COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes AD/CL-600/22 Engine Fire Detection, Indication and Extinguishing Systems Applicability: CL-600-1A11 - all serial numbers; CL-600-2A12 - all serial numbers; CL-600-2B16 - serial numbers 5001 to 5049 inclusive. Requirement: For CL-600-1A11 aircraft; 1. Carry out an engine fire extinguishing system check in accordance with paragraph 2.A of Canadair Service Bulletin A600-0581. 11/91 DM 2. Modify the engine fire extinguishing system wiring harnesses and perform a functional test in accordance with paragraphs 2.B and 2.C of Canadair service bulletin A600-0581. For CL-600-2A12 and applicable CL-600-2B16; 3. Perform an engine fire extinguishing system check and an engine fire detection and warning system check in accordance with paragraph 2.A of Canadair Service Bulletin A601-0309. 4. Modify the engine the engine fire extinguishing system wiring harnesses and perform a functional test in accordance with paragraphs 2.B and 2.C of Canadair service bulletin A601-0309. Note: Transport Canada Airworthiness Directive CF-91-24 also refers. Compliance: Requirements 1 and 3, prior to 30 August 1991. Requirements 2 and 4, prior to 28 February 1992 or on the next occasion the fire bottles are removed from the aircraft, whichever occurs first. Background: The possibility exists that disconnection and subsequent reconnection of the engine fire extinguishing wiring harness, and the engine fire detecting and extinguishing harness on the affected aircraft may lead to possible cross connections of these harnesses. This could result in a fire bottle being discharged into the wrong engine, or failure of the fire warning system to annunciate a warning in the event of an engine fire.