Narrative:

Received an left bleed duct amber message at approximately FL210 during a climb to FL250. Proceeded with QRH for left bleed duct. Checklist did not resolve problem. I then assumed control of the aircraft and requested my first officer check to make certain the checklist was completed properly. As a precaution as we were operating with only the right pack; I requested a lower altitude from ATC and received a clearance to 11;000 ft. I initiated a rapid descent to 11;000. During the descent to as we neared 11;000 ft we received a left bleed duct red message. It extinguished in approximately 10 seconds. We completed the appropriate QRH checklist. During that event the right engine bleed was closed by the aircraft. We were unable to reestablish control of the bleed and the pack. I requested a further descent and we descended to 5;000 ft and completed the unpressurized checklist. At no time was the cabin altitude higher than 9500 ft. During our descent from 11;000 ft.

Related reports:

Google
 

Original NASA ASRS Text

Title: CRJ-700 descended below 10;000 MSL for balance of flight when a bleed duct malfunctioned causing eventual complete loss of pressurization.

Narrative: Received an L Bleed Duct Amber message at approximately FL210 during a climb to FL250. Proceeded with QRH for L Bleed Duct. Checklist did not resolve problem. I then assumed control of the aircraft and requested my First Officer check to make certain the checklist was completed properly. As a precaution as we were operating with only the right pack; I requested a lower altitude from ATC and received a clearance to 11;000 FT. I initiated a rapid descent to 11;000. During the descent to as we neared 11;000 FT we received a L Bleed Duct Red message. It extinguished in approximately 10 seconds. We completed the appropriate QRH checklist. During that event the right engine bleed was closed by the aircraft. We were unable to reestablish control of the bleed and the pack. I requested a further descent and we descended to 5;000 FT and completed the unpressurized checklist. At no time was the cabin altitude higher than 9500 FT. during our descent from 11;000 FT.

Data retrieved from NASA's ASRS site as of April 2012 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.