Punctured pressure cabin.

"John R Weiss" wrote:


(Again: the above is quoted from rec.aviation.piloting)

...which doesn't mean anything as far as credibility goes! Who wrote that?!? I
am almost ROTFL at some of the assertions made up there (salient parts
retained)!


I agree...I'm very familiar with the 9MM Parabellum round having
owned a Waltzer P-38 for a few years had having access to a
practically unending supply of ammo from the RCAF for it. (having
a good buddy who was also a gun nut AND an armourer in the RCAF
didn't hurt) plus being quite familiar with a/c I can attest to
your views here.
--

-Gord.

"Cub Driver" wrote in message
...

A normal bullet hole would be no problem. There's already a much
larger vent to the outside, which stabilizes cabin pressure against
the fresh & heated air being pumped in from the engines. People
smarter than I say that this hole is about three inches in diameter.

More detail on this: over on rec.aviation.piloting, there's a parallel
and very busy thread on this same subject. Here's what a Big Spam Can
Driver had to say on the subject of the vent hole(s):

"Actually, a little bigger. There are two outflow valves that work in
tandem. On the 747 they're located on the aft belly, and each is a
touch smaller in area than one aircraft window -- an oval about 4in by
12in. There are also two relief valves on the left side of the
airplane, and they are about 8" in diameter."

So upon reflection it doesn't seem that even the blow-out of a window
could cause more than terror and discomfort, especially since it would
almost certainly be followed by an emergency descent to lower
altitude.

That is the problem with overgeneralization--it is usually wrong. It "could"
indeed cause more than terror and discomfort. The Brazilian airliner lost a
passenger when it had two windows taken out; a Piedmont airliner suffered a
passenger fatality during a rapid decompression that did not involve any
large opening at all. Having been through a few nasty eardrum ruptures, I
can tell you that the pain involved adds up to a bit more than "discomfort"
(when blood and pus are ejected a couple of inches out of the ear you can
imagine the sensation involved)--the passengers on that Aer Lingus 737 might
attest to that.

Brooks


One of the pilots commented: "I always wear my seat-belt when flying.
Don't you?" Something to add to your resolutions for 2004


all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

"Kevin Brooks" wrote in message
news



That is the problem with overgeneralization--it is usually wrong. It
"could"
indeed cause more than terror and discomfort. The Brazilian airliner lost
a
passenger when it had two windows taken out; a Piedmont airliner suffered
a
passenger fatality during a rapid decompression that did not involve any
large opening at all. Having been through a few nasty eardrum ruptures, I

Brooks


Direct quote from NTSB report ATL89IA099 concerning the Piedmont
incident: (emphasis added)

THE PASSENGER WAS TAKEN TO A DAYTON HOSPITAL AND
DIED AT ABOUT 6 HOURS AND 50 MINUTES LATER. THE
MONTGOMERY COUNTY CORONER RULED THAT DEATH WAS
DUE TO NATURAL CAUSES.
-----------------------

Henry Bibb

"Henry Bibb" wrote in message
hlink.net...

"Kevin Brooks" wrote in message
news



That is the problem with overgeneralization--it is usually wrong. It
"could"
indeed cause more than terror and discomfort. The Brazilian airliner
lost
a
passenger when it had two windows taken out; a Piedmont airliner
suffered
a
passenger fatality during a rapid decompression that did not involve any
large opening at all. Having been through a few nasty eardrum ruptures,
I

Brooks


Direct quote from NTSB report ATL89IA099 concerning the Piedmont
incident: (emphasis added)

THE PASSENGER WAS TAKEN TO A DAYTON HOSPITAL AND
DIED AT ABOUT 6 HOURS AND 50 MINUTES LATER. THE
MONTGOMERY COUNTY CORONER RULED THAT DEATH WAS
DUE TO NATURAL CAUSES.
-----------------------

Henry Bibb

Yep. Natural causes brought on by rapid decompression, no doubt. Trauma
induced, in other words, whether it be too much strain on the poor guy's
ticker or respiratory arrest. Or are you thinking his requirement for
immediate hospitalization just *happened* to be simultaneous to the
decompression event? Rather unlikely it was not tied to it, IMO.

Brooks

That is the problem with overgeneralization--it is usually wrong. It "could"
indeed cause more than terror and discomfort. The Brazilian airliner lost a
passenger when it had two windows taken out; a Piedmont airliner suffered a
passenger fatality during a rapid decompression that did not involve any
large opening at all. Having been through a few nasty eardrum ruptures, I
can tell you that the pain involved adds up to a bit more than "discomfort"
(when blood and pus are ejected a couple of inches out of the ear you can
imagine the sensation involved)--the passengers on that Aer Lingus 737 might
attest to that.

Still, you are surely not preferring to see your airplane go down into
Times Square?

Losing a passenger or an eardrum is a heck of a lot better than losing
200 passengers, the crew, and the people on the ground.

all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

"Cub Driver" wrote in message
...

