As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED-AT FL330 GOT BLD VLV 2 FAIL. EXECUTED QRH. RETURNED TO OPF. CORR ACTION- REMOVED, CLEANED, INSPECTED AND REINSTALLED FAN AIR VALVE FILTER #2. INSPECTED ALL SENSE LINES AROUND FAN AIR VALVE #2 AS WELL AS LEAK CHECKS WITH ENGINES RUNNING. PERFORMED OPS CHECK OF ENGINE BLEED VALES WITH OPS CHECK GOOD.