Background
Before the incident, the pilot contacted the state division of aeronautics to inquire about the legality of landing on sandbars in the river where the accident later occurred.
Accident Sequence
While cruising at 700-800 feet above ground level, the airplane's engine began running roughly and experienced a loss of power. The pilot enriched the mixture and then applied carburetor heat, which caused the engine to run rougher, so he removed it. The engine continued to lose power until level flight could no longer be maintained.
The pilot decided to land in a farmer's field, but irrigation equipment was present, so he chose to land on a beach along a river. The airplane touched down fast and subsequently floated. Nearing the end of the beach, the pilot attempted to abort the landing. When he advanced the throttle, the engine responded with about 15 percent power. The wheels contacted the water, and the airplane nosed over, coming to rest upside down in the river.
Conditions
Ambient temperature and dewpoint conditions at the time were favorable for moderate carburetor icing at cruise power and serious carburetor icing at glide power.