Date: 201503
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pneumatic Ducting
Component problem: Malfunctioning
Reporter organization: Fractional
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Flight Deck / Cabin / Aircraft Event Illness / Injury
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Landed As Precaution; Flight Crew Diverted
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Climbing through 28;500 feet we received a left duct bleed warning message; We followed the QRH which advised us that if the condition continues for thirty seconds which it did then all bleed sources will be shut down and we will need to follow the procedure for unpressurized flight. I advised ATC of our situation and our need to execute an emergency descent to 10;000 feet. I notified the flight attendants of the situation and our intention to divert. As we descended we heard from the flight attendants that there was now smoke in the cabin. We choose to divert to [a suitable airport] which was about 80 miles away. We notified our company and ATC of our intentions to land and requested emergency services meet us upon landing. After landing and deplaning the passengers the fire department boarded the aircraft and found smoke coming from the overhead panels near the aft lav. Nobody was injured during the event.One thing that both myself and my first officer commented on after the event was that the oxygen masks were dirty and difficult to see through which was a threat. Also my first officer suffered from sinus block during the emergency descent.As a crew I believe we did a great job of course it can always be improved upon. One thing that I would do next time is use speed mode rather than vertical speed during the descent. From the company I would have liked if the oxygen masks were clean. It's a little late for that after we have donned our masks.


Second narrative: I realized later that I should have also run the QRH procedure for smoke/fumes in the cabin. There were multiple warning/caution messages after the initial triple chime; Bleed Duct warning; so in the high workload environment of using the QRH; donning oxygen; coordinating with ATC; the Flight Attendants and attempting to contact the company; it becomes challenging to process and prioritize duties. I believe this was a valuable lesson for me in many ways but I feel so fortunate to have been flying with such an experienced crew and especially a very capable Captain who made very proactive decisions when he saw that we were losing pressure.Also; it may have been simpler to use the divert feature of the ACARS than try to communicate via radio at 10;000 feet; where reception was not great.


Synopsis: A CRJ-900 flight crew reported receiving a L Bleed Duct warning in climb. The crew executed an emergency descent and diverted to the nearest suitable airport.