What happened
While performing maneuvers at a low altitude, the pilot experienced a sudden loss of engine power. The flight took place in conditions characterized by high humidity. According to statements provided to the FAA, the pilot had engaged the carburetor heat prior to beginning the maneuvers. Following the loss of power, the aircraft entered a spin. Although the pilot was able to regain control of the airplane, the descent could not be arrested in time to prevent the aircraft from impacting water.
The investigation
An examination of the aircraft revealed no evidence of mechanical malfunction. Investigators noted that while the carburetor heat box was damaged, the heat appeared to have been in the 'on' position. Meteorological data and the carburetor icing chart indicated that the temperature and dewpoint were within a range conducive to moderate icing at cruise power or serious icing at glide power.