What was found
ON APPROACH AFTER SELECTING GEAR DOWN, THE CREW REPORTED LEFT MAIN LANDING GEAR DID NOT INDICATE DOWN AND LOCKED. CREW SHOT A MISSED APPROACH WHILE THE FIRST OFFICER REPLACED THE BULB IN THE LANDING GEAR POSITION INDICATOR. AFTER BULB REPLACEMENT LEFT MIAN GEAR INDICATED DOWN AND LOCKED. ATC HAD ALREADY NOTIFIED THE AIRPORT AUTHORITIES AND EMERGENCY EQUIPMENT WAS CALLED OUT. THE AIRCRAFT LANDED WITHOUT INCIDENT. NO FUTHER ACTION WAS REQUIRED, AIRCRAFT REMAINED IN SERVICE.