Background
The pilot and passenger had been practicing landings at nearby airports before returning to their home airport. The pilot recalled that the approach for the night landing was uneventful, but could not remember the landing itself.
Accident Sequence
The passenger reported to airport police that the pilot was at the controls demonstrating a nighttime landing when the aircraft took a bad hop and crashed, landing upside down.
Wreckage Examination
Examination of the wreckage revealed that, after departing the runway, the airplane struck the ground in a nose down attitude. The impact separated the nose gear and both engines from their mounts. The airplane subsequently nosed over and came to rest inverted.