WPR09LA236

The pilot reported that he made a normal landing on the runway. During rollout, he felt a vibration coming from the landing gear. When he exited the runway, the airplane turned abruptly to the left, as if the left brake had locked up. The uncommanded sharp left turn resulted in the airplane exiting the pavement and impacting a cement culvert. The examination of the runway revealed witness marks consistent with a locked left wheel brake. An examination of the airplane's left wheel assembly revealed that the tire rotated freely. No external evidence of brake failure was found. The reason for the intermittent anomaly associated with the brake assembly or cylinder was not determined.

On May 10, 2009, about 1235 Pacific daylight time, a Cessna 140, N73017, ground looped following landing at the Mesquite Airport, Mesquite, Nevada. The accident occurred as the pilot taxied off the runway. The pilot owned and operated the airplane, and it was substantially damaged. Neither the commercial certificated pilot nor passenger was injured during the personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was performed under the provisions of 14 Code of Federal Regulations Part 91, and it originated from Mesquite about 1155. The pilot reported to the National Transportation Safety Board investigator that, following a normal landing, he felt a "substantial vibration coming from the landing gear" as the airplane rolled out on the runway. When the pilot exited the runway, the airplane "turned abruptly to the left." The pilot opined that the airplane's left brake may have locked up. The uncommanded sharp left turn resulted in the airplane exiting the pavement. The pilot reported to the Federal Aviation Administration (FAA) coordinator that he attempted to maintain directional control by applying right brake and rudder, but his efforts were ineffective. As the airplane approached a cement drainage culvert, the pilot applied full left rudder in order to avoid going into the culvert. This action kept the airplane from entering the culvert. However, the empennage contacted the cement edge of the culvert, which resulted in substantial airframe damage. Two airframe bulkheads and stringers were deformed, and the empennage was partially crushed. At the time of the mishap, the wind was light and variable. The FAA coordinator examined the runway. He reported observing tire witness marks that were consistent with a stuck brake on the airplane's left main landing gear wheel. According to the FAA coordinator, the left wheel and brake assembly were examined externally. The wheel was found to rotate freely. No evidence of a brake cylinder failure was noted. However, the FAA stated that "there is a good possibility of an intermittent failure of a brake cylinder consistent with possible momentary contamination of the system." The pilot reported having 7,250 total hours of flight time, of which 150 hours were obtained flying the accident model of airplane. The FAA coordinator indicated that he believed the pilot had sufficient flying experience to not have inadvertently applied improper brake pressure.