Narrative:

Flight was flight planned on an easterly routing to pek. This routing was more common practice from the other east coast hubs and rarely seen here. Initially not caught in flight ops due to concerns and briefings over lithium batteries; we initially missed the routing threats associated with this flight. It wasn't discovered until we leveled off and a thorough route analysis was performed. Due to the nature of the boarders for a non-supplemental flight over greenland was the threat first noticed. After an hour of plotting and building a no fly zone and sectors associated with decompression routes over greenland did we realize that the flight would pass within approximately 20 NM of the no fly zone. The exact distance is questionable since the coordinates given in the international manual are for fly to points and not borders for the different zones. It was our estimation we would be transiting no less than five separate zones in approximately 15-20 min time frame. Although in the end a non-event for us on this flight a small deviation could've led to a different operational impact.

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Original NASA ASRS Text

Title: B777 First Officer discovers enroute that his flight to ZBAA from an east coast hub; passes very close to several loss of cabin pressurization no fly zones.

Narrative: Flight was flight planned on an easterly routing to PEK. This routing was more common practice from the other east coast hubs and rarely seen here. Initially not caught in flight ops due to concerns and briefings over lithium batteries; we initially missed the routing threats associated with this flight. It wasn't discovered until we leveled off and a thorough route analysis was performed. Due to the nature of the boarders for a non-supplemental flight over Greenland was the threat first noticed. After an hour of plotting and building a no fly zone and sectors associated with decompression routes over Greenland did we realize that the flight would pass within approximately 20 NM of the no fly zone. The exact distance is questionable since the coordinates given in the International Manual are for fly to points and not borders for the different zones. It was our estimation we would be transiting no less than five separate zones in approximately 15-20 min time frame. Although in the end a non-event for us on this flight a small deviation could've led to a different operational impact.

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.