Old Smokey
Those operators who consider F/L315 a safe operation where the terrain reaches 24,500 feet must be carrying a prodigious amount of passenger oxygen, or are these aircraft depressurisation-proof?
You are somewhat missing the point. If you go to Google-Earth and run the curser over the terrain from HKG-PVG-PEK-URC [Urumqi] -KCA - REVKI . . . you will discover that there is plenty
lower terrain adjacent to the airway, and adjacent to the Tian Shan mountain range. So, if you have a pressurization problem, there is no need to stay on the airway and to maintain FL310 for long. You would turn off the airway to
lower terrain and land at a designated en route alternate/contingency airport. For example, Urumqi airport has an 11,800' [3600m] pavement at an elevation of only 2150' MSL.