Airworthiness Directives; Bombardier Model CL-600-2B16 (CL-604) Airplanes and Model CL-600-2B19 (Regional Jet Series 100 & 440) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier Model CL-600-2B16 (CL- 604) airplanes and Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. These models may be referred to by their marketing designations as RJ100, RJ200, CRJ100, CRJ200, and CL-65. This AD requires revising the Emergency Procedures section of the airplane flight manual (AFM) to advise the flightcrew of additional procedures to follow in the event of stabilizer trim runaway. For certain airplanes, this AD also requires revising the Abnormal Procedures section of the AFM to advise the flightcrew of procedures to follow in the event of MACH TRIM, STAB TRIM, and horizontal stabilizer trim malfunctions. This AD results from reports of uncommanded horizontal stabilizer trim motion. We are issuing this AD to ensure that the flightcrew is advised of appropriate procedures to follow in the event of stabilizer trim runaway. Failure to follow these procedures could result in excessive uncommanded movement of the horizontal stabilizer trim actuator (HSTA) and loss of ability to use trim switches to override uncommanded movement or yoke disconnect switches to disconnect the HSTA, which could result in reduction of or loss of pitch trim control and consequent reduced controllability of the airplane.