"Stefan" wrote in message
...
GeorgeB wrote:

What would have been the effect if the O2 bottle for the cockpit had
been inadvertently filled with breathing air rather than O2?

They would have tested the system before the flight and found it working.
They would have put on their mask in flight and thought it worked, slowly
fading away without recognizing it. You may or may not recognize hypoxia
when you suspect it and really watch your body, you definitely don't
recognize it when you're unwary.


The question was what happens when breathing air from the mask rather than
O2 and the answer is nothing at all at a cabin pressure of 10K feet.