On Friday, May 19, 2017 at 11:29:50 AM UTC-6, Duster wrote:
I remember reading an air force study some years ago where they found reduced judgement in their pilots at 5000 feet. I started using oxygen from 5K from then on.

Gary Kemp (NK)

Do you have a reference for that study?

https://www.faa.gov/pilots/safety/pi...lot_vision.pdf is primarily related to night vision (supplemental O2 above 5000MSL) but also have information regarding smoking effects. However, you may find that if you run and ride bikes frequently for moderate distances, you may find no noticeable effects well above the required O2 altitude. But, this is a double-edged problem which may be better understood by taking a flight physiology course and chamber ride. I tend to become rather euphoric at FL250 without O2 after five minutes, so that can mask other symptoms of hypoxia with a false sense of well-being which could lead to taking wrong decisions about the immediate situation.

Here in Colorado, my EDS is set for 10,000 MSL as the gliderport is 5500MSL..

YMMV,

Frank Whiteley