As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOUD RUMBLING SOUND FROM NOSE. CAME SUDDENLY DURING CLIMB-OUT. SOUNDED LIKE NOSE GEAR DOOR OPENED UP. MAINTENANCE INSPECTED AND FOUND NOSE GEAR DOORS WOULD NOT CLOSE ON GEAR RETRACTION. REPLACED NOSE GEAR DOOR PROXIMITY SWITCH. OPERATIONAL CHECKS WERE GOOD.