As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MIA - FLT 1845 - EN ROUTE MIA-ANU, ON CLIMB-OUT PASSING 24,000 FEET, HEARD CABIN ALTITUDE HORN. LEFT SIDE PACK MEL. RIGHT SIDE PACK UNABLE TO PRESSURIZE AIRCRAFT. DECLARED EMERGENCY, RETURNED MIA AND LANDED WITHOUT FURTHER INCIDENT. REPLACED OUTFLOW VALVE LUTS AND TWO RETAINERS. REPAIRED LEFT SIDE PACK RECIRCULATION FAN. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)