What was found
(CAN) DURING CLIMB, THE ENGINE TORQUE DROPPED TO ZERO AND THE PROPELLER WENT IN FEATHER. AN ENGINE RE-START WAS ABORTED DUE TO RAPIDLY INCREASING POWER TURBINE SPEED. THE ENGINE WAS SECURED AND THE ACFT RETURNED TO THE DEPARTURE POINT WHERE AN UNEVENTFUL SINGLE ENGINE LANDING WAS ACCOMPLISHED. POST FLIGHT TROUBLESHOOTING LED TO THE REPLACEMENT OF A DAMAGED AC GENERATOR, AIRFRAME PART, BEFORE THE ACFT WAS RETURNED TO SERVICE.