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/B737/141 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/B737/141 Amdt 1 Forward Pressure Bulkhead 9/2007 Applicability: Model 737-100, -200, -300, -400, and -500 series aircraft, with line numbers 1 through 2737. Requirement: Action in accordance with the technical requirements of FAA AD 2000-05-29 Amdt 39-11639. Note: Boeing Alert Service Bulletin (ASB) 737-53A1173 Revision 4, or later FAA approved revision, refers. Compliance: As specified in the Requirement document, with a revised effective date of 15 June 2000. The compliance time remains unchanged by this issue of the Directive. This Amendment becomes effective on 30 August 2007. Background: The FAA received reports of numerous fatigue cracks found on critical areas of the forward pressure bulkhead. The actions specified by this Directive are intended to prevent such cracking, which could result in rapid decompression of the fuselage. Amendment 1 is issued to amend the Requirement note to list the latest Boeing Alert Service Bulletin related to FAA AD 2000-05-29. David Villiers Delegate of the Civil Aviation Safety Authority 20 July 2007