What was found
THE TOWER REPORTED THAT THE NR 1 ENGINE HAD SPARKS COMING FROM EXHAUST AREA AFTER TAKEOFF. THE CREW REPORTED THAT THERE WERE NO UNUSUAL NR 1 ENGINE INSTRUMENT INDICATIONS AND OPERATION APPEARED NORMAL. THE ENGINE WAS NOT SHUTDOWN. THE AIRCRAFT WAS RETURNED TO EWR WHERE IT LANDED WITHOUT INCIDENT. THE NR 1 ENGINE WAS REMOVED AND REPLACED. *S/D* ENGINEERING CONCLUDED THAT THE PRIMARY CAUSE OF ENGINE FAILURE WAS DUE TO A BROKEN C-7 BLADE.