How can an aircraft be brought down by a small firebomb?

[David Newman]

I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.

But the X-ray screening of hand baggage will pick up large strong metal
casings. Wouldn't that mean that bombers would, at best, be able to
improvise a small firebomb from their smuggled nitroglycerin, TNT or
whatever? So how could that cause the aeroplane to crash? I haven't
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

[Peter]

Post by David Newman
I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.

An explosive does indeed "burn" but (if correctly detonated) it burns
very fast, with the chemical reaction propagating through the material
at some thousands of feet per second. This causes rapid expansion;
what is called an "explosion". No metal casing is needed.

[Greg]

Post by David Newman
I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.
But the X-ray screening of hand baggage will pick up large strong metal
casings. Wouldn't that mean that bombers would, at best, be able to
improvise a small firebomb from their smuggled nitroglycerin, TNT or
whatever? So how could that cause the aeroplane to crash? I haven't
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

Do you really want to know how pointless all this screening is?:

http://tomshardware.co.uk/2006/07/13/ntsb_laptopbattery_upsfire/

Most laptops contain a large Lithium Polymer battery which is basically
an incendiary device waiting to detonate, once started it can not
easily be extinguished as it contains it's own oxidiser. What does it
take to detonate it?, a paper clip or similar shorted across the
terminals...I leave it for you to work out the rest.

I work in electronics and we used to have real problems a few years ago
as there was a tight limit to the amount of lithium we could put in a
product which was going to be transported by air, and that was before
lithium polymer cells added the oxidiser. Then laptops and mobiles
started to use them and the safety rules went out of the window.

Can you imagine a total and permenant ban on laptops, mobile phones and
indeed any electronics that use this type of battery anywhere in any
plane?

Greg

[Peter]

Post by Greg
Most laptops contain a large Lithium Polymer battery which is basically
an incendiary device waiting to detonate

"detonate" is a bit emotive :)

The funniest thing is that commercial aircraft somke detectors use
lithium batteries...

Actually they rarely catch fire, and shorting one doesn't start a
fire. The cases of fires tend to be mechanical damage, causing an
internal short.

A NIMH or NICD battery can go up in flames just as easily, and a short
*is* all that is required.

Aircraft holds have fire control systems, and there is no reason why a
battery there should suddenly go up in flames.

In the passenger compartment, you can put the fire out manually.

[pietro]

Post by Peter

Post by Greg
Most laptops contain a large Lithium Polymer battery which is basically
an incendiary device waiting to detonate

"detonate" is a bit emotive :)
The funniest thing is that commercial aircraft somke detectors use
lithium batteries...
Actually they rarely catch fire, and shorting one doesn't start a
fire. The cases of fires tend to be mechanical damage, causing an
internal short.
A NIMH or NICD battery can go up in flames just as easily, and a short
*is* all that is required.
Aircraft holds have fire control systems, and there is no reason why a
battery there should suddenly go up in flames.
In the passenger compartment, you can put the fire out manually.

Dell Computers are recalling 4 million Laptops because "The
batteries that have been used can suddenly catch fire"
Makes you wonder doesn't it?

P

[Steve Firth]

Post by Peter
In the passenger compartment, you can put the fire out manually.

Very difficult in the case of a Lithium laptop battery - I mean would you
throw water on it for example?

[Greg]

Post by Steve Firth

Post by Peter
In the passenger compartment, you can put the fire out manually.

Very difficult in the case of a Lithium laptop battery - I mean would you
throw water on it for example?

It wouldn't make any real difference, once ignited they decompose to produce
oxygen so can burn without air, and generate enough heat to vaporise water
around them so the water can't cool the materials sufficiently to extinguish
the fire, you just have to let them burn out.

Greg

[Greg]

Post by Peter
The funniest thing is that commercial aircraft somke detectors use
lithium batteries...

The thing is there are several types of Lithium batteries, smoke
detectors use primary cells in metal cans which are long proven to be
safe. laptops and phones started to use secondary (rechargeable)
Lithium Ion in metal cans which were not too dangerous. But then came a
particular type of Lithium Ion called Lithium Polymer which include
their own oxidiser so can't be extinguished easily, and are in plastic
film packets instead of cans so are very vulnerable.

Post by Peter
Actually they rarely catch fire, and shorting one doesn't start a
fire. The cases of fires tend to be mechanical damage, causing an
internal short.

