
Flying High Unpressurized (2016) - Hooke
https://www.planeandpilotmag.com/article/flying-high-unpressurized/
======
paulgerhardt
A hard drive crash once caught me off guard at high altitude.

Admittedly less of a concern these days, but back in the era of spinning disks
I thought it would be fun to take my netbook up loaded with approach plates.

Turns out yes, the read write head is supported by a thin cushion of air. As
the air becomes less dense so does the cushion until - yup you guessed it -
head crash.

It’s well documented now of course but I understand it also used to be a
problem in Tibet and Chile.

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DanielBMarkham
Great article, both informative and detailed.

One thing I would add is that most sea-level habituated people are measurably
hypoxic over 5,000 feet or so. It's just not as obvious.

If you're a pilot, there's an interesting self-test you can do on yourself the
next time you fly VFR at night. At about 8 or 9,000MSL, without oxygen, take a
look at the landscape below. Looks normal, right? Now breathe some oxygen
while continuing to look.

For most people, it's like having the contrast turned way down on a TV and not
realizing it. Once the contrast comes back up, there's all this depth of
color, vibrance and detail you had been missing -- and have not been aware of
it.

If you're like me, the crazy part isn't that you were hypoxic. It's that
everything seems completely normal. You can't use an out-of-whack system (your
brain) to judge whether it's out-of-whack or not.

~~~
perl4ever
My impression is that cabin altitude on a pressurized airliner might be up to
8,000 ft.

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chiph
Destin at Smarter Every Day shows you the effects of hypoxia and why you
should put your mask on first before helping a child or other passenger.

[https://www.youtube.com/watch?v=kUfF2MTnqAw](https://www.youtube.com/watch?v=kUfF2MTnqAw)

~~~
acjohnson55
My wife still remarks that she'll put on our daughter's first, and I'm like
please, please, please don't do that, there's a reason they say this. If you
pass out, you can't help anyone else. It doesn't seem to get through to her.

~~~
Pyrodogg
I was just flying today and noticed times printed on the safety card. I recall
it had getting your own mask secured in 5-7 seconds and getting to assisting
children by 10 seconds.

It's the first time I recall seeing times printed and it really illustrates
how quickly it'll hit the fan. 10 seconds isn't alot of time but the order is
still critical.

I wonder if that clarity on timing would frame it better for other people
instead of an open ended 'me before them' blanket rule.

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poof131
Reminded me of the two times I’ve been hypoxic. One was in the altitude
chamber. The Navy was great about training and had all pilots experience
hypoxia so they could understand how the symptoms effect them in particular.
My first indications was tingling fingers. The second time was flying into
Iraq. I had skimped on the preflight checklist and missed the cabin pressure
switch, which was always in the on position, but had somehow been set to off.
Took my mask off at 20k heading in country and started to feel light headed
with tingling fingers. Told my commanding officer / flight lead something was
wrong. We started to return to the carrier. During the emergency procedure
checklist hit the step to check the cabin pressure switch. Oops. “Sir, we
don’t have to abort the mission!” The Navy had some great training that saved
my life on more than one occasion.

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asteli
I was in a Cessna 206 headed to Oshkosh. Our pilot had planned to fly
Eastbound at 17,000ft to avoid an air current. We all got nasal cannulae for
supplemental oxygen. We departed at 3AM, and following takeoff I immediately
fell asleep.

I woke up somewhere around 14,000ft, dizzy and confused, and realized I hadn't
put my cannula in before falling asleep. I fixed this, and within a minute the
brain fog was gone and I proceeded back to sleep.

Then we hit turbulence, which in a small craft like a 206 means you
occasionally whack your head on the ceiling. Couldn't sleep through that.

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_ks3e
The author mentions that he would design a system with a continuously
monitored pulse oximeter that could trigger the EPS descent mode
automatically. Do wrist-mounted versions (fingertip ones would probably be too
bulky/uncomfortable for continuous use by someone at the controls) of such
continuous oximeters exist at the moment? The Apple Watch apparently has a
sensor capable of measuring blood oxygen content, but disabled that
functionality for unstated reasons (FDA regs?) [1], and I'm unaware of any
extant wrist-worn device with that functionality enabled.

[1] [https://9to5mac.com/2015/04/24/apple-watch-blood-
oxygen/](https://9to5mac.com/2015/04/24/apple-watch-blood-oxygen/)

Some more information about the physiology of hypoxia can be found here:
[https://web.archive.org/web/20150318011408/dr-
amy.com/rich/o...](https://web.archive.org/web/20150318011408/dr-
amy.com/rich/oxygen)

~~~
durandal1
Autopilot descent triggered by hypoxia alarm has been available for quite a
while. It uses responsiveness heuristics rather than oximeter input.

[https://www.aviationpros.com/press_release/10393999/cirrus-a...](https://www.aviationpros.com/press_release/10393999/cirrus-
aircraft-announces-significant-new-software-features-for-cirrus-perspective-
by-garmin-avionics-suite)

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aphextron
Unpressurized high performance single engines are basically the number one
private pilot killer. Dentists and business men with a few hundred IFR hours
will go up solo in their new million dollar TBM, lose oxygen, descend into
icing, and that's a wrap. Don't be one of those guys.

~~~
benmarks
...are there stats on that? It's my impression that poor pre-departure
decision making - especially regarding WX and w & b - are the very, very
simple things which tend to kill private pilots.

~~~
bronco21016
Arguably, taking off along a route where one could potentially be stuck in
icing for an extended period, in an aircraft not capable of that, is the
definition of poor pre-departure decision making. Commercial airliners have
relief to dispatch with malfunctioning anti-ice gear. The procedures almost
always dictate that flight in known or forecast icing conditions is
prohibited. Basically, if it’s not summer and there’s a cloud in the sky
you’re not going. Icing is not something to mess around with in an aircraft
not properly equipped for it.

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unparagoned
Its extremely hard to detect hypoxia in yourself. Since your own detection
apparatus is faulty it usually doesn't work. Your best bet is to see if anyone
else looks like they have hypoxia, and if so should trigger the thought that
you might as well. Think of it like being able to tell if you are in a dream,
it takes most people some practice to tell, even though it seems like it
should be simple

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killjoywashere
that audio for Cirrus, N591WA ... oooohhhh.... mmmyyyy ....

[https://www.faa.gov/data_research/accident_incident/2011-05-...](https://www.faa.gov/data_research/accident_incident/2011-05-17/media/N591WA%20redacted.mp3)

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cameldrv
If you’re going to do this, spend $30 and get a can of BOOST oxygen and a
pulse oximeter with an alarm.

