On August 16, 2015, about 1915 mountain daylight time, a Taylorcraft BC-12D, N43616, experienced a brake system malfunction during the landing roll at the Libby Airport, Libby, Montana. A private individual owned the airplane and the pilot was operating it under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot and passenger were not injured; the airplane sustained substantial damage. The cross-country personal flight departed from a remote grass airstrip in Yaak, Montana about 1845 with a planned destination of Libby. Visual meteorological conditions prevailed and the pilot had not filed a visual flight rules (VFR) flight plan. The pilot stated that after completing the approximate 20 minute flight, he configured the airplane to land on runway 33 at the Libby Airport. Upon touchdown, the airplane began to veer to the left. The pilot used both the brake and rudder inputs in an effort to return to the runway center. Despite the pilot's attempts to regain directional control, the airplane continued off the left side of the runway and ground looped. The airplane incurred substantial damage to the wing spar. The pilot further stated that the loss of directional control was precipitated by a landing gear malfunction. He opined that the left brake likely seized after touchdown, which was evident from the skidmark on the runway surface. The brake system was the original cable-operated drum brake. The left landing gear was locked immediately after the accident, but after several hours was free to turn again. A Federal Aviation Administration (FAA) certified airframe and powerplant mechanic examined and disassembled the left landing gear. He stated the examination of the braking system revealed no evidence of mechanical malfunction or failure that would have precluded normal operation. He further stated that he could smell a burned odor from the brake, but they functioned normally.