As the result of the crash of an aeromedical Cessna Citation 550 into Lake Michigan more than two years ago, the NTSB has recommended that the FAA require all Part 91K and Part 135 operators to incorporate upset recovery into their training syllabi. Further, the Board wants to require Cessna to redesign and retrofit the yaw damper and autopilot switches on the autopilot control panel in Citations to make them easily distinguishable and to guard against unintentional pilot activation. The probable cause of the accident, the Board said, was mismanagement of an abnormal flight control situation through improper actions, including failing to control airspeed and to prioritize control of the airplane, along with a lack of crew coordination. Evidence indicated that the two most likely scenarios were a runaway trim or the inadvertent engagement of the autopilot, rather than the yaw damper, on takeoff from General Mitchell International Airport in Milwaukee. The two pilots and four passengers aboard were killed in the June 4, 2007 crash, and the airplane was destroyed.