The FAA Thursday invited comments on a proposal for a new airworthiness directive to correct flap failures on Bombardier Challenger CL-600-2B19 twin jet commuter aircraft, after the agency received a report that a previous AD was "not effective." According to the FAA, flap failures on the aircraft have been reported over several years with the flaps sticking in various positions. The failures have resulted in flight diversions, higher fuel consumption and longer landing-distance requirements for affected aircraft. The proposed AD would revise the airplane flight manual to incorporate operational procedures and corrective maintenance actions, including a pressure test of the flexible drive-shaft and low temperature torque test of the flap actuator. The FAA estimates the cost of the proposed AD to be $ 1,440 per some 680 aircraft working in the U.S. The requirements are expected to eventually encompass about 1,000 Bombardier CRJ models worldwide.
Operators and other interested parties may find the complete language of the proposed AD published, here. The FAA is requesting comments to be received no later than Jan. 20.