Narrative:

On the prior (about 4 hours earlier) departure from phx we had a tail compartment temperature high light illuminate. We had declared an emergency. The light then extinguished. We canceled the emergency. Burned off gas to get down to landing weight and landed without event in phx. When contract maintenance inspected the airplane in phx they said there 'might' be some bleed air leakage around the left pack. We discussed the issue with the contract maintenance and our maintenance control. The best plan of action seemed to be to defer the left pack. All maintenance personnel and myself felt that the real issue was probably the 109 degree temperature in phx. When we departed phx the second time the tail compartment temperature high light illuminated again. This time we waited for a min or so before doing or saying anything. The light went out and we continued our climb. The MEL limits our cruising altitude to FL250 on 1 pack. Climbing out of FL230 we had a flow light illuminate. We continued on to FL250 and the light went out for 30-60 seconds. (Note: essentially a flow light indicates that more air is going out of the aircraft than is coming in.) because of the hot temperatures in phx, the pack was putting out all cold air. By turning the supply temperature up slightly (supply temperature was raised from 0 degrees to 5 degrees C) some warm air bypasses the back. When we did this, the flow light extinguished and the cabin began to descend. Unfortunately, the light came back on in another 10 mins or so, again we were able to increase airflow into the cabin by raising the temperature. This lasted another 10 mins or so. The light came on again. We were able to extinguish it but to do so we were now warning an already very uncomfortable cabin. At this time we elected to descend to FL230 to lower the differential pressure. We were able to lower the temperature and keep the light out for another 10 mins or so. Then we started the entire process again. We continued on to mci. We eventually descended to 15000 ft. At that altitude the flow light would come on only intermittently. We landed at mci without incident. Talking to our company maintenance a couple of days later, they told me they found some leaks around the right pack, the one that was operating. This leads me to believe the contract maintenance may have misidented the problem area. It also could mean that the tail compartment temperature high light we had was because of a bleed air leak or combination of a small leak and the hot temperatures. In looking back on this, the thing I keep coming back to is the tail compartment temperature high light. It just didn't seem to be a genuine problem. The system had just been inspected and the one possible leak had been deferred. The DC9, MD80 family is known to have this light come on in very hot WX with no mechanical malfunction associated. However, now it appears that maintenance in phx may have not idented the problem correctly. If that is true, then our flow light and tail compartment temperature high light were probably related. Should we have returned to phx when the tail compartment temperature highlight came on? Probably yes. I did not think the light was a genuine problem. There were plenty of reasons to think it was a false light. Plus it did extinguish on its own. However, I've found a good test of a decision is 'how's it going to look in tomorrow's paper?' the decision to continue flunks that test. After reaching altitude, should we have continued or should we have returned to phx? I believe taking into account the good WX, no significant terrain conflicts, etc, that continuing was an ok decision. The worst did happen. We had to divert. How would it look in the paper? I think it passes the test. This event certainly is a valuable reminder to me that non aviation factors affect a decision. The desire to 'complete the mission' is always there. The decision to continue on from phx was certainly influenced by the potential embarrassment, to me and the company, at having to return for the same problem again.

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Original NASA ASRS Text

Title: MD82 HAS TAIL COMPARTMENT TEMP HIGH LIGHT ON 2 SUCCESSIVE FLTS WITH A MAINT DEFERRAL AFTER THE FIRST ONE. DIVERT TO ENRTE ARPT AS RESULT.

