Primary finding
Probable cause
The helicopter pilot’s improper maneuvering at low altitude in gusty wind conditions, which resulted in the helicopter entering a vortex ring state, and hard landing during a subsequent autorotation.
Investigator assessment
Analysis narrative
As part of a law enforcement simulation exercise, the helicopter pilot was orbiting near the departure airport between 200 to 300 ft above ground level, at 20 to 40 knots indicated airspeed. The pilot described that while the helicopter was in a left orbit the airspeed decreased to near 0. At that time, the helicopter began to descend in a vortex ring state (VRS). Due to the low altitude, the pilot was not able to recover from VRS and entered an autorotation to a grass area on the airport. The helicopter subsequently landed hard and came to rest upright in the grass area resulting in substantial damage to the helicopter’s tail boom. The pilot reported that there were no preimpact mechanical malfunctions or failures of the helicopter.