NTSB Didn’t Test Other Aircraft for Mistrim Problem

 - July 24, 2008, 12:09 PM

In a safety recommendation issued last Thursday (A-08-48 and A-08-49), the NTSB raised concerns about mistrim rotation characteristics in the Bombardier Challenger, following the overrun accident of a Challenger on Feb. 2, 2005, at Teterboro (N.J.) Airport. Although the accident Challenger was loaded forward of the forward cg, the jet would have rotated beyond V2 speed, if the pilots had not aborted the takeoff, according to the NTSB, which recommended that pilots be trained to prevent mistrims and that the FAA revise certification advisory material to address mistrim-takeoff rotation delays. According to an NTSB spokesman, while investigators tested the mistrim scenario in a Challenger simulator, they did not do so in any other jets. The mistrim problem, he added, was studied well before the Teterboro accident by European regulators and addressed in NPA 25B-335, published for comment in 2002. “The relevant mistrim takeoff language [in the NPA] was developed on the basis of service experience with airplanes other than the [Challenger],” the spokesman said. “Consequently, simulator testing of additional aircraft was not necessary to support the Teterboro investigation or recommendations A-08-48 and A-08-49.”