As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF, THE GEAR RETRACTED BUT THE NOSE (RED) UNSAFE LIGHT REMAINED ON, AIRCRAFT TAIL SWAP WITH 819NK. T/S FOUND NOSE GEAR DOWNLOCK PROX SENSOR AT MAX CLEARANCE. REMOVED AND REPLACED PROXIMITY SENSOR AND RESHIMMED PROXIMITY SWITCH FOR DESIRED TARGET SENSOR CLEARANCE - PERFORMED BITE CHECK ON NLG. (K)