What happened
During the initial taxi for takeoff, the pilot noted that the left brake was grabbing. Upon reaching the end of the runway, the dragging sensation persisted, prompting the pilot to decide to return to the maintenance company from which the aircraft had been acquired.
While taxiing back toward the maintenance facility, the brakes failed completely. The pilot continued the taxi using the emergency brake. As the aircraft approached the ramp area, the pilot detected the smell of smoke and subsequently shut down the engine. Immediately following the engine shutdown, a tire blew out. As the pilot exited the aircraft, the second tire also blew out. Both main landing gear tires were observed to be on fire. Personnel at the maintenance company arrived and extinguished the flames.
The investigation
A mechanic inspected the aircraft following the incident and observed that the parking brake had been engaged approximately three-quarters of the way. Upon disassembling the braking system, the mechanic found no mechanical discrepancies or defects that would have caused the brakes to drag.