ACR RETURNING TO LAND AFTER LOSING 1 AIR-CONDITIONING PACK DUMPS FUEL WITHOUT CONSULTING CHKLIST OR NOTIFYING ATC.

Narrative

UPON DEP; IT WAS DISCOVERED THAT THE ACFT WAS PRESSURIZING ABNORMALLY. AFTER TROUBLESHOOTING THE PROB; THE CREW DETERMINED THAT THE R AIR-CONDITIONING PACK WAS INOP AND THAT THE FLT WOULD HAVE TO RETURN INSTEAD OF CONTINUING ON AS SCHEDULED. ATC WAS NOTIFIED (13500 FT MSL; 34 DME ON THE VHP 263 DEG RADIAL); AND THE FLT WAS GIVEN A VECTOR BACK TOWARDS THE ARPT AND ISSUED A DSCNT. THE CREW THEN DETERMINED THAT FUEL WOULD NEED TO BE DUMPED; IN ORDER TO MEET THE LNDG WT OF OUR ACFT. FUEL DUMP CALCULATIONS NEEDED TO BE MADE ALONG WITH THE TASKS OF OBTAINING ARR INFO; NOTIFYING THE COMPANY OF OUR PROB; BRIEFING THE INST APCH; AND COMPLETING THE APCH CHKLIST. BECAUSE OF OUR CLOSE PROX TO THE ARPT; THERE WAS A LOT TO DO IN A VERY SHORT TIME. DURING THIS HIGH WORKLOAD PERIOD; THE FUEL DUMP CHKLIST WAS OVERLOOKED AND FUEL WAS DUMPED PROCEDURALLY 'BY MEMORY.' THE CREW FAILED TO NOTIFY ATC THAT FUEL NEEDED TO BE DUMPED AS REQUIRED BY THE COMPANY'S FUEL DUMPING CHKLIST. 8000 LBS OF FUEL WAS DUMPED BTWN 13500 FT MSL AND APPROX 5000 FT MSL. THE FLT LANDED UNEVENTFULLY BACK AT INDIANAPOLIS AT XA44 AM LCL. THE PREOCCUPATION WITH THE POSSIBLE CAUSES OF THE PACK FAILURE AND THE DETERIORATING WX CONDITIONS BACK AT INDIANAPOLIS ALONG WITH THE HIGH PLT WORKLOAD WERE CONTRIBUTING FACTORS TO THIS OCCURRENCE. CREW FATIGUE; DUE TO THE LATE HR; ALSO PLAYED LARGE PART. BECAUSE THE ACFT AND CREW WERE IN NO IMMEDIATE DANGER; COUPLED WITH THE FACT THAT THE ACFT HAD PLENTY OF FUEL; THE CREW COULD AND SHOULD HAVE ELECTED TO NOTIFY ATC THAT A HOLD OR DELAY VECTOR WOULD NEED TO BE INITIATED TO MAKE SURE ALL REQUIRED CHKLISTS WERE COMPLETED.