What was found
DURING APPROACH INTO ATL FROM EVV AFTER SELECTING GEAR DOWN THE CREW RECEIVED A GEAR DISAGREE WARNING MESSAGE. THE CREW EXECUTED A GO AROUND AND COMPLIED WITH THE QRH. THE CREW SELECTED THE GEAR HANDLE TO THE UP POSITION AND RECEIVED A GEAR DOWN INDICATION OF ALL GREEN AND NORMAL WITH THE ONLY EXCEPTION BEING THE NOSE GEAR DOOR REMAINING OPEN. AN EMERGENCY WAS DECLARED WITH EMERGENCY EQUIPMENT REQUESTED TO BE ON STANDBY AS A PRECAUTION. THE AIRCRAFT LANDED SAFELY IN ATL. MAINTENANCE REMOVED AND REPLACED THE NOSE GEAR DOOR SELECTOR VALVE. OPERATIONAL CHECKS GOOD. AIRCRAFT OK FOR SERVICE. (M)