What was found
ON FLIGHT 4058 (DTW TO BHM) ON DEPARTURE RECEIVED NOSE DOOR OPEN AND LANDING GEAR UNSAFE MASTER WARNINGS OCCURED AFTER GEAR RETRACTION ON TAKEOFF/CLIMB. NOSE GEAR SHOWED IN DOWN POSITION RAN QRH AND ALL 3 LANDING GEAR SHOWED IN DOWN POSITION WITH GREEN COLOR. COMPLY WITH PA 05-018 REV J. PERFORMED AIR RETURN TO DTW. REPLACED NOSE GEAR CENTERED/EXTENDED PROXIMITY SENSOR BRACKET. RERIGGED NOSE GEAR CENTERED/EXTENDED PROXIMITY SENSOR. REPLACED NOSE GEAR CENTERED/EXTENDED PROXIMITY SENSOR TARGET. PERFORMED GEAR EXTENSION/RETRACTION CHECKS. ALL REFERENCE CRJ 200 CMM 32-20-04 CRJ 200 AMM 32-61-05 AND 32-61-05 AND 32-30-00. COMPLIED WITH PA05-018 REV J SCENARIO 1.