Accident Summary
Witnesses observed an airplane contacting the surface of a lake while performing a low pass, then emerging from a cloud of water and entering a climb trailing white vapor. As the aircraft neared the lake shore, the right propeller ceased rotating. Subsequently, the airplane entered a steep right bank and impacted the ground.
Investigation Findings
Examination of the cockpit controls revealed that the right propeller lever was in the feather position. Teardown analysis of the propellers showed signatures consistent with the right propeller being feathered and the left propeller operating in the low pitch range at the time of impact. Disassembly of both engines found no evidence of pre-impact mechanical anomalies. In the opinion of the engine manufacturer, both engines appeared capable of producing power prior to impact.
Toxicological Findings
Toxicological tests detected ethanol in various bodily fluids: 178.000 mg/dl (0.178%) in vitreous fluid, 90.000 mg/dl (0.09%) in blood, and 114.000 mg/dl (0.114%) in brain fluid. Additionally, acetaldehyde was found at 3.000 mg/dl in brain fluid and 22.000 mg/dl in blood, and 2-propanol was present at 4.000 mg/dl in brain fluid. The levels of ethanol indicate ingestion of alcohol, and the presence of acetaldehyde and 2-propanol, metabolites of ethanol, support this conclusion.
Probable Cause
The official probable cause was determined to be the pilot's impairment of judgment and performance due to alcohol, which resulted in his improper decision to shut down an engine and his failure to maintain adequate airspeed for single-engine flight.