ON A B727; SUDDEN SMOKE FILLED THE CABIN WHILE ON THE TXWY IN SLC; RESULTING IN RETURN TO GATE FOR MAINT ACTION.

Narrative

DURING TAXI FOR TKOF WITH BOTH AIR CONDITIONING PACKS OPERATING IN AUTO MODE; I NOTICED A 'HOT AIR CONDITIONING' SMELL. I ALERTED THE FLT ATTENDANT AND WE WERE IMMEDIATELY FACED WITHIN RAPID SUCCESSION; A DUCT OVERHEAT; PACK TRIP OFF/OVERHEAT AND SMOKE THROUGHOUT THE ACFT. PANDEMONIUM ENSUED AS PEOPLE; MOSTLY CHILDREN; BEGAN SCREAMING AND MOVING INTO THE AISLE. 3 OF OUR 4 FLT ATTENDANTS WERE; FORTUNATELY; VERY EXPERIENCED; AND RECOGNIZED THE SOURCE OF THE SMOKE/SMELL AS AIR CONDITIONING. THEIR QUICK REACTION WAS INSTRUMENTAL IN CALMING PAX WHO WERE RAPIDLY REACHING PANIC MODE. I PICKED UP THE PA MIKE AND URGED PEOPLE TO REMAIN SEATED; BUT IN SOME SECTIONS OF THE CABIN; MY REPEATED PA'S WERE DROWNED OUT BY SCREAMING KIDS. THE FLT ATTENDANTS' IMMEDIATE PRESENCE IN THE AISLE MOST LIKELY PREVENTED AN UNCOMMANDED; UNCTLED EVAC ON THE TXWY. A RETURN TO THE GATE FOR MAINT ACTION REVEALED THE CAUSE OF THE PACK OVERHEAT TO BE AN INOP COOLING FAN DOOR; AND WE WERE SUBSEQUENTLY DISPATCHED WITH THAT AIR CONDITIONING PACK INOP ON THE GND. IT'S INTERESTING TO NOTE THAT OUR RELATIVELY NEW FLT ATTENDANT; WHO DID NOT IMMEDIATELY RECOGNIZE THE SOURCE OF THE SMOKE; DID IMMEDIATELY PRODUCE A FIRE EXTINGUISHER; UNTIL SHE WAS ADVISED BY HER CO-WORKER OF THE ACTUAL SOURCE. ALSO; ONCE PEOPLE UNDERSTOOD THE ACTUAL PROB; THEY WERE VERY COOPERATIVE AND VERY UNDERSTANDING. EFFECTIVE; IMMEDIATE FLC COM IN THE EARLY MOMENTS OF THIS INCIDENT PREVENTED A PANIC SIT IN THE CABIN.