As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT DECK VERY LOUD EVEN WITH RIGHT RECIRC OFF. MAINT TEXT: USED DECIBLE METER PER MAINT TIP - 73DB WITH BOTH PACKS ON AND RIGHT RECIRC OFF. 75 DB WITH RIGHT RECIRC ON. REPLACED RIGHT PACK FLOW CONTROL VALVE PER MM. OP CHECKED AND LEAKED CHECKED OK FOUND DECIMAL LEVELS PER MM 21-22-00 WITHIN LIMITS SHOWN AT 70 DB.