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

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes. That AD currently requires revising the airplane flight manual (AFM) to provide the flightcrew with revised procedures for checking the flap system. The existing AD also requires revising the maintenance program to provide procedures for checking the flap system, and performing follow-on actions, if necessary. This new AD requires installing new flap actuators, a new or retrofitted air data computer, a new skew detection system, and new airspeed limitation placards; and revising the AFM to include revised maximum allowable speeds for flight with the flaps extended, and a new skew detection system/crosswind-related limitation for take-off flap selection. This AD results from a number of cases of flap system failure that resulted in a twisted outboard flap panel. We are issuing this AD to prevent an unannunciated failure of the flap system, which could result in a flap asymmetry and consequent reduced controllability of the airplane.