What was found
F/A REPORTED AIRFLOW IN CABIN EXTREMELY LOUD FROM OVERHEAD DUCTING. AIRFLOW SUFFICIENT THROUGHOUT A-C BUT STRONGER AND NOISIER IN SEVERAL AREAS. SUGGEST A-C MAY NEED ENTIRE A-C DUCT CLEANING TO EQUALIZE AIRFLOW THROUGHOUT CABIN. NOISE IS FROM RISERS ON BOTH SIDES OF A-C. WILL NEED 2 - 3 SHIFTS FOR DUCT CLEANING. LM INFO: 3SS REQUESTED VIA RQSLOT.: AIRCRAFT HAS BEEN CHECKED FOR BLOCKAGE & IS REPORTED TO HAVE SUFFICENT AIRFLOW. SUGGEST RPL BOTH RECIRC FAN FILTERS. PCN=152-3408.THNX SAMT. REPLACED RECIRC FAN FILTERS AND FLIGHT DECK FILTER ALSO FOUND HOSE DISCONNECTED FROM F/A GASPER FAN, RAN AIR THROUGH CABIN OPS CHECK OKAY.