What was found
(CAN) A POPPING SOUND WAS HEARD IMMEDIATELY AFTER TAKEOFF ACCOMPANIED BY DECAYING PARAMETERS AND AN "ENGINE OUT" WARNING LIGHT ON NR1 ENGINE. THE ENGINE WAS SHUTDOWN AND THE AIRCRAFT RETURNED TO ITS DEPARTURE POINT. POST FLIGHT INSPECTION FOUND THE MAIN FUEL CONTROL UNIT TO BE FAULTY. THE MAIN FUEL WAS REPLACED AND THE AIRCRAFT RETIURNED TO SERVICE.