Livermore, CA, USA
N92VA
Gunnoe Velocity
The mechanic/pilot performed engine maintenance on the experimental airplane and was taking the airplane out for a high-speed taxi and check flight. He said that during the takeoff roll the right brake did not feel as he expected it to, and he decided to abort the takeoff. As the airplane exited the runway and proceeded onto the taxiway, the pilot activated the right brake to straighten the airplane when the right brake failed. The airplane began to spin and came to rest on an adjacent grassy area where the right brake ignited a fire burning the grass and the airplane. By the time the fire department arrived, the airplane's engine section, firewall, and part of the fuselage had been fire damaged. A postaccident inspection by a Federal Aviation Administration inspector revealed that the right brake caliper had been restricted by the wheel pant. This caused drag on the brake rotor allowing it to build up heat and eventually caused the fluid line to fail.
On June 19, 2009, at 1610 Pacific daylight time, an experimental Gunnoe Velocity, N92VA, experienced a brake fire in the right brake after aborting the takeoff at Livermore Municipal Airport (LVK), Livermore, California. The mechanic/pilot operated the airplane under the provisions of 14 Code of Federal Regulations Part 91, as a maintenance test flight. The airplane sustained structural damage to the fuselage and firewall. The pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed for the local area flight, and no flight plan had been filed. In the pilot's written report to the National Transportation Safety Board, he stated that following maintenance on the engine, he decided to do a runway test and possible flight test. The engine started with no problems and he commenced to taxi the airplane to the runway. A normal run up was performed, and the winds were observed to be from the west at a quartering crosswind, gusting to 20 knots. As the pilot taxied the airplane onto the runway, he stated that he compensated for the wind with the use of left brake. The pilot reported that he added power slowly, and the engine sounded normal, but not quite what he expected. As the airplane started to build up speed, it was still not quite what he expected. The pilot stated that he had to increase the pressure on the left rudder as he started the takeoff roll, and then tapped the right brake as he had over corrected to the left. The pilot stated that was when he thought that the right brake did not feel right. He raised the nose up, but it did not feel right and he decided to abort the takeoff. On the rollout the pilot reported having to hold left rudder and light brake to slow down, but gave no more thought to the right brake. As he exited the runway onto the taxiway, he activated the right brake to straighten out the airplane, and the right brake failed completely. The airplane began to spin to the left and the airplane exited onto a grassy area adjacent to the taxiway. He was not able to get the airplane back onto the taxiway due to the soft grass. The tower controller then contacted the pilot and informed him that there was a grass fire under his airplane. The pilot shut down the engine and exited the airplane, observing that the right brake had caught the grass on fire. The pilot contacted tower personnel to tell them that the airplane was on fire, and attempted to move the airplane. When he was not able to move the airplane, he pulled the fuel cutoff valve and waited for the fire department to respond. According to a Federal Aviation Administration (FAA) inspector, who examined the airplane, the right brake caliper had been restricted from floating in its normal manner due to the clearance between the wheel pant half and the caliper itself. This caused the drag on the brake rotor and eventually heat buildup. The FAA inspector reported that the heat buildup caused the right brake fluid line to fail. He also examined the left brake assembly and noted indications of heat buildup in the left brake assembly as well.
The failure of the right brake due to a restricted brake rotor and subsequent brake fluid line failure as a result of inadequate maintenance.
Source: NTSB Aviation Accident Database
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