Summary
During an aerial agricultural spraying operation, the aircraft's engine experienced a total loss of power. The pilot immediately executed an autorotation landing. Upon touching down, the aircraft skidded approximately 8 feet until the front skid contacted a ground furrow, causing the aircraft to nose over. The main rotor blade then struck the ground and the tail boom assembly.
Pilot Report and Investigation
The pilot reported that prior to the flight, he had onboard approximately 10 to 12 gallons of fuel for a planned 5-minute flight. He believed that a malfunction of the fuel pump bypass valve caused the fuel to be "dumped overboard" through the system drain valve. Subsequent investigation revealed that the aircraft contained less than one half pint of fuel. The engine was functionally tested and operated normally.
Conclusion
The investigation did not establish a probable cause for the engine power loss. The pilot's assertion regarding the fuel pump bypass valve remains unconfirmed, and the engine's satisfactory operation during testing suggests that the fuel exhaustion may have been a contributing factor, though the source does not explicitly state causation.