Summary
We propose to adopt 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 proposed AD was prompted by reports of airspeed mismatch between the pilot and co-pilot's airspeed indicators, which occurred during or after heavy rain. This proposed AD would require, for certain airplanes, inspecting for drain bottles having certain part numbers, and replacing affected drain bottles. This proposed AD would require, for certain other airplanes, replacing drain bottles. We are proposing this AD to prevent pitot static tubing from becoming blocked by water, which if not corrected, could lead to erroneous airspeed and altitude indications, and consequent loss of control of the airplane.