Pilot reported a loss of pressurization that resulted in a diversion.

Attributes
ACN	1723397
Time
Date	202001
Local Time Of Day	0601-1200
Place
Locale Reference	ZNY.ARTCC
State Reference	NY
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 60 Flight Crew Total 2100 Flight Crew Type 600
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural MEL Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Other / Unknown

Narrative:

We had MEL'd pack 2 the night before for being unable to control cabin temperature (too hot). This occurred the following morning- we were on arrival into ZZZ. We were given a descent to cross a fix around; if I remember correctly FL180. We began our descent. In the descent I noticed the cabin altitude was high; around 9;100 ft. I pointed this out to the captain. Altitude kept climbing. Captain told me to get ready. Shortly thereafter the alarms sounded; we donned our O2 masks; I pulled and began running the QRH. The captain assumed control of the radios and after making an announcement for the flight attendant to sit down; initiated an [expedited] descent to 10;000 ft. I was able to get some control back through manual mode. We were given direct the field. Upon reaching 10;000 ft. We removed our masks and somewhat went back to a normal arrival; with checklists/etc. We were given priority handling in. Landed safely and went to our gate. Captain wrote up aircraft.

Original NASA ASRS Text

Title: Pilot reported a loss of pressurization that resulted in a diversion.

Narrative: We had MEL'd Pack 2 the night before for being unable to control cabin temperature (too hot). This occurred the following morning- we were on arrival into ZZZ. We were given a descent to cross a fix around; if I remember correctly FL180. We began our descent. In the descent I noticed the Cabin Altitude was high; around 9;100 ft. I pointed this out to the Captain. Altitude kept climbing. Captain told me to get ready. Shortly thereafter the alarms sounded; we donned our O2 masks; I pulled and began running the QRH. The Captain assumed control of the radios and after making an announcement for the Flight Attendant to sit down; initiated an [expedited] descent to 10;000 ft. I was able to get some control back through manual mode. We were given direct the field. Upon reaching 10;000 ft. we removed our masks and somewhat went back to a normal arrival; with checklists/etc. We were given priority handling in. Landed safely and went to our gate. Captain wrote up aircraft.

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.