At about 1015 Pacific time, the experimental airplane impacted the terrain. The private pilot and his flight instructor received fatal injuries. The airplane sustained substantial damage. Visual conditions prevailed.
Initial radar data indicates the plane had been maneuvering at about 10,500 feet msl. The airplane then performed a level 360-deg. right turn and climbed to about 11,700 feet msl. Its airspeed slowed from about 270 mph to about 130 mph. Within a few seconds after it reached 11,700 feet, the airplane descended near vertically into the terrain, which was about 8600 feet below the apex of the climb.