What was found
ON A SCHEDULED FLIGHT FROM RDU TO AAO THE LANDING GEAR WOULD NOT EXTEND ON FINAL APPROACH TO AAO. THE RETRACTION OUTBOUND RDU WAS NORMAL. THE LANDING GEAR REMAINED RETRACTED AFTER MULTIPLE ATTEMPTS TO EXTEND. THE AIRCRAFT DIVERTED TO ICT AND DECLARED AN EMERGENCY. THE LANDING GEAR WAS EXTENDED USING THE EMERGENCY SYSTEM AND THE AIRCRAFT LANDED UNEVENTFULLY. A LOCAL MAINTENANCE PROVIDER TROUBLE SHOT THE SYSTEM AND FOUND THE LG SELECTOR VALVE FAILED ON THE EXTEND SIDE. THE RETRACTION SIDE WORKED NORMALLY. THE VALVE WAS CHANGED AND THE ACFT RETURNED TO SERVICE