Paul thanks for info, with no O2 max of 10K for pilots, I thought that was airline max
There is a twisted web of rules. For airlines and charter, for cabin altitudes above 10,000, you are correct, O2 is required. I was referring to aircraft certification requirements rather than operational requirements.
And those certification requirements only apply to large airplanes.
Our turbo props have a maximum altitude of 41,000 feet, but have a cabin altitude of 10,000 that high.
To further muddy the waters, pilots not flying for hire can go to 14,000 for a half hour without O2, and can stay below 12,500 as long as they want.
And the last piece of the web is that passengers can have a cabin altitude of 15,0000 feet if there is enough O2 available to supply 10% of them.
Flying airplanes is easy, knowing the rules is another story…………
