On June 24, 20094, approximately 1130 central daylight time, a Stinson 108-3, N6939M, registered to and operated by a student pilot, was substantially damaged when it nosed over on landing roll at Llano Municipal Airport (AQO), Llano, Texas. Visual meteorological conditions prevailed at the time of the accident. The instructional flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The student pilot was not injured. The local flight originated from Llano approximately 1120. The student pilot was soloing for the first time. During the third landing rollout, the airplane began to pull to the left. The student pilot attempted to maintain directional control but the left main gear separated, causing the airplane to nose over onto its back. The left main wheel and brake caliper were located several hundred feet behind the airplane, along the rollout path. A mechanic who later inspected the airplane after the accident reported that the inner wheel half was broken around the brake disc mounting flange. The mechanic stated there was no bluing from excessive heat or any signs that the bearings had failed.