Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
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 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 and lightning tests showed that certain fuel tube self-bonded couplings do not provide sufficient lightning current capability. The assessment also showed that single failure of the integral bonding wire of the self-bonded couplingsor excessive axial clearance at the reducer ferrules of certain self-bonded couplings could affect electrical bonding between fuel tubes.
Insufficient electrical bonding between fuel tubes or insufficient current capability of fuel tube couplings, if not corrected, could result in arcing and potential ignition source inside the fuel tank during lightning strikes and consequent fuel tank explosion. * * *
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.