AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/AMD 50/30 and issues the following 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. AMD Falcon 50 and 900 Series Aeroplanes AD/AMD 50/30 Amdt 1 Fire Extinguisher Selector Switches 4/2003 DM Applicability: All Mystère Falcon 900 series aeroplanes. Requirement: 1. Inspect the safety wires on the fire extinguisher selector switches to ensure all wires comply with NFL 23.321 or MS20995CY15* (or NASM20995CY15*). All wires not complying with these standards must be removed. * 'CY' Copper specification A-A-59551, type "S", annealed, 0.015 inch. 2. Unless already accomplished in accordance with the original issue of this Directive, install fire extinguisher selector switch copper safety wires that either: 1. comply with NFL 23.321 or MS20995CY15 (or NASM20995CY15) standards, or 2. are copper having a maximum diameter of 0.4 millimetres and can withstand a rupture strength of less than 45 Newtons. 3. Incorporate Work Card MF900 26-203 temporary revision TC 115 into the Aircraft Maintenance Manual (AMM). 4. If copper safety wires were installed in accordance with Requirement 2.a. reinstall safety wires that comply with the Requirement 1 standards. Note: DGAC AD 2003-084(B) R1 refers. Compliance: For Requirement 1 - Remains unchanged as 'Before further flight after the effective date of the original issue of this Directive'. For Requirement 2 - Within eight days after the effective date of this Amendment. For Requirement 3 - Remains unchanged as 'Within eight days after the effective date of the original issue of this Directive'. For Requirement 4 - Within three months after the effective date of this Amendment. This Amendment becomes effective on 12 March 2003. AMD Falcon 50 and 900 Series Aeroplanes AD/AMD 50/30 Amdt 1 (continued) Background: The Direction Générale de l'Aviation Civile of France has advised that due to incorrect references on Work Card 26.203 incorrect safety (lock) wire may have been used to safety wire fire extinguisher selector switches following continuity checks between fire extinguishers and the fire control panel. The incorrect safety wire may prevent operation of the selector switches. The original issue of this Directive required inspection and, if necessary, removal of the safety wires and their replacement with wires that meet certain standards. Additionally, the AMM was required to be amended. This Amendment introduces a revised specification for copper wires and provides an alternative method of compliance. The original issue of the Airworthiness Directive became effective on 14 February 2003. James Coyne Delegate of the Civil Aviation Safety Authority 5 March 2003 The above AD is notified in the Commonwealth of Australia Gazette on 12 March 2003.