Date: 202003
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Aircraft: Regional Jet 200 ER/LR (CRJ200)
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: Air Conditioning and Pressurization Pack
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Human-Machine Interface
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: We were flying our third leg of the day. We had multiple MEL's on the aircraft one of which was deferred left pack that we deferred. We pushed and then had a gate return for an associated maintenance item that had to be addressed that popped up after we left the gate. After a quick visit from maintenance personnel we pushed. We took off without any issues. During climb out around 18;000 feet our right pack (the only operational pack on the aircraft) did an uncommanded shutdown. We had no EICAS cautions or warnings when the pack shut down we simply got an R Pack Off status message. The cabin was now not being pressurized and the cabin altitude was rising. I called for our immediate action items for a CABIN ALT/ EMER DESCENT. At that point we [notified ATC] and performed our emergency descent. No passenger oxygen masks deployed during this event. We ran all check lists and got all pertinent airport data for [diversion airport] and landed without issue. I detected the malfunction in flight prior to any of the cabin altitude cautions or warnings. The left pack had shut down by itself during our taxi in to the gate. We attempted to trouble shoot the problem with Maintenance to no avail and we deferred the left pack. We pushed off the gate for our flight back and during taxi out after we started the left engine we got an intermittent left pack HI TEMP caution message. We called Maintenance who advised us to return to the gate. We did that and Maintenance came out and performed the required work and signed the aircraft off. We deplaned the passengers and had ground air conditioning hooked up to the aircraft due to the high cabin temperature. We then pushed back and departed without any issues. During climb out we were being pressurized off the right engine bleed and had a successful swap of bleed air from the APU. While climbing up to 25;000 feet around 18;000 feet we encountered icing conditions and turned on the cowl anti-ice system. I checked the ECS (Environmental Control System) page after we turned it on and had no issues. Shortly after that I felt a sudden stop of air from the cooling vents in the flight deck. I immediately looked at EICAS and saw an R Pack Off Status message. I went to the ECS page and our right pack was colored white and off. I immediately tried to cycle the pack. It did not restart. We at no time got an over pressure or over temperature caution/warning on EICAS. We were now not being pressurized and the cabin altitude was increasing. We did our immediate action items for a CABIN ALT/EMER DESCENT; declared and emergency and executed our descent to 8;000 feet. The First Officer called the flight attendant to give him the [checklist] items. We finished all of our checklists at 8;000 feet while being vectored by ATC. We got ATIS; performance data and briefings done and were vectored for the approach and landed without issue and taxied to our gate where we deplaned. I cycled the PACK and that did not work. I commanded the CABIN ALT/EMER DESCENT immediate action items and the associated checklist. We began our emergency descent to an ATC assigned altitude of 8;000 feet. The cabin altitude reached 10;000 feet as we descended thru 10;000 feet. We finished our checklists once we leveled off at 8;000 feet. We went O2 Masks off and finished the non immediate action items portion of the check list. We got landing data; ATIS; and pertinent information for an ILS and landed without issue. Don't allow single PACK 200's to operate revenue flights.


Second narrative: The crew was flying its third leg of the day with multiple MELs on the aircraft. Among the MELs was a deferred left PACK; so we were single pack at takeoff and throughout the climb to FL250. During climb out; just after climbing through 18;000 feet; we lost the one remaining (right) PACK; causing pressurization in the aircraft to begin decreasing (Cabin altitude began climbing quickly). We executed an emergency descent procedure; [notified ATC]; and diverted. We lost the left PACK during taxi to the gate. The Captain wrote up the aircraft; and Maintenance had us defer the Left PACK. We did so; loaded up and pushed back for takeoff; but during the taxi; and after the number 1 engine was started; we began getting an intermittent LEFT PACK OVERHEAT caution message with the associated master caution chime. We asked Tower to hold and the Captain contacted Maintenance. Maintenance told us to return to gate. By this point the aircraft had become very warm due to the single PACK operations. We elected to deplane the passengers and get external low pressure air hooked up to cool the aircraft while Maintenance came onboard; performed their maintenance actions; and signed off the maintenance can. After the cabin was cooled; we reloaded; pushed back; and went on our way single PACK. As we climbed through about 18;500 feet; we saw weather off the nose; and turned on the cowl heat (wings on; cowls on; wings off). The Captain went to the ICE and the ECS page to see that everything was working correctly. He noticed that the right PACK was no longer on. The Captain cycled the PACK; and it did not come back on. He commanded the emergency descent procedure; and we both donned our masks. I established comms; and told ATC that we were descending to 10;000 feet. I pulled out the QRH; and started through the non-memory immediate actions. After descending through 10;000 feet; we doffed our O2 masks and went through the rest (non-immediate action-items) in chapter 5 of the checklist. We triple chimed the Flight Attendant and went through the [checklist] items; and we asked ATC for radar vectors to the nearest airport. We diverted to [diversion airport]. We made a max weight landing (47;000) with no injuries to passengers; aircrew; or damage to the aircraft. Single PACK operations have an increased operational risk. Fix PACK(s) issues as soon as possible.


Synopsis: Air carrier Flight Crew reported loss of pressurization and diverting for an emergency landing.