B737-300
Flight Crew Last 90 Days 102; Flight Crew Type 160
Human-Machine Interface
Aircraft Equipment Problem Critical
Flight Crew Diverted; General Maintenance Action; General Declared Emergency
Aircraft
The previous crew reported problems with the A autopilot and with the pressurization system. The A autopilot system was deferred. The pressurization controller was swapped. As a result we departed uneventfully approximately two hours late.During the climb we noticed the TCAS started to intermittently fail. Shortly thereafter; while climbing through FL320; we heard the Cabin Altitude Warning horn. We quickly accomplished the memory and QRH items; declared an emergency and began an emergency descent. On the descent and approach we received additional warnings such as 'Low Idle' and 'Speed Brake Do Not Deploy.'As soon as we could; the Captain called the flight attendants to advise them of our situation. Fortunately we were able to get to a lower altitude before the passenger masks deployed. We transferred control of the airplane and discussed making a PA. However; we were at 2000 feet; and decided to do it when we landed. Once landed; the First Officer made a PA explaining what had occurred. We landed overweight uneventfully and taxied to the gate. Finally; the Captain called Dispatch; SOD; Maintenance Control; and the Chief Pilot on call. During a conversation with Maintenance Control the Captain was advised that the most likely cause of our pressurization controller fault and other multiple failures was a faulty air/ground sensor.
No additional substantive information was provided in the secondary report.
A B737-300 flight crew experienced a loss of cabin pressure climbing through FL320.  They declared an emergency; descended and diverted to a nearby airport.