Incident Overview
A pilot conducting aerial application flights experienced a loss of engine power after approximately 26 minutes of operation. According to the pilot's report, the pre-flight inspection indicated the 61-gallon fuel tank was just over a quarter full. During the flight, the helicopter yawed left and a warning light flickered, though the pilot was unable to identify which light had illuminated.
Pilot Actions and Fuel Indications
Suspecting a fuel issue, the pilot checked the fuel quantity gauge, which showed a reading two needle-widths below a quarter tank. Despite this indication, the pilot continued spraying. Several seconds later, the turbine engine stopped producing power. The pilot then turned left and executed an autorotation run-on landing to a field.
Post-Event Findings
After the helicopter came to a stop, the main rotor blades flexed downward and severed the tail boom. Subsequent examination revealed that approximately 1.75 gallons of fuel was drained from the two fuel tanks. The pilot reported that the usual fuel consumption rate was about 25 gallons per hour, and the tanks contained approximately 4 gallons of unusable fuel.
Pilot Statement
The pilot stated there were no mechanical problems prior to the accident and that the engine was most likely starved of fuel due to the low fuel level and the unusual attitudes inherent to helicopter aerial applications.