Date: 201203
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 700 ER/LR (CRJ700)
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pneumatic Ducting
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Diverted; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Climbing through 24 or 25 thousand feet; the airplane announced a red DUCT FAIL warning on the left side. I pulled out the checklist and the first line said that if the message stays red for 30 seconds all the bleed sources would shutoff. I told the First Officer to get an immediate descent and about that time the bleeds all closed. The cabin climbed about 800 FT/minute with no packs; so we were able to catch it at about 6;000 FT but it was still uncomfortable. On the way down the red message stayed on; and given the excessive maintenance history of PRSOV and pack problems (all ops checked good) on the left side; I told the First Officer to get an immediate turn toward the airport (40 miles) in case the bleed leak was still there. We landed (under landing weight) in the airport; and the message finally went away on short final. The bleed leak was a threat. Multiple write-ups for the same thing only to be operations checked good over and over are probably a sign that something might go wrong. Diversions are always a pain; getting new weather; FMS; speeds; operations; etc. We finally got a text to the Dispatcher when we were on a 15 mile final. Here's something though; that I think could be a problem. In the bleed leak checklist; if the message stays red; all the bleed sources close--that's good; but then it immediately leads you to unpressurized flight procedure which involves ram air open; and EMER depress on. Let's say a quick crew got this message at FL390; and in the initial descent got the checklist done down to this point; one would hope they would not hit EMER depress open until they had caught the cabin. You could be still up high with the cabin slowly climbing through 5;000 FT and create a rubber jungle; ear-drum exploding nightmare by hitting EMER DEPRESS. We had to wait for almost 5 minutes until we could get down to where the cabin was and we only started in the mid 20's. Oh and another thing; the systems book is wrong; the ram air check valve doesn't hold cabin pressure (at least with no packs) when the ram air valve is selected open. (Tried it on the way down as part of the unpressurized flight procedure; but quickly decided to wait until we caught the cabin).




Synopsis: CRJ700 Captain experiences a red DUCT FAIL warning on the left side passing FL240 during climb. Cabin begins to depressurize as the bleed valves are automatically closed and the flight diverts to a suitable airport. The aircraft had a history of duct fail warnings that could not be duplicated by maintenance.