O2 and Cypriot airliner crash

George Patterson wrote:
Bruce Hoult wrote:


My recollection of my O2 training is that the rule is 30 minutes over
10,000 ft, or if you go over 12,500 ft at *all*.


No. 12,500' if you exceed it for 30 minutes or 14,000' if you go over
that at all. At 15,000', passengers also have to be on oxygen. Section
91.211.

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.

You should check Bruce's Lat/Long in his sig before you start quoting
him US FARs.

Shawn

George Patterson wrote:
No. 12,500' if you exceed it for 30 minutes or 14,000' if you go over
that at all. At 15,000', passengers also have to be on oxygen. Section
91.211.

actually the passengers must be *provided* with oxygen; notice
the different wording between 91.211(a)(2) and 91.211(a)(3);
i.e., your passengers do not have to be *on* oxygen (makes
for much quieter passengers, and saves on o2 refills :-)))

--Sylvain

T o d d P a t t i s t wrote:
Wrong. the partial pressure has everything to do with it.

Wrong, the partial pressure has nothing to do with it.

The lungs (or more accurately the blood in the lungs) need
O2 pressure to pick up O2. That O2 pressure is referred to
as the partial pressure of O2. You can be at altitude on
100% O2 and have the same partial pressure as at sea level
on partial O2

The lungs (not the blood) need pressure to allow gas exchange
(respiration) in the alveoli. The pressure (or lack thereof)
determines the effectiveness of respiration. Reduced effectiveness can
be compensated for with supplemental oxygen.

Sounds like you don't understand the process.

I think we're talking about different parts of the process. It sounds
like you don't know what I mean by respiration.

You may be referring to the breathing reflex
that requires sufficient CO2 to trigger breathing ...

I did not refer to that.

The original question was why you lose consciousness faster
at altitude than if you hold your breath at sea level.

The original question is why you lose consciousness at altitude with
supplemental oxygen when the partial pressure of oxygen appears to be
the same as at sea level. It had nothing to do with holding one's
breath.

True - because the PP drops too low for consciousness or
life. It's all about PP of O2.

True because the lungs become unable to respirate effectively at
reduced atmospheric pressure, which leads to hypoxia.

In article GqcMe.161$zb.155@trndny04,
George Patterson wrote:

Bruce Hoult wrote:

My recollection of my O2 training is that the rule is 30 minutes over
10,000 ft, or if you go over 12,500 ft at *all*.

No. 12,500' if you exceed it for 30 minutes or 14,000' if you go over that at
all. At 15,000', passengers also have to be on oxygen. Section 91.211.

I don't see a section 91.211 in the New Zealand regulations.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

In some ways Derricks' point is well made but as always
there are other factors. The point concerning the bereaved
and jumping to early conclusions without know facts
is particulary cogent. It is very easy to find a solution
to a problem that does not exist or even worse a solution
which is worse than the original problem.
On the other hand some accidents can give us all a
heads up to the things that might cause us harm. It
is perfectly legitimate to take the outcome of an accident
and think of ways in which we can avoid that outcome
without speculating on the causes which led up to the
particular incident. It is difficult to achieve a balance
and perhaps taking a little time to reflect on the
effect such discussion might have on others is required.
In the case of the incident which started this thread
I feel the lesson is simple. If you intend to fly at
altitude you better make damm sure you have an adequate
supply of oxygen. While I find the discussion of partial
oxygen pressure and the way in which I might come to
harm interesting I think that all I really need to
know is that if I go high without oxygen I will probably
die from it, why is of lesser importance. I am keen
to avoid dying, I have no intention of exploring the
way in which this could happen.

DAJ
ASW17 401 - Wave flying floats my boat.

At 22:24 15 August 2005, Derrick Steed wrote:
Tom wrote:
Derrick,
We (people) have a very short memory when it comes
to many safety
issues. Wouldn't it be nice if the highway authorities
left auto
wrecks on the side of the road for a few days or weeks
to remind us of
how dangerous driving is?

When an unfortunate event occurs, it reminds some of
us of our
mortality. Confronted with that, a portion want to
talk about their
fears and concerns.

Consider a ground level railroad crossing. Pretty dangerous
if you
ignore the signals, but after a while people get complacent
and
actually even stop on the tracks due to traffic congestion.
Then
someone gets hurt or killed and an uproar wells up
to have a bridge
built. After a few weeks it dies down and life goes
on. A few weeks
later, we again see people stopped on the tracks...

