Bell 206B N240SJ accident near Bennet, Nebraska

Probable cause

A total loss of engine power due to fuel contamination, which resulted from the pilot’s inadequate preflight inspection. Contributing to the accident was the operator’s failure to properly maintain the fuel storage tank.

NTSB analysis

The pilot reported that he refueled the helicopter from a stationary fuel tank that the operator had recently had filled. After sumping the helicopter's fuel tank and the airframe fuel filter and noting that the strained fuel was absent of debris and water, the pilot departed on the flight. About 12 to 15 minutes into the flight, the engine lost total power. The pilot made a low-altitude autorotation to a field, and the helicopter subsequently slid about 10 to 15 ft and struck a berm. No preaccident mechanical deficiencies were found that would have precluded normal operation of the engine.

The pilot said that he thought the power loss was due to fuel contamination, so he sumped fuel from the helicopter and the storage tank, and the fuel from each source was dark brown with visible contaminants. Postaccident examination of a large sample of fuel drained from the storage fuel tank confirmed that the fuel was brown with visible contaminants. The tank's filter was also found to be contaminated, and sludge was observed in the bottom of the tank. Contaminated fuel was found in the helicopter's fuel tank and fuel filter bowl, and the fuel nozzle was covered with a hardened dark brown substance.

Review of fueling records revealed that the fuel contractor had delivered a 1,000-gallon fuel storage tank labeled "diesel" to the fueling site and that the contractor placed 920 gallons of Jet A fuel in the tank 14 days later (5 days before the accident). It could not be determined what type of fuel was in the tank before it was filled with Jet A fuel.

Text from the NTSB. Open the NTSB docket for CEN14LA390 for the full record.