Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition
Company Policy; Human Factors; Procedure
Upon landing; on roll out; got 'SPEED TRIM FAIL' light. Upon turning off runway; got left 'PACK' light followed by right 'PACK' light. ACARS had no 'on' time.  I asked [the First Officer] to check if we were depressurized- we were not. We went to manual pressurization and opened the outflow valve. It seemed pretty obvious that we had an air/ground sensor type problem as the ACARS scratchpad also indicated 'buffet alert.' I wrote all this up and I saw the Mechanic and told him about it. The next day; I called Maintenance Control to find out what happened to that plane. He told me they dried out some harnesses and could not duplicate [the problem] and signed it off. He then said that on takeoff roll; the [next flight crew] experienced similar problems; got airborne; declared an emergency and landed at [a diversion airport].  I am not pointing fingers at anyone; I just believe that with this type of problem; with obvious; specific write ups/descriptions of problems; that this is NOT what being a leader in safety and compliance is all about.
During troubleshooting of an apparent air-ground disagree problem; Maintenance personnel were unable to duplicate the problem. They signed off the discrepancy and released the aircraft for service. The anomaly appeared again on the next flight; which resulted in a diversion.