At approximately 1140 Central time, the airplane was destroyed when it departed controlled flight, impacting power lines and terrain one mile northwest of the Mineral Wells (Texas) Municipal Airport. Visual conditions prevailed for the test flight by a Commercial pilot and Private-pilot rated passenger. Both sustained fatal injuries. According to several witnesses, the accident airplane was observed flying over Runway 31 at approximately 150 feet AGL and flying rather slow. The airplane then pulled-up hard and banked to the right. and was observed to descend below the tree line. The airplane was found, inverted, in an open field, directly under power lines. A power pole, located 430 feet west of the airplane was broken. The northern power line was down.