Boeing 757 flight crew reported the failure of the remaining air conditioning pack resulted in cabin...

Attributes
ACN	1563280
Time
Date	201807
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZZ.ARTCC
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) Flight Crew Multiengine Flight Crew Instrument
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

While at cruise maintaining FL300 the left air conditioning pack valve failed. The right a/C pack was already deferred per MEL so the aircraft started to depressurize. We the crew donned our oxygen masks and assessed the problem while [notifying ATC]. A descent was initiated to 10;000 ft with a turn toward ZZZZ airport. We ran the appropriate checklists and were unable to re-establish pressurization. We attempted to coordinate with [dispatch] and were unable due to insufficient com coverage for using ACARS. The aircraft was not equipped with satcom phone capability. [ATC] informed us ZZZZ airport would not be open until [later] as they had no staff until this time. We looked at our alternate divert page and collectively decided ZZZZ1 was the nearest suitable airport. We obtained clearance to ZZZZ1 and proceeded to ZZZZ1 airport with an uneventful landing. Enroute to ZZZZ1 the ACARS com coverage became available and we coordinated with [dispatch] for our diversion into ZZZZ1.

Original NASA ASRS Text

Title: Boeing 757 flight crew reported the failure of the remaining air conditioning pack resulted in cabin depressurization and diversion to nearest airport.

Narrative: While at cruise maintaining FL300 the left air conditioning pack valve failed. The right A/C pack was already deferred per MEL so the aircraft started to depressurize. We the crew donned our oxygen masks and assessed the problem while [notifying ATC]. A descent was initiated to 10;000 ft with a turn toward ZZZZ airport. We ran the appropriate checklists and were unable to re-establish pressurization. We attempted to coordinate with [Dispatch] and were unable due to insufficient com coverage for using ACARS. The aircraft was not equipped with SATCOM phone capability. [ATC] informed us ZZZZ airport would not be open until [later] as they had no staff until this time. We looked at our alternate divert page and collectively decided ZZZZ1 was the nearest suitable airport. We obtained clearance to ZZZZ1 and proceeded to ZZZZ1 airport with an uneventful landing. Enroute to ZZZZ1 the ACARS com coverage became available and we coordinated with [Dispatch] for our diversion into ZZZZ1.

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.