MD Helicopters 500E crash near Langtora, Sweden

A Visimind AB MD Helicopters MD 500E (SE-JVM) began to rotate violently while hovering prior to takeoff from Enkoping/Langtora Airfield at approximately 10:53. The helicopter was preparing for a power line inspection flight. After engine start, the helicopter hovered up to just above ground level and began rotating clockwise. The pilot was unable to stop the rotation despite full pedal travel. The helicopter rotated while rising to approximately 15 metres before descending and hitting the ground. Both crew members (pilot and system operator) escaped with help from witnesses and suffered minor injuries. The SHK investigation found the helicopter was operating at high power output and relatively high takeoff weight (2,811 lbs) with the relative wind from the rear right, causing the fin to act like a weather vane. These conditions exceeded the tail rotor thrust capacity, resulting in an unanticipated right yaw. The pilot had incorrectly perceived the wind as coming from the front.