Hypoxia and FAA regulations

[fly8slep]

Just wondering when does hypoxia set in and when is it a problem as far as jeopardizing your ability to fly? Is there a big difference of flying say 8k and 11K? You hear it's recommended to have oxygen above 10K but in the regs it says up to 12.5 it's ok not to have it. Are these just random numbers or has the FAA actually done their studies? Any clarification would be appreciated.

[My Flight Surgeon]

The original data came from young military pilots. There is no specific answer to apply to everyone. If you are older, have lung disease or heart disease you will not tolerate 12,000 feet as well as an 18 year old with no disease.

I personally find that if I use oxygen above 10,000 feet, I am not as fatigued when I arrive at my destination.

[staplegun]

Originally Posted by fly8slep

Just wondering when does hypoxia set in and when is it a problem as far as jeopardizing your ability to fly? Is there a big difference of flying say 8k and 11K? You hear it's recommended to have oxygen above 10K but in the regs it says up to 12.5 it's ok not to have it. Are these just random numbers or has the FAA actually done their studies? Any clarification would be appreciated.

I know from my own experience and having been in the altitude chamber 4 times that I get mild hypoxia at 10,001 feet! I personally would never fly unpressurized above 10,000 without O2. JMHO, YMMV!

Kevin

[flyguy]

I've never been in an altitude chamber, but I did an IFR flight a few months ago with an MEA at 10K for about 50 miles. That was the longest I'd been that high in a GA plane. I filed for 10K but was cleared for 12K and decided to give it a try. Once I got passed the terrain the MEA dropped to 8K but I didn't get a clearance to descend right away. I wasn't feeling any Hypoxia and the weather was beautifull at 12K so I decided to stay there a little while longer. After about 45 minutes I noticed my smoker pasenger in the back seat was asleep, and I also started to feel a tiny bit dizzy. The dangerous thing was that it felt kinda good and I didn't really want to descend. That's when I knew I needed to ask for lower right away, while I still had the judgement to make that decision. Got down to 8K and the sympoms went away almost immediately and my passenger woke up as if from a pleasant nap. That's really the only time I can remember feeling Hypoxia that wasn't alcohol induced.

[staplegun]

Originally Posted by flyguy

The dangerous thing was that it felt kinda good and I didn't really want to descend. That's when I knew I needed to ask for lower right away, while I still had the judgement to make that decision. Got down to 8K and the sympoms went away almost immediately and my passenger woke up as if from a pleasant nap. That's really the only time I can remember feeling Hypoxia that wasn't alcohol induced.

Thanks! You made my point for me... #^P

Kevin