Incident Summary
On June 19, 2009, at 1610 Pacific daylight time, an experimental Gunnoe Velocity, registered N92VA, experienced a brake fire in the right brake after aborting the takeoff at Livermore Municipal Airport (LVK), Livermore, California. The aircraft sustained structural damage to the fuselage and firewall. The pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed for the local area flight, and no flight plan had been filed.
Aircraft and Flight Details
The pilot, also a mechanic, operated the airplane under 14 Code of Federal Regulations Part 91 as a maintenance test flight. Following engine maintenance, he planned a runway test and possible flight test. The engine started without issues, and the pilot taxied to the runway. A normal run-up was performed, and winds were observed from the west at a quartering crosswind, gusting to 20 knots.
Event Sequence
As the pilot taxied onto the runway, he compensated for the wind with left brake application. He added power slowly; the engine sounded normal but not as expected. During the takeoff roll, the pilot increased pressure on the left rudder and tapped the right brake to correct an overcorrection to the left. He felt the right brake was not right, raised the nose, and decided to abort. On the rollout, he used left rudder and light braking to slow down. Upon exiting the runway onto the taxiway, he activated the right brake to straighten the aircraft, and the right brake failed completely. The airplane spun to the left and left the taxiway onto a grassy area. The soft grass prevented the pilot from returning to the taxiway.
The tower controller then informed the pilot of a grass fire under the airplane. The pilot shut down the engine and exited, observing that the right brake had ignited the grass. He contacted tower personnel, attempted to move the aircraft unsuccessfully, pulled the fuel cutoff valve, and waited for the fire department to respond.
Examination Findings
A Federal Aviation Administration (FAA) inspector examined the airplane and found that the right brake caliper had been restricted from floating in its normal manner due to insufficient clearance between the wheel pant half and the caliper itself. This restriction caused drag on the brake rotor, leading to heat buildup. The heat buildup eventually caused the right brake fluid line to fail. The inspector also examined the left brake assembly and noted indications of heat buildup there as well.