What was found
AIR TURNBACK, AFTER DEPARTURE NR 3 ENGINE UNSPOOLED AND WHEN POWER LEVER WAS ADVANCED ENGINE WOULD NOT ACCELERATE. RETURNED TO TUS WITHOUT INCIDENT. INSPECTED ENGINE INLET, TAILPIPE, OIL AND FUEL FILTERS. NO DEFECTS NOTED. REMOVED AND REPLACED FCU, MAIN OIL PUMP AND P AND D VALVE. ENGINE DOES NOT ACCELERATE ABOVE IDLE. THREE ENGINE FERRIED TO MIA FOR ENGINE CHANGE CAUSE OF FAILURE UNDER INVESTIGATION.