Incident Overview
During flight, the pilot contacted air traffic control to report engine difficulties. Radar data subsequently indicated that the aircraft descended at an average rate of approximately 1,090 feet per minute over the following four minutes.
Witness Observation
A witness on the ground observed the airplane approaching from the south at an altitude described as "tree top level." The airplane appeared to be attempting an emergency landing on a nearby highway. As it neared the roadway, the aircraft struck an asphalt compactor and immediately "burst into flames."
Engine Examination
A teardown examination of the engine was conducted. The examination revealed that the #2 connecting rod had separated from the crankshaft while the engine was operating. No evidence of lubrication distress was found in the engine. Further, the fractured surfaces from the connecting rod components all displayed characteristics consistent with overload.
Findings
The investigation concluded that the engine failure resulted from a mechanical separation of the #2 connecting rod from the crankshaft, with the fracture surfaces indicating an overload condition.