Cessna U206F N33243 accident near Islesboro, Maine

Probable cause

A loss of engine power due to fuel contamination.

NTSB analysis

During preflight, the pilot sumped the fuel tanks and noticed water in the samples. He continued to sump the tanks until the fuel samples were absent of water. The accident flight was the fourth flight of the day and the airplane accrued 50 minutes of flight time during the 3 previous flights. On the accident flight, engine start, taxi, and takeoff were "normal" until 200 to 300 feet above the ground when "the power started slowly coming off". The pilot rejected an open field to his left for landing due to lack of altitude/glide distance, and chose to land straight ahead in heavily wooded terrain, which resulted in substantial damage to the airplane. After recovery of the airplane, the engine started immediately using the airplane’s battery power, and ran continuously utilizing the airplane’s own fuel system. Fuel drained from the right header tank contained water and a mass that resembled a snail (land mollusk). The mass subsequently dissolved in the sample jar, but the remains were suspended in the water at the bottom of the jar. Fuel sample test results revealed that the fuel sample contained "plasticizers," which are present in many greases, and the bottom of the sample jar contained droplets of water, and a "black particulate" matter that contained both the plasticizers and methyl cellulose, which is a material commonly used in filters.

Text from the NTSB. Open the NTSB docket for ERA09LA352 for the full record.