AD/B737/235 Amdt 1 - Fuselage Skin Area at the Dorsal Fin Assembly (Cth)

AIRWORTHINESS DIRECTIVE On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B737/235 and issues the following AD under subregulation 39.001(1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Boeing 737 Series Aeroplanes AD/B737/235 Amdt 1 Fuselage Skin Area at the Dorsal Fin Assembly 6/2009

Applicability: All Model 737-300, -400, and -500 series aircraft. Requirement: Action in accordance with the technical requirements of FAA AD 2009-07-11 Amdt 39-15870.

Note: Boeing Alert Service Bulletin 737-53A1266 original issue, or later FAA approved revision, and Boeing Message Number 1-QX035, dated 13 October 2004, refer. Compliance: As specified in the Requirement document, with a revised effective date of 4 June 2009. This Amendment becomes effective on 4 June 2009. Background: The FAA received 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. Such damage could result in fatigue cracking due to cabin pressurisation, and consequent rapid in-flight decompression of the aircraft fuselage.

Amendment 1 is issued in response to a new FAA AD, which introduces an inspection for any chafing or cracking 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.