What was found
ABOUT 10 MINUTES IN TO CRUSE AT FL410 WE FELT A SMALL THUMP AND THE GEAR UNLOCK LIGHT CAME ON. IT REMAINED ON ALL THROUGH CRUSE. WHILE AT CRUSE FELT LIGHT FLUTTER IN RUDDER PEDALS. IN THE DESCET WHILE DESCENDING THROUGH FL280 WE FELT ANOTHER THUMP AND THE UNLOCK LIGHT EXTINGUISHED AND THE FLUTTER STOPPED. GEAR EXTENDED NORMALLY AT DESTINATION. CORRECTIVE ACTION: REMOVED AND REPLACED NLG UPLOCK SWITCH, RIGGED, AND COMPLIED WITH GEAR SWINGS/OPS CHECKS, NO DEFECTS NOTED AT THIS TIME. RETURNED AIRCRAFT BACK TO ORIGINAL AND NORMAL CONFIGURATION AT THIS TIME. WORK REF. CE680 MM 32-60-00.