Date: 201203
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Night
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pressurization Control System
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Other / Unknown; Time Pressure; Human-Machine Interface
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance; Flight Crew Overcame Equipment Problem; General Declared Emergency
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: This event began with a short notice call from Scheduling. The Captain arrived first to the airplane; readying it completely for the already delayed flight. The First Officer then arrived to the already boarded and ready-to-go aircraft. The cockpit crew had flown previously and was familiar with each other. The Captain said everything was done preflight wise. The First Officer said okay; they ran the checklist; and pushed back. Climbing through around FL310; the Cabin Altitude Warning Horn sounded. The crew performed the memory items; descended to 10;000 FT; and then ran the QRH Checklist. The First Officer was pilot not flying; therefore; running the checklist. It was discovered during this process that the landing altitude was set to 11;000 FT. The mistake was evident; corrected; and the flight continued on with no further event.I believe this occurred for a number of reasons. First; [there was] complacency on the First Officer's side in trusting the Captain to do the First Officer's job. Second; the Captain had a bad vantage point with the analog pressurization panel; so the mistake was an easy one to make. Third; the pressure of getting a delayed flight out as soon as possible resulted in skipping steps that would've prevented this. What could be done differently is to not succumb to the pressure of on time.


Second narrative: The flight was ready to go except the First Officer had not arrived yet. As a result; I did the preflight and incorrectly set the landing altitude as 11;000 FT instead of 1;000 FT. It was the analog system and I could not see the extra one from where I was sitting in the Captain's seat. At cruise; the Cabin Altitude Warning Horn sounded. We accomplished the memory items and declared an emergency requesting an immediate descent. Center approved the request. The cabin altitude got as high as 10;000 FT. No masks dropped in the cabin. When we started running the checklist items; the crew noticed the error. We reset the panel and continued on to destination uneventfully. I learned a lesson in confirming the altitude in the window by leaning over and getting a better look. Also; a crosscheck by the First Officer would be helpful.


Synopsis: B737-300 reserve flight crew reports operating a delayed flight with the Captain arriving first and doing the cockpit set up and the First Officer arriving with the passengers already boarded and the flight ready to depart. Passing FL310 the cabin altitude warning horn sounds and an emergency descent is initiated. It is discovered that the landing elevation is incorrectly set to 11;000 FT instead of 1;000 FT.