As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IND - FLT 866 - DURING CRUISE, EN ROUTE FROM CLT TO IND, CREW WAS UNABLE TO MAINTAIN CABIN PRESSURE IN AUTO MODE. CREW DESCENDED AIRCRAFT TO FL140 AND SWITCHED TO MANUAL PRESSURIZATION MODE TO KEEP CABIN WITHIN LIMITS. PASSENGERS WERE UNAWARE OF PRESSURIZATION PROBLEM. FLIGHT CONTINUED ONTO IND AND LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. MAINTENANCE REMOVED AND REPLACED THE PRESSURE REGULATOR VALVE. PRESSURIZED AIRCRAFT. OPERATIONAL CHECK GOOD PER MM 21-58-31. (M)