What was found
ACFT WAS UNDERGOING A 100 HR INSPECTION. REMOVED LT & RT MLG WHEEL ASSEMBLIES TO COMPLETE NDT AND UPON WHEEL REMOVAL ONE OF THE WHEEL BRAKE DISC ASSEMBLIES FELL ONTO FLOOR IN 2 SEPARATE PIECES. THE LT AND RT BRAKE ASSEMBLIES BOTH SHOWED SEPARATED BRAKE DISCS. THE BRAKE DISC ASSEMBLIES WERE NOT THE ORIGINAL BRAKE ASSEMBLIES. THE AFFECTED BRAKE ASSEMBLIES WERE INSTALLED AT AN EARLY DATE AND TAGGED AS REMOVED FROM ANOTHER ACFT. THE OPERATOR DID NOT NOTICE ANY ABNORMAL SOUNDS OR CONDITIONS DURING ACFT OPERATIONS. THE TECH DID NOT NOTICE ANY ABNORMAL SOUNDS OR CONDITIONS DURING RUN UP OPS AND THE WEAR GUIDE PINS SHOWED NORMAL. SYS FUNCTIONED PROPERLY.