What happened
The pilot was conducting a post-maintenance evaluation flight using two recently overhauled engines and propellers. During the flight, witnesses observed the aircraft flying at a low altitude with both engines operating at high power. One witness, who is also a pilot, noted that the aircraft's speed was fast and not near a stall or Vmc (minimum controllable airspeed).
Following this observation, the airplane was seen to roll to the right and descend into a wooded area. The impact resulted in the fragmentation of the wings and fuselage.
The investigation
Investigators located cut wood and impact marks at the accident site that corresponded to both engines. A mechanical examination of the aircraft failed to reveal any mechanical failure or malfunction.
A review of the aircraft logbooks showed no recent maintenance had been performed on the flight control system. Additionally, a medical review of the pilot's records indicated there were no outstanding medical problems.