As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT 28000 FT HEARD A POP AND THEN THE AIRCRAFT WOULD NOT MAINTAIN CABIN ALTITUDE. CABIN ALTITUDE STARTED TO CLIMB AT 500 FT/MIN. FOUND NR 2 PACK WATER SEPARATOR COVER BLOWN LOOSE. REPLACED SEAL AND CLAMP ON THE NR 2 PACK SEPARATOR. OPS CHECKED SATISFACTORY. PRESSURIZED ACFT. CHECKED CARGO DOORS AND PAX DOORS AND ALL AREA'S. CHECKED SATISFACTORY.