What was found
AFTER 1.5 HOURS AT FL430, WHILE DESCENDING THROUGH FL180 AT 240 KNOTS, THE CREW HEARD A LOUD RUSHING NOISE FROM FRONT OF THE AIRCRAFT AND THE NOSE GEAR LIGHT CAME ON FOR 2 SECONDS. THE LIGHT THEN WENT OUT, THE NOISE STOPPED AND THE GEAR LOWERED NORMALLY IN THE TRAFFIC PATTERN. MAINTENANCE CHECKED AND ADJUSTED THE NOSE GEAR UPLOCK SWITCH AND PERFORMED A SATISFACTORY OPERATIONAL CHECK. THE AIRCRAFT THEN PERFORMED A SATISFACTORY OPERATIONAL CHECK FLIGHT WITH A DATA MONITORING UNIT INSTALLED IAW MM. MFG FACILITY REPLACED THE LANDING GEAR CONTROL MANIFOLD AND RETURNED AIRCRAFT TO SERVICE.