AD/CL-600/99 Fuel Tank Climb Vent Loop (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-600/99 Fuel Tank Climb Vent Loop 7/2008

Applicability:

Bombardier Inc. Model CL-600-2C10 aircraft, serial numbers 10003 through 10169 and CL-600-2D24 aircraft, serial numbers 15001 through 15025.

Requirement:

Modify the fuel tank climb vent loop pipes by installing shrouding boots according to the Accomplishment Instructions of Bombardier Service Bulletin (SB)
670BA-28-011, Revision B, dated 4 July 2007, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Modification of climb vent pipe prior to the effective date of this directive according to the original issue or Revision A of the above-noted service bulletin satisfies the requirements of this directive.

Note:  Transport Canada AD CF-2008-01 dated 3 January 2008 refers.

Compliance:

Within 4500 hours flight time after the effective date of this directive.

This Airworthiness Directive becomes effective on 3 July 2008.

Background:

Bombardier Aerospace has completed a system safety review of the
CL-600-2C10/CL-600-2D24 aircraft fuel system against new fuel tank safety standards, introduced in Chapter 525 of the Airworthiness Manual through Notice of Proposed Amendment (NPA) 2002-043.  The identified non-compliances were assessed using Transport Canada Policy Letter No. 525-001 to determine if mandatory corrective action is required.

This assessment showed that rupture of the fuel tank climb vent loop pipe or leakage from pipe couplings could result in fuel coming in contact with hot anti-ice ducts, creating potential fire on top of the centre fuel tank.

To correct the unsafe condition, this directive mandates the modification of the fuel tank climb vent loop by installing shrouding boots that direct leaked fuel safely overboard.

James Coyne
Delegate of the Civil Aviation Safety Authority

22 May 2008