What was found
DURING CLIMB RECEIVED CABIN ALTITUDE EICAS MESSAGE. DONNED OXYGEN MASKS AND DESCENDED BELOW 10,000 FT. NOTICED OUTFLOW VALVE IN FULL CLOSED POSITION WITH RIGHT PACK OPERATIVE WHICH SHOULD HAVE PRESSURIZED THE AIRCRAFT WITH NO PROBLEM. DM REMOVED AND REPLACED RT PACK FLOW CONTROL SHUTOFF VALVE. REF MM 21-51-01-2. OPS CHECK AND TESTED GOOD. RAN PACKS WITH HUFFER AT 48PSI, BOTH PACKS OPERATED NORMAL. OUTFLOW VALVE OPERATED NORMAL. AIRCRAFT GOOD FOR SERVICE. PART OFF MANUFACTURER: PNEUMATICS SYSTEMS PART OFF:396480-1, FLOW CONTROL VALVE,SERNO OFF 313`