Summary
We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model BD-700-1A10 and BD-700-1A11 airplanes. This proposed AD was prompted by a report of several events where pilots experienced difficulty in lateral control of the airplane after doing a climb through heavy rain conditions and a determination that the cause was water ingress in the aileron control pulley assembly. This proposed AD would require, for certain airplanes, inspecting for correct clearance and rework if necessary, and, for certain other airplanes, installing a cover for the aileron pulley assembly. We are proposing this AD to prevent water ingress in the aileron control pulley assembly, which could freeze in cold conditions and result in reduced control of the airplane.