As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 3269 ENROUTE TO KCLE @ FL350 WHILE OPERATING ON A SINGLE PACK, CABIN ALTITUDE EXCEEDED 9000' WITH A CABIN DIFFERENTIAL OF 8.6. DECENDED TO FL 310 AND CABIN ALTITUDE CONTINUED TO CLIMB TO A MAX ALTITUDE OF 9500 FEET. DESCENDED TO FL 250 AND CABIN ALTITUDE RETURNED TO NORMAL VALUES. CORRECTIVE ACTION: R&R CPC PER A320 AMM 21-31. OPS CK GOOD AFTER PART REPLACEMENT. (7689030)