On June 9, 1995, about 2030 eastern daylight time, a Bronislaus Challenger II homebuilt airplane, N8101Z, lost total engine power while in the traffic pattern at the Mountain Meadow Airstrip near Burlington, Connecticut. The airplane descended and impacted a field. The student and instructor pilots were seriously injured. The airplane was destroyed. Visual meteorological conditions prevailed. The local flight was conducted under 14 CFR Part 91. According to the student pilot, the purpose of the flight was to receive instruction in his newly purchased Challenger II. The student pilot was seated in the front seat and the instructor pilot was seated in the rear seat. The rear seat cabin area did not contain any flight controls. The student pilot stated, "We had flown around the pattern once with no problem. On the second pattern I knew that the airplane was low in the pattern but was not sure why." The student pilot stated that he does not remember the accident sequence. The instructor pilot stated that he could not remember any of the circumstances surrounding the accident. A witness located near the airport stated, "...I observed a silver gray plane flying north and then turning east. As it was turning east I heard the engine stop. I know it stopped because its a loud noise when its on. Then the plane turned north and then it started dropping down. It then made a nose-dive before hitting the ground." Another witness located on Field View Drive near the airport stated, "...I observed a small ultra-light plane flying I believe south towards Bristol then they made a very sharp U-turn flying towards the Burlington Airport. While they were making the U-turn I heard the planes engine stall. The plane started to nose dive and soon after the plane started spinning...." Postaccident examination of the accident site revealed the airplane impacted the ground, nose down, and came to rest 40 feet beyond the initial impact point. The two throttle controls, one located at each pilots station, were found in the closed (idle) position. Surface control continuity was established. Fuel was found throughout the fuel system and in the engine's carburetors. There was no evidence of contaminated fuel. The airplane's recovery parachute safety pin was pulled out but the chute had not been deployed. The parachute was intentionally deployed after the accident and no anomalies were noted. Examination of the engine revealed that the right carburetor was torn away from the engine and both cylinders had their spark plug leads ripped from their spark plugs. Compression and continuity throughout the engine was established. The spark plug leads were reconnected by safety wire and the right carburetor was reinstalled to the engine. Fuel taken from the accident airplane's fuel tanks was used to start the engine. The engine was started and ran without any anomalies noted. According to the student pilot's log book, he had accumulated a total of 30 flight hours, of which 7.2 were pilot in command. The student pilot had no logged time in the Challenger II. The instructor pilot stated that he had a total of about 2,250 flight hours. His log book was not recovered.