2005-20-03: Intercostal webs, attachment clips, and stringer splice channels

2005-20-03 Boeing: Amendment 39-14296. Docket No. FAA-2005-18788; Directorate Identifier 2003-NM-203-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective November 1, 2005. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, as identified in Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003; certificated in any category. \n\nUnsafe Condition \n\n\t(d) This AD was prompted by reports of fatigue cracks on several Boeing Model 737-200 series airplanes. We are issuing this AD to detect and correct fatigue cracking of the intercostals on the forward and aft sides of the forward entry door, which could result in loss of the forward entry door and rapid decompression of the airplane. \n\nCompliance \n\n\t(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\nServiceBulletin Definition \n\n\t(f) The term "service bulletin," as used in this AD, means Boeing Special Attention Service Bulletin 737-53-1204, dated June 19, 2003. \n\nInitial Compliance Time \n\n\t(g) Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after the effective date of this AD, whichever occurs later: Do the inspections specified in paragraph (h) or (i) of this AD, as applicable. \n\nInspection for Passenger Configuration Airplanes \n\n\t(h) For Group 1 passenger airplanes identified in the service bulletin: Perform a detailed inspection of the intercostal web, attachment clips, and stringer splice channels for cracks; and a high frequency eddy current inspection of the stringer splice channels, located forward and aft of the forward entry door, for cracks; per Parts 1 and 2 of the Work Instructions of the service bulletin. \n\nInspection for Cargo Configuration Airplanes \n\n\t(i) For Group 2 cargo airplanes identified in the service bulletin: Perform a detailed inspection of the intercostal webs and attachment clips located forward of the forward entry door for cracks, per Part 3 of the Work Instructions of the service bulletin. \n\nRepetitive Inspections \n\n\t(j) If no crack is found during any inspection required by paragraph (h) or (i) of this AD, repeat the inspections in paragraph (h) or (i) of this AD at the applicable time specified in Table 1 of this AD, except as provided by paragraph (k) of this AD. \n\n\tTable 1.--Repetitive Inspection Interval \n\n\nAirplane group number in Service Bulletin \nFor intercostal location- \nRepeat inspections at intervals not to exceed- \nGroup 1\nStringer-16L (S-16L), from Body Stringer 348.2 to BS 360 (aft of door) \n4,500 flight cycles. \nGroup 1 \nS-7L through S-15L, from BS 348.2 to BS 360 (aft of door) \n25,000 flight cycles. \nGroup 1 and 2\nS-7L through S-16L, from BS 294.5 to BS 303.9 (forward of door) \n25,000 flight cycles. \n\nDeferral of Certain Repetitive Inspections(k) For intercostal webs at S-16L from BS 348.2 to BS 360: Installation of the repair as a preventative modification or corrective action per Part 1 of the Work Instructions of the service bulletin defers the repetitive inspections to intervals not to exceed 25,000 flight cycles. For Model 737-400 series airplanes, use 737-400 Structural Repair Manual (SRM) 53-10-04, Figure 201, instead of Figure 202. \n\nCorrective Actions \n\n\t(l) If any crack is found during any inspection required by paragraph (h) or (i) of this AD, perform the actions specified in paragraphs (l)(1) through (l)(3) of Table 2 of this AD, as applicable. Repeat the inspections at the applicable time specified in Table 1 of this AD, except as provided by paragraph (k) of this AD. \n\n\tTable 2.--Corrective Actions \n\n\nDuring any inspection specified in- \nIf any crack is found in- \nAt intercostal location- \nBefore further flight- \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n(i)The intercoastal web \nS-16L, from BS 348.2 to BS 360 (aft of door). \nRepair per Part 1 of the Work Instructions of the service \nbulletin, except the service bulletin specifies to contact Boeing for repair instructions, before further flight, do the repair specified in paragraph (m) of this AD. Use 737-400 SRM 53-10- 04, Figure 201, instead of Figure 202, as applicable (see Note 1). \n\n\n\n\n(1) Part 1 of the Work Instructions of the service bulletin. \n(ii) An attachment clip or stringer splice channel. \nS-16L, from BSDo 348.2 to BS 360 (aft of door). \nDo the repair specified in paragraph (m) of this AD. \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n(2) Part 2 of the Work Instructions of the service bulletin. \nAn intercoastal web, attachment clip, or stringer splice channel. \nS-7L through S-16L, from BS \n294.5 to BS 303.9 (forward of \ndoor); and S-7L through S- \n15L, from BS 348.2 to BS 360 \n(aft of door). \nDo the repair specified in paragraph (m) of this AD. \n\n\n\n\n\n\n\n\n(3) Part 3 of the Work Instructions of the service bulletin. \nAn intercoastal web or attachment clip. \nS-7L through S-16L, from BS \n294.5 to BS 303.9 (forward of \ndoor). \nDo the repair specified in paragraph (m) of this AD. \n\n\tNote 1: The service bulletin specifies to repair any crack found at the S-16L intercostal (BS 348.2-360) on Boeing Model 737- 400 series airplanes per 737-400 SRM 53-10-04, Figure 202. Figure 202 does not exist; the correct figure is 737-400 SRM 53-10-04, Figure 201. \n\nRepair \n\n\t(m) At the time specified in Table 2 of this AD, repair 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 an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane and the approval must specifically refer to this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(n)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. \n\n\t(2) An AMOC that provides an acceptable level of safety may be used for corrective actions per data meeting the type certification basis of the airplane approved by a Boeing DOA Organization AR who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the approval must specifically reference this AD. \n\nMaterial Incorporated by Reference \n\n\t(o) You must use Boeing Special Attention Service Bulletin 737- 53-1204, dated June 19, 2003, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service information, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. To view the AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC. To review copies of the service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www. archives.gov/federal--register/ code--of --federal-- regulations/ ibr-- locations. html.