On Sun, 29 Jun 2008 16:17:47 -0500, Michael Ash
wrote:

In rec.aviation.student Mxsmanic wrote:
muff528 writes:

If that's as high as your airplane will go you probably should get another
airplane. At least don't fly around out west where the hills are higher than
that. Sometimes even the ground is higher than that! :-)

I try to avoid the mountains when flying a small plane. There are some
extensive flat areas in the American west, but it is true that sometimes to
get between two points it's hard to avoid the mountains, short of crossing
half the continent to go around them. Even if the aircraft has the requisite
ceiling, carrying oxygen for everyone is awkward and will not inspire
confidence in passengers.

You don't legally need oxygen for the passengers until 15,000ft, and even
the "it's a good idea even though it's not required" range probably isn't
until 10,000ft or so. If you start out at sea level, those will get you
into nice cool air.

At the risk of turning this thread into something useful, does anyone have
any recommendations as to when it's a good idea to give oxygen to
passengers? I'm not talking about the legal requirements, but just when
it's the smart thing to do. For example, as the pilot I like to start my
oxygen at about 10,000ft even though it's not required until quite a bit
higher. But then again, it doesn't really matter too much if my passengers
have mildly impaired judgement during the flight, even though I'd really
want to avoid that myself.

This is really an academic question since I don't plan to take anybody
that high to begin with, but I'm curious.

mike it depends entirely on your level of blood oxygenation.
go and buy yourself a little device that clips over your finger called
a 'Pulse Oximeter'. you can get little battery powered ones.
they shine two lasers of different frequencies through your tissue and
infer the oxygenation from the ratio of the attenuation. they are
quite accurate.
if your blood oxygenation drops below 95% you can start up the oygen.

the commercial aviation standard of 8,000ft is based on the onset of
difficulty that an obese person will have.
obesity means increased tissue to perfuse, compared to a normal weight
person, with just the same lung surface area. obesity brings on
hypoxia earlier.

Stealth Pilot