The pilots of a Cessna Citation II 550 business jet carrying an organ transplant team and organs for the University of Michigan Health System had "difficulty with directional control of the aircraft shortly after take-off" from General Mitchell International airport, according to preliminary analysis of the cockpit voice recorder recovered from the crash site in Lake Michigan. All six onboard the Part 135 flight, including the two pilots, were killed about three minutes after departure in the 4 June accident.

Based on preliminary analysis, the CVR conversations are consistent with air traffic control tapes in which the pilots declared an emergency and reported runaway trim early in the planned 42min flight to Willow Run airport in Ypsilanti, Michigan. In a later transmission, one pilot was heard telling the other pilot to hold the aircraft's controls so that he could pull the circuit breakers, according to the National Transportation Safety Board. Pilots are often instructed to disable circuitry by "pulling breakers" if electrical equipment will not respond to commands.

Preliminary analysis of the wreckage showed pitch, roll, and yaw settings that were not in the neutral position. "The Board will continue to assess the significance of these settings," says the NTSB.

Radar data showed the aircraft reached 4,400ft (1,341m) pressure altitude, after which it entered a descending left turn for the remaining 69s of data. Average descent rate during that time was 2,260fpm, according to the NTSB.

Source: Flight International