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Punctured pressure cabin.



 
 
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  #1  
Old January 1st 04, 12:06 AM
M. J. Powell
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Default Punctured pressure cabin.


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
  #2  
Old January 1st 04, 12:21 AM
Steve Hix
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In article ,
"M. J. Powell" wrote:

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?


Unnoticeable is almost all cases. A mild annoyance in the remainder, as
long as we're discussing smallarm-caliber rounds.
  #3  
Old January 1st 04, 12:23 AM
Steven P. McNicoll
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"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?


There won't be decompression via a bullet-sized hole. There are already a
variety of leaks in the pressure vessel. There are simply some things which
must penetrate the vessel. They're sealed reasonably well, but there's
still some unavoidable leakage. The pressure is maintained by controlling
the outflow of pressurized air. Another small hole will simply cause the
control valve to close a bit to compensate.


  #4  
Old January 1st 04, 01:23 AM
Cub Driver
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What do readers think is the result of decompression via a bullet hole?


Whose bullet? The American sky marshals (and presumably others) use
frangible bullets, which wouldn't make a hole.

The Brit argument is that the terrorist would use their guns in a
"shoot-out" caused (of course!) by the sky marshal's gun. Okay, we've
postulated that the terrorist has successfully smuggled a gun on
board. Why is that? So he can crash the plane into a target? Could be,
huh?

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.


all the best -- Dan Ford
email:

see the Warbird's Forum at
www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com
  #5  
Old January 1st 04, 02:11 AM
Tex Houston
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"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


  #6  
Old January 1st 04, 03:15 AM
Jack G
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I think it depends on WHO the bullet passes through on its way to the
outside...

Jack

"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



  #7  
Old January 1st 04, 03:55 AM
Jim Yanik
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Cub Driver wrote in
:


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


Whose bullet? The American sky marshals (and presumably others) use
frangible bullets, which wouldn't make a hole.


To the best of my knowledge,that's wrong;US Sky Marshals use .40 cal JHP
(jacketed hollowpoint) ammo(premium,the good stuff),as they might need to
penetrate some barrier that a hijacker hid behind.

Frangible ammo can be defeated by some forms of clothing,or a
shield.(briefcase?)

--
Jim Yanik
jyanik-at-kua.net
  #8  
Old January 1st 04, 03:58 AM
Jim Yanik
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Default

"Tex Houston" wrote in
:


"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




Even then,it's very hard for a bullet to get to the electrical or hydraulic
systems(besides actually hitting them),those being UNDER the passenger
deck.You'd have to shoot at a fairly steep angle,and the bullet would lose
energy pretty quickly.

--
Jim Yanik
jyanik-at-kua.net
 




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