As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING THE A/C WALK AROUND, MAINTENANCE NOTICED THE NR 4 TIRE WAS FLAT. THE WHEEL/TIRE ASSY WAS REMOVED AND UPON INVESTIGATION, A CRACK WAS IDENTIFIED IN THE RADIUS AREA WERE THE BRAKE DRIVE KEYS MOUNT IN THE WHEEL ASSY. THE FAULTY NR 4 WHEEL ASSY WAS REPLACED AND THE A/C WAS RETURNED TO SERVICE WITHOUT FURTHER INCIDENT.