AD/CL-600/88 Fuel System Safety Electrical Bonding (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-600/88 Fuel System Safety - Electrical Bonding 12/2007

Applicability:	Model CL-600-2B19 aircraft, serial numbers 7003 through 7067 and 7069 through 7797.
Requirement:	1.    Carry out a detailed visual inspection for the presence of an anodised (blue colour) fuel boost pump reducer coupling according to the Accomplishment Instructions of Bombardier Service Bulletin (SB) 601R-28-057, dated 4 December 2003, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.  If the inspection reveals that none of the fuel boost pump reducer coupling is anodised, no further action is required by this Directive.
2.    If the Requirement 1 inspection reveals the presence of any anodised fuel boost pump reducer coupling, replace the anodised coupling with a coupling having ion vapour deposition (IVD) coating according to the Accomplishment Instructions of SB 601R-28-057 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.
Note:  Transport Canada AD CF-2007-18 refers.
Compliance:	For Requirement 1 - Within 5 000 hours time in service after the effective date of this Directive.
For Requirement 2 - Prior to further flight after the Requirement 1 inspection.
This Airworthiness Directive becomes effective on 22 November 2007.
Background:	Transport Canada has advised that Bombardier Aerospace has completed a system safety review of the CL-600-2B19 aircraft fuel system against new fuel tank safety standards introduced in Chapter 525 of the Transport Canada 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.

The assessment showed that if the fuel boost pump reducer coupling is anodised, insufficient electrical bonding between the boost pump canister and the pressure pick-up line could occur.  Insufficient electrical bonding between the boost pump canister and the pressure pick-up line, if not corrected, could result in arcing and potential ignition source inside the fuel tank during lightning strikes and consequent fuel tank explosion.  To correct the unsafe condition, this Directive mandates a detailed visual inspection of the fuel boost pump for the presence of anodised reducer couplings.  All anodised couplings found are to be replaced with couplings having IVD coating.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

24 September 2007