Incident Overview
The pilot of a helicopter was preparing to land at an off-airport landing site when he encountered a wind shift or wind shear on the base leg of the approach. This caused an uncommanded yaw followed by a rapid descent rate. The pilot managed to reduce the descent rate and level the helicopter before impact, but the helicopter rolled over during the accident sequence. The accident site was desert terrain that sloped downward from the right to the left.
Weather Conditions
People on the ground informed the pilot that a sudden wind storm passed through the area just prior to the accident. These individuals were forced to take shelter inside an enclosure to escape the wind. The pilot had no communication with the people at the landing site and was unaware of the wind storm. The closest weather observation station, located 25 miles to the west, reported westerly winds at 20 knots with gusts to 26 knots at the time of the accident.
Mechanical Status
The pilot stated that the helicopter and its engine experienced no mechanical failures or malfunctions during the flight.
Conclusion
The accident occurred while the pilot was attempting to land at an off-airport site, encountering unexpected wind conditions that led to a loss of control and subsequent rollover. No further details were provided by the pilot regarding the specific helicopter type or registration.