What was found
FLT 410 - DURING FLIGHT, PILOT REPORTED A BANG ON NR 2 ENGINE. PILOT REDUCED POWER AND MADE A QRF. LANDING PERFORMED WITHOUT INCIDENTS. AT THE BASE, ENGINE WAS BORESCOPED BEFORE ANY ATTEMPT TO RESTART. DAMAGE FOUND ON 6TH, 7TH, AND 13TH STAGES COMPRESSOR GROUPS BLADES. DEBRIS IMPACTED ON TURBINE STAGES AND MIXER WITHOUT MAJOR DAMAGE. ENGINE WAS REPLACED, GROUND TEST PERFORMED SUCCESSFULLY. ACFT RETURNED TO SERVICE.