The private pilot was flying over the ocean and just off the coast of Miami when an air traffic controller asked him to descend to 500′.
He reduced power and applied carburetor heat until he reached the assigned altitude. He then attempted to increase engine power and level off, however, even with the throttle full forward, the engine power remained at its previous setting.
The pilot attempted to resolve the situation, but he was unable to maintain altitude and ditched the airplane in the ocean.
Although weather conditions were conducive to serious icing at glide power, the pilot had applied carburetor heat during the descent, which should have melted any carburetor ice during the descent.
A post-accident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The cause for the partial loss of engine power could not be determined.
Probable cause: A partial loss of engine power for reasons that could not be determined.
NTSB Identification: ERA16LA103
This February 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.