Incident Overview
On January 24, 2011, at 1100 eastern standard time, a Cirrus SR-22, registration N690KY, operated by an airline transport pilot under 14 CFR Part 91, experienced a brake and wheel fire during taxi at Pittsburgh International Airport (PIT), Pittsburgh, Pennsylvania. The flight, conducted under an instrument flight rule (IFR) flight plan in visual meteorological conditions, was originating at the time of the accident. The pilot and passenger were not injured, and the airplane sustained substantial damage.
Sequence of Events
According to the pilot, after conducting a preflight inspection, he obtained his IFR clearance and was given taxi instructions to taxi from the fixed base operator to runway 10R. During the taxi, the pilot reported no indication of trouble from the brakes, and normal braking pressures were used. Upon reaching runway 10R, the takeoff checklist was started. The pilot increased engine rpm as per the checklist, and the airplane moved forward slightly. As pressure was applied to the brakes, the right brake "popped" and the right pedal lost all pressure. The airplane began a 180-degree turn to the left, and the engine was shut down. Smoke was observed coming from under the right wing, and the tower was alerted. As the pilot and passenger exited the airplane, they saw smoke emanating from the right wheel pant. Flames appeared around the base of the wheel pant, and the pilot attempted to extinguish the fire unsuccessfully. The airport firefighting crew arrived and extinguished the fire.
Examination Findings
A Federal Aviation Administration inspector examined the airplane and found the right wheel assembly heavily fire-damaged and broken away from the strut. The strut coating was burnt to the fibers, and the underside of the wing was heavily blistered. Further examination revealed that the remaining wheel assembly components were destroyed by fire. Examination of the left brake assembly did not reveal any evidence of mechanical failure.
The airplane was equipped with an Avidyne avionics system including a multi-function display (MFD). Data from the MFD, extracted and analyzed by the National Transportation Safety Board's Vehicle Recorder Division, indicated that the pilot reached ground speeds of 30 knots, and engine power during taxi ranged from 1,100 to 1,900 rpm. Review of the airplane's pilot operating handbook revealed that the maximum recommended continuous engine power for taxiing is 1,000 rpm. The handbook further states that if engine power is exceeded and proper braking procedures are not observed during taxi, wheel brake damage or fire could occur.