Accident Overview
On June 25, 2020, at approximately 1200 eastern daylight time, a Bell 206-L1 helicopter, registration N5013G, was involved in an accident at Tradewinds Park in Coconut Creek, Florida. The pilot sustained serious injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 133.
Flight Purpose and Operations
According to the owner/operator and FAA inspectors, the flight's purpose was to perform external load operations using a 100-foot long line over wooded terrain, requiring hover outside of ground effect (HOGE). The loads included bags of stone and sections of pipe for a drainage project. Due to weight limitations, only 150 lbs of fuel were added during refueling. The pilot had made two refueling stops before the accident.
Pilot's Account
The pilot reported checking fuel status and aircraft systems before hovering the load into position, estimating 65 to 70 lbs of fuel onboard. While hovering with a 4-foot load height, the helicopter was applying about 85% torque, with turbine outlet temperature (TOT) within normal range. The pilot focused on the task and thought he had 10 to 15 minutes of fuel remaining. Within 1 to 2 minutes, while manipulating the load, the engine flamed out. He maneuvered into the wind away from the ground crew, performed a forced landing, made a full collective application before entering trees. The helicopter came to rest upright with substantial damage to the fuselage and tailboom. The pilot did not observe the low-fuel caution light before the power loss.
Wreckage Examination
An FAA inspector examined the helicopter immediately after the accident. No fuel odor or spillage was noted. The extended-range fuel device was removed, and visual inspection of the fuel tank revealed no fuel. Sumping the fuel system recovered no fuel. During recovery, a defueling hose inserted into the main tank recovered no residual fuel. Control continuity was confirmed through some fractures, with features consistent with overstress.
A detailed examination showed the fuel system intact, containing no fuel, and operating normally when serviced. After servicing with 30 gallons of fuel and purging air, the engine started immediately and accelerated smoothly to 100% N2. It ran for about 15 minutes with normal indications, decelerated and accelerated several times without anomalies, and was shut down normally. Defueling followed.
Fuel System Findings
The fuel gauge indicated 40 lbs at the accident site and when electrical power was applied with empty tanks. It showed 100 lbs when tanks contained about 60 lbs, and 240 lbs when tanks contained about 200 lbs. It could not be determined if the 40-pound discrepancy was due to pre-accident calibration or impact forces. The low-fuel caution light, independent of the fuel quantity system, extinguished when tanks contained about 70 lbs (11 gallons). During defueling after the engine run, it illuminated within the normal range (50 to 75 lbs).
Fuel Consumption Analysis
Examination of fueling and aircraft records showed the helicopter operated 4.0 hours from last full fuel (110 gallons or 750 lbs) to the accident. During operations at Tradewinds Park, it was fueled twice with an estimated total of 43 gallons (288 lbs). The nominal fuel consumption rate per manufacturer and operator was 35 to 37 gallons per hour in cruise. Average consumption using 153 gallons over 4 hours was 38 gallons per hour.
The rotorcraft flight manual provides fuel flow charts for level flight starting at 60 knots, but not for hover. It recommends operators conduct fuel consumption checks. According to the FAA Helicopter Flying Handbook and U.S. Army manual, more power is required to hover than any other regime. Bell Engineering calculated HOGE fuel flow rates for a Bell 206L1 with C30P engine: at 4,000 lbs gross weight, fuel flow is 41.9 gal/hour; at 4,200 lbs, it would exceed that.
Probable Cause
Not stated in the source.