As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT ROLLED OFF RAMP DUE TO PARK BRAKE FAILURE. LH MAIN AND NOSE GEAR OFF PAVEMENT. ENGINES WERE NOT RUNNING. REMOVED FROM SERVICE. R&R PARK BRAKE CONTROL VALVE, REF Q400 32-44-01-000/400-801. ALL REQUIRED CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.