NTSB Factual Report

On September 24, 2015, about 1040 central daylight time, a Bell 206B helicopter, N648CA, experienced a loss of engine power and made a forced landing to a field near Woodville, Texas. The commercial rated pilot, sole occupant, was seriously injured and the helicopter sustained substantial damage. The helicopter was registered to and operated by Chem-Air LLC, Shreveport, Louisiana, under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed. The local flight originated about 1035 from the company support truck.

The operator reported that the pilot was conducting an aerial application flight over a heavily wooded area. He had been conducting aerial application operations since 0630. The helicopter was filled with 80 gallons of herbicide and about 20 gallons of fuel. After departure from the support truck the pilot made a climbing right turn when the helicopter's engine experienced a loss of power. The helicopter was above a group of tall pine trees, which the pilot was able to avoid and then he lowered the nose of the helicopter in attempt to regain rotor rpm. The pilot was unable to attain sufficient altitude to regain rotor rpm and the helicopter impacted terrain. During the forced landing, the helicopter came to rest on its right side. The helicopter sustained substantial damage to the fuselage, tailboom and rotor blades.

On October 6, 3015, a Federal Aviation Administration (FAA) inspector, along with technical representatives from Bell Helicopter and Rolls Royce, examined the wreckage. Damage to the airframe, drive system, main rotor, tail rotor and flight controls was consistent with impact forces and no pre-impact anomalies were observed in any of the systems. There was no evidence of engine mechanical failure or malfunction.

The engine and airframe were tested for water contamination in multiple locations. Water detecting paste, Kolor Kut, was used on the fluid samples. Water was found in the helicopter fuel tank, airframe fuel filter, engine fuel filter, and in the engine's fuel spray nozzle supply line. Water was also found in the lower right portion of the intact crash resistant fuel tank. The airframe fuel filter contained mostly orange/brown colored water (as confirmed by Kolor Kut) and a small amount of fuel. The fuel filter canister was full of fluid and the paper filter was relatively clean, but the bottom of canister contained dirt and particulates. The engine fuel filter mostly contained clear water with drops of fuel. The fuel spray nozzle supply line, which effectively traps and protects the fuel being fed to the engine, was loosened and the contents examined. The captured fluid smelled of jet fuel, but exhibited a division line which is typical of a fuel/water mixture. The division line indicated about a 1/3 fuel and 2/3 water ratio.

The support fuel truck was tested for water contamination at three locations. No water was found at the pump sump, the lowest part in the truck's fuel supply system. Water was observed in the fuel filter sump; the filter was removed and did not appear to be bulging from water absorption. Water was observed in the truck's fuel nozzle; the fuel sample was yellow in color.

NTSB Probable Cause

The loss of engine power due to water contamination in the fuel system. Contributing to the accident were the pilot’s inadequate preflight inspection of the fuel tanks and the operator’s inadequate inspection of the fuel supply truck that did not detect water contamination.