Accident Overview
A helicopter engaged in aerial application operations encountered a loss of engine power while returning to the loading site after a 45-minute sortie. The flight was conducted over heavily wooded mountainous terrain. According to the pilot, the helicopter had been serviced with 30 gallons of fuel for a mission to dispense 100 gallons of pesticides.
Sequence of Events
While en route back to the loading site, the pilot experienced a loss of engine power. The engine temporarily regained power, then lost power again 5 to 8 seconds later. The pilot executed an autorotation, guiding the helicopter above the tree tops, and settled through the trees. The aircraft came to rest in an upright position.
Post-Accident Findings
Examination of the accident site revealed no evidence of a fuel spill. No fuel was found in the fuel cell. The average fuel burn rate for the helicopter is 25 to 26 gallons per hour. The engine was subsequently removed and successfully run in an engine test cell, with no anomalies noted.