Aviation Accident Summaries

Aviation Accident Summary CEN14LA390

Bennet, NE, USA

Aircraft #1

N240SJ

BELL 206B

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.

Factual Information

On July 26, 2014, at 1430 central daylight time, N240SJ, a Bell 206B helicopter, sustained substantial damage during a forced landing to a soybean field after a total loss of engine power near Bennet, Nebraska. The commercial pilot was not injured. The helicopter was registered to and operated by a private company. Visual meteorological conditions prevailed and no flight plan was filed for the local, aerial application flight conducted under 14 Code of Federal Regulations Part 137.In a telephone conversation, the pilot stated that he had flown 4 uneventful hours that day and had to stop to refuel. He said the operator had just purchased fuel, which had been placed into a stationary fuel storage tank and this was the first time he was using fuel from that tank. The pilot pumped 25 gallons of fuel into the helicopter, then sumped the airframe fuel tank and fuel filter. The pilot said the strained fuel was absent of water and debris. He then departed. About 12-15 minutes into the flight, when the helicopter was about 16 feet above the ground, at an airspeed of 80 miles per hour (mph), the turbine-engine lost total power. The pilot made an autorotation to a soybean field and slid about 10-15 feet into a berm. Due to the rocking motion from hitting the berm, the main rotor blade severed the tail boom. The pilot said that he thought the engine "flame-out" was due to fuel contamination so he sumped the helicopter's airframe fuel filter and the stationary fuel storage tank after the accident. The drained fuel from both sources was dark brown with visible contaminates. A post accident examination of the helicopter and stationary fuel storage tank was conducted on August 5, 2014, by the Federal Aviation Administration (FAA), Bell Helicopter and Rolls Royce. Examination of the stationary fuel storage tank's fueling receipt and company records revealed that on July 7, 2014, the operator's fuel contractor delivered a 1,000 gallon Flameshield tank to the remote fueling site. This tank was marked "Diesel" on the side. On July 21, 2014, the fuel contractor placed 920 gallons of Jet A fuel into the 1,000 gallon "Diesel" tank. The FAA drained a large fuel sample from the tank and it was dark brown in color with contaminates. The tank's filter was also contaminated and visible sludge was observed at the bottom of the tank. Contaminated fuel was also found in the helicopter's fuel tank and fuel filter bowl, and the fuel nozzle was covered with a hardened dark brown substance. There were no other pre-mishap mechanical deficiencies observed that would have precluded normal operation of the engine.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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