As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED, LOST THE CABIN ALTITUDE INDICATION IN MANUAL PRESSURIZATION MODE. AUTO-PRESSURIZATION WAS ALREADY ON MEL. THE AIRCRAFT RETURNED TO KPIT AND LANDED WITHOUT INCIDENT. MAINTENANCE LOCKED BOTH OUTFLOW VALVES OPEN AND DEFERRED AUTO AND MANUAL PRESSURIZATION MODES. THE DEFERRAL WAS CLEARED BY SDF MAINTENANCE ON 9/30/2011 BY CHANGING THE CABIN PRESSURE ACQUISITION MODULE. OPERATIONAL AND PRESSURIZATION CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.