As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SJU - CREW REPORTED RIGHT PACK FAILED AND LEFT PACK WAS UNCONTROLLABLE. VERBAL COMMUNICATION BETWEEN PILOTS AND FLIGHT ATTENDANTS WAS NOT POSSIBLE DUE TO AIRFLOW NOISE. EMERGENCY DECLARED FLIGHT RETURNED SJU LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED LEFT AND RIGHT PACK FLOW CONTROL VALVES. SYSTEM GROUND CHECK NORMAL OPERATION.