Narrative:

We were cruising to airport ZZZ at 14;000 ft when both pitot heat 1 and pitot heat 2 caution light illuminated. We ran the checklist and descended out of icing conditions. Conditions at 14;000 feet were -3 degrees celsius and rain. At 8;000 feet we were out of icing conditions. We looked for popped circuit breakers and found pitot heat 2 popped. I was calling dispatch to ask if we should reset the breaker when we got smoke in the cockpit. We performed the memory action item and put on our oxygen masks. After [advising ATC] I started on the emergency checklist. We asked ATC for the nearest suitable airport which was airport ZZZ1 which was paved and had over 5000 ft of runway. The flight attendant called shortly after that as the lavatory smoke detector started sounding. We talked as best we could and I advised her we would be landing within a few minutes and also made a PA we would be evacuating when we touched down. I called back but she was fighting the fire and someone else picked up the phone and I decided to continue calls over the PA and land.we asked for fire and rescue and ATC advised fire and rescue were being dispatched to the airport. We had the weather for ZZZ already and determined the best runway would be runway xy. We were high and started a left 360 to lose altitude. I took control of the airplane for landing and the first officer continued through the checklist until landing. After shutdown everyone was evacuated and there were no reported injuries or aircraft damage. Fire and rescue inspected the aircraft for signs of fire after plane was evacuated.

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Original NASA ASRS Text

Title: A DHC-8 flight crew experienced dual pitot heat failure. As they were working with the failure; smoke appeared in the cockpit and the lavatory smoke detector sounded. They diverted to the nearest suitable airport and landed in an emergency condition. They shut down the aircraft and evacuated the passengers.

Narrative: We were cruising to Airport ZZZ at 14;000 FT when both pitot heat 1 and pitot heat 2 caution light illuminated. We ran the checklist and descended out of icing conditions. Conditions at 14;000 feet were -3 degrees Celsius and rain. At 8;000 feet we were out of icing conditions. We looked for popped circuit breakers and found pitot heat 2 popped. I was calling dispatch to ask if we should reset the breaker when we got smoke in the cockpit. We performed the memory action item and put on our oxygen masks. After [advising ATC] I started on the emergency checklist. We asked ATC for the nearest suitable airport which was Airport ZZZ1 which was paved and had over 5000 FT of runway. The flight attendant called shortly after that as the lavatory smoke detector started sounding. We talked as best we could and I advised her we would be landing within a few minutes and also made a PA we would be evacuating when we touched down. I called back but she was fighting the fire and someone else picked up the phone and I decided to continue calls over the PA and land.We asked for fire and rescue and ATC advised fire and rescue were being dispatched to the airport. We had the weather for ZZZ already and determined the best runway would be RWY XY. We were high and started a left 360 to lose altitude. I took control of the airplane for landing and the FO continued through the checklist until landing. After shutdown everyone was evacuated and there were no reported injuries or aircraft damage. Fire and rescue inspected the aircraft for signs of fire after plane was evacuated.

Data retrieved from NASA's ASRS site 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.