Accident Details
The helicopter experienced a loss of control after being left unattended with the engine running. The pilot had landed and set the cyclic and collective friction locks before exiting the helicopter with a passenger. Approximately two minutes later, the helicopter began to lift off and subsequently struck the ground, causing substantial damage. Winds in the vicinity were from the southeast at 21 knots, gusting to 30 knots.
Pilot Actions
After landing, the pilot engaged the cyclic and collective friction locks and left the helicopter running while he and his passenger disembarked. Following the accident, the pilot reported that the friction locks were still found engaged after the helicopter impacted the terrain.
Manufacturer Guidance
According to the manufacturer, the cyclic and collective friction locks are designed to allow the pilot to remove their hands from the controls to perform cockpit portions of preflight and postflight operations. The manufacturer's pilot operating handbook includes a caution stating, "Never leave helicopter flight controls unattended while engine is running." Additionally, a safety notice issued in November 1984 reads: "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."