AD 2006-12-17 Airworthiness Directives; Boeing Model 737-200C Series Airplanes

Models named: 737-200C series. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to all Boeing Model 737-200C series airplanes, certificated in any category.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Restatement of Requirements of AD 99-12-08 One-Time External Detailed Inspection (f) Prior to the accumulation of 29,000 total flight cycles or within 250 flight cycles after August 9, 1993 (the effective date AD 93-13-02, amendment 39-8615, which was superseded by AD 99-12-08), whichever occurs later, accomplish an external detailed inspection to detect cracks of the fuselage skin between stringers 19 left and 25 left and at BS 360 to BS 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 paragraphs (f)(1) and (f)(2) of this AD. (1) Perform an internal detailed inspection to detect cracks of the frames between stringers 19 left and 25 left and at BS 360 to BS 500B, in accordance with either service bulletin. (2) Repair all cracks in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), Transport Airplane Directorate, FAA. Internal Detailed Inspections (g) Within 3,000 flight cycles after completing the requirements of paragraph (f) of this AD, unless accomplished within the last 6,000 flight cycles prior to August 9, 1993, perform an internal detailed 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 inspection at intervals not to exceed 9,000 flight cycles. If any crack is found during any inspection required by this paragraph, before further flight, repair as specified in paragraph (g)(1) or (g)(2) of this AD, as applicable. (1) If 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 a method approved by the Manager, Seattle ACO; or in accordance with the procedures specified in paragraph (k)(4) of this AD. The SRM is one approved source of information for accomplishing the requirements of this paragraph. Repeat the internal detailed inspection thereafter at intervals not to exceed 9,000 flight cycles. (2) If any crack is found that exceeds the limits specified in the SRM, repair the crack in accordance with a method approved by the Manager, Seattle ACO; or in accordance with the procedures specified in paragraph (k)(4) of this AD. Repeat the internal detailed visual inspection thereafter at intervals not to exceed 9,000 flight cycles. Install Doublers (h) Prior to the accumulation of 75,000 total flight cycles, or within 3,000 flight cycles after July 16, 1999 (the effective date of AD 99-12-08), whichever occurs later, install doublers on the specified frames located between stringers 19 left and 25 left from BS 360 to BS 500B, in accordance with Boeing Service Bulletin 737-53A1160, Revision 1, dated April 29, 1993. Installing these doublers on the specified fuselage frames ends the repetitive inspections required by paragraphs (f) and (g) of this AD. New Requirements of This AD Repetitive Inspection of Certain Frames (i) Within 9,000 flight cycles after accomplishing the modification required by paragraph (h) of this AD, or within 4,500 flight cycles after the effective date of this AD, whichever occurs later, perform an internal detailed inspection to detect cracking in the fuselage frame at BS 360 and the fuselage frame at BS 500, between stringers 19 left and 25 left, 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 inspection of the BS 360 and BS 500 frames at intervals not to exceed 9,000 flight cycles. (j) If any crack is found during any inspection required by paragraph (i) of this AD, before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (k) of this AD. Note 1: For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.” Alternative Methods of Compliance (AMOCs) (k)(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. (2) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office. (3) AMOCs approved previously in accordance with AD 99-12-08, including AMOCs approved previously in accordance with AD 93-13-02, are approved as AMOCs for the corresponding provisions specified in paragraphs (f), (g), and (h) of this AD. (4) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes 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. Material Incorporated by Reference (l) You must use Boeing Alert Service Bulletin 737-53A1160, dated October 24, 1991; or Boeing Service Bulletin 737-53A1160, Revision 1, dated April 29, 1993, as applicable, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of these documents on August 9, 1993 (58 FR 36863, July 9, 1993). Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at 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. Issued in Renton, Washington, on June 5, 2006. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 06-5287 Filed 6-12-06; 8:45 am] BILLING CODE 4910-13-P

This AD results from multiple reports that the modification required by AD 99-12-08 is not fully effective in preventing cracks in the body station (BS) 360 and BS 500 fuselage frames. We are issuing this AD to detect and correct cracking of the fuselage frames from BS 360 to BS 500B, which could lead to loss of the cargo door during flight and consequent rapid decompression of the airplane.