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/B737/33 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/B737/33 Amdt 1 Forward and Aft Cargo Compartments 10/2006 Applicability: Model 737 series aircraft, line numbers 1 through to 967, excluding cargo aircraft. Requirement: Action in accordance with Boeing Service Bulletin 737-53A1027 Revision 7, dated 14 December 1989. Note 1: The FAA has approved the inspection, modification, and repair procedures contained in the Requirement document as an alternative to the earlier service bulletin issue specified in this Directive. Note 2: FAA AD 89-11-06 R1 Amdt 39-6515 refers. Compliance: As specified in the Requirement document. This Amendment becomes effective on 28 September 2006. Background: Reports were received of extensive cracking of cargo compartment frames, including one aircraft with three adjacent frames completely severed, on aircraft with between 29,300 and 50,300 flight cycles and 21,600 to 32,600 flight hours. Amendment 1 is issued to introduce a Requirement note that specifies FAA approval of work accomplishment in accordance with the latest service bulletin issue. David Villiers Delegate of the Civil Aviation Safety Authority 28 July 2006