N5013GBell Helicopter Textron 206L-1 · 1979

On June 25, 2020, about 1200 eastern daylight time, a Bell 206-L1 helicopter, N5013G, was involved in an accident at Tradewinds Park in Coconut Creek, Florida. The pilot was seriously injured. The flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 133.

According to the owner/operator and the Federal Aviation Administration (FAA) aviation safety inspectors on site, the purpose of the flight was for the pilot to perform external load operations with a 100-ft long line over wooded terrain, which required the helicopter to hover outside of ground effect (HOGE). The external loads lifted and placed by the helicopter included bags of stone and sections of pipe for a drainage project inside the park. Due to the weight of each load the helicopter was performance limited. As a safety margin, only 150 lbs of fuel were added when the helicopter was refueled. The pilot had made two refueling stops during the operation before the accident.

The pilot stated he checked fuel status and aircraft systems before hovering the load into position. At that time, he estimated there was between 65 and 70 lbs of fuel onboard. The pilot hovered the helicopter to maintain a 4-ft load height to assist the ground crew with releasing the material from the bag. The pilot said that with the load on the hook, the helicopter was hovering with about 85% torque applied and the turbine outlet temperature (TOT) within the normal range. He said the task focused all of his attention and at that time he was thinking, “Okay, let’s wrap this up. I have 10-15 minutes of fuel. I’ll only be here for a minute, and then I’ll land and refuel.” Within 1 to 2 minutes, while manipulating the load to assist the ground crew, the engine “flamed out.” He maneuvered the helicopter into the wind and away from the ground crew for a forced landing and made a full collective application before entering trees. The helicopter came to rest upright with substantial damage to the fuselage and tailboom. The pilot said he did not see the low-fuel caution light illuminate before the engine lost power.

According to the operator’s chief pilot, he and the accident pilot performed weight and balance and performance planning calculations based upon a 200-lb fuel load, an external load weight of 1,320 lbs, and a total aircraft weight of 4,250 lbs. At the site, the HOGE power required with the load was 90%.

The helicopter was examined by an FAA aviation safety inspector at the site immediately after the accident. There was no odor of fuel, and no evidence of fuel spillage at the scene. The extended-range fuel device was removed, and visual inspection of the fuel tank revealed no fuel. The inspector then sumped the fuel system per the manufacturer's Rotorcraft Flight Manual and recovered no fuel. During recovery of the helicopter, the recovery crew inserted a defueling hose in the main tank and activated a pump to recover all residual fuel, and no fuel was recovered. Control continuity was confirmed through some fractures to all flight control surfaces. The fractures displayed features consistent with overstress.

A detailed examination of the wreckage revealed that the helicopter’s fuel system was intact, contained no fuel, and operated normally when serviced with fuel.

The helicopter was serviced with 30 gallons of fuel, and the fuel system was purged of air by motoring the engine using the helicopter’s battery. Once fuel flowed at the fuel control, an engine start was attempted, and the engine started immediately and accelerated smoothly to 100% N2. The engine ran for about 15 minutes with normal instrument indications and no leaks. During the run, the engine was decelerated to idle and back to 100% several times with no anomalies noted. A normal shutdown was performed, and the helicopter was defueled.

The fuel gauge showed a static indication of 40 lbs both at the accident site and when electrical power was applied for the wreckage exam with the fuel tanks empty. The fuel gauge subsequently showed 100 lbs when the tanks contained about 60 lbs of fuel and 240 lbs when the tanks contained about 200 lbs of fuel. It could not be determined if the 40-pound discrepancy was due to an out-of-calibration condition pre-accident or to impact forces.

The low-fuel caution light, a system independent of the fuel quantity indicating system, extinguished at the point when the fuel tanks contained about 70 lbs (11 gallons) of fuel. Per the manufacturer, the normal range for the light to illuminate is between 50 and 75 lbs. The light illuminated inside the proper range during defueling following the engine run.

Examination of fueling and aircraft records revealed that the helicopter was operated 4.0 hours from when it was last full of fuel (110 gallons or 750 lbs) to the time of the accident. While operating inside the Tradewinds Park, the helicopter was fueled twice with an estimated total of 43 gallons (288 lbs). According to the manufacturer and the operator, the nominal fuel consumption rate for the helicopter was between 35 to 37 gallons per hour in a cruise configuration. The average fuel consumption rate using 153 gallons over 4 hours was 38 gallons per hour.

According to the manufacturer’s rotorcraft flight manual, the fuel flow charts for the helicopter present fuel consumption in level flight and begin at 60 knots. The manual does not provide fuel consumption rates at a hover. The manual recommends that the operator conduct fuel consumption checks to adjust the presented data as necessary.

According to the FAA Helicopter Flying Handbook (FAA-H-8083-21B) and the U.S. Army (FM 3-04-203 Fundamentals of Flight), more power is required to hover than any other flight regime. Bell Engineering calculated the HOGE fuel flow rates for a Bell 206L1 equipped with the C30P engine.

Gross Weight (lbs)

HOGE Power (ESHP)

Fuel Flow (lbs/hour)

Fuel Flow (gal/hour)

3000

285

234

34.9

3500

342

255

38.1

4000

404

280

41.9

HOGE fuel flow rates for a helicopter at a gross weight of 4,200 lbs would exceed 41.9 gal/hour.