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. Learjet 45 Series Aeroplanes AD/LJ45/10 APU Fuel Shutoff Valve 7/2007 Applicability: Learjet Model 45 aeroplanes, serial numbers 45-005 through 45-321, equipped with an auxiliary power unit (APU). Requirement: Deactivate the APU, cap/plug the fuel lines to the APU, and remove the APU fuel shutoff valve, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A45-49-11, dated 26 March 2007. Note: FAA AD 2007-09-03 Amdt 39-15033 dated 16 April 2007 refers. Compliance: Within 50 flight hours after the effective date of this AD, unless previously accomplished. This Airworthiness Directive becomes effective on 5 July 2007. Background: This AD results from reports of fuel leaking from the APU fuel shutoff valve into a flammable fluid fire protection area that is also interconnected with the main landing gear's wheel well bay. The issuing of this AD is to prevent fuel leaking from the fuel shutoff valve of the APU, which could result in an uncontrollable fire and adversely affect the aeroplane's continued safe flight and landing. Charles Lenarcic Delegate of the Civil Aviation Safety Authority 2 May 2007