AD/CL-600/81 Vertical Beams on Pressure Bulkheads at FS 409+128 and FS 559 (Cth)

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-600/81 Vertical Beams on Pressure Bulkheads
at FS 409+128 and FS 559 9/2007

Applicability:	Model CL-600-2B19 aircraft, serial numbers 7003 through 7999.
Requirement:	Action in accordance with the requirements of Transport Canada AD CF-2003-08.
Compliance:	As specified in the Requirement document, with a revised effective date of 30 August 2007.
This Airworthiness Directive becomes effective on 30 August 2007.
Background:	Cracks were detected on the vertical beams on pressure bulkheads at fuselage stations 409+128 and 559 on several Regional Jet in-service aircraft.  Failure of the vertical beams at the pressure bulkheads, which have been identified as principal structural element, would compromise the structural integrity of the pressure bulkheads.

David Villiers
Delegate of the Civil Aviation Safety Authority

11 July 2007