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/B747/258 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 747 Series Aeroplanes AD/B747/258 Amdt 1 Engine Pylon Diagonal Brace Underwing Fitting 4/2006 Applicability: Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, 747SR, and 747SP series aircraft, as listed in Boeing Alert Service Bulletin 747-57A2312 Revision 1, or later FAA approved revision. Requirement: Action in accordance with the technical requirements of FAA AD 2005-14-08 Amdt 39-14185. Compliance: As specified in the Requirement document with a revised effective date of 13 April 2006. This Amendment becomes effective on 13 April 2006. Background: The FAA requires certain inspections/actions to prevent loss of the underwing fitting load path due to missing or damaged alloy-steel taperlock fasteners, which could result in separation of the engine and strut from the aircraft. Amendment 1 is issued in response to a new FAA AD, which expands applicability to include additional aircraft models and requires a new inspection to determine fastener material. The FAA received reports indicating that cracked fasteners made of A286 material were found on aircraft that had only fasteners made of A286 material installed in the area common to the diagonal brace underwing fittings. David Punshon Delegate of the Civil Aviation Safety Authority 27 February 2006