Piper PA-28-140 N7470R accident near Buford, Georgia

Probable cause

Water contamination in the fuel system that was not observed during the preflight inspection, resulting in a total loss of engine power and forced landing.

NTSB analysis

The student pilot and his flight instructor were on a local flight and were practicing maneuvers before returning to their home airport. Shortly after the student switched fuel tanks, the engine unexpectedly lost all power. The flight instructor confirmed that the throttle was full forward and the mixture was full rich. Unable to reach an airport due to their altitude, the flight instructor performed a forced landing to a local interstate highway. During the landing, the airplane’s nose landing gear collapsed and the right wing was damaged. The pilots were not injured.

Examination of the engine, including a test run, revealed no evidence of any mechanical malfunctions or anomalies that would have precluded normal operation. During the examination of the carburetor, about 1 ounce of cloudy water was found in the carburetor bowl; no water was found in the gascolator. The flight instructor reported that no water was observed during the preflight inspection. Based on this information, it is likely that, as the student switched fuel tanks, previously undetected water from within the fuel system was introduced into the carburetor, resulting in the total loss of power.

Text from the NTSB. Open the NTSB docket for ERA23LA117 for the full record.