
Malaysia Airlines 'loses contact with plane' - sbashyal
http://www.bbc.com/news/world-asia-26492748
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jodkdkd
This is hacker news, not reddit.

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marquis
I fly a lot and am very very interested in what happens in the airspace with
large planes. When the plane is found there will also be detailed technical
discussion, undoubtedly.

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frisco
What are you interested in specifically? I'm a pilot--private, not commercial
--and would be happy to explain the basics of airspace and flight rules.

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marquis
Not in aircraft itself, but a technical interest in why aircraft goes down.
When you are in a plane you are not flying you have zero control, and as
safety measures are improved by each failure I would say I feel just a little
bit safer after they learn why something failed.

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frisco
There's lots of data on this. Every accident and incident are logged and
analyzed:

\-
[https://www.ntsb.gov/investigations/reports_aviation.html](https://www.ntsb.gov/investigations/reports_aviation.html)

\-
[http://www.ntsb.gov/aviationquery/month.aspx](http://www.ntsb.gov/aviationquery/month.aspx)

\- [http://www.ntsb.gov/aviationquery/](http://www.ntsb.gov/aviationquery/)

Notice that actual accidents, especially Part 121 ("scheduled airline")
carriers, are rare. Major airliners are actually so safe now that there are no
"common failures" anymore - every failure is new and weird in its own way. But
as you can read through in the links above, there's lots of data and even
small incidents are analyzed in depth.

There's another program, NASA ASRS, which are voluntary self-reports of
usually minor incidents and can be interesting to read to get a sense of how
seriously safety is taken in aviation:
[http://asrs.arc.nasa.gov/search/database.html](http://asrs.arc.nasa.gov/search/database.html)

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marquis
I was reading that at 35,000 feet, if the plane loses power then decompression
happens and everyone loses consciousness. This seems like a fairly friendly
way to meet the end, could you comment on this?

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frisco
a) "Plane loses power" isn't that simple. There are multiple different
independent "power" systems for different things, each with their own
redundancies. Particularly critical systems, like engines, often don't need
anything else in the aircraft to be functional to continue to work. Power
failures, even fairly catastrophic ones, are trained for and there are
checklists for such events. (This goes all the way to the point of losing
power so badly that you have no instruments and no radios, there are
procedures for using a very simple battery-powered radio transponder to alert
ATC of this fact, who can flash high-powered light beacons at you to give you
landing instructions when you get close.)

b) Ignoring the "power failure" question, decompression at altitude is also a
known danger with its own procedures. At FL350 (35,000 feet), you'd have 30 -
60 seconds of "useful consciousness"[1]. Aircrews can don oxygen masks in much
less time than that; this is trained for. Further, continuous use of oxygen
masks by at least one pilot is mandatory when flying over at an altitude
greater than FL410 with multiple pilots, or above FL350 with a single pilot.
Again, if things fail so catastrophically that aircraft-supplied oxygen
doesn't work, there are small standalone oxygen tanks on hand to provide at
least 10 minutes of air, which is more than enough time to make an emergency
descent to a breathable altitude.

Also, to the premise of the question, cabin pressure should never be lost in
response to an electrical failure; these things are designed to fail "safe".
There are mechanical components that have to be actively thrown for
decompression, which can be done by hand if electricity is unavailable and
won't be triggered during a loss of power. Uncontrolled decompression is
usually the result of a structural failure (seal or gasket failure; metal
structural failure; etc).

[1]
[http://en.wikipedia.org/wiki/Time_of_useful_consciousness](http://en.wikipedia.org/wiki/Time_of_useful_consciousness)

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marquis
Thank you.

