Accident Narrative
A pilot reported that during a descent to 2,100 feet, intermediate level-offs were performed at 5,000, 4,000, and 3,000 feet. At 2,200 feet, carburetor heat was removed and power was applied to level off. When the throttle was advanced, the engine began running rough and would not sustain level flight. The pilot tried all combinations of power and carburetor heat, but the condition did not improve.
Forced Landing and Recovery
The power loss occurred over a dense forest, prompting the pilot to execute a forced landing in a lake. The aircraft sank in 14 feet of water and was later recovered. Examination revealed no preimpact part failure or malfunction. The carburetor heat cable was found loose, but impact damage was present in that area.
Environmental Conditions
The temperature and dew point were 74°F and 68°F, respectively. According to icing probability charts, carburetor icing would have been possible if the carburetor heat had not been used or had not functioned.