On Tuesday, July 23, 2019 at 8:57:52 AM UTC-7, Tango Eight wrote:
The smart guys are on O2 at 10,000 during the day and 5,000 at night. Most humans are measurably impaired at 12,500.

T8

The Air Force have done tests that show flight decision making can be negatively affected without supplemental Oxygen above 6000 feet. I always put mine on when I got into the cockpit when releasing above 6000 feet.

gkemp