B757 captain reported receiving a cabin altitude warning during cruise.

Attributes
ACN	1500733
Time
Date	201712
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B757-200
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 Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural MEL

Narrative:

At cruise received cabin altitude warning. Cabin was at 10;000 ft. We descended from FL280 to FL100 then further descent to 5;000 ft. [Advised ATC] and landed. QRH complied with O2 masks. Right pack [failed] to maintain pressurization; left pack had been deferred.

Original NASA ASRS Text

Title: B757 Captain reported receiving a cabin altitude warning during cruise.

Narrative: At cruise received cabin altitude warning. Cabin was at 10;000 ft. We descended from FL280 to FL100 then further descent to 5;000 ft. [Advised ATC] and landed. QRH complied with O2 masks. Right pack [failed] to maintain pressurization; left pack had been deferred.

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.