What was found
PIT/SDF - FLT 1805 - AFTER TAKEOFF AND GEAR RETRACTION,THE NOSE GEAR RED LIGHT REMAINED ILLUMINATED, NO ABNORMAL VIBRATION WAS NOTED. THE LANDING GEAR WAS CYCLED, BUT THE LIGHT REMAINED ON. THE AIRCRAFT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE NOSE GEAR UPLOCK PROXIMITY SENSOR. (X)