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. Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes AD/CL-600/108 Air Driven Generator Power Feeder Harness 7/2009 Applicability: CL-600 series aeroplanes as follows: Model Serial Number Range CL-600-1A11 (600 Variant) 1004 through 1085 CL-600-2A12 (601 Variant) 3001 through 3066 CL-600-2B16 (601-3A Variant) 5001 through 5131 Requirement: 1. If not previously accomplished, inspect the Air Driven Generator (ADG) power feeder harness for wire type, in accordance with the Accomplishment Instructions in Part A of Bombardier Service Bulletin (SB) 600-0737 or 601-0591 (as applicable), both dated 23 July 2007. If the wire type is not Kapton, complete the instruction in Part A of the applicable SB and compliance with Directive is complete. 2. If the wire type is Kapton, replace the ADG power feeder harness in accordance with the Accomplishment Instructions in Part B of SB 600-0737 or 601-0591 (as applicable). Later revisions of the above SBs, approved by the Chief, Continuing Airworthiness, Transport Canada are acceptable for compliance with this Directive. Note: Transport Canada AD CF-2009-18 refers. Compliance: Before 19 July 2011. This Airworthiness Directive becomes effective on 2 July 2009. Background: Transport Canada has received two reports of instances in which the ADG has failed to power the essential bus following in-flight deployment as part of its periodic operational check. Subsequent inspection revealed that the ADG power feeder harness wire (Kapton) had chafed on the backshell of its own connector (P1XC), resulting in a short circuit, wire damage and disconnection of the wire from the ADG. Coupled with a dual generator failure, such a disconnection would result in the loss of emergency power to critical systems, with a consequent adverse effect on the controllability of the aircraft. This Directive mandates an inspection to determine the type of wire in the installed ADG power feeder harness. If the wires are a Kapton type, the ADG power feeder harness is to be replaced with one incorporating non-Kapton type wire. James Coyne Delegate of the Civil Aviation Safety Authority 18 May 2009