AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/232 and issues the following AD under subregulation 39.1 (1) of CAR 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 747 Series Aeroplanes AD/B747/232 Amdt 1 Crew Rest Area Heat Exchanger - 2 13/2001 Applicability: Model 747-400 series aircraft, line numbers 1 through 1205; equipped with dual crown skin heat exchangers. Requirement: Inspect in accordance with the technical requirements of FAA AD 2001-18-04 Amdt 39-12430. Note: Boeing Alert Service Bulletins 747-21A2412 and 747-21A2412 Revision 2 refer. Compliance: As specified in the Requirement document with a revised effective date of 27 December 2001. This amendment becomes effective on 27 December 2001. Background: The FAA received reports of cracking and buckling of the front edge of the crew rest heat exchanger on several aircraft. Investigation revealed that certain heat exchangers were manufactured with material that is too thin. On one aircraft, the heat exchanger buckled and bulged enough to make contact with the rudder and elevator cables located below the heat exchanger. Amendment 1 is issued in response to a new FAA AD which adds a new requirement for a one-time inspection to determine the part number and shop code of the shell of the crew rest heat exchanger, and follow-on actions if necessary, which terminate the currently required repetitive inspections. The original issue of this Airworthiness Directive became effective on 10 August 2000. David Alan Villiers Delegate of the Civil Aviation Safety Authority 8 November 2001 Page 1 of 1 The above AD is notified in the Commonwealth of Australia Gazette on 5 December 2001. Page 2 of