AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/172 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/B747/172 Amdt 1 Nose Wheel Well Vertical Beams and Fuselage Frames 11/2001 Applicability: Model 747 series aircraft, line numbers 1 through 685; except for aircraft excluded by the applicability table specified in the Requirement document. Requirement: Inspect in accordance with the technical requirements of FAA AD 2001-14-18 Amdt 39-12329. Replacement of vertical beams and frames, as applicable, in accordance with the applicable procedure in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2293 Revision 8, constitutes terminating action for the requirements of this Directive. Compliance: As specified in the Requirement document with a revised effective date of 1 November 2001. This Amendment becomes effective on 1 November 2001. Background: The FAA received a report of severed fuselage frames at BS 300 and BS 320 approximately 10 inches outboard of the nose wheel well side panel, which resulted in accelerated fatigue cracking and subsequent failure of the adjacent nose wheel well vertical beams. Amendment 1 is issued in response to a new FAA AD which expands applicability to include additional aircraft, and adds new requirements for repetitive inspections to detect fatigue cracking of the webs and frames from BS 260 to BS 320. The AD also provides for optional terminating action. Boeing 747 Series Aeroplanes AD/B747/172 Amdt 1 (Continued) The original issue of this Airworthiness Directive became effective on 27 March 2001. David Alan Villiers Delegate of the Civil Aviation Safety Authority 19 September 2001 The above AD is notified in the Commonwealth of Australia Gazette on 10 October 2001.