Not any more, LiPO has changed all that,

Post by Peter
Aircraft holds have fire control systems,

Which don't work as you'll see,

Post by Peter
and there is no reason why a
battery there should suddenly go up in flames.

again LiPo changed all that,

Post by Peter
In the passenger compartment, you can put the fire out manually.

and that...

We could a argue this 'til the cows come home but it would be academic
as a laptop battery has probably already brought a plane down:
http://tomshardware.co.uk/2006/07/13/ntsb_laptopbattery_upsfire/

The initial report is here:
http://www.ntsb.gov/Events/2006/PhiladelphiaPA/iic_opening_text.htm

and it cites other cases of laptop batteries spontaniously igniting
including one where the crew attempted to put it out but failed,
fortunately they were on the ground and got it out of the plane.

And here's another one:
http://www.theinquirer.net/default.aspx?article=32550

In the case of flight 1307 they were very, very fortunate that they
were on the aproach when it happened, in fact they only got an alarm
2.5 minutes before touchdown (though had smelt something earlier) and
yet the cockput was full of dense smoke as they evacuated, it couldnt't
have been much closer than that could it.

If it had been full of passengers and at cruising height would 2.5
minutes from the alarm to dense smoke and electrical systems failing
have been enough?, even if they had responded to the smoke would 25
minutes have been enough?. I don't know as I'm not a pilot, but I'm
professionally involved in batteries and I can tell you that LiPO's are
a very dangerous development that people aren't taking seriously
enough. Are air crews being educated to this new threat?, I'm afraid it
doesn't appear so.

Greg

[Greg]

Further investigation shows the authorities are actively covering up
the risk from LiPO batteries in planes, there was a hearing into the
accident:

http://www.ntsb.gov/Events/2006/PhiladelphiaPA/agenda.htm

which only made one mention of the new technology and that was to claim
that it was the same chemistry, which is blatantly untrue as it's
accepted they include an oxidiser so can't be extinguished by Halon etc
as claimed in the hearing.

Yet again the aviation industry burries it's head in the sand until a
lot of people die 8-(.

Greg

[Steve Firth]

Post by David Newman
I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.

Umm no. What you are describing is a low explosive such as gunpowder. High
explosives such as nitroglycerine (hence gelignite and dynamite which are
nitroglycerine packaged for safety), TNT, plastic explosives etc. are so
energetic that they do not need a casing.

To bring down an aircraft at altitude all that is needed it to breach the
skin of the aircraft and to allow decompression to do the work, as on the
PanAm flight over lockerbie.

[Peter]

Post by Steve Firth
Umm no. What you are describing is a low explosive such as gunpowder. High
explosives such as nitroglycerine (hence gelignite and dynamite which are
nitroglycerine packaged for safety), TNT, plastic explosives etc. are so
energetic that they do not need a casing.

On nitroglycerine, which according to the media is what might have
been used in "current events", how would one set that off? Films about
19th century mining activities suggest one has to only drop the bottle
on the floor...

[Steve Firth]

Post by Peter
On nitroglycerine, which according to the media is what might have
been used in "current events", how would one set that off? Films about
19th century mining activities suggest one has to only drop the bottle
on the floor...

I haven't seen a reference to nitroglycerine, and I've seen comments in the
few reports that I have read that suggest a different liquid explosive
slightly more stable than "nitro".

In the case of nitroglycerine and the other liquid the sure way to set it
off is to use a detonator, this is the part of any plot to cause explosions
that causes problems for the would-be bomber. Detonators tend to be a bit
of a giveaway. However in the case of "nitro" as you say it's easier to
detonate because it is shock sensitive. The problem for a bomber is that of
avoiding premature explosion, treating nitro so that it is less shock
sensitive also makes it harder to initiate an explosion.

The other explosive I was thinking of seems more likely, it's easier to
transport, it looks exactly like water unlike nitro which is oily, it's
available readily for innocent uses that don't require an explosives
licence and IIRC although a detonator is useful it is possible to make it
go bang without one.

[Sla#s]

Post by Steve Firth

Post by Peter
On nitroglycerine, which according to the media is what might have
been used in "current events", how would one set that off? Films about
19th century mining activities suggest one has to only drop the bottle
on the floor...

