Narrative:

The air leak detection system was deferred per MEL for our flight. Approximately 50 NM west of our departure airport and at 17;000 MSL; the right bleed duct master warning posted. We referenced the ecs synoptic page and also referenced the pom (pilot operating manual). The pom states that if the message persists beyond 30 seconds; all bleed air sources will be closed causing loss of pressurization. By the time we got the checklist out and were referencing the proper action; the 30 second window passed; which resulted in both bleed valves being closed. The checklist does not provide any means of re-acquiring a bleed source once both engine bleed valves are closed. We were now starting to de-pressurize. We began a descent to 10;000 MSL. We then completed the unpressurized flight procedure at 10;000 ft. We elected to return to our departure airport due to being unpressurized. Dispatch was notified of the situation and operations was notified by dispatch. We were too heavy for landing at the time the checklist was completed. We discussed burning off the fuel to bring us under structural landing weight. After assessing the cabin temperatures from the flight attendants and the ecs synoptic page; we elected to return to our departure airport as temperatures were becoming very uncomfortable due to the lack of air conditioning. We verified we would have a gate to park at as soon as possible after landing. We elected to declare an emergency due to the fact that we would be landing over maximum structural landing weight of 75;100. ATC was given all required information prior to landing. Finally; I briefed the flight attendants and passengers of the situation. After all checklists were completed; we completed the approach and landing without incident. The weight at touchdown was 76;300. The rate of descent was approximately 200 FPM at touchdown with no abnormalities noted during landing and rollout. We taxied to the gate and deplaned. Maintenance control was notified of two discrepancies; the bleed duct messages and the overweight landing.

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Original NASA ASRS Text

Title: A CRJ-900 flight crew completed the appropriate checklists; declared an emergency and returned to their departure airport following the automatic shut down of both engine pneumatic bleeds due to a bleed duct warning.

Narrative: The air leak detection system was deferred per MEL for our flight. Approximately 50 NM west of our departure airport and at 17;000 MSL; the Right Bleed Duct Master Warning posted. We referenced the ECS synoptic page and also referenced the POM (Pilot Operating Manual). The POM states that if the message persists beyond 30 seconds; all bleed air sources will be closed causing loss of pressurization. By the time we got the checklist out and were referencing the proper action; the 30 second window passed; which resulted in both bleed valves being closed. The checklist does not provide any means of re-acquiring a bleed source once both engine bleed valves are closed. We were now starting to de-pressurize. We began a descent to 10;000 MSL. We then completed the unpressurized flight procedure at 10;000 FT. We elected to return to our departure airport due to being unpressurized. Dispatch was notified of the situation and Operations was notified by Dispatch. We were too heavy for landing at the time the checklist was completed. We discussed burning off the fuel to bring us under structural landing weight. After assessing the cabin temperatures from the flight attendants and the ECS synoptic page; we elected to return to our departure airport as temperatures were becoming very uncomfortable due to the lack of air conditioning. We verified we would have a gate to park at as soon as possible after landing. We elected to declare an emergency due to the fact that we would be landing over maximum structural landing weight of 75;100. ATC was given all required information prior to landing. Finally; I briefed the flight attendants and passengers of the situation. After all checklists were completed; we completed the approach and landing without incident. The weight at touchdown was 76;300. The rate of descent was approximately 200 FPM at touchdown with no abnormalities noted during landing and rollout. We taxied to the gate and deplaned. Maintenance Control was notified of two discrepancies; the bleed duct messages and the overweight landing.

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.