What was found
DURING APPROACH INTO PITTSBURGH, PA, PILOT SELECTED GEAR DOWN AND DID NOT GET A LT MAIN DOWN AND LOCK INDICATION. AFTER PILOT ABORTED APPROACH, FLAPS WERE SELECTED UP, BUT REMAINED IN 'LANDING' POSITION. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED LT MAIN INDICATOR LAMP AND FLAP MOTOR RELAY. AIRCRAFT WAS THEN RETURNED TO SERVICE. REFERENCE CONTROL NR MASA 9515.