Narrative:

We arrived at the aircraft at approximately XA15 for an XB20 departure from ZZZ. We were informed that the jetway was not working and we would have to board through an alternate operations door and not use the jetway. Walking up to the aircraft; we noticed a very slick ramp due to what appeared to be deicing fluid. The aircraft looked like it had been deiced but there were still noticeable areas of ice adhering to the aircraft. Opening the aircraft; we noticed that the aircraft was extremely cold. We tracked in deice fluid on our feet and had to wipe down the entrance stairs; entryway and our feet. I wanted to wait to board the aircraft until we could get the APU running and get some heat flowing through the cabin. It was much too cold to board 1/2 hour prior to our departure time. The fueler was attached to the aircraft at this time so I had to wait until he finished to start the APU. I didn't want to be late but the aircraft was far too cold to board. Once the fueler disconnected from the aircraft; we started the APU to try and warm up the aircraft as best we could. It was slow going; but we needed to board shortly so we could get off the gate on time. At approximately XB00 am we informed operations we were ready to board. I was still concerned about the deice fluid around the airplane and the passengers tracking it in and slipping so I had the first officer go out and assist in the boarding process. He had a blanket that we used earlier so he could wipe down the stairs every few people. Once safely boarded up; asked operations whether or not we would deice with them at the gate area or go to an alternate site like we had the week prior. They informed us the airplane had already been deiced before our arrival. I told them we still needed to be deiced fully because ice was adhering to the airplane in many areas. At this point the push crew showed up and tried to establish communications with me. They had trouble and had to constantly jiggle their wire. The deice truck was immediately behind them waiting for them to get out of the way so they could begin deicing. The deice truck was using the operations frequency and we told them we would like type 1 on all surfaces because we still had ice. The push crew disconnected and moved out of the way. They only pushed us a few yards from the gate and pulled us up abeam the gate. I wanted to start an engine at this time but they disconnected before I had a chance. I asked but they were looking down and I suspect having trouble with the communications. I then watched as the deice truck began deicing on my side of the aircraft. The APU was on and I knew it shouldn't be; however; the bleed air for the APU was off. I did not think we would ingest any deice fluid. We tried to tell them the APU was on but they did not respond. At this time the aircraft was extremely cold and probably borderline unbearable for the passengers. The deice was slow going. I believed they were clear of the APU at this time on the right side of the aircraft. I then turned on the APU bleed air to warm up the airplane as quickly as we could. I was sure the passengers were extremely uncomfortable. In my mind; I figured as long as the bleeds were off and the deice was away from the back of the airplane it would be ok to run the bleed air. 1-2 minutes after selecting the bleed air on; I noticed smoke on my left side near my flight case. I glanced at the first officer and uttered something along the lines of; 'do you see smoke?' once I looked back; the entire cockpit was filled with smoke to the point I had trouble even seeing the first officer. I started to choke from the smoke and immediately shut off the bleed air to the APU and opened the cockpit door. The entire cabin was filled with smoke. I was amazed at how fast the smoke progressed. It filled the cockpit in about 5 seconds. I yelled to the back to evacuate and opened the main cabin door. Everyone in the back including the fas were seated. The flight attendant in 'a' was not in her position. I opened the door; lowered the stairs; and began to evacuate the passengers. I believe one of the fas opened the rear door for evacuation but nobody exited through the rear. I believe we had everyone out of the airplane in 1 minute. I told the passengers to assemble by the jetway. Once everyone was off; I instructed the first officer to follow the people inside and make sure everyone was ok. He reported back that everyone was ok and not complaining of any injuries. The fire trucks arrived on the scene and scanned the airplane with a thermal camera and then cleared the airplane. They wanted me to restart the APU and asked several times but I told them we would have to wait until maintenance arrived to determine a cause. The event I believe occurred due to deice fluid being ingested into the APU inlet. We briefly spoke to the deice crew after the event and they said they did not spray anywhere near the APU or APU inlet. They were getting ready to spray down the right wing when they saw the airplane being evacuated.

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Original NASA ASRS Text

Title: A DHC8-400 Captain allowed passenger boarding on an extremely cold day as the APU warmed the aircraft. Late in the de-ice procedure the APU bleeds were reopened to allow heating. Subsequently the aircraft filled with smoke and was evacuated.

