Incident Overview
A student pilot was conducting a touch-and-go landing and initiated a climb for another approach. At approximately 800 feet, the engine lost power. The pilot reported turning on carburetor heat, which resulted in an immediate increase in power followed by a subsequent drop in power. The power loss persisted, forcing the pilot to execute a forced landing in a river.
Post-Incident Examination
After the incident, the Federal Aviation Administration (FAA) dried the engine and successfully ran it smoothly during a run-up period. No evidence of fuel contamination was found.
Observations
The sequence of events involved a power loss at a critical phase of flight, a brief response to carburetor heat, and a forced landing off-airport. The engine's satisfactory performance after drying suggests a possible issue related to moisture or induction system icing, but the investigation did not confirm a specific cause.