I haven't seen a reference to nitroglycerine, and I've seen comments in the
few reports that I have read that suggest a different liquid explosive
slightly more stable than "nitro".
In the case of nitroglycerine and the other liquid the sure way to set it
off is to use a detonator, this is the part of any plot to cause explosions
that causes problems for the would-be bomber. Detonators tend to be a bit
of a giveaway. However in the case of "nitro" as you say it's easier to
detonate because it is shock sensitive. The problem for a bomber is that of
avoiding premature explosion, treating nitro so that it is less shock
sensitive also makes it harder to initiate an explosion.
The other explosive I was thinking of seems more likely, it's easier to
transport, it looks exactly like water unlike nitro which is oily, it's
available readily for innocent uses that don't require an explosives
licence and IIRC although a detonator is useful it is possible to make it
go bang without one.

From the explanations I've seen so far it seems to be the same type of
explosive as used in the Oklahoma bombing. It's a binary of very stable,
easy to disguise components and very easy to make in the plane's toilet.

The only way to stop it is to not allow any liquids or powders on board.

So if you are on a plane and you smell model airplane fuel... do something!

(I'm not giving anything away - that part is in lots of reports)

Slatts

[Peter]

Post by Sla#s
So if you are on a plane and you smell model airplane fuel... do something!
(I'm not giving anything away - that part is in lots of reports)

One can google with

"model airplane fuel" explosive

to get the details :)

I should think it is well known.

Model airplane fuel (nitromethane) is disgusting smelly stuff, gets
everywhere.

[Sla#s]

Post by Peter

Post by Sla#s
So if you are on a plane and you smell model airplane fuel... do something!
(I'm not giving anything away - that part is in lots of reports)

One can google with
"model airplane fuel" explosive
to get the details :)
I should think it is well known.
Model airplane fuel (nitromethane) is disgusting smelly stuff, gets
everywhere.

Model fuel is only 35% nitro the rest being Methanol.

But God I love the smell of nitro in the morning!
And afternoon & Evening :-)
(Though strictly speaking I think Nitro its self has no smell, its the
methonol one notices.)
Must go to Santa Pod again this year. :-) Watching it on TVs not the same.

Slatts

[Eeyore]

Post by Sla#s
From the explanations I've seen so far it seems to be the same type of
explosive as used in the Oklahoma bombing.

That was sold and was several hundredweight of the stuff !

Post by Sla#s
It's a binary of very stable,
easy to disguise components and very easy to make in the plane's toilet.

No such thing exists.

Post by Sla#s
The only way to stop it is to not allow any liquids or powders on board.

Utter nonsense.

Post by Sla#s
So if you are on a plane and you smell model airplane fuel... do something!
(I'm not giving anything away - that part is in lots of reports)

You're just making it up. Considering your idea of what happened in Oklahoma City
you have zero credibility.

Graham

[Mike Tomlinson]

Post by Sla#s
From the explanations I've seen so far it seems to be the same type of
explosive as used in the Oklahoma bombing. It's a binary of very stable,
easy to disguise components and very easy to make in the plane's toilet.

This article disputes the "very easy to make" bit. Worth a read.

http://www.theregister.co.uk/2006/08/17/flying_toilet_terror_labs/

[Sla#s]

Post by Mike Tomlinson

Post by Sla#s
From the explanations I've seen so far it seems to be the same type of
explosive as used in the Oklahoma bombing. It's a binary of very stable,
easy to disguise components and very easy to make in the plane's toilet.

This article disputes the "very easy to make" bit. Worth a read.
http://www.theregister.co.uk/2006/08/17/flying_toilet_terror_labs/

Yes I read it but strangely they are talking about completely different
chemicals. Disinformation? But that's unlike the Register.

What I'm saying is one could take on-board a litre of "water" and a
large "talcum powder". Then all that is needed is a blasting cap to set
it off. Correctly placed that would blow the side out a toilet. As to
whether that would bring down the whole ship...

I would therefore ban all liquids, powders and include in that
disposable nappies as the filler could be suspect. I'd also like to ban
pens as these could be used as weapons or hide the aforesaid detonator.
All these items could be available on-board for free.

Slatts

[Eeyore]

Post by Sla#s

Post by Mike Tomlinson

Post by Sla#s
From the explanations I've seen so far it seems to be the same type of
explosive as used in the Oklahoma bombing. It's a binary of very stable,
easy to disguise components and very easy to make in the plane's toilet.

