Brake Failure and Fire
The pilot reported that the aircraft's brakes failed after taxiing from base operations to the runway, a distance of 2.1 miles. Upon exiting the aircraft, the pilot observed brake fluid leaking onto the ground and smoke emanating from the right wheel brake. The pilot called for fire equipment and was walking to a ramp fire extinguisher when the right brake ignited.
Damage Assessment
FAA inspectors subsequently reported that the right main landing gear had been involved in a fire which consumed the tire and wheel fairing, and burned a hole in the wing above. The left main landing gear and wheel, which did not burn, showed evidence of high temperature. The brake caliper was leaking fluid, the brake disk was distorted and discolored, and the tire sidewall was heat damaged in the area adjacent to the brake disk.
Pilot Attribution
The pilot attributed the fire to the parking brake master cylinder or parking brake linkage failure causing a minor binding of brakes. A lineman at the flight's point of origin reported having to help the pilot start the engine and that he could hear the brakes dragging as the aircraft taxied away.