Mythbusters and explosive decompression

"MichaelR" wrote in message
...
Why do airliner cockpit windows have heaters?
The answer is to keep the windows warm enough and flexible enough so they
don't shatter if they hit a bird.

Why do they run them at altitudes that birds don't fly?

If Mythbusters had cooled that side window to -50C, it would have
disintegrated when the bullet hit it.

Tom Sixkiller wrote:

[ heated airliner windscreens]

Why do they run them at altitudes that birds don't fly?

I assume your question is rhetorical, but the range of altitudes at
which birds may be found is far greater than most people suspect. I have
seen them 14,000 msl over the lower 48, and that is no record.

Other reasons: ice & snow, FOD (balloons and their payloads, kites,
model aircraft, wind- and vertical current-borne objects and material),
and of course the ever-present possibility of mid air collision -- all
of which must be considered at all altitudes within the operating envelope.

But these considerations have little to do with the advisability of
preventing skyjacking by any means necessary, including the use of
firearms by Federal Sky Marshals. As a cockpit crew member, a blown out
window is something I can deal with -- a medium sized problem: a team of
terrorists controlling the cabin is going to be a much bigger problem,
and it will have ramifications well beyond anything we are likely to
include in our discussions here.


--
Jack

"Cave ab homine unius libri"

In article , Jack
wrote:

I assume your question is rhetorical, but the range of altitudes at
which birds may be found is far greater than most people suspect. I have
seen them 14,000 msl over the lower 48, and that is no record.


As a side note on this, I'm pretty sure I once heard in a lecture or
presentation -- no!, it was in a wonderful quasi-documentary movie about
birds; was the title perhaps something like "Flight"? -- which described
one species of fairly small birds that migrate annually by taking off
from near or at sea level and flying over the Himalayas to a destination
far to the north, reaching altitudes higher than the top of Everest en
route -- and doing it nonstop.

Hope I don't have the details too far wrong here -- but if it stimulates
someone to dig out the movie itself, you may find it worth my possibly
erroneous memories.

As a side note on this, I'm pretty sure I once heard in a lecture or
presentation -- no!, it was in a wonderful quasi-documentary movie about
birds; was the title perhaps something like "Flight"? --


"Winged Migration". Excellent movie, every pilot should see it. Twice.

Jose

--
(for Email, make the obvious changes in my address)

They don't. They turn them on during descent because otherwise they would
still be cold enough to be fragile even after getting down into warmer air.



Why do they run them at altitudes that birds don't fly?

If Mythbusters had cooled that side window to -50C, it would have
disintegrated when the bullet hit it.

On Sun, 11 Jul 2004 19:55:36 -0400, MichaelR wrote:

They don't. They turn them on during descent because otherwise they would
still be cold enough to be fragile even after getting down into warmer air.

My company's procedure for the 737 is to turn on the window heat a
minimum of ten minutes prior to takeoff and leave it on until parked at
the arrival gate. The window heat can be left all day long if desired.

-Jack Davis
B737


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Few notes -

Some years ago I hit a red-tail hawk on the left windscreen of a 707
at 16,000 ft climbing out of Houston. Made a mess - no damage. If we
lost windshield heat, our limitation was 250 kts below 14,0000 ft.
Guess that bird didn't know he shouldn't fly that high.

Also some years ago, I saw a Gulfstream that belonged to a Middle
East head of state at a US repair facility with a bullet hole that
entered in the belly and went out the top. They flew it normally all
the way to the States The Gulfstream carries a higher pressure
differential than any airliner I know of with an 8,000 ft cabin at
51,000 ft. and usually cruises about M .82 on long flights.

Aircraft pressurization is controlled by how much air gets let out by
the outflow valve/s. With a small hole or two, the outflow valve/s
would automatically close a bit and the aircraft would pressurize
normally anyway. If you do a ground pressure check on any aircraft,
they leak all over the place anyway. In flight it would just whistle
a bit louder and that's all.

Forget the pressure vessel as far as I'm concerned. What about those
rather large wire bundles being fed by a couple of 120 KvA generators?
Ask Swiss air. How about the primary control system, hydraulic
systems, or 20,000 gal of fuel? Fuel; ask TWA/ American. What would
happen if that 9 mm went through the fly-by-wire boxes on a B-777 or
Airbus? Don't know that one yet, but I hope we never find out.

Myself, I'd be just as happy if they'd leave the cockpit door locked
and used the crash axe if necessary. Besides, I know some of those
guys that fly those things and there are a few I wouldn't want to see
with a gun!!!

"Don Hammer" wrote in message
...

Myself, I'd be just as happy if they'd leave the cockpit door locked
and used the crash axe if necessary. Besides, I know some of those
guys that fly those things and there are a few I wouldn't want to see
with a gun!!!

Would you fly with them?

"Don Hammer" wrote in message

... Besides, I know some of those
guys that fly those things and there are a few I wouldn't want to see
with a gun!!!

Amen to that, Don.

"John Gaquin" wrote in message
...

"Don Hammer" wrote in message

... Besides, I know some of those
guys that fly those things and there are a few I wouldn't want to see
with a gun!!!

Amen to that, Don.

And this proves...what?