Narrative:

Loss of cabin pressure FL310. Departed after deicing aircraft due to overnight snow. Flight normal at FL350 until mid point when left EPR indication decreased to 1.47 to 1.52. Aircraft was in clear after departure area. Engine anti-ice used in an attempt to clear any possible frozen diluted deice fluid from PT2 probe. Attempted was unsuccessful. Shortly after we noticed the left supply psi low at about an index of 6. I attempted a procedure from the manual and was unsuccessful in restoring supply pressure. We then sent appropriate maintenance codes on ACARS to alert maintenance. On the arrival south routing we started our descent early to be able to keep some power on the right engine to maintain pressurization. We asked for lower and were cleared to FL310. First officer was flying keeping power about 1.18 to 1.24 EPR. I leveled off at FL310 as power came up through 1.41 on right side with matched RPM on left side I saw the right EPR bump up and then a psi change in my ears. I then looked at the right supply psi which was low and the cabin rate indicator rapidly got to about full deflection climb. First officer manually locked outflow valve closed; we donned masks and started an emergency descent. ATC was called several times as we started down and ATC shortly thereafter responded. We descended to 10000 ft and were given direct to our destination. Oxygen masks were deployed by switch. As we continued the left EPR returned to operation. I cycled the supply switches off again for several minutes and then reinstated to see if they came back as the EPR on the left did. After about three minutes; I cycled them back on and they both operated normally to landing. At gear down the outboard left and right anti-skid fail lights illuminated. I tested the system and got four lights and it returned to an outboard fail indication. I checked for breakers out and cycled the system off and back on with no change in indication. We touched down on speed at a light weight and rolled out to about 80 KTS before applying light braking. After landing airport rescue and fire fighting personnel inspected and heat gunned brakes and tires. All checked normal and they escorted us to gate. System problems were annotated in the maintenance log and the maintenance manager personally briefed.

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Original NASA ASRS Text

Title: A MD80 crew declared an emergency and began an emergency descent after both packs failed in flight. ATC did not respond to the crew's first emergency declaration.

Narrative: Loss of cabin pressure FL310. Departed after deicing aircraft due to overnight snow. Flight normal at FL350 until mid point when left EPR indication decreased to 1.47 to 1.52. Aircraft was in clear after departure area. Engine anti-ice used in an attempt to clear any possible frozen diluted deice fluid from PT2 probe. Attempted was unsuccessful. Shortly after we noticed the left supply PSI low at about an index of 6. I attempted a procedure from the manual and was unsuccessful in restoring supply pressure. We then sent appropriate maintenance codes on ACARS to alert Maintenance. On the arrival south routing we started our descent early to be able to keep some power on the right engine to maintain pressurization. We asked for lower and were cleared to FL310. First Officer was flying keeping power about 1.18 to 1.24 EPR. I leveled off at FL310 as power came up through 1.41 on right side with matched RPM on left side I saw the right EPR bump up and then a PSI change in my ears. I then looked at the right supply PSI which was low and the cabin rate indicator rapidly got to about full deflection climb. First Officer manually locked outflow valve closed; we donned masks and started an emergency descent. ATC was called several times as we started down and ATC shortly thereafter responded. We descended to 10000 FT and were given direct to our destination. Oxygen masks were deployed by switch. As we continued the left EPR returned to operation. I cycled the supply switches off again for several minutes and then reinstated to see if they came back as the EPR on the left did. After about three minutes; I cycled them back on and they both operated normally to landing. At gear down the outboard left and right anti-skid fail lights illuminated. I tested the system and got four lights and it returned to an outboard fail indication. I checked for breakers out and cycled the system off and back on with no change in indication. We touched down on speed at a light weight and rolled out to about 80 KTS before applying light braking. After landing Airport Rescue and Fire Fighting personnel inspected and heat gunned brakes and tires. All checked normal and they escorted us to gate. System problems were annotated in the Maintenance Log and the Maintenance Manager personally briefed.

Data retrieved from NASA's ASRS site as of April 2012 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.