AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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/B747/335 Station 980 Upper Deck Floor Beam 11/2005 Applicability: Model 747-400 and 747-400D series aircraft, as listed in Boeing Alert Service Bulletin 747-53A2503, dated 11 November 2004, or later FAA approved revision. Requirement: Action in accordance with the technical requirements of FAA AD 2005-16-10 Amdt 39-14215. Compliance: As specified in the Requirement document, with a revised effective date of 27 October 2005. This Airworthiness Directive becomes effective on 27 October 2005. Background: The FAA received reports of corrosion under the lift cart threshold at the station 980 upper deck floor beam. The actions required by this Directive are intended to detect and correct such corrosion, which could result in a cracked or broken floor beam, extensive damage to adjacent structure, and possible rapid decompression of the aircraft. David Villiers Delegate of the Civil Aviation Safety Authority 16 September 2005