Fortunately, in aviation we don't have too many of
these folks who stop
on the tracks. We generally have experienced pilots
doing something
that confounds (some of) us. So we talk it out and
try to explore all
the ways WE might get into and out of the same situation.
We're not
always analyzing the specific accident, rather we examine
the
circumstances that have been brough before us and how
we might deal
with a similar situation.

-Tom

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~

Tom,

I'm aware of the points you make and have been for
(more than three)
decades. It doesn't make the recent posts any more
the right way to
approach the subject, especially considering the distress
it would cause
some who might read it.

But, in a way, I suppose you're right. _My_ expectations
of people _are_
probably way too high.

Rgds,

Derrick Steed

There are other, important, limiting factors. The alveoli need to exchange
two gases--CO2 and O2 and pressure gradients are needed for this. The fly in
the ointment is that water vapor pressure in the alveoli remains near
constant at 47mm Hg (Torr). The CO2 comes from diffusion across the
capillary-alveolar barrier, from the blood, and therefore remains somewhat
high and at 30,000 ft is about 30 mm Hg. So the O2 must ovecome this
pressure and about 30 mm more to get into the blood effectively. So unless
the O2 is above about 107 mm Hg you don't get enough in your blood to do you
any good.

--
Hartley Falbaum,


"Brien K. Meehan" wrote in message
oups.com...
T o d d P a t t i s t wrote:
Wrong. the partial pressure has everything to do with it.

Wrong, the partial pressure has nothing to do with it.

The lungs (or more accurately the blood in the lungs) need
O2 pressure to pick up O2. That O2 pressure is referred to
as the partial pressure of O2. You can be at altitude on
100% O2 and have the same partial pressure as at sea level
on partial O2

The lungs (not the blood) need pressure to allow gas exchange
(respiration) in the alveoli. The pressure (or lack thereof)
determines the effectiveness of respiration. Reduced effectiveness can
be compensated for with supplemental oxygen.

Sounds like you don't understand the process.

I think we're talking about different parts of the process. It sounds
like you don't know what I mean by respiration.

You may be referring to the breathing reflex
that requires sufficient CO2 to trigger breathing ...

I did not refer to that.

The original question was why you lose consciousness faster
at altitude than if you hold your breath at sea level.

The original question is why you lose consciousness at altitude with
supplemental oxygen when the partial pressure of oxygen appears to be
the same as at sea level. It had nothing to do with holding one's
breath.

True - because the PP drops too low for consciousness or
life. It's all about PP of O2.

True because the lungs become unable to respirate effectively at
reduced atmospheric pressure, which leads to hypoxia.

At 12:54 16 August 2005, Hl Falbaum wrote:
There are other, important, limiting factors. The alveoli
need to exchange
two gases--CO2 and O2 and pressure gradients are needed
for this. The fly in
the ointment is that water vapor pressure in the alveoli
remains near
constant at 47mm Hg (Torr). The CO2 comes from diffusion
across the
capillary-alveolar barrier, from the blood, and therefore
remains somewhat
high and at 30,000 ft is about 30 mm Hg. So the O2
must ovecome this
pressure and about 30 mm more to get into the blood
effectively. So unless
the O2 is above about 107 mm Hg you don't get enough
in your blood to do you
any good.

--
Hartley Falbaum,


Good for you Hartley !

The alveolar 'head of steam' is, very much, the ******
in the gas exchange woodpile at altitude.

OOPS - PC - as if I care !!

s(a)ta13nski.

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

Interesting! Do you have a reference?

Tony V.

Bucky wrote:
wrote:
40,000 15 seconds
35.000 20 seconds
30,000 30 seconds

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 you try to hold your breath your lungs will explode when the outside
pressure drops. That's why in altitude chambers they never tell you when
they're going to give the explosive decompression. When it happens the air
in your lungs automatically expels from your body since it is at a much
higher pressure than the ambient air. Pressure breathing through an oxygen
mask is difficult since your must manually forcibly exhale and just relax to
inhale.

--

Darrell R. Schmidt
B-58 Hustler History: http://members.cox.net/dschmidt1/
-

At 13:18 16 August 2005, Tony Verhulst wrote:
Stewart Kissel wrote:
Also, many of the high-altitude climbers who do not
use oxygen have shown significant brain damage when
cat-scanned.

Interesting! Do you have a reference?

Tony V.

Yep...

http://www.batnet.com/mfwright/everest.html

If you google about on this subject, there is some
interesting stuff. FWIW, I have heard secondhand
and completely unsubstantiated that some of the wave
flyers of the '60's and '70's, when going way high
was more in vogue, are also exhibiting damage.