As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEAR UP DISAGREE & NOSE DOOR OPEN WARNING, AFTER TAKEOFF NOSE GEAR FAILED TO RETRACT WITH GEAR LEVER IN UP POSITION. RAN QRH & DID AN AIR RETURN IAW QRH. REPLACED NLG WOW NR 2 & CENTERED HARNESS ASSEMBLY & CENTERED PROXIMITY SENSOR BRACKET IAW CRJ200 AMM 32-61-25. OPERATIONS CHECKED GOOD, COMPLIED WITH PA 05-018 REV K SCENARIO 1.