What was found
ON APPROACH TO YYZ FROM PHL, AS CREW SET FLAPS TO 10 UNITS, THE LEFT SIDE STOPPED AT 5 UNITS AND THE FLAPS LOCKED OUT. CAPTAIN ELECTED TO PERFORM A GO-AROUND AND REVIEW QUICK REFERENCE HANDBOOK PROCEDURES. FLAPS WERE CYCLED AND WENT TO 10 UNITS, THEN EXTENDED ONTO 30 UNITS. NO ROLL OR YAW WAS REPORTED AT ANY TIME. FLIGHT LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. MAINTENANCE REMOVED AND REPLACED THE FLAP POSITION INDICATOR. OPERATIONAL CHECK GOOD.