Airworthiness Directives; Bombardier Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A and -3R), and CL-600-2B19 (Regional Jet Series 100) Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Bombardier Model CL-600-1A11, CL-600-2A12, CL-600-2B16, and CL-600-2B19 series airplanes, that currently requires an inspection to detect cracking in the rudder control quadrant; replacement of any cracked quadrant with a new assembly; and retorquing of the castellated nut, as necessary. This amendment requires a follow- on inspection of certain rudder control quadrants to detect cracks that start at the inside root radius of the spigot; modification of any cracked quadrant; and eventual modification of certain quadrants. This amendment also adds airplanes to the applicability of the existing AD. This amendment is prompted by the development of a modification, which, when installed, will positively address the identified unsafe condition. The actions specified by this AD are intended to prevent loss of rudder control due to stress corrosion of the rudder control quadrant.