As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
COCKPIT EXTREMELY LOUD WITH OR W/O RT REC FAN ON. TOO MUCH AIRFLOW FROM VENTS ABOVE WINDOWS. COMPARED FLIGHT DECK NOISE TO OTHER ACFT ON THE FIELD, SOUND LEVEL VERY COMPARABLE, ALSO FLIGHT DECK NOISE LEVEL IS REDUCED WITH RT RECRIC FAN OFF. CLEANED CABIN DUCTS. INBOUND DECIBLE READINGS 73 WITH RT FAN OFF 76 WITH BOTH FANS AFTER CLEANING 71 RT FAN OFF 73 BOTH FANS ON.