Emmanuel.Gustin wrote:
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?

A bullet hole would not in itself cause for much concern.
The loss of a cabin window would be more serious, not
because the pressurisation system would be unable to cope,
but because the strong air current could move (in the worst
case, blow out through the window) or wound passengers. In
extreme cases, rapid pressure loss (or perhaps
more accurately, an internal pressure differential) can
lead to major structural failures, especially around
bulkheads that are insufficiently vented -- the pressure
differential is enough to make these collapse -- or in
fuselages that are already 'tired'. Apart from the Comet
disasters, I know of no loss of aircraft caused by the
loss of windows (although some passengers have been lost)
but a number of aircraft have been lost when doors failed.

There is also the risk of bullets bouncing around inside
the plane and doing damage to power lines, fuel systems,
etc. Historically, fire has been the major killer of
aircraft following projectile damage.

Seems to me that although loss of cabin pressure is serious
concern (IIRC military aircraft were designed to maintain
lower cabin pressure than airliners, to limit the damage
amplification following a hit) but not the most serious one.
The worst problem is the prospect of a gun battle in a cabin
packed with people. Almost every stray bullet is going to
hit someone; even if the sky marshall hits the right man
(or woman) the bullet seems likely to hit others as well.

This is going to require very fine judgment by the sky
marshall. He or she also has to distinguish between a
conventional hijack best dealt with by negotiation (are
sky marshalls trained to conduct hostage-release
negotiations?) which are the vast majority of cases,
and a rare attempt to use an airliner as a suicide bomb.
This seems to be a job requiring very extensive training,
a very cool head, and fine judgment. I am not convinced
that the large number of sky marshalls rapidly trained
and deployed now have the right capabilities, and I don't
think it is wise at all to give guns to pilots after
minimal training.

You have touched a sore spot here on this last point. You seem
to be under the impression that there might be "conventional"
highjackings. These are a thing of the past. The minute that
passengers and cabin crew subdued Richard Reid, it was clear that
"conventional" highjackings, were no longer. There is no negotiation
skill required. Kill anyone that is attempting to commandeer an
aircraft. Time has to be divided into pre 9/11 and post 9/11. Your
statement applies to pre 9/11 highjackings only. The judgement required
of the sky marshal--- Is this person an unruly/drunk passenger, or is he
intent on mischief. If he is a drunk, or unruly passenger, subdue, and
restrain him. If he (or she) is intent on mischief, deadly force is
mandatory.
KenG