This article disputes the "very easy to make" bit. Worth a read.
http://www.theregister.co.uk/2006/08/17/flying_toilet_terror_labs/

Yes I read it but strangely they are talking about completely different
chemicals. Disinformation? But that's unlike the Register.

The register may be a bit sarcy bit iIve never seen intentional factual errors.

I suspect loads of disinformation is being spread about this terror plot. Take a
look at this for example....

" The explosive found in the suitcase is HMTD, which is very easy to detonate
through heat, shock or friction. It is often used in blasting caps and other
primary charges "
http://blogs.abcnews.com/theblotter/2006/08/explosives_link.html

Then check this out.

" Measure 9 teaspoons of hydrogen peroxide into a container. In 3 portions,
dissolve 2.5 teaspoons of crushed hexamine in the peroxide. Keep the
solution cool for 30 minutes by placing the container in a pan of cold
water. In 5 portions, dissolve 4.5 teaspoons of crushed citric acid in the
hexa-peroxide solution. Permite solution to stand at room temperature or in
the refrigerator until solid particles for at the bottom of the container.

Note: Complete precipitation will take place in 8-24 hours

Filter the mixture through a coffee filter into a container to collect the
solid particles. Wash the solid particles collected in the coffee filter
with 6 teaspoons of distilled water by pouring the water over them. Discard
the liquid in the container. Allow to dry. In a COOL dry place. NOT IN THE
SUN! Place these explosives in a container. "
http://business.fortunecity.com/executive/674/hmtd.html

On an American site btw !

Post by Sla#s
What I'm saying is one could take on-board a litre of "water" and a
large "talcum powder". Then all that is needed is a blasting cap to set
it off. Correctly placed that would blow the side out a toilet. As to
whether that would bring down the whole ship...
I would therefore ban all liquids, powders and include in that
disposable nappies as the filler could be suspect. I'd also like to ban
pens as these could be used as weapons or hide the aforesaid detonator.
All these items could be available on-board for free.

"All these items could be available on-board for free. "

Most sensible suggestion I've seen - at least wrt carrying plenty of water esp
for long-haul flights.

Graham

[Sla#s]

Eeyore wrote:
<SNIP>

I agree with you that the "Chemical factory" in the toilet they and
several other sites describe is complete tosh.

Post by Eeyore

Post by Sla#s
I would therefore ban all liquids, powders and include in that
disposable nappies as the filler could be suspect. I'd also like to ban
pens as these could be used as weapons or hide the aforesaid detonator.
All these items could be available on-board for free.

"All these items could be available on-board for free. "
Most sensible suggestion I've seen - at least wrt carrying plenty of water esp
for long-haul flights.

...and whilst we're at it ban alcohol as well! (Duty Frees - give them a
voucher to redeem at the other end.)

Slatts

[Eeyore]

Post by Sla#s
<SNIP>
I agree with you that the "Chemical factory" in the toilet they and
several other sites describe is complete tosh.

I'm uterly amazed how this story has been swallowed up uncritically by the media.
It's truly fantasy.

Post by Sla#s

Post by Eeyore

Post by Sla#s
I would therefore ban all liquids, powders and include in that
disposable nappies as the filler could be suspect. I'd also like to ban
pens as these could be used as weapons or hide the aforesaid detonator.
All these items could be available on-board for free.

"All these items could be available on-board for free. "
Most sensible suggestion I've seen - at least wrt carrying plenty of water esp
for long-haul flights.

...and whilst we're at it ban alcohol as well! (Duty Frees - give them a
voucher to redeem at the other end.)

I strongly suspect that we may see that happening actually. It would keep some
weight off the plane and not be a distraction for cabin crew too.

Graham

[Sla#s]

Post by Eeyore

Post by Sla#s
<SNIP>
I agree with you that the "Chemical factory" in the toilet they and
several other sites describe is complete tosh.

I'm uterly amazed how this story has been swallowed up uncritically by the media.
It's truly fantasy.

The media over here is talking about a completely different mix to the
US claims. It does not require the "Chemical factory toilet" scenario
hence is a credible claim.

Slatts

[Eeyore]

Post by Sla#s

Post by Eeyore

Post by Sla#s
<SNIP>
I agree with you that the "Chemical factory" in the toilet they and
several other sites describe is complete tosh.

