As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PILOT'S PRE-FLIGHT, HE FOUND WHAT APPEARED TO BE ROTOR BRAKE LINING BELOW THE ENGINE DRIVE SHAFT AFT OF THE FIREWALL. MAINTENANCE REMOVED BOTH BRAKE CALIPERS AND FOUND LT FWD AND RT AFT LININGS MISSING. LINING APPEARS TO HAVE DEBONDED AND FELL INTO THE ENGINE DECK. BOTH THE ROTOR BRAKE DISK AND LININGS SHOWS NO SIGNS OF OVERTEMP. (X)