O2 and Cypriot airliner crash

Also, many of the high-altitude climbers who do not
use oxygen have shown significant brain damage when
cat-scanned.



At 14:00 15 August 2005, Stefan wrote:
John Kirksey wrote:

How, then, can someone like Ed Viesturs repeatedly
climb the tallest
mountain peaks in the world without supplemental oxygen?
Is it because of
the slower ascent and the time spent acclimating to
the higher altitudes?

First, acclimatisation.

Second, walking (and climbing) is different from flying.
You don't need
much brain to walk. When piloting, however, everything
is about
thinking. And it's the brain which needs the most oxygen.

And maybe a third reason: There are exceptional people
who are just
better suited for such things than you and me.

Stefan

Peter Duniho wrote:
"Bucky" wrote in message
oups.com...

I don't get it. Can't a person stay conscious for longer than 30
seconds without breathing? Most people can hold their breath for over
a minute.


When they do that, they are using up a small reserve of oxygen-filled air
contained in their lungs. Exhale as much air from your lungs as you can,
and THEN see how long you can hold your breath.

At high altitude you breath out the oxygen bound to the hemoglobin in
your blood. Your blood gives up its O2 to the air. Hold your breath or
just stop breathing and you may last longer (never done the experiment
though ;-) ).

Shawn

"John Kirksey" wrote in message
news:cZ0Me.4596$H_4.4209@trnddc07...
Tlme of useful
consciousness
Altitude (ft) without oxygen

40,000 15 seconds
35.000 20 seconds
30,000 30 seconds
28,000 1 minute


How, then, can someone like Ed Viesturs repeatedly climb the tallest
mountain peaks in the world without supplemental oxygen? Is it because of
the slower ascent and the time spent acclimating to the higher altitudes?

That and by breathing like he's running a marathon. Sleep and you die.

mo

On Mon, 15 Aug 2005 04:21:32 UTC, wrote:

: Yet, I was once told by an ATP that at 40k feet (admittedly
: this plane was at 35k) O2 supply by itself will not suffice to keep you
: conscious...

Oxygen is only part of it. The breathing reflex is triggered by the
carbon dioxide partial pressure in your lungs: when atmospheric
pressure falls below that you never get the trigger and your lungs
just stop working. This is a Bad Thing.


Ian


--

Happy Dog wrote:

That and by breathing like he's running a marathon. Sleep and you die.

This is just plain bull****. It's all about partial pressure.

Stefan

Ash Wyllie wrote:

Seems to me that astronauts use 3psi of pure O2 during EVAs.


-ash
Cthulhu in 2005!
Why wait for nature?


Correct and 3psi of pure O2 is about the same as the ppO2 in Air at Sea
Level.
--
--------------------
Scott F. Migaldi
CP-ASEL-IA
N8116B

PADI MI-150972
Join the PADI Instructor Yahoo Group
http://groups.yahoo.com/group/PADI-Instructors/

--------------------

"Bert Willing" wrote in
message ...
If the pressure drop is rapid, they need to exhale, otherwise their lungs
will burst. Just like surfacing in scuba diving.

I don't believe there's ever been a case of pulmonary barotrauma (absent of
prior lung pathology) from decompression in commercial aviation. The
differential between 50,000' and 8,000' is less than that typically involved
in scuba incidents. May be possible though.

moo

"Stefan" wrote in message
...
Happy Dog wrote:

That and by breathing like he's running a marathon. Sleep and you die.

This is just plain bull****. It's all about partial pressure.

Breathing technique is crucial to high altitude activity. The technique is
very similar to that used by joggers.

moo

Bucky wrote:

I don't get it. Can't a person stay conscious for longer than 30
seconds without breathing? Most people can hold their breath for over
a minute.

If the aircraft loses pressure at 35,000', you cannot hold your breath. The
pressure difference will force you to exhale. Nothing you can do about it.

But that's not the biggest deal. The biggest problem is the fact that the
ambient pressure at that altitude is too low to keep oxygen in your bloodstream.
All the oxygen immediately begins to flow out of your bloodstream into your
lungs and out into the surrounding air. It doesn't matter whether you breathe
or not.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.

wrote:

Any thoughts or corrections to my reasoning?

The ATP is correct. While people do vary greatly, and some people have been able
to perform adequately without oxygen at 20,000' or more, most people can't go
much higher than 10,000' without suffering some ill effects. Because of this,
the FAA requires that a pilot use oxygen if they spend over 30 minutes above
12,500'.

In general, people can use a cranula or similar device to provide oxygen up to
about 20,000' (the FAA limits use of these to 18,000'). These simply bleed
oxygen into the air you breathe. Above that, you need a low-pressure mask. These
ensure that all you are breathing is oxygen and are good up to about 25,000'.
Above that, you need a pressure mask. Those increase the pressure of the oxygen
and work well up to about 35,000'. Above that, you need a pressure suit or a
pressurized aircraft.

The emergency drop-down masks for airline passengers are low-pressure. They
won't keep you conscious at 35,000', but they may keep you alive.

George Patterson
Give a person a fish and you feed him for a day; teach a person to
use the Internet and he won't bother you for weeks.