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-600/56 APU Cooling Air Exhaust 7/2002

Applicability: CL-600-2B19 series 100/200 aircraft serial numbers 7003 through 7067 inclusive, and serial numbers 7069 through 7254 inclusive.

Requirement: Modify the APU cooling air exhaust in accordance with Bombardier SB 601R-49- 015.

Note: Canadian AD CF-2002-21 refers.

Compliance: Unless previously accomplished; within 2000 flight hours from the effective date of this Directive.

This Airworthiness Directive becomes effective on 11 July 2002.

Background: Incomplete drainage of the APU enc losure has been reported when operating on the ground. This can be a potential fire hazard. Negative pressure may contribute to this problem. Reworking of the APU enclosure will prevent negative pressure from developing and subsequently reduce drainage problems from the enclosure.

James Coyne

Delegate of the Civil Aviation Safety Authority 23 May 2002

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The above AD is notified in the Commonwealth of Australia Gazette on 19 June 2002.

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