On September 2, 2013, about 1600 central daylight time, an American Champion 7GCB, N9967Y, was substantially damaged during a go-around at McKinley Field Airport (T30), Pearsall, Texas. The pilot and passenger sustained minor injuries. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The local flight originated at 1545. According to the pilot, the rudder cable separated in flight. The pilot was able to return to the airport and align the airplane to land on runway 31. During the landing flare the airplane began to drift and the pilot was not able to correct the drift. The pilot initiated a go-around, stalled the airplane, and subsequently impacted terrain. Both wings and the fuselage were substantially damaged. The right rear rudder cable was visually examined in the National Transportation Safety Board Materials Laboratory. The cable had separated through the wire rope section about 68 inches from the forward end and 101 inches from the aft end. The wire rope section had a nominal 1/8 inch diameter and was composed of 7 strands, each containing 19 wires. The examinations of the separation area found melting of all wires on 3 strands and several individual melted wires on the other 4 strands. The adjacent 2 ½ inches of the cable displayed darkening and oxidation consistent with localized high temperature exposure. The remaining wires in the cable displayed fractures indicative of overstress with significant elongation at the points of separation. The melting and localized heating were consistent with electrical arcing. The elongation and oxidation of the overstressed wires was consistent with separation at high temperature. According to the pilot, the passenger had gotten his foot caught in the rudder cable and believed that the rudder cable came in contact with the battery at that time. A photograph of the battery box, provided by the Federal Aviation Administration, illustrated that the battery box did not have a cover and the positive terminal of the battery was unguarded.