Narrative:

In cruise at FL360; we were about 200 NM from destination; when we received an 'ice' amber caution message. This was the second time on this leg we had received that message even though both times we were not in icing conditions. There had been a previous write up for the same thing in the logbook. Both times we turned on the wing/cowl anti-ice. The first time; over time; the 'ice' caution disappeared and we then selected the wing/cowl anti-ice off. However the second time we selected the wing/cowl anti-ice on when we got the 'ice' caution message; after a period on 10-15 minutes; we then received a red left wing bleed duct master warning with 'bleed air duct' aural and I believe a triple chime. The first officer's and my first instinct was to turn off the wing/cowl anti-ice; which we did. That accomplished nothing. The master warning persisted and we then decided that since it was his leg that he'd fly and do the radios as I got out the QRH. By the time I had gotten to the emergency in the QRH we both started to feel the pressure in the plane change. QRH emergency 'if left or right bleed duct warning message persists for 30 seconds; all bleed air sources will be closed causing a loss of pressurization.' we could feel it in our ears and chest. We both then noticed that the cabin pressure altitude was climbing. It was not rapid but it still seemed like it was climbing fast. I asked ATC for a descent. It was not immediately granted. As the cabin continued to climb we both said to put on our masks. Once our masks where on and we established crew communication I declared an emergency with ATC telling them we were in a emergency descent to 10;000 ft and we wanted to go to [a nearby airport]. At this point getting the masks on and executing the emergency descent became priority over the QRH procedure. While this was happening we started to receive cabin altitude messages; amber then red meaning that the cabin had gone over 14;500 cabin alt and the masks had dropped in the cabin. During this time confusion was a factor as multiple EICAS messages were appearing and we were communicating with ourselves and ATC wearing our masks. At this point the flight attendant called us to ask what was going on. I told her we had lost cabin pressure and were in an emergency descent. I also told her that we were going to [the nearest airport] and we'd be there in 15 minutes. In hindsight I wish my communication with her was better; giving her a better idea of what to expect etc. But communication via masks combined with work load during the descent was difficult. As we descended through about FL200 I was then able to complete the QRH procedure. We then reach 10;000 MSL and we took off or masks. Now at a safe altitude I did a PA advising the cabin of our situation and that masks were no longer needed. We then set up for a normal landing into [the divert airport]. I advised ATC we didn't need emergency trucks standing by. Again in hindsight I wish I had briefed that it was going to be a normal landing to the flight attendants. There was some confusion on whether they needed to prepare the cabin to brace and evacuate. We landed with out incident and taxied to the gate. Passengers were then let into the terminal. After the passengers had deplaned I got the crew together to see how everyone was feeling. We were all noticeably stressed out as well as the flight attendants complained about the fumes/odor of the overhead passenger oxygen. The fumes had filled the cabin and were causing headaches and scratchy eyes. We all agreed that continuing to fly was not safe. It's important to note that the experience/ability of my first officer was exceptional and as passengers later told me in the terminal the flight attendants where calm and professional which really helped the passenger's nerves.

Related reports:

Google
 

Original NASA ASRS Text

Title: CL600 flight crew experiences a 'L WING BLEED DUCT' master warning with 'BLEED AIR DUCT' aural at FL360. The wing/cowl anti-ice is turned off to no avail and while consulting the QRH the cabin altitude is noted to be climbing. An emergency descent is initiated with a diversion to a suitable airport.

Narrative: In cruise at FL360; we were about 200 NM from destination; when we received an 'ICE' amber caution message. This was the second time on this leg we had received that message even though both times we were not in icing conditions. There had been a previous write up for the same thing in the logbook. Both times we turned on the wing/cowl anti-ice. The first time; over time; the 'ICE' caution disappeared and we then selected the wing/cowl anti-ice off. However the second time we selected the wing/cowl anti-ice on when we got the 'ICE' caution message; after a period on 10-15 minutes; we then received a red L WING BLEED DUCT master warning with 'BLEED AIR DUCT' aural and I believe a triple chime. The First Officer's and my first instinct was to turn off the wing/cowl anti-ice; which we did. That accomplished nothing. The master warning persisted and we then decided that since it was his leg that he'd fly and do the radios as I got out the QRH. By the time I had gotten to the emergency in the QRH we both started to feel the pressure in the plane change. QRH Emergency 'If L or R BLEED DUCT warning message persists for 30 seconds; all bleed air sources will be closed causing a loss of pressurization.' We could feel it in our ears and chest. We both then noticed that the cabin pressure altitude was climbing. It was not rapid but it still seemed like it was climbing fast. I asked ATC for a descent. It was not immediately granted. As the cabin continued to climb we both said to put on our masks. Once our masks where on and we established crew communication I declared an emergency with ATC telling them we were in a emergency descent to 10;000 FT and we wanted to go to [a nearby airport]. At this point getting the masks on and executing the emergency descent became priority over the QRH procedure. While this was happening we started to receive CABIN ALT messages; amber then red meaning that the cabin had gone over 14;500 cabin alt and the masks had dropped in the cabin. During this time confusion was a factor as multiple EICAS messages were appearing and we were communicating with ourselves and ATC wearing our masks. At this point the Flight Attendant called us to ask what was going on. I told her we had lost cabin pressure and were in an emergency descent. I also told her that we were going to [the nearest airport] and we'd be there in 15 minutes. In hindsight I wish my communication with her was better; giving her a better idea of what to expect etc. But communication via masks combined with work load during the descent was difficult. As we descended through about FL200 I was then able to complete the QRH procedure. We then reach 10;000 MSL and we took off or masks. Now at a safe altitude I did a PA advising the cabin of our situation and that masks were no longer needed. We then set up for a normal landing into [the divert airport]. I advised ATC we didn't need emergency trucks standing by. Again in hindsight I wish I had briefed that it was going to be a normal landing to the flight attendants. There was some confusion on whether they needed to prepare the cabin to brace and evacuate. We landed with out incident and taxied to the gate. Passengers were then let into the terminal. After the passengers had deplaned I got the crew together to see how everyone was feeling. We were all noticeably stressed out as well as the flight attendants complained about the fumes/odor of the overhead passenger oxygen. The fumes had filled the cabin and were causing headaches and scratchy eyes. We all agreed that continuing to fly was not safe. It's important to note that the experience/ability of my First Officer was exceptional and as passengers later told me in the terminal the flight attendants where calm and professional which really helped the passenger's nerves.

Data retrieved from NASA's ASRS site as of July 2013 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.