What was found
ON 12/8/17 AIRCRAFT N499LX DEPARTED MCN AIRPORT AT APPROXIMATELY 0125 UTC. THE TAKEOFF WAS NORMAL, THE LANDING GEAR RETRACTION WAS NORMAL (ALL LIGHTS EXTINGUISHED). I RECEIVING CLEARANCE TO 10,000 SHORTLY AFTER TAKEOFF. AFTER LEVELING AT 10,000 AND 250 KIAS, JUST PRIOR TO ACCELERATING, THERE WAS A LOUD RUSH OF NOISE IN THE COCKPIT, WHICH WAS NOT NORMAL. WE PERFORMED A VISUAL SCAN OF THE INSTRUMENTS AND COCKPIT AREA AND DISCOVERED THE NOSE GEAR LIGHTS SHOWED DOWN AND LOCKED (GREEN “NOSE” LIGHT WAS ILLUMINATED). I SLOWED THE AIRCRAFT TO BELOW 200 KIAS AND ASKED ATC FOR THE CLOSEST AIRFIELD (ABY). I DECIDED TO DECLARE AN EMERGENCY BECAUSE I DIDN’T KNOW IF THERE WAS ANY STRUCTURAL DAMAGE TO THE NOSE GEAR DUE TO THE 50 KNOT OVERSPEED. THE LANDING WAS UNEVENTFUL.