Airworthiness Directive · Amendment 39-15870 · Boeing Model 737-300, -400, and -500 Series Airplanes
Boeing Model 737-300, -400, and -500 Series Airplanes
This AD applies to all Boeing Model 737-300, -400, and -500 series airplanes, certificated in any category.
The FAA is superseding an existing airworthiness directive (AD), which applies to all Boeing Model 737-300, -400, and -500 series airplanes. That AD currently requires repetitive inspections for discrepancies of the fuselage skin under the dorsal fin assembly, and repairing if necessary. This new AD requires an inspection for any chafing or crack in the fuselage skin and abrasion resistant coating at the dorsal fin landing, an inspection for damage to the dorsal fin seals, attach clip, and seal retainer, and other specified and corrective actions as necessary. The new requirements will end the need for the existing repetitive inspections. This AD results from 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, and additional reports of fuselage skin wear. We are issuing this AD to prevent 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.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
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. Accomplishing all of the applicable actions specified in paragraph (i) of this AD terminates the repetitive inspections required by this paragraph.
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 November 12, 2004 (the effective date of AD 2004-22-05), 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 November 12, 2004, 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 November 12, 2004, whichever is later.
(3) For airplanes with line numbers 1001 through 2828 inclusive that have been inspected, but not repaired or modified as of November 12, 2004, 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 November 12, 2004, whichever is later.
(4) For airplanes with line numbers 1001 through 2828 inclusive that have been inspected and repaired or modified as of November 12, 2004, 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 November 12, 2004, 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.
If any discrepancy (wear or cracking) is found during any inspection required by paragraph (f) of this AD, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or using a method approved in accordance with the procedures specified in paragraph (1) of this AD.
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.
(i) At the applicable compliance times specified in paragraph 1.E. of Boeing Alert Service Bulletin 737-53A1266, dated August 30, 2007, except as provided by paragraph (j) of this AD: Do a detailed inspection for any chafing (abrasion) or crack in the fuselage skin of the dorsal fin landing and abrasion resistant coating, do a detailed inspection for damage to dorsal fin seals, attach clip, and seal retainers, and do all the applicable other specified and corrective actions, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1266, dated August 30, 2007, except as provided by paragraph (k) of this AD. Accomplishing all of the applicable actions specified in this paragraph terminates the repetitive inspections required by paragraph (f) of this AD.
Where Boeing Alert Service Bulletin 737-53A1266, dated August 30, 2007, specifies counting the compliance time from “* * * the date on the service bulletin,” this AD requires counting the compliance time from the effective date of this AD.
If any damage is found aft of body station 908 during any inspection required by this AD, and Boeing Alert Service Bulletin 737-53A1266, dated August 30, 2007, specifies to contact Boeing for appropriate action: Before further flight, repair the fuselage skin using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
