As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHEN TECHNICIAN TOW THE A/C INTO THE HANGAR, HE SAW BLACK POWDER ON THE GROUND. THE TECHNICIAN FOUND MAIN WHEEL BRAKE ASSY #3 OUTER STATOR & ROTOR DAMAGED. THE BRAKE AND THE WHEEL ASSEMBLIES WERE REPLACED AND THE AIRCRAFT RETURNED TO SERVICE. BRAKE SYSTEM PRESSURE TEST AND BRAKE METERING VALVES PRESS TEST PERFORMED. ALL PRESS INDICATION FOUND WITHIN MM LIMITS. (TC# 20190801004)