AN MD80 CREW CONDUCTED AN EMER DSCNT FOLLOWING A GRADUAL CABIN DEPRESSURIZATION.

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DEPARTED WITH L PACK AUTO TEMP CONTROLLER INOP. ON CLBOUT; ALT APPROX 10000 FT; ENTERED ICING CONDITIONS; TURNED AIRFOIL AND ENG ANTI-ICE ON. RECEIVED 'L/R ICE PROTECTION TEMP HIGH' AFTER ABOUT 2 MINS OF ENG AND WING ANTI-ICE BEING ON. COMPLETED 'ICE PROTECTION TEMP HIGH' CHKLIST. MESSAGES EXTINGUISHED. RECEIVED 'FLOW' LIGHT WARNING ON PRESSURIZATION PANEL; RAN 'FLOW LIGHT' CHKLIST. UNABLE TO MAINTAIN CABIN PRESSURIZATION (CABIN CLBING); 'CABIN ALT WARNING' WENT OFF. RAN 'RAPID DECOMPRESSION/CABIN ALT WARNING' CHKLIST. CAPT INITIATED EMER DSCNT AT FL270; CABIN CONTINUED TO CLB WHILE ACFT DSNDED. MAX CABIN ALT REACHED WAS 15500 FT. PAX OXYGEN MASKS DEPLOYED ABOVE 10000 FT CABIN ALT FOR APPROX 2 1/2 MINS. NONE OF THE CHKLISTS REFED DIRECTED LOOKING AT PACK PRESSURES. THIS SHOULD BE A REQUIRED STEP IN THE 'FLOW LIGHT' CHKLIST. VERY BUSY TIME FOR BOTH OF US FROM APPROX 10000 FT TO FL270 AND THEN DOWN TO 6000 FT. NUMEROUS COMS WITH ATC; FLT ATTENDANTS AND OTHER PLT. INITIALLY CAPT FLEW ACFT; TALKED ON RADIO AND COMMUNICATED WITH FLT ATTENDANTS. AFTER CHKLIST COMPLETION; I FLEW ACFT AND COMMUNICATED WITH ATC. EMER DSCNT COMPLETE WHEN I BEGAN FLYING. BOTTOM LINE: PAX AND CREW ALL OK. ONLY DISTR WAS THAT PACK PRESSURES WERE NOT SPECIFICALLY REFED IN ANY OF THE CHKLISTS RUN. PACK PRESSURES WERE PROBABLY LOW TO ZERO -- CHKLIST(S) SHOULD ADDRESS PACK PRESSURES EARLY ON. THIS MAY HAVE AIDED IN OUR ABILITY TO RECOVER PRESSURE IN THE CABIN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT BECAUSE OF THE 'FLOW LIGHT' INDICATION AT ABOUT 8000 FT CABIN ALT; THE CREW WAS READY FOR THE AURAL ANNUNCIATION 'CABIN ALT' AND THE WARNING HORN. THEY WERE IN THE PROCESS OF EXECUTING THE LOSS OF PRESSURE CHKLIST AND INITIATING A DSCNT WITH ATC WHEN THE MASKS DROPPED. THE CABIN WAS ASCENDING AT ABOUT 1500 FPM. RPTR FEELS THAT THE AIRLINE'S SYS KNOWLEDGE REQUIREMENT IS TOO LOW AND THAT WHILE MORE KNOWLEDGE WOULD NOT HAVE HELPED THEM OVERCOME OR MANAGE IN THIS SIT; SYS KNOWLEDGE IN GENERAL MAY HAVE HELPED THEM UNDERSTAND WHAT WAS OCCURRING. A KNOWN ANOMALY WITH THE MD88 IS A PACK OVERHEAT WITH NORMAL PRESSURE INDICATIONS. THE KEY TO SYS OP IN THE EVENT OF AN OVERHEAT IS THE FLOW INDICATION. THE CREW DID NOT DETERMINE NOR DID MAINT INFORM THEM WHAT CAUSED THE PROB.