Narrative:

During climbout; through 24;000 ft; we received a left bleed duct master warning. I got my flight manual out and started running the checklist. Working through the checklist I pulled up the ecs page and noticed that the left bleed was red and closed. The right bleed was open at that time initially for a few seconds. Then the right bleed closed and the cabin pressure started to climb. Following the checklist we started a descent to 10;000 ft. We completed the unpressurized flight checklist per the flight manual and the cabin pressure never exceeded 8;000 ft. Once all the checklists were completed we returned and landed uneventfully. The aircraft sensed a problem with a possible bleed air leak in the left engine and automatically shut down the system. This aircraft had a related bleed duct warning the previous day. When we arrived at the airport the mechanics were working on this aircraft all night. The problem was deferred by maintenance and signed off. The captain coordinated with dispatch; maintenance; the director of operations; and the fleet manager; who all felt that this problem was solved. The left bleed duct checklist in our flight manual can be misleading on which path to choose. Initially we had one bleed closed; but seconds later the other bleed closed; so we followed the both bleeds closed checklist which led us to unpressurized flight.

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Original NASA ASRS Text

Title: A CRJ900's left engine developed an engine bleed air leak and subsequently both bleed engine's bleed valves closed causing cabin pressure to rise. The crew returned to the departure airport.

Narrative: During climbout; through 24;000 FT; we received a L BLEED DUCT master warning. I got my Flight Manual out and started running the checklist. Working through the checklist I pulled up the ECS page and noticed that the left bleed was red and closed. The right bleed was open at that time initially for a few seconds. Then the right bleed closed and the cabin pressure started to climb. Following the checklist we started a descent to 10;000 FT. We completed the unpressurized flight checklist per the Flight Manual and the cabin pressure never exceeded 8;000 FT. Once all the checklists were completed we returned and landed uneventfully. The aircraft sensed a problem with a possible bleed air leak in the left engine and automatically shut down the system. This aircraft had a related bleed duct warning the previous day. When we arrived at the airport the mechanics were working on this aircraft all night. The problem was deferred by Maintenance and signed off. The Captain coordinated with Dispatch; Maintenance; the Director of Operations; and the Fleet Manager; who all felt that this problem was solved. The L BLEED DUCT checklist in our Flight Manual can be misleading on which path to choose. Initially we had one bleed closed; but seconds later the other bleed closed; so we followed the both bleeds closed checklist which led us to unpressurized flight.

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.