What was found
DURING OUR INITIAL DESCENT, AROUND 36,000 FEET, WE COULD FEEL A CHANGE IN PRESSURIZATION. I LOOKED AT THE PRESSURE CONTROLLER AND SAW THAT THERE WAS A RATE OF CHANGE OF -2500 FEET PER MINUTE (CABIN PRESSURE RISING). IT ALSO INDICATED THAT OUR CURRENT CABIN PRESSURE WAS APPROXIMATELY 8000 FEET AND CLIMBING. IT WOULD TYPICALLY BE BETWEEN 6 AND 7000 FEET. COMMUNICATED TO CENTER CONTROL THAT WE NEEDED AN IMMEDIATE DESCENT DUE DO A PROBLEM WITH OUR PRESSURIZATION SYSTEM. WE HAD A NORMAL APPROACH AND LANDING AT MEMPHIS WITHOUT FURTHER PROBLEMS.