‘Runaway Trim’ Questioned in 2007 Citation Crash

 - April 14, 2009, 11:52 AM

An NTSB interim factual report and findings from a flight simulation issued late last week suggest that pilot error, not a runaway trim condition, doomed a Cessna Citation II that crashed into Lake Michigan near Milwaukee on June 4, 2007. The twinjet, N550BP, was being operated on an IFR flight plan as a Part 135 medical transport flight that originated from the General Mitchell International Airport in Milwaukee about three minutes before the accident. Its intended destination was Willow Run Airport near Detroit. Both ATP-rated pilots and a four-member organ transplant team from University of Michigan Health System were killed in the accident. Recordings retrieved from the airplane’s cockpit voice recorder contained comments by the captain indicating that he was “fighting the controls” about 18 seconds after the copilot called out “rotate,” 11 seconds after the captain called for the yaw damper and less than one second after the copilot acknowledged a turn to a 50-degree heading. Later in the recording, the captain said, “Something is wrong with the trim… I’m fighting the controls. It wants to turn left hard…she’s rolling on me. Help me, help me.” However, findings from a simulation conducted by the NTSB’s recorded radar and airplane performance study group “are consistent with the copilot inadvertently hitting the autopilot button” instead of the yaw damper. The study group said that an engaged autopilot could have resisted the captain’s efforts to control the Citation. The NTSB has not yet issued any probable causes for this accident.