NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The flight instructor reported that the purpose of the flight was to complete a tail-wheel endorsement for the pilot. After about 1 hour of total flight time, while attempting to take off for the fourth full-length runway departure, the flight instructor realized that the engine was not producing enough power for a successful takeoff, so he took control of the airplane and began applying maximum braking; however, the airplane departed the runway end, collided with a ditch, and then nosed over.
During postaccident examination of the airplane, no anomalies were found that would have precluded normal operation. Atmospheric conditions in the area were conducive to the formation of serious icing at cruise power. The flight instructor reported that he believed that carburetor icing led to the loss of engine power. He added that carburetor heat was applied before each landing but that it was turned off when they taxied for departure. Therefore, it is likely that carburetor ice accumulated during the taxi and that the carburetor heat was not on long enough to melt the ice before takeoff, which resulted in the partial loss of engine power.