I'm uterly amazed how this story has been swallowed up uncritically by the media.
It's truly fantasy.

The media over here is talking about a completely different mix to the
US claims. It does not require the "Chemical factory toilet" scenario
hence is a credible claim.

Could you elaborate on that ?

Graham

[Sla#s]

Post by Eeyore

Post by Sla#s

Post by Eeyore

Post by Sla#s
<SNIP>
I agree with you that the "Chemical factory" in the toilet they and
several other sites describe is complete tosh.

I'm uterly amazed how this story has been swallowed up uncritically by the media.
It's truly fantasy.

The media over here is talking about a completely different mix to the
US claims. It does not require the "Chemical factory toilet" scenario
hence is a credible claim.

Could you elaborate on that ?

http://www.guardian.co.uk/terrorism/story/0,,1842283,00.html

"Another possibility would be the industrial solvent and fuel
nitromethane, which is fairly easy to obtain because it is used to fuel
model aeroplanes and racing cars. To work as a bomb, nitromethane would
need to be combined with an oxidiser such as ammonium nitrate (fertiliser).
Timothy McVeigh used this chemical combination to blow up the Alfred P
Murrah building in Oklahoma City in 1995, killing 168 people."


http://news.independent.co.uk/uk/crime/article1218318.ece

"As well as powering model planes, nitromethane is used commercially,
both as an explosive and an industrial solvent.
'It's quite easy to get hold of in relatively small quantities,' said Dr
Alford.
To be used in a bomb, nitromethane would first have to be combined with
another sensitising substance.
A similar alternative, nitroethane, is less well known but equally as
effective. There are fewer restrictions on obtaining and transporting
this chemical."

And another reason for banning alcohol:-
http://news.com.com/Liquid+explosives+threaten+air+travel/2100-7348_3-6104475.html

"Saboteurs are believed to have used liquid explosives smuggled on board
in a bottle of alcohol to attack Korean Air flight 858 in 1987. The
bomb, apparently left on board by passengers who deplaned, killed 115
people" (that one was left in a Luggage rack).


Slatts

[Simon Hobson]

Post by Eeyore

Post by Sla#s
...and whilst we're at it ban alcohol as well! (Duty Frees - give them a
voucher to redeem at the other end.)

I strongly suspect that we may see that happening actually. It would keep some
weight off the plane and not be a distraction for cabin crew too.

Not a chance, you don't think they cart all that weight around for no reason
do you ? They make a LOT of money from it, that's why they do it, and why
they won't stop without significant incentives.

[Eeyore]

Post by Simon Hobson

Post by Eeyore

Post by Sla#s
...and whilst we're at it ban alcohol as well! (Duty Frees - give them a
voucher to redeem at the other end.)

I strongly suspect that we may see that happening actually. It would keep
some weight off the plane and not be a distraction for cabin crew too.

Not a chance, you don't think they cart all that weight around for no reason
do you ? They make a LOT of money from it, that's why they do it, and why
they won't stop without significant incentives.

You hardly need to tell *me* !

I've been involved with the hardware involved to do this ! I designed some of it
myself even !

In the long term however it makes no sense to carry duty-free on board airliners
when the cost of the accompanying 'security' hugely outweighs it !

It's quite literally a fuel.

Buy a couple of bottles of high strength alccohol and use it as an ignition
source ! That aircraft will be screwed ! Think SR 111

Graham

[Eeyore]

Post by Steve Firth
The other explosive I was thinking of seems more likely, it's easier to
transport, it looks exactly like water

I believe this is pure fiction invented by the 'authorities' to scare ppl.

Graham

[Eeyore]

Post by Steve Firth

Post by David Newman
I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.

Umm no. What you are describing is a low explosive such as gunpowder. High
explosives such as nitroglycerine (hence gelignite and dynamite which are
nitroglycerine packaged for safety), TNT, plastic explosives etc. are so
energetic that they do not need a casing.
To bring down an aircraft at altitude all that is needed it to breach the
skin of the aircraft and to allow decompression to do the work, as on the
PanAm flight over lockerbie.

That's rubbish. Plenty of aircraft have survived quite serious losses of skin.

Graham

[Steve Firth]

Post by Eeyore

Post by Steve Firth

Post by David Newman
I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.

