What was found
FJ44-3A ENGINE SERIAL NUMBER 141530, FROM AIRCRAFT 525B-0257 (N32AC), WAS RETURNED TO THE REPAIR STATION FOR UNSCHEDULED REPAIR. ENGINE EXHIBITED A "HUM" NOISE DURING FLIGHT. ENGINE OEM DIRECTED A BORESCOPE INSPECTION OF THE ENGINE'S COMPRESSOR SECTION, WHICH REPORTEDLY REVEALED DAMAGE TO HIGH PRESSURE (HP) COMPRESSOR BLADES AND 3RD-STAGE INTERMEDIATE PRESSURE COMPRESSOR (IPC) ROTOR BLADES. DISASSEMBLY OF THE ENGINE REVEALED ONE LIBERATED 3RD STAGE IPC ROTOR BLADE, WHICH APPEARS TO HAVE MOVED DOWNSTREAM, DAMAGING THE HPC ROTOR BLADES.