Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-604 Variants) airplanes. This AD was prompted by reports of deformation at the neck of the pressure regulator body on the oxygen cylinder and regulator assemblies (CRAs), and an electrical wiring harness in the area of the oxygen cylinder with no protective conduit sleeving. This AD requires inspecting to determine if certain oxygen pressure regulators are installed and replacing oxygen CRAs containing pressure regulators that do not meet the required material properties. This AD also requires inspecting for damaged wiring, and repairing or replacing wiring if necessary. We are issuing this AD to prevent rupture of the oxygen cylinder, which in the case of cabin depressurization, would lead to oxygen not being available when required; and to detect and correct unprotected wiring that could chafe against the oxygen system components or surrounding structure in the area, and lead to electrical arcing and an oxygen-fed fire.