As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MEDIUM FREQUENCY NOISE AND VIBRATION NOTED IN FLIGHT. POSSIBLY COMING FROM NOSE AREA, FORWARD OF FLIGHT DECK. THE AIRCRAFT WAS GROUNDED. ACCOMPLISHED A REPAIR IAW EA 288510 TO THE EXTERNAL POWER ACCESS DOOR. IAW TSM 05-50-00-810-801-A. NO OTHER ISSUES NOTED.