Narrative: We arrived at the aircraft at approximately XA15 for an XB20 departure from ZZZ. We were informed that the jetway was not working and we would have to board through an alternate operations door and not use the jetway. Walking up to the aircraft; we noticed a very slick ramp due to what appeared to be deicing fluid. The aircraft looked like it had been deiced but there were still noticeable areas of ice adhering to the aircraft. Opening the aircraft; we noticed that the aircraft was extremely cold. We tracked in deice fluid on our feet and had to wipe down the entrance stairs; entryway and our feet. I wanted to wait to board the aircraft until we could get the APU running and get some heat flowing through the cabin. It was much too cold to board 1/2 hour prior to our departure time. The fueler was attached to the aircraft at this time so I had to wait until he finished to start the APU. I didn't want to be late but the aircraft was far too cold to board. Once the fueler disconnected from the aircraft; we started the APU to try and warm up the aircraft as best we could. It was slow going; but we needed to board shortly so we could get off the gate on time. At approximately XB00 am we informed operations we were ready to board. I was still concerned about the deice fluid around the airplane and the passengers tracking it in and slipping so I had the First Officer go out and assist in the boarding process. He had a blanket that we used earlier so he could wipe down the stairs every few people. Once safely boarded up; asked operations whether or not we would deice with them at the gate area or go to an alternate site like we had the week prior. They informed us the airplane had already been deiced before our arrival. I told them we still needed to be deiced fully because ice was adhering to the airplane in many areas. At this point the push crew showed up and tried to establish communications with me. They had trouble and had to constantly jiggle their wire. The deice truck was immediately behind them waiting for them to get out of the way so they could begin deicing. The deice truck was using the operations frequency and we told them we would like Type 1 on all surfaces because we still had ice. The push crew disconnected and moved out of the way. They only pushed us a few yards from the gate and pulled us up abeam the gate. I wanted to start an engine at this time but they disconnected before I had a chance. I asked but they were looking down and I suspect having trouble with the communications. I then watched as the deice truck began deicing on my side of the aircraft. The APU was on and I knew it shouldn't be; however; the bleed air for the APU was off. I did not think we would ingest any deice fluid. We tried to tell them the APU was on but they did not respond. At this time the aircraft was extremely cold and probably borderline unbearable for the passengers. The deice was slow going. I believed they were clear of the APU at this time on the right side of the aircraft. I then turned on the APU bleed air to warm up the airplane as quickly as we could. I was sure the passengers were extremely uncomfortable. In my mind; I figured as long as the bleeds were off and the deice was away from the back of the airplane it would be OK to run the bleed air. 1-2 minutes after selecting the bleed air on; I noticed smoke on my left side near my flight case. I glanced at the First Officer and uttered something along the lines of; 'Do you see smoke?' Once I looked back; the entire cockpit was filled with smoke to the point I had trouble even seeing the First Officer. I started to choke from the smoke and immediately shut off the bleed air to the APU and opened the cockpit door. The entire cabin was filled with smoke. I was amazed at how fast the smoke progressed. It filled the cockpit in about 5 seconds. I yelled to the back to evacuate and opened the main cabin door. Everyone in the back including the FAs were seated. The FA in 'A' was not in her position. I opened the door; lowered the stairs; and began to evacuate the passengers. I believe one of the FAs opened the rear door for evacuation but nobody exited through the rear. I believe we had everyone out of the airplane in 1 minute. I told the passengers to assemble by the jetway. Once everyone was off; I instructed the First Officer to follow the people inside and make sure everyone was OK. He reported back that everyone was OK and not complaining of any injuries. The fire trucks arrived on the scene and scanned the airplane with a thermal camera and then cleared the airplane. They wanted me to restart the APU and asked several times but I told them we would have to wait until maintenance arrived to determine a cause. The event I believe occurred due to deice fluid being ingested into the APU inlet. We briefly spoke to the deice crew after the event and they said they did not spray anywhere near the APU or APU inlet. They were getting ready to spray down the right wing when they saw the airplane being evacuated.

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.