AD 2008-05-06 Airworthiness Directives; Boeing Model 737-100, -200, -300, -400, and -500 Series Airplanes

Models named: 737-100, -200, -300, -400, -500 series. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, certificated in any category; as identified in Boeing Service Bulletin 737-57-1296, dated June 13, 2007.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Repetitive Inspections (f) Do the various inspections for fatigue cracks in the longitudinal floor beam web, upper chord, and lower chord, located at the applicable body stations specified in the Accomplishment Instructions of Boeing Service Bulletin 737-57-1296, dated June 13, 2007, by doing all the actions specified in the Accomplishment Instructions of the service bulletin, except as provided by paragraph (g) of this AD. Do the inspections at the time specified in paragraph (f)(1) or (f)(2) of this AD, as applicable. (1) For Groups 1 and 2 airplanes as identified in the service bulletin: Do the inspections at the applicable initial compliance time listed in paragraph 1.E., “Compliance,” of the service bulletin; except, where the service bulletin specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. Repeat the inspections thereafter at the intervals specified in paragraph 1.E., “Compliance,” of the service bulletin. (2) For Group 3 airplanes as identified in the service bulletin: Do the inspections at the applicable initial compliance time listed in paragraph 1.E., “Compliance,” of the service bulletin; except, where the service bulletin specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. Repeat the inspections thereafter at the intervals specified in paragraph 1.E., “Compliance,” of the service bulletin. (g) If any crack is found during any inspection required by this AD, and Boeing Service Bulletin 737-57-1296, dated June 13, 2007, specifies contacting Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (h) of this AD. Alternative Methods of Compliance (AMOCs) (h)(1) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. (2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. (3) 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. Material Incorporated by Reference (i) You must use Boeing Service Bulletin 737-57-1296, dated June 13, 2007, to do the actions required by this AD, unless the AD specifies otherwise. (1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. (2) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. (3) You may review copies of the service information incorporated by reference at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at 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 February 20, 2008. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E8-3810 Filed 3-3-08; 8:45 am] BILLING CODE 4910-13-P

This AD results from several reports of cracks in the center wing box longitudinal floor beams, upper chord, and lower chord. We are issuing this AD to detect and correct fatigue cracking of the upper and lower chords and web of the longitudinal floor beams, which could result in rapid loss of cabin pressure.