As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, WHILE DECENDING TO FL220, THE CREW REPORTED THAT THEY COULD NO LONGERCONTRO THE AIRCRAFT CABIN PRESSURE SYSTEM. CREW DECLARED AN EMERGENCY & DECENDED TO FL10000, IN THAT TIME REGAINED CABIN PRESSURE CONTROL. NO PAX ABOARD. LANDED WITHOUT ISSUE. ROOT CAUSE NOT DETERMINED & UNDER INVESTIGATION. OPEN