AD 2004-22-05 Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes

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

This AD applies to all Boeing Model 737-300, -400, and -500 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. Repetitive Detailed Inspections (f) For airplanes specified in either paragraph (f)(1), (f)(2), (f)(3), or (f)(4) of this AD: Accomplish a detailed inspection for discrepancies (wear or cracking) of the fuselage skin under the dorsal fin assembly by doing all the actions specified in Boeing Message Number 1-QXO35, dated October 13, 2004. Repeat the inspection thereafter at intervals not to exceed 9,000 flight cycles. 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.” (1) For airplanes with line numbers 1001 through 2828 inclusive that have not been inspected as of the effective date of this AD, in accordance with Boeing Service Bulletin 737-55-1057, dated December 12, 1996; or Revision 1, dated July 22, 1999: Inspect before the accumulation of 18,000 total flight cycles, or within 90 days after the effective date of this AD, whichever is later. (2) For airplanes with line numbers 2829 through 3132 inclusive that are not included in the effectivity of Boeing Service Bulletin 737-55-1057, dated December 12, 1996; or Revision 1, dated July 22, 1999: Inspect before the accumulation of 18,000 total flight cycles, or within 90 days after the effective date of this AD, whichever is later. (3) For airplanes with line numbers 1001 through 2828 inclusive that have been inspected, but not repaired or modified as of the effective date of this AD, in accordance with Boeing Service Bulletin 737-55-1057, dated December 12, 1996; or Revision 1, dated July 22, 1999: Inspect within 9,000 flight cycles after accomplishing the inspection, or within 90 days after the effective date of this AD, whichever is later. (4) For airplanes with line numbers 1001 through 2828 inclusive that have been inspected and repaired or modified as of the effective date of this AD, in accordance with Boeing Service Bulletin 737-55-1057, dated December 12, 1996; or Revision 1, dated July 22, 1999: Inspect within 18,000 flight cycles after accomplishing the repair or modification, or within 90 days after the effective date of this AD, whichever is later; and if a repair doubler is installed, before further flight, inspect the repair doubler for discrepancies (wear or cracking). Note 2: Boeing Message Number 1-QXO35, dated October 13, 2004, references Part I of Boeing Service Bulletin 737-55-1057, Revision 1, dated July 22, 1999; as an additional source of service information for accomplishing the actions required by paragraph (f) of this AD. Repair (g) If any discrepancy (wear or cracking) is found during any inspection required by this AD, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER) who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically refer to this AD. Note 3: No terminating action is currently available for the repetitive inspections required by this AD. Reporting Not Required (h) Although Boeing Message Number 1-QXO35, dated October 13, 2004, specifies to report any fuselage skin cracking found during the detailed inspections, this AD does not include that requirement. Alternative Methods of Compliance (AMOCs) (i)(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) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the approval must specifically refer to this AD. Material Incorporated by Reference (j) You must use Boeing Message Number 1-QXO35, dated October 13, 2004, 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. For copies of the service information, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. You can review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW, room PL-401, Nassif Building, Washington, DC; 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 October 18, 2004. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 04-23924 Filed 10-26-04; 8:45 am] BILLING CODE 4910-13-P

This AD was prompted by a report of an 18-inch crack found in the fuselage skin area under the blade seals of the nose cap of the dorsal fin due to previous wear damage. We are issuing this AD to find and fix discrepancies of the fuselage skin, which could result in fatigue cracking due to cabin pressurization, and consequent rapid in-flight decompression of the airplane fuselage.