----- Original Message -----
Sent: Friday, August 05, 2005 11:35
AM
Subject: [FlyRotary] Re: Back from
Osh/ Dave & Buly repair notes
On 8/5/05, Ernest
Christley <echristley@nc.rr.com>
wrote:
John
Slade wrote:
> I will want one suitable for two
users. My back seater won't go over
> 10,500 without
it.
>
> Tracy.
> Glad you survived that one. We'd
miss you for all sorts of reasons :)
> Take a look at http://www.aeromedix.com
> I
got their 2 place system for around $400 complete with a full 640 ox
> bottle. It's gone up a bit since. Haven't had a chance to use
it yet,
> but the quality and service seem good.
>
Regards,
> John
>
I've bookmarked this
page. Very interesting stuff. I'm basically
healthy, and don't plan on much FL flying. But I think
one of their
miniature, $289 systems would be useful for the type of
situation Tracy
found himself in. If I had that and the
Nonin Flightstat, it would
minimize the weight I carry around but
still maximize safety. $600 for
a complete oxygen system
isn't all that bad.
David, this is probably a good question for
you. Would it be necessary
to carry one of the oxygen
monitors all the time, or would it be enough
for someone to wear one
for a few flights to characterize how their body
reacts and then just
use oxygen in those conditions? In other words,
can a
person expect to react the same everytime, or is it unpredictable?
Difficult question. In general over the short term you will
react pretty much the same as long as nothing else changes. Also, it
is not so much your O2 saturation that matters as your ability to tolerate
lower saturations. For example, some mountain climbers can
function in strenuous environments with SpO2 in the low 30's!!!
Others will begin to notice significant effects in the low 90's.
Some people live in the low 80's at sea level.
With age, in general, tolerance declines while the amount your
saturation drops increases. Many things affect your tolerance such
as smoking or other carbon monoxide exposure, lung disease, dehydration,
anemia, cerebral vascular disease, heart disease, change in activity
level or even a hang over.
So really, the SpO2 monitor tells you very little. It will drop
more or less predictably with altitude, but there is no way to say
what number is a safe decline.
As expected, the FAA regulations are set for a reasonable lowest
common denominator. That means that a few people will
experience significant effects even while following the letter of the law,
while most can tolerate significantly higher altitudes.
A few years ago I spent about 10 min at 27,000' in an altitude
chamber. I was somewhat dizzy, but could communicate and do
math. My O2 sat was in the low 70's and dropping. Longer
exposure might change things somewhat. Probably couldn't do that
now. I notice very little effects at 23k (in a chamber) except for
loss of color vision and slight uncoordination - I certainly would have
the where-with-all to fly en-route stuff for short periods.
What is hard for me to remember is that I am getting older, as I am
in denial. Either way, the important thing is to be able to
recognize the subtle effects and say "that's enough," above
14.5k or not.
If you get the opportunity, a chamber ride is an excellent
experience. A few people, even those young and in great shape, do
react very strangely - and it can vary day to day.
Also, having O2 readily available even if not continuously used would
be an excellent and cost effective safety measure for those fly at
altitudes where there is the possibility of an issue.
--
Dave Leonard