Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Total 20000
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action
Aircraft
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.
B767 First Officer reported loss of pressurization at cruise.