeing Service Bulletin 737-52-1079, dated December 16, 1983; Revision 1, dated December 15, 1988; Revision 2, dated July 20, 1989; Revision 3, dated May 17, 1990; or Revision 4, dated February 21, 1991; are considered acceptable for compliance with paragraph (c) 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. 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 4: 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(e)\tSpecial flight permits may be issued in 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(f)\tExcept as provided by paragraph (b) of this AD, the inspections, repair, replacement, and modification (if accomplished), shall be done in accordance with Boeing Service Bulletin 737-52-1079, Revision 5, dated May 16, 1996. 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 December 24, 1998.