As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXCESSIVE NOISE LEVELS ON FLIGHT DECK, HAVE BEEN FOUND TO BE CAUSED BY DEBRIS BLOCKING AIR CONDITIONING OUTLETS THROUGHOUT THE A/C SYSTEM. DIFFUSER PLATE INSTALLED IN THE OUTBOARD OUTLETS SHOWN IN THE ABOVE REFERENCED IPC AND AMM TRAP THE DEBRIS AND BECOME BLOCKED. REMOVED DEBRIS FROM OUTLETS AND FLEX HOSES IAW MM.