As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHX-OAK - FLT NR 577 - CABIN WOULD NOT PRESSURIZE. AIRCRAFT RETURNED TO PHX AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND AFT CARGO DOOR SEAL TORN AT LOWER FORWARD CORNER. MAINTENANCE REMOVED AND REPLACES SEAL PER BMM 52-31-12. OPS AND LEAK CHECK GOOD. AIRCRAFT RETURNED TO SERVICE. (M)