Crj-200 captain reported that one a/C pack was deferred and the other a/C pack tripped off during cr...

Narrative:

Received the airplane with deferred MEL 21-xx-xx rh pack. Followed MEL procedure before pushing off the gate. Started the right engine conducted after start; combined with taxi checklist; then taxied. As we got closer to the runway first officer performed delayed before start followed by before takeoff [checklists]. Then we got cleared for takeoff. I was pilot monitoring. Conducted after takeoff checklist [in accordance with] MEL 21-xx-xx then continued climbing. Got to cruise FL250 everything seemed normal; then couple minutes after lh pack hi temperature combined with lh pack hi press caution messages appeared; which was mentioned in the MEL. Referenced MEL 21-xx-xx; ran QRH for messages appeared; then pack tripped off and cabin altitude started climbing rapidly. [Advised] ATC and started the descent. On the descent cabin altitude caution message followed by cabin altitude warning. Preformed immediate action followed by QRH which directed us to land at the nearest suitable airport; advise company; ATC; flight attendants; and passengers. Diverted to [nearby alternate]. Passenger oxygen didn't deploy.maintenance checked the aircraft and signed it off. We took off again. Message didn't reoccur; but we got L14th duct warning message! Not sure if that means lh pack needs to be rechecked because it's not supplying enough for the a/C demands while single pack; or it was just a high load?

Original NASA ASRS Text

Title: CRJ-200 Captain reported that one A/C pack was deferred and the other A/C pack tripped off during cruise.

Narrative: Received the airplane with deferred MEL 21-XX-XX RH PACK. Followed MEL procedure before pushing off the gate. Started the right engine conducted after start; combined with taxi checklist; then taxied. As we got closer to the runway First Officer performed Delayed Before Start followed by Before Takeoff [checklists]. Then we got cleared for takeoff. I was pilot monitoring. Conducted After Takeoff checklist [in accordance with] MEL 21-XX-XX then continued climbing. Got to cruise FL250 everything seemed normal; then couple minutes after LH PACK HI TEMP combined with LH PACK HI PRESS caution messages appeared; which was mentioned in the MEL. Referenced MEL 21-XX-XX; ran QRH for messages appeared; then PACK tripped off and Cabin Altitude started climbing rapidly. [Advised] ATC and started the descent. On the descent CABIN ALT caution message followed by CABIN ALT warning. Preformed immediate action followed by QRH which directed us to land at the nearest suitable airport; advise Company; ATC; Flight Attendants; and passengers. Diverted to [nearby alternate]. Passenger oxygen didn't deploy.Maintenance checked the aircraft and signed it off. We took off again. Message didn't reoccur; but we got L14th Duct Warning Message! Not sure if that means LH PACK needs to be rechecked because it's not supplying enough for the A/C demands while single PACK; or it was just a high load?

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1535058
Time
Date	201804
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 200 ER/LR (CRJ200)
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural MEL

Crj-200 captain reported that one a/C pack was deferred and the other a/C pack tripped off during cruise.