A B767-200 flight crew was assigned the the same aircraft in which they had returned after the takeoff the previous day due to multiple air conditioning and autoflight system anomalies. After much discussion with maintenance and a high speed taxi test to evaluate several of the autoflight systems they accepted the aircraft only to return to the field yet again due to the recurrence of air conditioning anomalies. The passengers expressed their displeasure in vocal terms.

Narrative

I contacted system scheduling from hotel and was informed we were going to take the same aircraft outbound in which we had returned under emergency conditions the previous day with multiple system anomalies. When arriving at airport. I talked to Dispatch and Maintenance Control told me station mechanics found a circuit breaker popped underneath the aft right panel. The circuit breaker was reset and all systems checked. I then contacted the mechanic that I had spoken with the night before who also worked on the airplane and they did not find any circuit breakers popped. They did check and followed maintenance control procedures and could not duplicate any of the problems. I was uncomfortable with the results maintenance found and signed off for service. I felt that all problems were related and told them I wanted to do a high speed taxi down the runway to see if the auto throttles would engage and map would update. Everything worked normal and I agreed to take the airplane. We started boarding the aircraft; when the agent came down and said there were 40 passengers who would not board unless I spoke to them. I went to boarding area and gave a simple explanation; and assured them that maintenance had done a complete check and it was safe to board the aircraft. All but one passenger choose not to board. We taxied out; all systems were normal. We took off; the map updated; Auto throttles engaged; VNAV; LNAV worked properly; and center auto pilot engaged. Climbing through 8000 feet a flight attendant called saying the cabin was getting hot again like it had the previous day. We leveled off at 16000 feet; trying every combination with the packs and could not get control of the heat in the cabin (temperatures were approaching mid the 90's). We advised ATC we were declaring an emergency and returning. We accomplished all normal and QRH check lists and made an overweight landing. Taxied to the gate; had to wait for agent; passengers became unruly and close to becoming out of control on runway. Agent arrived to deplane the aircraft.The First Officer; Relief Pilot and I remained on aircraft with maintenance talking to maintenance control on my cell phone discussing all problems. Eight hours later we did a test flight and found we still could not control the temperature. In summary; these are the problems that occurred: Auto Throttles inoperative; Map would not update; VNAV; LNAV and Left EEC anomalies; no control of both packs; Autobrakes inoperative; Speed brakes inoperative; Emergency Exit Lights on in cabin during flight. With all these write-ups; maintenance signed the logbook off as 'ground checks OK' and put the aircraft back in service without finding anything wrong. I didn't go far enough and should have requested a flight test before we boarded; but I am more upset with maintenance control for not requiring a flight check.