

Why do airplanes float in water? A better answer from Fluther. - sferik
http://www.fluther.com/disc/32715/why-do-airplanes-float-in-water/

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jws
_When US Airways Flight 1549 landed in the Hudson, it remained on the surface
of the water for quite some time before sinking. Why does a heavy aircraft
float for even a minute?_

What an odd question to ask.

1) They can be seen floating in air, why not water which is 800 times denser?

2) The weight seems to have an issue in the asker's thought process.
Battleships float, and they weigh about 600 times as much as an airbus 320.

3) Maybe there is something about the "sink eventually" time constant that
causes confusion. Perhaps battleships get an exemption because they remain
floating for long periods. If you can live the lie long enough, people will
believe you.

Now let's review some answers we get at fluther by "tapping the collective":

 _There is air inside it, making it somewhat buoyant. Think about how a
submarine works._

Using a sinking object to explain floating is not going to win points for
clarity.

 _like the titanic. when the ship was cracked into half, the other half stayed
like 1 minute before sinking into the deep sea. i would say its due to the
buoyant force by the water acting on the ship is temporarily higher than the
weight of ship because the ship breaking into two releases the water contained
in the in the ship. Or probably the sinking of the other half of the ship
displaces the water to generate force to support the remainning half._

A whiff of truth passes through this answer, but it is fleeting. "the ship
breaking into two releases the water contained in the in the ship"?? I can't
even begin to fathom what leads to that statement.

 _They are designed to do so. The bottom half is a sealed compartment (full of
air), they do eventually sink, but by NTSB saftey guidelines they are required
to remain aflote for a certain period of time._

Ignoring the "by definition" aspect, this answer has truth in it, but I like
the part where they stay afloat for a "certain period of time" because of NTSB
requirements. I imagine a plane buoyed solely by the power of government
mandate.

(And just to clear some of the misinformation in the article's comments: A
rear door of the airbus was opened and did let water in, and the pilots
allegedly neglected to throw the "ditch switch" which closes various openings
to prevent water entry. The engineering team for the airbus deserves a big
round of applause.)

