COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES 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 39.1 (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. Israel Aircraft Industries 1123 and 1124 (Westwind) Series Aeroplanes AD/IAI-W/26 Oxygen Shut-off Valve 1/2003 Applicability: Model 1123, 1124 and 1124A series aeroplanes. Requirement: Remove the existing oxygen shut-off valve and replace it with a Scott® slow opening valve having part number 27550-3 in accordance with Israel Aircraft Industries Alert Service Bulletin (ASB) 1123-35-048 or ASB 1124-35-137 both dated 23 September 2002, as applicable. Note: Israel CAA AD 35-02-10-12 refers. Compliance: Within 200 hours time in service after the effective date of this Directive. This Airworthiness Directive becomes effective on 23 January 2003. Background: The oxygen system of the Astra is designed so that high oxygen pressure is maintained from the cylinder to the pressure reducer-regulator located downstream of the shut-off valve. If this valve is quickly opened, overheating and subsequent fire may occur due to rapid adiabatic compression. This Directive requires the replacement of the existing oxygen shut-off valve with a slow opening valve. James Coyne Delegate of the Civil Aviation Safe ty Authority 25 November 2002 The above AD is notified in the Commonwealth of Australia Gazette on 18 December 2002. Page 1 of 1