The airplane was being positioned to another airport at night. The flight was over mountainous terrain. The airplane collided with the top of a 4,600-foot bluff. The pilot had a history of transient global amnesia. Examination of the accident site revealed a 567-foot long wreckage path, oriented along the direct course line from the departure point to the destination. Damage to the engine and propeller indicated that the engine was developing power at impact.