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. AMD Falcon 50 and 900 Series Aeroplanes AD/AMD 50/23 Electronic Flight Instrument System Displays 12/2001 DM Applicability: Mystère Falcon 900 aeroplanes, serial numbers 1 to 178 inclusive, except 169, equipped with an SPZ 8000 avionics system. Requirement: 1. Identify the part numbers and modification status of the Electronic Flight Instrument System (EFIS) Symbol Generators. 2. If, as a result of Requirement 1, the following symbol generators are identified: Symbol Generator Part Number Modification Status SG-820 7007356-901 or -902 or 7007356-903 or -904 without Mod S MG-820 7009289-801 or -802 or 7009289-803 or -804 without Mod V 1. Insert Temporary Change No 86 in the Aircraft Flight Manual. b. Modify the Symbol Generators in accordance with Dassault Aviation Service Bulletin F900-281 dated 21 March 2001. Note: DGAC AD 2001-466-033(B) refers. Compliance: For Requirement 1 - Before 14 November 2001. For Requirement 2.a. - Immediately any of the EFIS Symbol Generators listed in Requirement 2 are identified. For Requirement 2.b. - Within 18 months after the effective date of this Directive. This Airworthiness Directive becomes effective on 17 October 2001. Background: The Direction Générale de L'Aviation Civile of France has advised that during certain phases of flight the quantity of data to be processed by the EFIS Symbol Generators may lead to the saturation of the processor's computing capability. This saturation may result in the EFIS display ether flashing or going off altogether. AMD Falcon 50 and 900 Series Aeroplanes AD/AMD 50/23 (Continued) This Directive initially requires a temporary Flight Manual change that introduces measures designed to decrease the load on the processor, followed by a modification that increases the computing speed of the display processors. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 9 October 2001 The above AD is notified in the Commonwealth of Australia Gazette on 17 October 2001.