Accident Overview
The pilot reported that while conducting an airborne seismic survey at approximately 150 feet AGL, the engine lost power without warning. The pilot lowered the collective and turned the helicopter into the 10-knot prevailing wind. During the flare for an autorotation landing, the rotor RPM decreased and the helicopter touched down hard.
Fuel Contamination Investigation
A fuel sample was taken from the fuel filter sump, located between the fuel tank and the throttle body of the fuel-injected engine. Analysis of the sample revealed a substantial amount of water. FAA inspectors, accompanied by the operator, inspected the fuel storage tank used for refueling. Examination of the fuel filter in the trailer-mounted tank showed the presence of water and rust.
Aircraft Information
The helicopter was a 1995 model that had accumulated 713 flight hours at the time of the incident.