What was found
DURING AIRCRAFT RUN, AND RELEASE OF PARKING BRAKE, PILOT'S RIGHT YAW PEDAL STUD BROKE WHICH AFFIXES THE BRAKE CYLINDER TO THE PEDAL ASSEMBLY, WHICH LED TO THE INABILITY FOR THE PILOT IN COMMAND TO USE THE THE RIGHT BRAKE. THE PILOT SECOND IN COMMAND APPLIED BRAKES, AND AIRCRAFT SHUT DOWN, CANCELLING THE FLIGHT.