Mr. Cloud,
17,500 ft alt all day and no ill effects? I made a similar claim in a shorter altitude chamber run once, but was convinced otherwise after the tech showed me the acuity test results.

ATC audio of a pilot at a higher altitude.

https://www.youtube.com/watch?v=XGdYb2J6Wbk


"Unable to control altitude
Unable to control airspeed
Unable to control heading
Other than that, everything A-OK!"

yea, sure