Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier, Inc., Model CL-600-1A11 (600), CL-600-2A12 (601), and CL-600-2B16 (601-3A and 601-3R Variants) airplanes. This proposed AD was prompted by reports of the loss of all air data system information provided to the flightcrew, which was caused by icing at high altitudes. This proposed AD would require revising the exisitng airplane flight manual (AFM) to provide the flightcrew with procedures for ``Unreliable Airspeed'' that stabilize the airplane's airspeed and attitude. The FAA is proposing this AD to address the unsafe condition on these products.