Robinson R22 Beta crash near Harlingen, TX, United States

After landing the helicopter, the pilot set the cyclic and collective friction locks and left the helicopter "running" while he and his passenger disembarked the helicopter. After being left unattended for about two minutes, the helicopter began to lift-off and subsequently impacted terrain resulting in substantial damage. The pilot reported that the friction locks were still found engaged after the helicopter impacted the terrain. Winds in the vicinity of the accident were from the southeast at 21 gusting to 30 knots. According to the manufacturer, the cyclic and collective frictions are designed to allow the pilot to remove their hands from the controls to perform the cockpit portion of the preflight and postflight operations. A "caution" in the manufacturer's pilot operating handbook states, "Never leave helicopter flight controls unattended while engine is running." In addition, the pilot operating handbook has a safety notice issued November 1984, which states, "Never exit helicopter with engine running. Several accidents have occurred when pilot momentarily left their helicopters unattended with the engine running and rotors turning. The collective can creep up, increasing both pitch and throttle, allowing the helicopter to lift off or roll out of control."