As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BUF - FLT 2101 - DURING CLIMB-OUT, THE FLIGHT CREW WAS NOT ABLE TO MAINTAIN THE PROPER PRESSURIZATION SCHEDULED. THE AIRCRAFT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED A TORN FLEXIBLE DUCT AT THE LEFT ACM. THE RIGHT AIR CONDITIONING PACK WAS ON MEL AT THE TIME. (M)