What was found
(CAN) FLIGHT CREW REPORTED A RUMBLE NOISE HEARD FROM COCKPIT AND CABIN CONTINUOUSLY WITH BLEED AIR / AIR CONDITIONING. UNABLE TO ISOLATE WITH AIR CONDITIONING PACKS. DURING INVESTIGATION, MAINTENANCE FOUND THE GROUND AIR CONDITIONING DUCT ( COMPOSITE ) RUPTURED AT THE AIR CONDITIONING PLENUM. DUCTING ASSEMBLY REPLACED.AT THIS TIME WE RE UNABLE TO DETERMINE IF DUCT WAS DAMAGE DURING PREVIOUS INSTALLATIONOR COMPOSITE MATERIAL FAILURE. DUCTING WILL BE SENT TO AIRBUS FOR EVALUATION.