Cessna 170 N3812V accident near Biddeford, Maine

Probable cause

A total loss of engine power due to water contamination of the fuel. Contributing to the accident was the pilot/owner’s inadequate preflight inspection.

NTSB analysis

According to the pilot/owner and his instructor, the preflight inspection and the engine start, taxi, and takeoff checks were all completed in accordance with the checklists with no anomalies noted. The pilot/owner reported that during the takeoff roll, the airplane seemed to “take forever” to reach takeoff speed and that it used “the whole runway.” When the airplane reached about 1,000 feet mean sea level, the engine stopped producing power, and the instructor took control of the airplane. He turned the airplane back toward the departure airport and performed remedial actions to regain engine power but was unsuccessful. When he determined the airplane would not reach the airport, he performed a forced landing to wooded terrain. The airplane sustained substantial damage to the wings, fuselage, and empennage. Both pilots egressed without assistance. Examination of the wreckage revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. Examination of the fuel system found it intact. Removal of the fuel pump caused water to spill from the pump. The pump was actuated by hand, and water was ejected from the pump. The carburetor float bowl contained a “50-50” mixture of water and fuel. The water in the fuel system, which should have been detected during a preflight inspection, led to the loss of engine power during takeoff.

Text from the NTSB. Open the NTSB docket for ERA12LA397 for the full record.