B767 first officer reported loss of pressurization at cruise.

Attributes
ACN	1606210
Time
Date	201812
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Total 20000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

At FL390; EICAS message rt pack heat and rt pack off message. Followed QRH. I then noticed the cabin rate of climb was still increasing and the cabin altitude was at 15;000 feet. We donned our oxygen masks; established communication; [notified ATC;] and started an emergency descent. We leveled at 10;000 feet and contacted company and decided to continue to [destination].captain and I believe that there is a problem with the L4 door being closed and seated properly.

Original NASA ASRS Text

Title: B767 First Officer reported loss of pressurization at cruise.

Narrative: At FL390; EICAS message RT Pack Heat and RT Pack OFF message. Followed QRH. I then noticed the cabin rate of climb was still increasing and the cabin altitude was at 15;000 feet. We donned our oxygen masks; established communication; [notified ATC;] and started an emergency descent. We leveled at 10;000 feet and contacted company and decided to continue to [destination].Captain and I believe that there is a problem with the L4 door being closed and seated properly.

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.