Narrative:

The originator flight was running over an hour late; due to crew legality problems. ZZZ had experienced record winter storms; with ice and snow buildup which overtaxed all of the ground equipment for days. Between passenger service representative understaffing; around-the-clock ground crews who had not been home in days; and baggage carts which could barely make it through the snow on the ramp; it was not surprising that we pushed back late and it took a long time to load the airplane. The aircraft in question had been in ZZZ for approximately 3 days. Deicing was required and was accomplished with type I and type iv fluid. It took an unusually long time to deice the aircraft. The deice crew explained that it took them so long because there was so much ice and snow adhering to the fuselage and wings which was difficult to dislodge. At last we were done and ready for pushback. After pushing back from gate; and starting both engines; the 'equipment cooling' amber light illuminated. The status page indicated equipment cooling and forward equipment fan messages. On the B757 the equipment overheat light illuminating can indicate any of several conditions: a selected supply or both aft ventilation fans inoperative; the overboard exhaust valve failed to open; or insufficient air flow on the ground. Due to the lengthy period of time in which we were configured for deicing; we presumed that it was most likely the insufficient airflow on the ground causing the indication. We performed the irregular checklist and selected equipment cooling switch to alternate. In this condition the warning light illuminated but the status message remained. We called dispatch who patched us into maintenance control. We also noted that the circuit breaker F17 forward equipment cooling supply fan had popped. Maintenance control directed us to reset the circuit breaker with the equipment cooling switch in normal position and attempt to clear the status messages. After following maintenance control's instructions: 1) the circuit breaker F17 (15 amps) popped again. 2) the amber EICAS message equipment overheat returned. 3) the amber equipment cooling light illuminated. 4) the status messages equipment cooling and forward supply illuminated. 5) an acrid smoke smell became noticeable in the cockpit. We then took the following actions: 1) informed maintenance dispatch and ramp; all on frequency; that we had smoke and needed an immediate return to the gate and jetway driver; we would attempt to deplane via the jetway. 2) donned oxygen masks. 3) called the fas. They advised that they did not notice any smoke or odor in the cabin and we advised them that we were returning to the gate for a rapid disembarkation; possible evacuation if the situation deteriorated; and requested cabin advisory. 4) advised ground control who asked if we needed crash fire rescue equipment. We asked for equipment to stand by. 5) began taxiing to the gate from which we had just pushed back. There were some apparent communication and coordination delays: 1) despite explaining smoke in the cockpit now; maintenance control continued to tie up the frequency with a lengthy discussion of why the item was not deferrable and why we would need to return to the gate and alert ZZZ maintenance; including how he would write it up and what paperwork entries would be required. 2) ZZZ ramp did not have a jetway driver. After 2 or 3 calls in which we demanded a jetway driver now; reiterating that we had smoke; someone finally showed up; after the fire trucks. We determined that the acrid smoke seemed to be dissipating; there was no sign of fire; and that it would be most prudent to pull up and disembark through the jetway. Upon reaching the gate; the flight attendants did an excellent job of expediting people to get up and leave their belongings and exit the aircraft. Meanwhile; we shut down both engines; and ran a parking checklist. Unfortunately; the passenger service representative who boarded the aircraft did not seem to have received the correct information. She wanted to keep the passengers on the aircraft until maintenance had determined the nature of the problem; despite the flight attendants' efforts to explain there was smoke on board and expedite passengers' exit. She continued to inquire who should make the announcements; etc; despite the presence of firemen on board using their sensing equipment to search for hot spots; literally working around her. After some concerted effort by the flight crew to explain the situation to the passenger agent; she ceased to delay the passengers' exit. The fire department scanners indicated no hot spots in the forward or mid galley areas; or cockpit. The first officer went outside to show the fire department to the equipment cooling bay while the captain remained on board to coordinate activities inside. Approximately 3-4 minutes later; the situation deteriorated. Avionics equipment in the cockpit began to fail sequentially; temperatures increased rapidly and a very strong acrid smoke began to fill the cockpit. After determining that everything was off the captain went back to expedite the passengers' departure. By this time; first class and the first part of economy were vacant. People were moving slowly and many were ignoring the flight attendants' directives to leave their belongings behind. The sight of the captain moving backwards through the empty cabin and sharply ordering people to move and move now; and 'come this way; leave your things; come this way now' considerably expedited the departure process. The flight attendants standing at 2L immediately picked up the cue and began urging people to 'come this way; come this way' in a commanding tone. The rear half of the airplane made it out in a much quicker manner. Incredibly; despite the presence of several families with young children in the very rear of the aircraft; there were a few people who insisted on blocking the aisle while struggling to get their backpacks and personal belongings. These individuals received some rather barking orders to leave their things behind and come this way now. (Passenger service may receive some complaints.) all of the flight attendants worked very well together as a team to respond the rapidly changing situation and got the passengers off rapidly. After determining there was no active fire; and that the smoke was no longer increasing; we left the aircraft in the hands of ZZZ maintenance.

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Original NASA ASRS Text

Title: A B757 was deiced with three days of ice and snow on the aircraft. During taxi the EQUIP COOLING EICAS alerted along with a popped circuit breaker and an electrical smell. An emergency was declared with a return for a gate evacuation.

