What was found
FLT 3968 - ON APPROACH TO EWR UPON LANDING GEAR EXTENSION, LEFT MAIN GEAR DOWN INDICATION WAS IN OPERATIVE. CREW VERIFIED GEAR POSITION WITH ALTERNATE INDICATION SYSTEM. AN UNEVENTFUL LANDING WAS ACCOMPLISHED. REMOVED AND REPLACED BULBS IN LEFT MAIN LANDING GEAR DOWN INDICATOR. OPERATIONAL CHECK NORMAL. AIRCRAFT RETURNED TO SERVICE. (M)