What was found
IAD-DAY - FLT 6290 - DURING CLIMB-OUT, RETURNED TO IAD DUE TO THE LEFT MAIN GEAR INTRANSIT LIGHT REMAINED ILLUMINATED AFTER LANDING GEAR SELECTED UP. A PRECAUTIONARY EMERGENCY WAS DECLARED AND GEAR WAS SELECTED DOWN WITH BOTH MAIN AND STANDBY INDICATORS CONFIRMING GEAR DOWN AND LOCKED. AIRCRAFT LANDED AT IAD WITH NO FURTHER INCIDENTS. MAINTENANCE PERFORMED SEVERAL GEAR SWINGS AND REPLACED THE LEFT MAIN UPLOCK SWITCH. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)