What was found
(CAN) AT CRUISE ALTITUDE AT FL110 ON A MEDEVAC FLIGHT DESCENT CHECKS WERE CARRIED OUT. AS TURBULENCE WAS EXPECTED A RATE OF 500 RPM AND SPEED OF 170 KIAS WAS BRIEFED AFTER DESCENT. CLEARANCE RECEIVED POWER LEVERS WERE PULLED BACK TO APPROX 3000 TORQUE. NR 3 ENG TORQUE, RPM, T5 AND NG REMAINED AT CRUISE POWER. SEVERAL POWER LEVER EXCURSIONS WERE CARRIED OUT BUT THERE WAS NO CHANGE. CAPT CALLED FOR QRH ACTION. ENGINE NR 3 SHUT DOWN IAW QRH. ATC NOTIFIED. ERV REQUESTED. A 3 ENG LANDING CARRIED OUT. AFTER AC SHUT DOWN ON RAMP, MAINTENANCE STAFF REMOVED NR 3 COWLING TO DETERMINE IF LINKAGE HAD FAILED. INITIAL ASSESSMENT WAS FAILURE OF FUEL CONTROL UNIT. SUBSEQUENT APPROVAL RECEIVED TO CONDUCT 3 ENGINE FERRY FLIGHT.