The FAA is adopting a new airworthiness directive for certain Bombardier CL600-2B16s (CL601-3A, CL601-3R, and CL604 variants). It was prompted by reports of airspeed mismatch between the pilot’s and copilot’s airspeed indicators during or after heavy rain. The AD requires inspecting for drain bottles having certain part numbers and replacing affected drain bottles. The AD is intended to prevent pitot-static tubing from becoming blocked by water, which, if not corrected, could lead to erroneous airspeed and altitude indications and possible loss of control of the airplane. This AD takes effect December 5.