What was found
DURING TAKE OFF FROM ISP, PILOTS REPORTED HEARING A BANG AND OBSERVED SPARKS COMING FROM THE RIGHT ENGINE EXHAUST DUCT. ENGINE WAS SHUT DOWN AND AIRCRAFT RETURNED TO GATE WITH NO FURTHER EVENT. PILOTS PERFORMED WALK AROUND INSPECTION AND DISCOVERED DENTS AND HOLES IN THE RIGHT ENGINE EXHAUST STACK. MAINTENANCE WAS DISPATCHED AND DISCOVERED DAMAGE TO THE POWER TURBINE DISC. ENGINE WAS CHANGED AND AIRCRAFT WAS RETURNED TO SERIVCE.