The pilot’s failure to use carburetor heat in conditions conducive to the formation of carburetor ice, which resulted in a partial loss of engine power due to fuel starvation. Contributing to the outcome was her failure to attain a proper touchdown point during the subsequent diversionary landing, which resulted in a runway excursion.

The pilot's failure to roll throttle back on (return the power to the normal operating range) during an attempted power recovery from an autorotation, and his subsequent failure to maintain aircraft control.