The evening before the accident the second pilot told his fiancee he and the pilot were going to perform 'maneuvers, top gun type of stuff.' A witness observed the ex-military jet airplane perform two loops and two roll maneuvers. At the end of the second roll the witness observed the aircraft enter a spin from about 2,000 feet above ground level. This witness and two additional witnesses then observed the airplane descend in a spin to the left accompanied by loud engine noise. Two of the witnesses reported that when the airplane was about 200 feet agl it appeared the spin stopped and the nose of the aircraft was coming up to a level flight attitude when the airplane rolled abruptly to the right and spun to the ground. The wreckage distribution was consistent with a high energy, steep flight path angle, impact with the ground. The pilot was a former helicopter and utility aircraft pilot in the U.S. Army. He received 6 hours of training in the accident aircraft about 2 months before the accident, which did not include any aerobatic training. He stated his intent to return for additional training, to include aerobatics, at a later date after he was more experienced in the aircraft. The pilot was issued an FAA Letter of Authority to operate the experimental-category aircraft about 3 weeks before the accident.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows: