As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNIDENTIFIABLE NOISE IN FIRST CLASS CABIN. MULTIPLE LEAKS IN CTR DISTRIBUTION DUCT IN AREA OF UPPER BEACON. LOUD VIBRATION WITH DUCTS PRESSURIZED AT UPPER BEACON ACCESS POINT. EXTERNALLY SEALED AFFECTED AREAS OF OVERHEAD CENTER DISTRIBUTION DUCT. NO FURTHER VIBRATIONS NOTED DURING OPERATIONAL LEAK CHECK.