Tim Little <tim@[EMAIL PROTECTED]
> wrote:
> On 2008-04-27, Michael Ash <mike@[EMAIL PROTECTED]
> wrote:
>> Wandering a bit, this discussion makes me wonder about the
>> possibilities for unpressurized passenger aircraft.
>
> A terrible idea. Quite apart from the discomfort and need for
> concentrated oxygen for breathing, there are plenty of medical
> problems for which this would be very much more dangerous. Most
> non-pressurized aircraft are limited to about 3 km altitude, and even
> below that low altitude there are plenty of conditions where flight is
> strongly contraindicated. Including *very* common things like
> pre-symptomatic colds, where you can rupture your sinuses.
The altitude limit is a function of the oxygen delivery system, not of
altitude. Cheap systems are limited to around 18,000ft, but a mask system
will take you up to about 35,000ft.
As for the sinus thing, I'm familiar with the problem having experienced
two flights which ended in a great deal of pain this past winter. But
still, current airliners aren't pressurized to 1 atmosphere, they're
pressurized to around 8,000ft equivalent. I'm sure less pressure expands
the problems, but it's not as if you go from no problems to having
problems.
>> The obvious solution would be to give everybody oxygen masks. They
>> do that anyway, but these would be for regular use.
>
> Which means you can't go to the toilet without a portable oxygen tank,
> and if you somehow dislodge your mask while doing your stuff in the
> toilet, you will quite likely pass out - and if not noticed in time,
> suffer brain damage and even die.
Yeah, that's a bit of a problem alright. However some very small airliners
don't have bathrooms in the first place, and are really too small to make
getting up and walking around useful in any way, maybe this technique
could be used for them.
>> Would it make sense to have an aircraft cabin that's fairly well
>> sealed but not pressurized, such that it could be filled with pure
>> oxygen at altitude?
>
> Routine pure oxygen atmosphere in the cabin? And you think
> pressurization is dangerous?
What exactly would be dangerous about it? My understanding is that pure
oxygen at a reasonable breathable pressure is essentially the same fire
hazard as the standard atmosphere. Presumably you'd have a regulator which
keeps the partial pressure of oxygen at the same value all the way up, so
you'd gradually go from 20% at whatever your reference altitude is
(8,000ft again?) up to 100% at your max altitude.
--
Michael Ash
Rogue Amoeba Software
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