The crash of an aeromedical Cessna Citation 550 into Lake Michigan more than two years ago has prompted the NTSB to recommend that the FAA require all Part 91K and Part 135 operators to incorporate upset recovery and related checklists and procedures into their training programs.
Noting that many Part 121 operators use upset recovery training aids, the Board urged the FAA to identify airplanes other than the Citation series with autopilot control panel designs that may lead to inadvertent activation of the autopilot and require manufacturers to redesign and retrofit the autopilot control panels to make the buttons easily distinguishable and to guard against unintentional activation.
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 determined, 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.
Although the aircraft had no data recording system, 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.
Operated by Marlin Air, the aircraft was carrying a human organ for a transplant operation in Michigan. The two pilots and four passengers aboard were killed in the June 4, 2007, crash and the airplane was destroyed.
A Controllable Scenario
The NTSB determined that the event would have been controllable had the captain not allowed the airspeed and resulting control forces to increase while he tried to troubleshoot the problem. By letting the Citation’s airspeed increase while engaging in poorly coordinated troubleshooting efforts, the pilots allowed an abnormal situation to escalate into an emergency.
If the pilots had simply maintained a reduced airspeed while they responded to the situation, the Board concluded, the aerodynamic forces on the airplane would not have increased significantly. At reduced airspeeds, the pilots would have been able to maintain control of the airplane long enough either to troubleshoot successfully and resolve the problem or to return safely to the airport.
Among other recommendations aimed at Cessna, the NTSB wants the agency to require the airframer to modify all Citations by incorporating an aural pitch trim-in-motion warning and contrasting color bands on the pitch trim wheel to help pilots recognize a runaway pitch trim condition before control forces become unmanageable.
The Board issued recommendations to the American Hospital Association regarding airplane and system deficiencies, FAA oversight and the safety ramifications of an operator’s financial health.