Narrative:

Everything was normal until liftoff on takeoff. The captain was flying and once we were airborne we got a TCAS fail indication and when we checked in with departure control they could not pick up our transponder. I switched from number 1 to number 2 transponder; however; departure was unable to pick us up. Once we leveled off at 5000 ft; the captain noticed that the autothrottles were not working as the aircraft accelerated through 250 KTS. He immediately clicked off the autothrottles. We were told by departure to fly a 250 degree heading to intercept a victor airway. At this time we noticed that LNAV was not available and had to manually intercept the radial. At this time we made the determination that the problem was not related to the transponder. All circuit breakers in and electrical systems looked ok. It became real busy in the cockpit and the captain transferred control to me so that I could fly the aircraft and he could coordinate with maintenance and dispatch to determine what our problem was. I noticed at this time ACARS was displaying a delay message and when I looked at the flight data page; it showed we had not taken off. Departure continued our climb with leveloffs at 7000 ft and then 12000 ft. I made a comment to the captain stating that I thought the plane still thinks we are on the ground. At 12000 ft we were in cloud layer with anti-ice on. We decided to climb to VMC conditions to handle the problem. Center gave us a climb to FL200. At this time the captain glanced up at the cabin altitude and stated that it looked fine. As we were leveling off at FL200 the cabin altitude alert horn sounded and I noticed that the cabin altitude was 10100 ft. We donned our oxygen masks and requested an immediate descent to 10000 ft. At this point; we declared an emergency with center and requested the nearest airport. They stated that ZZZ was our closest. The cabin altitude reached a maximum altitude of 10300 ft. At this time the captain was trying to reach dispatch and maintenance; however; the low altitude made communications difficult. At approximately 47 miles from ZZZ; the captain closed his call with dispatch and maintenance and we briefed the approach and accomplished all checks for an uneventful landing at ZZZ.

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Original NASA ASRS Text

Title: B737-500 EXPERIENCES MULTIPLE SYSTEM ANOMALIES INCLUDING FAILURE TO PRESSURIZE. FLT CREW DECLARED AN EMER AND LANDED UNEVENTFULLY. DIAGNOSIS POINTS TO AN AIR/GND SENSING FAILURE.

Narrative: EVERYTHING WAS NORMAL UNTIL LIFTOFF ON TKOF. THE CAPT WAS FLYING AND ONCE WE WERE AIRBORNE WE GOT A TCAS FAIL INDICATION AND WHEN WE CHKED IN WITH DEP CTL THEY COULD NOT PICK UP OUR XPONDER. I SWITCHED FROM NUMBER 1 TO NUMBER 2 XPONDER; HOWEVER; DEP WAS UNABLE TO PICK US UP. ONCE WE LEVELED OFF AT 5000 FT; THE CAPT NOTICED THAT THE AUTOTHROTTLES WERE NOT WORKING AS THE ACFT ACCELERATED THROUGH 250 KTS. HE IMMEDIATELY CLICKED OFF THE AUTOTHROTTLES. WE WERE TOLD BY DEP TO FLY A 250 DEG HDG TO INTERCEPT A VICTOR AIRWAY. AT THIS TIME WE NOTICED THAT LNAV WAS NOT AVAILABLE AND HAD TO MANUALLY INTERCEPT THE RADIAL. AT THIS TIME WE MADE THE DETERMINATION THAT THE PROBLEM WAS NOT RELATED TO THE XPONDER. ALL CIRCUIT BREAKERS IN AND ELECTRICAL SYSTEMS LOOKED OK. IT BECAME REAL BUSY IN THE COCKPIT AND THE CAPT TRANSFERRED CTL TO ME SO THAT I COULD FLY THE ACFT AND HE COULD COORDINATE WITH MAINT AND DISPATCH TO DETERMINE WHAT OUR PROBLEM WAS. I NOTICED AT THIS TIME ACARS WAS DISPLAYING A DELAY MESSAGE AND WHEN I LOOKED AT THE FLT DATA PAGE; IT SHOWED WE HAD NOT TAKEN OFF. DEP CONTINUED OUR CLB WITH LEVELOFFS AT 7000 FT AND THEN 12000 FT. I MADE A COMMENT TO THE CAPT STATING THAT I THOUGHT THE PLANE STILL THINKS WE ARE ON THE GND. AT 12000 FT WE WERE IN CLOUD LAYER WITH ANTI-ICE ON. WE DECIDED TO CLB TO VMC CONDITIONS TO HANDLE THE PROBLEM. CTR GAVE US A CLB TO FL200. AT THIS TIME THE CAPT GLANCED UP AT THE CABIN ALT AND STATED THAT IT LOOKED FINE. AS WE WERE LEVELING OFF AT FL200 THE CABIN ALT ALERT HORN SOUNDED AND I NOTICED THAT THE CABIN ALT WAS 10100 FT. WE DONNED OUR OXYGEN MASKS AND REQUESTED AN IMMEDIATE DSCNT TO 10000 FT. AT THIS POINT; WE DECLARED AN EMER WITH CTR AND REQUESTED THE NEAREST ARPT. THEY STATED THAT ZZZ WAS OUR CLOSEST. THE CABIN ALT REACHED A MAXIMUM ALT OF 10300 FT. AT THIS TIME THE CAPT WAS TRYING TO REACH DISPATCH AND MAINT; HOWEVER; THE LOW ALT MADE COMMUNICATIONS DIFFICULT. AT APPROX 47 MILES FROM ZZZ; THE CAPT CLOSED HIS CALL WITH DISPATCH AND MAINT AND WE BRIEFED THE APCH AND ACCOMPLISHED ALL CHKS FOR AN UNEVENTFUL LNDG AT ZZZ.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.