COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/61 Amdt 1 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. AD/B747/61 Amdt 2 Rear Pressure Bulkhead 11/2000 Applicability: Model 747 series aircraft, line positions 1 through 671. Requirement: Action in accordance with the technical requirements of FAA AD 2000-15-08 Amdt 39-11840. Note: Boeing Service Bulletin 747-53-2275 through Revision 5 and 747-53A2275 Revision 6 refer. Compliance: As specified in the Requirement document with a revised effective date of 2 November 2000. This Amendment becomes effective on 2 November 2000. Background: Damage including dents, tears, nicks, gouges, and scratches, has been found on some aircraft. Fatigue cracking may occur on high time aircraft and undetected damage may lead to premature fatigue cracking. The required inspections are intended to ensure the continued structural integrity of the bulkhead. Amendment 1 was prompted by reports indicating that the inspections required by FAA AD 87-23-10 may not detect cracking of the bulkhead web in a timely manner, and certain inspection changes were introduced. Amendment 2 is issued in response to a new FAA AD which requires that a currently required one-time inspection to detect cracking of the upper segment of the bulkhead web be accomplished repetitively, and adds additional repetitive inspections to detect cracking of the upper and lower segments of the aft bulkhead web. Amendment 1 to this Airworthiness Directive became effective on 31 December 1998. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES The original issue of this Airworthiness Directive became effective on 24 March 1998. David Alan Villiers Delegate of the Civil Aviation Safety Authority 13 September 2000 The above AD is notified in the Commonwealth of Australia Gazette on 4 October 2000.