What was found
(CAN) SHORTLY AFTER TAKE-OFF, WHILE GEARS WERE BEING RETRACTED, NR 2 ENGINE TORQUE WENT FROM 90 TO 70 PERCENT. APPROXIMATELY 5 SECONDS LATER, THE TORQUE DROPPED TO 40 PERCENT, THEN TO ZERO. FOLLOWED PROCEDURES AND SAFELY LANDED BACK AIRPORT OF ORIGIN. THE PRELIMINARY INSPECTIONS REVEALED EXTENSIVE DAMAGE TO THE NR 2 ENGINE POWER TURBINE. SOME ENGINE DEBRIS HAVE BEEN FOUND ON THE RUNWAY. PUNCTURES AND DENT HAVE BEEN REPORTED ON JET AND EXHAUST PIPES SKINS. THE RGB FILTER INDICATOR FOUND POPPED-OUT. THE ENGINE IS BEING INSPECTED AND POWER TURBINE DAMAGE WAS CONFIRMED AND METALLIC DEBRIS FOUND IN EXHAUST DUCT.