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. Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes AD/CL-600/44 Power Transfer Contactors 10/2001 DM Applicability: Model CL-600-2B19 'Regional Jet' aeroplanes serial numbers 7003 through 7495, 7497 through 7502 and 7505 through 7507. Requirement: 1. Determine, in accordance with the procedures in Bombardier Alert Service Bulletin (ASB) A601R-24-105 dated 4 July 2001 or Revision A dated 20 July 2001, if installed air driven generator (ADG) emergency hydraulic power transfer contactor K1XC, ADG emergency electrical power transfer contactor K2XD and AC essential power transfer contactor K3XD, all Part Number (P/N) H-A4A-039, have a manufacturing date code of 0011 through 0050. (The power transfer contactors with manufacturing date code 0011 through 0050 are hereafter referred to as 'suspect contactors'.) 2. For aircraft, determined in accordance with Requirement 1, to have a suspect K1XC and/or a K2XD contactor installed, dispatch with an inoperative Integrated Drive Generator (IDG) or Auxiliary Power Unit (APU) generator is prohibited until such time as the suspect contactor(s) is/are replaced as detailed in Requirement 3 and 4 of this Directive. 3. Replace suspect K1XC contactors in accordance with ASB A601R-24-105 or A601R-24-105 Rev A. 4. Replace suspect K2XD and K3XD contactors in accordance with the above- mentioned ASB. 5. Power transfer contactors K1XC, K2XD and K3XD P/N H-A4A-039 that have a manufacturing date code of 0011 through 0050, may not be installed in any aircraft. Note: Transport Canada AD CF-2001-27 refers. Compliance: For Requirement 1 - Within 14 calendar days after the effective date of this Directive. For Requirement 2 - Immediately with effect from the date that the Requirement 1 determination was made. Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes AD/CL-600/44 (Continued) For Requirement 3 - Within 500 hours time in service (TIS) after the effective date of this Directive. For Requirement 4 - Within 1000 hours TIS after the effective date of this Directive. For Requirement 5 - As of the effective date of this Directive. This Airworthiness Directive becomes effective on 15 August 2001. Background: Transport Canada has advised that power transfer contactors K1XC, K2XD and K3XD, manufactured between 12 March 2000 and 10 December 2000, may have defective moving blade assemblies that could result in premature failure of these contactors. This Directive requires an inspection to determine whether the 'suspect contactors' are installed and, if so, restricts the despatch of the aircraft with an inoperative IDG or APU generator. The Directive also requires the eventual replacement of 'suspect contactors'. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 9 August 2001 The above AD is notified in the Commonwealth of Australia Gazette on 15 August 2001.