AD FAA-2017-0528

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model CL-600-2B16 (CL-604 Variant) airplanes. This AD was prompted by reports of in-service incidents regarding the loss of all air data system information provided to the flightcrew. This AD requires revising the airplane flight manual (AFM) to provide "Unreliable Airspeed" procedures to the flightcrew to stabilize the airplane's airspeed and attitude for continued safe flight and landing. We are issuing this AD to address the unsafe condition on these products.