What happened
Nine days prior to the accident, the pilot had topped off the fuel tanks of the helicopter and conducted a 15-minute flight. On the day of the accident, an additional 5 gallons of fuel were added to the aircraft. Approximately 1 1/2 hours after takeoff, the engine lost power. The pilot performed an autorotation into a field, resulting in a hard landing.
The investigation
An examination of the engine revealed no abnormalities or malfunctions. The helicopter has a total fuel capacity of 64 gallons, with 63.4 gallons being usable. During the investigation, when the aircraft was leveled and electrical power was applied, the low fuel light illuminated. The fuel boost pump subsequently pumped out 5 3/4 gallons of fuel.
A review of the pilot's logbook indicated that the pilot was not helicopter rated; however, the pilot held a helicopter solo endorsement that had expired approximately 60 days before the accident.
Findings
According to the helicopter's flight manual, at low fuel levels, a sideslip may cause the fuel tank outlet to become uncovered, which can lead to fuel starvation.