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/B737/276 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/B737/276 Amdt 1 Nacelle Support Fitting Attachment Fasteners 5/2007 Applicability: Model 737-600, -700, -700C, and -800 series aircraft, line numbers 1 through 761; except for line numbers 596, 683, 742, 749, 750, 751, 754, 755, 759, and 760. Requirement: Action in accordance with the technical requirements of FAA AD 2005-24-03 R1 Amdt 39-14955. Note: Boeing Service Bulletin 737-57-1275 Revision 3, or later FAA approved revision, refers. Compliance: As specified in the Requirement document, with a revised effective date of 10 May 2007. This Amendment becomes effective on 10 May 2007. Background: The FAA received a report from the manufacturer that in production, during the installation of certain attachment fasteners for the nacelle support fittings, only one washer was installed instead of two. Inadequate fastener clamp-up could result in cracking of the fastener holes, cracking along the lower wing skin panels, fuel leaking from the wing fuel tanks onto the engines, and possible fire. Amendment 1 is issued in response to a revision of the Requirement document, which introduces Revision 3 of related Boeing Service Bulletin 737-57-1275. David Punshon Delegate of the Civil Aviation Safety Authority 28 March 2007