Date: 201509
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Weather elements / visibility: Thunderstorm; Turbulence
Light: Daylight
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pneumatic Valve/Bleed Valve
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Time Pressure; Troubleshooting; Workload
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; General Evacuated
Contributing factors: Aircraft; Equipment / Tooling
Primary problem: Aircraft

Narrative: This is the first flight of the day. The aircraft was dispatched with an MEL; the right PACK is inop. We were flying at FL240 near ZZZ VOR; and were given instructions by ATC to proceed direct to ZZZZ intersection for the arrival into ZZZ; at this point; the in-range checklist-to-the-line was already completed. The warning message 'L Bleed Duct' then appeared on the EICAS; we followed standard procedures to cancel and identify; I was in control of the aircraft and have the radio; the captain referenced the EPC and QRH; which instructed us to don our oxygen mask and emergency descent to 10;000 ft. We then [advised ATC]; and were given direct to airport; with vectors to final approach for visual runway XXR. Meanwhile the captain continued the procedures; and communicates with the cabin crew and company Ops. We landed normally on runway XXR; and exited to the left on taxiway; and came to a complete stop as advised from tower. The firefighters came on frequency and asked if we need to evacuate the aircraft; the captain then called the cabin crew; and we discover that cabin is filled with smoke; and I notice a faint burnt smell; we decided to emergency evacuate. We stayed onboard the aircraft and completed the evacuation and shutdown checklist. The only item we did not do on the emergency evacuation is to arm the APU; R Engine and L Engine fire squib; because everyone on board was already evacuated; firefighters are already on the scene; and we have no indication of engine fire.


Second narrative: Talked to maintenance control regarding the MEL of pack; everything was fine. As well as comply with the Written MEL of R pack INOP checked the RAM air as well open. Prior to ZZZ1 VOR climbed for traffic; as well as started to paint on the radar over the VOR and ask to be vector around [plus] continues ignition as I suspected that I was in a vicinity of a storm. Flight attendants already had cabin ready for arrival; as I suspected it's going to be bumpy on the way down. They were sitting. In range to the line checklist has been conducted prior to the event. Turned on anti-ice systems; as I was in a vicinity of some weather approximately over ZZZ1 VOR while getting radar vectors flew at 24000 and got a 'left bleed warning +3 chimes.' FO conduct memory items for emergency descent per my command while I pulled the oxygen mask and QRH and [advised ATC] and worked the QRH while FO fly and communicate; and deal with weather. Flight attendants has been TEST. Must say that I had to hold to oxygen mask in one hand as it couldn't sit right on my face. Ran in range below the line checklist and also verified with the QRH I did everything right. On final talked to FA she said it was foggy; after landing fire department asked me if we need evacuation; I called the back and asked them how things in the back; she said there is a smoke; and people struggling while I smell weird smell. So I ordered evacuation on the taxiway and follow the EPC and QRH for Evacuation; was a slight confused while I pulled the QRH as it was FO duty to challenge me and fixed it right away. Passenger evacuated in a minute; via all exits; on taxiway. Turned on APU (to keep electricity) the only thing I didn't do I didn't push APU Left and right engine switch; we determined that everyone off plane and didn't want to cause extra damage to the plane; (was no indication of fire from engines or APU).


Synopsis: While preparing to descend to the destination airport; regional jet crew experienced a 'Left Bleed Duct' warning annunciation. An emergency descent was accomplished and direct routing to the destination was facilitated by ATC. Upon landing the Captain elected to evacuate the aircraft due to considerable smoke in the cabin.