What was found
ON GEAR RETRACTION AFTER TAKEOFF RECEIVED NOSE DOOR OPEN AND GEAR DISAGREE MASTER CAUTION MESSAGES. PERFORMED QRH PROCEDURE AND LANDED BACK AT SFO. (FLIGHT 5638 - FILED CLOSED) FOUND NLG OLEO CENTERED PROXIMITY SENSOR AND BRACKET DAMAGED, REMOVED AND REPLACED NLG OLEO CENTERED PROXIMITY SENSOR /HARNESS ASSEMBLY AND BRACKET WITH NEW IN REF TO CRJ200 MM CH 32-61-05 AND PERFORMED GEAR SWINGS IN REF TO CRJ2OO MM CH32-30-00, GEAR DISAGREE CAUTION AND NOSE DOOR OPEN CAUTION MESSAGES NO LONGER PRESENT, OPS CHECKS GOOD, RESTORED AIRCRAFT TO NORMAL CONFIGURATION