The airplane was destroyed when it impacted terrain at approximately 0650 Mountain time following a loss of control while maneuvering. The Private pilot and sole occupant was fatally injured. Visual conditions prevailed. According to preliminary ATC information, the airplane entered a 5000-fpm descent and executed a left 180-deg. turn. The airplane then entered a 2000-fpm climb and a slight right turn to the north. Shortly thereafter, the airplane entered a 3000-fpm descent and radar contact was lost.