What was found
PNS - FLIGHT 2506, THE CREW REPORTED THAT ON THE FIRST GEAR EXTENSION, THE LEFT MAIN LANDING GEAR REMAINED RETRACTED, AFTER SEVERAL ATTEMPTS, THE LANDING GEAR EXTENDED AND THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT, INSTALLED THE GEAR PINS, AND THE AIRCRAFT WAS FERRIED TO IAH WHERE MAINTENANCE REMOVED AND REPLACED THE LEFT MAIN LANDING GEAR UPLOCK BOX, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.