On April 29, 1997, at about 1805 eastern daylight time, N9213A, a Amateur Built Challenger II, owned and operated by the private pilot, sustained substantial damage after impacting an unmarked electrical wire approximately 40 feet above the ground while making a low pass over a potential landing area in Mansfield, Pennsylvania. The pilot and sole occupant received serious injuries. Visual Meteorological conditions existed and no flight plan was filed. The flight was conducted under the provisions of 14 CFR Part 91. According to the pilot, he had been in flight about an hour before he spotted an airstrip in a field. The pilot stated he decided to fly low over the strip to observe its condition. He set up an approach to the south. According to the pilot, when he was about 50 to 100 yards before the threshold, the airplane struck an electrical wire with the left wing. The pilot stated the airplane became uncontrollable and descended into the ground. The full serial number for this aircraft is: CH2-0395-CW-1317.