Narrative: ON THE PRIOR (ABOUT 4 HRS EARLIER) DEP FROM PHX WE HAD A TAIL COMPARTMENT TEMP HIGH LIGHT ILLUMINATE. WE HAD DECLARED AN EMER. THE LIGHT THEN EXTINGUISHED. WE CANCELED THE EMER. BURNED OFF GAS TO GET DOWN TO LNDG WT AND LANDED WITHOUT EVENT IN PHX. WHEN CONTRACT MAINT INSPECTED THE AIRPLANE IN PHX THEY SAID THERE 'MIGHT' BE SOME BLEED AIR LEAKAGE AROUND THE L PACK. WE DISCUSSED THE ISSUE WITH THE CONTRACT MAINT AND OUR MAINT CTL. THE BEST PLAN OF ACTION SEEMED TO BE TO DEFER THE L PACK. ALL MAINT PERSONNEL AND MYSELF FELT THAT THE REAL ISSUE WAS PROBABLY THE 109 DEG TEMP IN PHX. WHEN WE DEPARTED PHX THE SECOND TIME THE TAIL COMPARTMENT TEMP HIGH LIGHT ILLUMINATED AGAIN. THIS TIME WE WAITED FOR A MIN OR SO BEFORE DOING OR SAYING ANYTHING. THE LIGHT WENT OUT AND WE CONTINUED OUR CLB. THE MEL LIMITS OUR CRUISING ALT TO FL250 ON 1 PACK. CLBING OUT OF FL230 WE HAD A FLOW LIGHT ILLUMINATE. WE CONTINUED ON TO FL250 AND THE LIGHT WENT OUT FOR 30-60 SECONDS. (NOTE: ESSENTIALLY A FLOW LIGHT INDICATES THAT MORE AIR IS GOING OUT OF THE ACFT THAN IS COMING IN.) BECAUSE OF THE HOT TEMPS IN PHX, THE PACK WAS PUTTING OUT ALL COLD AIR. BY TURNING THE SUPPLY TEMP UP SLIGHTLY (SUPPLY TEMP WAS RAISED FROM 0 DEGS TO 5 DEGS C) SOME WARM AIR BYPASSES THE BACK. WHEN WE DID THIS, THE FLOW LIGHT EXTINGUISHED AND THE CABIN BEGAN TO DSND. UNFORTUNATELY, THE LIGHT CAME BACK ON IN ANOTHER 10 MINS OR SO, AGAIN WE WERE ABLE TO INCREASE AIRFLOW INTO THE CABIN BY RAISING THE TEMP. THIS LASTED ANOTHER 10 MINS OR SO. THE LIGHT CAME ON AGAIN. WE WERE ABLE TO EXTINGUISH IT BUT TO DO SO WE WERE NOW WARNING AN ALREADY VERY UNCOMFORTABLE CABIN. AT THIS TIME WE ELECTED TO DSND TO FL230 TO LOWER THE DIFFERENTIAL PRESSURE. WE WERE ABLE TO LOWER THE TEMP AND KEEP THE LIGHT OUT FOR ANOTHER 10 MINS OR SO. THEN WE STARTED THE ENTIRE PROCESS AGAIN. WE CONTINUED ON TO MCI. WE EVENTUALLY DSNDED TO 15000 FT. AT THAT ALT THE FLOW LIGHT WOULD COME ON ONLY INTERMITTENTLY. WE LANDED AT MCI WITHOUT INCIDENT. TALKING TO OUR COMPANY MAINT A COUPLE OF DAYS LATER, THEY TOLD ME THEY FOUND SOME LEAKS AROUND THE R PACK, THE ONE THAT WAS OPERATING. THIS LEADS ME TO BELIEVE THE CONTRACT MAINT MAY HAVE MISIDENTED THE PROB AREA. IT ALSO COULD MEAN THAT THE TAIL COMPARTMENT TEMP HIGH LIGHT WE HAD WAS BECAUSE OF A BLEED AIR LEAK OR COMBINATION OF A SMALL LEAK AND THE HOT TEMPS. IN LOOKING BACK ON THIS, THE THING I KEEP COMING BACK TO IS THE TAIL COMPARTMENT TEMP HIGH LIGHT. IT JUST DIDN'T SEEM TO BE A GENUINE PROB. THE SYS HAD JUST BEEN INSPECTED AND THE ONE POSSIBLE LEAK HAD BEEN DEFERRED. THE DC9, MD80 FAMILY IS KNOWN TO HAVE THIS LIGHT COME ON IN VERY HOT WX WITH NO MECHANICAL MALFUNCTION ASSOCIATED. HOWEVER, NOW IT APPEARS THAT MAINT IN PHX MAY HAVE NOT IDENTED THE PROB CORRECTLY. IF THAT IS TRUE, THEN OUR FLOW LIGHT AND TAIL COMPARTMENT TEMP HIGH LIGHT WERE PROBABLY RELATED. SHOULD WE HAVE RETURNED TO PHX WHEN THE TAIL COMPARTMENT TEMP HIGHLIGHT CAME ON? PROBABLY YES. I DID NOT THINK THE LIGHT WAS A GENUINE PROB. THERE WERE PLENTY OF REASONS TO THINK IT WAS A FALSE LIGHT. PLUS IT DID EXTINGUISH ON ITS OWN. HOWEVER, I'VE FOUND A GOOD TEST OF A DECISION IS 'HOW'S IT GOING TO LOOK IN TOMORROW'S PAPER?' THE DECISION TO CONTINUE FLUNKS THAT TEST. AFTER REACHING ALT, SHOULD WE HAVE CONTINUED OR SHOULD WE HAVE RETURNED TO PHX? I BELIEVE TAKING INTO ACCOUNT THE GOOD WX, NO SIGNIFICANT TERRAIN CONFLICTS, ETC, THAT CONTINUING WAS AN OK DECISION. THE WORST DID HAPPEN. WE HAD TO DIVERT. HOW WOULD IT LOOK IN THE PAPER? I THINK IT PASSES THE TEST. THIS EVENT CERTAINLY IS A VALUABLE REMINDER TO ME THAT NON AVIATION FACTORS AFFECT A DECISION. THE DESIRE TO 'COMPLETE THE MISSION' IS ALWAYS THERE. THE DECISION TO CONTINUE ON FROM PHX WAS CERTAINLY INFLUENCED BY THE POTENTIAL EMBARRASSMENT, TO ME AND THE COMPANY, AT HAVING TO RETURN FOR THE SAME PROB AGAIN.

Data retrieved from NASA's ASRS site as of July 2007 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.