As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NLG: AFTER TAKEOFF NOSE LANDING GEAR DID NOT RETRACT. ACCOMPLISHED QRH. LOWERED GEAR PER QRH. OBSERVED 3 GREEN DN INDICATION. RETURNED FOR LANDING. NORMAL LANDING. DID NOT BLOW GEAR DOWN. CORRECTIVE ACTION: REPLACED UPLOCK SWITCH. OPS CHECK GOOD. IAW CE680A MM 32-32-00.