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/B747/349 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/B747/349 Amdt 1 Crew Oxygen Cylinder Support 6/2008 Applicability: Model 747-400 series aircraft, as identified in Boeing Special Attention Service Bulletin 747-35-2114 Revision 1, or later FAA approved revision. Requirement: Action in accordance with the technical requirements of FAA AD 2006-12-10 R1 Amdt 39-15485. Compliance: As specified in the Requirement document, with a revised effective date of 5 June 2008. This Amendment becomes effective on 5 June 2008. Background: The FAA received a report indicating that certain oxygen cylinder supports may not have been properly heat-treated. The actions required by this Directive are intended to prevent failure of the oxygen cylinder support under the most critical flight load conditions, which could cause the oxygen cylinder to break loose and cause a loss of oxygen for the flight crew. Also, a fire hazard could result from oxygen leakage. Amendment 1 is issued in response to a revision of the related FAA AD, which expands the applicability to include certain aircraft that are not on the US Register. David Villiers Delegate of the Civil Aviation Safety Authority 24 April 2008