Date: 201201
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Light: Daylight
Aircraft: Regional Jet 900 (CRJ900)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Air Conditioning and Pressurization Pack
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Workload; Distraction; Communication Breakdown
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Flight Attendant
When detected: In-flight
Result: Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action; General Flight Cancelled / Delayed; General Declared Emergency; General Maintenance Action
Contributing factors: Procedure; Aircraft
Primary problem: Aircraft

Narrative: We were to begin the first leg of a four day. Our original aircraft arrived and was subsequently taken off line to the hangar by maintenance for a failed AILC. Two hours later our replacement aircraft arrived reporting a burning smell on takeoff that almost caused the crew to return immediately to the departure airport. Maintenance ran up the aircraft at the remote and determined a malfunction with left pack. The left pack was deferred. Passengers were boarded and we pushed from gate about three hours late. As the pilot flying; I advanced the thrust levers for takeoff. Immediately upon rotation; we received the emergency bell notification from the lead Flight Attendant and I noticed white smoke in the cockpit accompanied by a burning smell. I donned my oxygen mask and established communications with the Captain who relayed from the Flight Attendant there was white smoke in the cabin as well. The Captain as the pilot not flying declared an emergency and asked for an immediate return for landing and ARFF activation. I leveled at 3;000 FT and engaged the autopilot. We flew a right traffic pattern in IMC and flew the ILS 18C to minimums. I noticed the cockpit become very hot and verified uncommanded unusually high temperature output on the right pack while on short final. Since the smoke dissipated on downwind we proceeded after landing with ARFF escort to the gate to park and deplane the passengers by jetbridge about thirty five minutes. Upon debrief with the Chief Pilot and Assistant Chief Pilot we learned Maintenance had determined the right pack had a similar overheat and internal failure to the left pack diagnosed prior to our flight. I was informed Maintenance would remove and replace the right pack and the aircraft would be ferried by a Ready Reserve crew to pick up passengers for the rest of the day of flying with the left pack still deferred. I asked for further research about why both packs would simultaneously fail catastrophically within hours of each other and if any CRJ90 had ever had both packs fail together before. I also expressed my discomfort flying the same aircraft out single pack again without first determining the possible root cause of such a statistically improbable simultaneous failure. I hope there is enough information gathered as a result of this incident to determine the root cause and eliminate the recurrence in other CRJ aircraft in the future.


Second narrative: [Narrative #2 had no additional information.]


Synopsis: A CRJ900 left pack failed in flight and was MEL'ed. On the next takeoff the right pack failed causing cabin smoke and an excessively high temperature so the crew declared an emergency and returned to the departure airport.