That is the problem with overgeneralization--it is usually wrong. It
"could"
indeed cause more than terror and discomfort. The Brazilian airliner lost
a
passenger when it had two windows taken out; a Piedmont airliner suffered
a
passenger fatality during a rapid decompression that did not involve any
large opening at all. Having been through a few nasty eardrum ruptures, I
can tell you that the pain involved adds up to a bit more than
"discomfort"
(when blood and pus are ejected a couple of inches out of the ear you can
imagine the sensation involved)--the passengers on that Aer Lingus 737
might
attest to that.

Still, you are surely not preferring to see your airplane go down into
Times Square?

Losing a passenger or an eardrum is a heck of a lot better than losing
200 passengers, the crew, and the people on the ground.

Damnit, for the last time--I HAVE NOT DISAGREED WITH THAT CONCLUSION! What I
have disagreed with is the assertion that the loss of a window, or any other
RAPID decompression scenario, is a trivial affair--you are going to suffer
injuries, some possibly serious ones, and yes, there have been deaths
attributed to, or related to, it. That said, and for one last time--the
danger of such a decompression resulting from a bullet, even one that might
take out a window, is less than the danger involved in a successful hijack.
Get it?

Brooks

all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

"Cub Driver" wrote...

"Actually, a little bigger. There are two outflow valves that work in
tandem. On the 747 they're located on the aft belly, and each is a
touch smaller in area than one aircraft window -- an oval about 4in by
12in. There are also two relief valves on the left side of the
airplane, and they are about 8" in diameter."

I don't know about the 747 Classic, but the -400 has 2 rectangular outflow
valves, each about 1 x 3 feet. The -400 also also has 3 A/C packs vs the 2 in
the Classic for pressurization.

In message , Cub Driver
writes

What do readers think is the result of decompression via a bullet hole?

snip

So are you worse off risking explosive decompression, or of crashing
into Times Square at midnight?

As to the possibility of explosive decompression, as I understand the
matter, it could happen if a bullet fractured a window (though not if
it went through the skin). That's a mere possibility, as opposed to
the certainty of a suicide dive, absent the sky marshal.

A normal bullet hole would be no problem. There's already a much
larger vent to the outside, which stabilizes cabin pressure against
the fresh & heated air being pumped in from the engines. People
smarter than I say that this hole is about three inches in diameter.

I'm glad you mentioned 3" in diameter. During my RAF service my wireless
mechanics had to pass a camera cable from a bomb bay into the pressure
cabin in a Valiant. To my surprise they found a hole about 3" diameter
in a convenient place.

I said 'surprise' because I was in Signals and knew nothing about the
structural properties of the aircraft. I imagined that the pressure
cabin would be tightly sealed.

What about the loss of a window due to bullet strike? Would there be
structural failure?

Mike
--
M.J.Powell

"M. J. Powell" wrote:

In message , Cub Driver
writes

What do readers think is the result of decompression via a bullet hole?

snip

So are you worse off risking explosive decompression, or of crashing
into Times Square at midnight?

As to the possibility of explosive decompression, as I understand the
matter, it could happen if a bullet fractured a window (though not if
it went through the skin). That's a mere possibility, as opposed to
the certainty of a suicide dive, absent the sky marshal.

A normal bullet hole would be no problem. There's already a much
larger vent to the outside, which stabilizes cabin pressure against
the fresh & heated air being pumped in from the engines. People
smarter than I say that this hole is about three inches in diameter.

I'm glad you mentioned 3" in diameter. During my RAF service my wireless
mechanics had to pass a camera cable from a bomb bay into the pressure
cabin in a Valiant. To my surprise they found a hole about 3" diameter
in a convenient place.

I said 'surprise' because I was in Signals and knew nothing about the
structural properties of the aircraft. I imagined that the pressure
cabin would be tightly sealed.


It is Mike (comparitevely at least)...they sure didn't use the
'outflow valve' nor the 'dump valve' (right beside it) to pass a
cable (unless they did it for testing on the ground or somesuch.
These valves need to 'modulate' the pressure inside the cabin
while climbing and during flight so you couldn't use them for
passing cables through during flight

What about the loss of a window due to bullet strike? Would there be
structural failure?

Mike

Most unlikely, the window frame is pretty strong and likely
wouldn't propagate cracks.
--

-Gord.

"M. J. Powell" wrote in message
...

There has been a bit of a furore over here concerning the new US
requirement to airlines to supply air marshals when requested. The
concern is mainly over the possible puncture of a pressure cabin.
What do readers think is the result of decompression via a bullet hole?

Mike
--
M.J.Powell

Unless it hits electrical or hydraulic systems pretty much nothing. Score
it as a miss. A bullet hole will not decompress an airplane. A hatch leak
will probably leak more and can be easily overcome by the pressurization
system.

Tex