Narrative: The originator flight was running over an hour late; due to crew legality problems. ZZZ had experienced record winter storms; with ice and snow buildup which overtaxed all of the ground equipment for days. Between Passenger Service Representative understaffing; around-the-clock ground crews who had not been home in days; and baggage carts which could barely make it through the snow on the ramp; it was not surprising that we pushed back late and it took a long time to load the airplane. The aircraft in question had been in ZZZ for approximately 3 days. Deicing was required and was accomplished with Type I and Type IV fluid. It took an unusually long time to deice the aircraft. The deice crew explained that it took them so long because there was so much ice and snow adhering to the fuselage and wings which was difficult to dislodge. At last we were done and ready for pushback. After pushing back from gate; and starting both engines; the 'equipment cooling' amber light illuminated. The Status Page indicated Equipment Cooling and Forward Equipment Fan messages. On the B757 the Equipment Overheat light illuminating can indicate any of several conditions: a selected supply or both aft ventilation fans inoperative; the overboard exhaust valve failed to open; or insufficient air flow on the ground. Due to the lengthy period of time in which we were configured for deicing; we presumed that it was most likely the insufficient airflow on the ground causing the indication. We performed the irregular checklist and selected equipment cooling switch to Alternate. In this condition the warning light illuminated but the status message remained. We called Dispatch who patched us into Maintenance Control. We also noted that the CB F17 Forward Equipment cooling supply fan had popped. Maintenance Control directed us to reset the CB with the Equipment Cooling switch in normal position and attempt to clear the status messages. After following Maintenance Control's instructions: 1) The CB F17 (15 amps) popped again. 2) The amber EICAS message Equipment Overheat returned. 3) The amber Equipment Cooling light illuminated. 4) The status messages Equipment Cooling and Forward Supply illuminated. 5) An acrid smoke smell became noticeable in the cockpit. We then took the following actions: 1) Informed Maintenance Dispatch and Ramp; all on frequency; that we had smoke and needed an immediate return to the gate and jetway driver; we would attempt to deplane via the jetway. 2) Donned oxygen masks. 3) Called the FAs. They advised that they did not notice any smoke or odor in the cabin and we advised them that we were returning to the gate for a rapid disembarkation; possible evacuation if the situation deteriorated; and requested cabin advisory. 4) Advised Ground Control who asked if we needed Crash Fire Rescue equipment. We asked for equipment to stand by. 5) Began taxiing to the gate from which we had just pushed back. There were some apparent communication and coordination delays: 1) Despite explaining smoke in the cockpit now; Maintenance Control continued to tie up the frequency with a lengthy discussion of why the item was not deferrable and why we would need to return to the gate and alert ZZZ Maintenance; including how he would write it up and what paperwork entries would be required. 2) ZZZ Ramp did not have a jetway driver. After 2 or 3 calls in which we demanded a jetway driver now; reiterating that we had smoke; someone finally showed up; after the fire trucks. We determined that the acrid smoke seemed to be dissipating; there was no sign of fire; and that it would be most prudent to pull up and disembark through the jetway. Upon reaching the gate; the Flight Attendants did an excellent job of expediting people to get up and leave their belongings and exit the aircraft. Meanwhile; we shut down both engines; and ran a parking checklist. Unfortunately; the Passenger Service Representative who boarded the aircraft did not seem to have received the correct information. She wanted to keep the passengers on the aircraft until Maintenance had determined the nature of the problem; despite the Flight Attendants' efforts to explain there was smoke on board and expedite passengers' exit. She continued to inquire who should make the announcements; etc; despite the presence of firemen on board using their sensing equipment to search for hot spots; literally working around her. After some concerted effort by the Flight Crew to explain the situation to the Passenger Agent; she ceased to delay the passengers' exit. The Fire Department scanners indicated no hot spots in the forward or mid galley areas; or cockpit. The First Officer went outside to show the Fire Department to the equipment cooling bay while the Captain remained on board to coordinate activities inside. Approximately 3-4 minutes later; the situation deteriorated. Avionics equipment in the cockpit began to fail sequentially; temperatures increased rapidly and a very strong acrid smoke began to fill the cockpit. After determining that everything was off the Captain went back to expedite the passengers' departure. By this time; First Class and the first part of Economy were vacant. People were moving slowly and many were ignoring the Flight Attendants' directives to leave their belongings behind. The sight of the Captain moving backwards through the empty cabin and sharply ordering people to move and move now; and 'come this way; leave your things; come this way now' considerably expedited the departure process. The Flight Attendants standing at 2L immediately picked up the cue and began urging people to 'come this way; come this way' in a commanding tone. The rear half of the airplane made it out in a much quicker manner. Incredibly; despite the presence of several families with young children in the very rear of the aircraft; there were a few people who insisted on blocking the aisle while struggling to get their backpacks and personal belongings. These individuals received some rather barking orders to leave their things behind and come this way now. (Passenger Service may receive some complaints.) All of the flight attendants worked very well together as a team to respond the rapidly changing situation and got the passengers off rapidly. After determining there was no active fire; and that the smoke was no longer increasing; we left the aircraft in the hands of ZZZ Maintenance.

Data retrieved from NASA's ASRS site as of May 2009 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.