As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYSTEM - ON TAXI IN PACS/RECIRCS GOT SO LOUD- EXCESSIVELY HI FLOW 30 PSI DUCT PRESS. WE COULDN'T COMMUNICATE W/ATC OR EACH OTHER. OPERATED BOTH PACK IAW AMM 21-51-00 WITH ENGINES RUNNING. COULD NOT DUPLICATE. OPS CHECK NORMAL. OK FOR SERVICE.