What was found
(CAN) DURING CRUISE, THE CREW NOTED A GRADUAL DECREASE IN ENGINE TORQUE DOWN TO 50 PERCENT. ACTIVATION OF THE ENGINE ICE VANE HAD LITTLE EFFECT AND AT 20 PERCENT TORQUE, THE ENGINE AUTO-FEATHERED. IT WAS SHUTDOWN AND SECURED. THE FLIGHT CONTINUED TO DESTINATION WHERE A SINGLE ENGINE LANDING WAS PERFORMED. TROUBLESHOOTING IDENTIFIED A FAULTY FUEL CONTROL UNIT, WHICH WAS REPLACED BEFORE THE ACFT WAS RETURNED TO SERVICE. MFG WILL CONTINUE INVESTIGATING THE EVENT AND ADVISE OF ROOT CAUSE ONCE ESTABLISHED.