Narrative:

About 45 minutes after departure we received a pack right EICAS message. The first officer was pilot flying and the captain was pilot not flying; the captain elected to take control of the aircraft and commanded the first officer to run the pack right checklist. This checklist was unsuccessful in resetting the pack and the right pack remained failed. Per the checklist; the pack was switched off. During this time at the captain's request I brought up the MEL for the right pack on my ipad and the MEL was read and discussed by the four of us. The captain contacted dispatch via satcom; and maintenance was brought online. Continuing the flight was discussed; and several captains further up the operational control chain were consulted. It was my belief that the flight should be aborted and returned to the departure airport; since we were early in the flight; and loss of the left pack would result in an unpressurized situation. However; it was pointed out that in the event of loss of the left pack the aircraft could descend to a lower altitude and proceed to an alternate; unpressurized. I acknowledged this plan of action but was unhappy with it; since we were going to be in a very remote area of the world and unpressurized polar operations was not something I felt should be considered so early into a long (15:40) flight. As we all know; MEL's are only controlling on the ground; but I have always considered them as advisory in nature for enroute failures; since there are reasons for limitations put forth in a MEL. In the case of a pack failure and MEL 21-51-01; there are a couple significant limitations that kept bothering me during my rest period. Under spec notes; east states that the aircraft must remain within 60 minutes of a suitable airport; G states that the overhead flight attendant rest area be considered inoperative; and ETOPS are not authorized in the flight planning restrictions. At the end of my rest period I realized what was bothering me. At the time I (incorrectly) believed that failure of the operating left pack would have left us unpressurized; and I finally realized that a left pack failure would have not only left us unpressurized; but it would have also left us without cabin heat. If cabin heat could not be maintained and an alternate landing field was not nearby or unsuitable except in dire emergency (such as the russian strips); the cold air temps passengers and crew would be subject to could have caused significant physical distress. By the time I realized this; my break was almost over and we were well beyond a return. I discussed the matter with the other flight crew members and we all agreed it was a factor that was missed earlier in the decision being made to press on with the flight. Digging into the aom during my layover; I was reminded me that if one pack is inoperative and the operating one fails the operating pack will go into standby cooling mode to maintain cabin pressure. However; it is unclear if cabin temperature can be maintained; and this could be a significant factor if the divert field was a considerable distance away. If cabin heat cannot be maintained and an alternate landing field was not nearby or unsuitable except in dire emergency (such as the russian strips); the cold air temperatures passengers and crew would be subject to could cause physical harm. I believe the decision to continue was flawed based on the fact that the MEL considered the ofar to be inoperative for normal operations; and the possibility that failure of the remaining pack may have resulted in a pressurized but unheated aircraft. Being only 1 hour into the flight; I think we should have returned for this malfunction. I request we examine single pack operations/failure and determine if the decision was correct or not; so that if this situation arises again we can be better prepared.

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Original NASA ASRS Text

Title: B777 Relief Pilot reports losing a pack early in in a 15 hour flight. The decision is made to continue the flight and the reporter questions this decision based on MEL restrictions for dispatch with a signal pack.

Narrative: About 45 minutes after departure we received a PACK R EICAS message. The First Officer was pilot flying and the Captain was pilot not flying; the Captain elected to take control of the aircraft and commanded the First Officer to run the PACK R Checklist. This checklist was unsuccessful in resetting the pack and the right pack remained failed. Per the checklist; the pack was switched off. During this time at the Captain's request I brought up the MEL for the right pack on my iPad and the MEL was read and discussed by the four of us. The Captain contacted Dispatch via SatCom; and Maintenance was brought online. Continuing the flight was discussed; and several Captains further up the operational control chain were consulted. It was my belief that the flight should be aborted and returned to the departure airport; since we were early in the flight; and loss of the left pack would result in an unpressurized situation. However; it was pointed out that in the event of loss of the left pack the aircraft could descend to a lower altitude and proceed to an alternate; unpressurized. I acknowledged this plan of action but was unhappy with it; since we were going to be in a very remote area of the world and unpressurized polar operations was not something I felt should be considered so early into a long (15:40) flight. As we all know; MEL's are only controlling on the ground; but I have always considered them as advisory in nature for enroute failures; since there are reasons for limitations put forth in a MEL. In the case of a pack failure and MEL 21-51-01; there are a couple significant limitations that kept bothering me during my rest period. Under Spec Notes; E states that the aircraft must remain within 60 minutes of a suitable airport; G states that the Overhead Flight Attendant Rest area be considered inoperative; and ETOPS are not authorized in the flight planning restrictions. At the end of my rest period I realized what was bothering me. At the time I (incorrectly) believed that failure of the operating left pack would have left us unpressurized; and I finally realized that a left pack failure would have not only left us unpressurized; but it would have also left us without cabin heat. If cabin heat could not be maintained and an alternate landing field was not nearby or unsuitable except in dire emergency (such as the Russian strips); the cold air temps passengers and crew would be subject to could have caused significant physical distress. By the time I realized this; my break was almost over and we were well beyond a return. I discussed the matter with the other flight crew members and we all agreed it was a factor that was missed earlier in the decision being made to press on with the flight. Digging into the AOM during my layover; I was reminded me that if one pack is inoperative and the operating one fails the operating pack will go into Standby Cooling Mode to maintain cabin pressure. However; it is unclear if cabin temperature can be maintained; and this could be a significant factor if the divert field was a considerable distance away. If cabin heat cannot be maintained and an alternate landing field was not nearby or unsuitable except in dire emergency (such as the Russian strips); the cold air temperatures passengers and crew would be subject to could cause physical harm. I believe the decision to continue was flawed based on the fact that the MEL considered the OFAR to be inoperative for normal operations; and the possibility that failure of the remaining pack may have resulted in a pressurized but unheated aircraft. Being only 1 hour into the flight; I think we should have returned for this malfunction. I request we examine single pack operations/failure and determine if the decision was correct or not; so that if this situation arises again we can be better prepared.

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.