Umm no. What you are describing is a low explosive such as gunpowder. High
explosives such as nitroglycerine (hence gelignite and dynamite which are
nitroglycerine packaged for safety), TNT, plastic explosives etc. are so
energetic that they do not need a casing.
To bring down an aircraft at altitude all that is needed it to breach the
skin of the aircraft and to allow decompression to do the work, as on the
PanAm flight over lockerbie.

That's rubbish.

No, it's not.

Post by Eeyore
Plenty of aircraft have survived quite serious losses of skin.

And plenty have not.

[lomcovak]

Post by Steve Firth
Umm no. What you are describing is a low explosive such as gunpowder. High
explosives such as nitroglycerine

FWIW, yesterday's announcements by the authorities specifically cited
hydrogen peroxide as part of the bomb-making gear found.

[Steve Firth]

Post by lomcovak
FWIW, yesterday's announcements by the authorities specifically cited
hydrogen peroxide as part of the bomb-making gear found.

That confirms my suspicion on the nature of the explosive, probably MEPK.
Although I don't know why one would try to synthesise it, since it can be
bought over the counter fairly easily.

[Graeme Wall]

Post by David Newman
I'm puzzled. I thought that most explosives will just burn harmlessly,
unless you detonate them inside a strong casing. It is the casing that
allows the pressure to build up until it shatters, producing a high
pressure blast that can cause damage.

No, the casing is usually to protect the contents until the point of delivery
where it then performs the secondary function of enhancing the damage of the
blast, usually by forming shrapnel.

Post by David Newman
But the X-ray screening of hand baggage will pick up large strong metal
casings. Wouldn't that mean that bombers would, at best, be able to
improvise a small firebomb from their smuggled nitroglycerin, TNT or
whatever? So how could that cause the aeroplane to crash? I haven't
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

I believe the bomb that destroyed the Pan Am aircraft at Lockerby contained
about a pound of explosive inside a transistor radio (or similar) casing

[Simon Hobson]

Post by David Newman
I haven't

Post by David Newman
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

I believe the bomb that destroyed the Pan Am aircraft at Lockerby contained
about a pound of explosive inside a transistor radio (or similar) casing

IIRC, there was a documentary about it on TV a while ago, and they were
explaining that part of the aircraft design helped the bombers.

In short, the initial explosion didn't actually breach the hull, instead a
pressure wave travelled around the inside of the skin until it met something
that stopped it - the floor. At this point, the pressure rose sharply, the
hull was breached, peeled apart, and you know the result.

Since then there's been work on removing such barriers to allow the shockwave
to continue for longer and get dissipated by friction - amongst other
measures of course.


In many explosions, the initial expansion itself isn't a problem, it's only
after the pressure wave has travelled a distance an formed a front or it
comes up against some form of containment does it get really bad. I knew
someone who had a leaky cooker, woke early one morning with a smell of gas,
and set off across the kitchen to turn off the gas. He was nearly there when
the timer for the heating turned on and he heard & felt a 'whoosh' go past.
It took off all his hair (including wiskers and eyebrows) but otherwise it
only just managed to knock him to the ground - but it did bow out the walls
of the house !

[Eeyore]

Post by Simon Hobson

Post by David Newman
I haven't

Post by David Newman
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

I believe the bomb that destroyed the Pan Am aircraft at Lockerby contained
about a pound of explosive inside a transistor radio (or similar) casing

IIRC, there was a documentary about it on TV a while ago, and they were
explaining that part of the aircraft design helped the bombers.
In short, the initial explosion didn't actually breach the hull, instead a
pressure wave travelled around the inside of the skin until it met something
that stopped it - the floor. At this point, the pressure rose sharply, the
hull was breached, peeled apart, and you know the result.
Since then there's been work on removing such barriers to allow the shockwave
to continue for longer and get dissipated by friction - amongst other
measures of course.

An improved baggage container has already been developed ( and tested to show it
works ) that attenuates the shock front but nobody want to pay for it.

Graham

[David Cartwright]

Post by David Newman
But the X-ray screening of hand baggage will pick up large strong metal
casings. Wouldn't that mean that bombers would, at best, be able to
improvise a small firebomb from their smuggled nitroglycerin, TNT or
whatever? So how could that cause the aeroplane to crash? I haven't
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

An explosion is merely something burning fast. In my time working for a
defence contractor I worked on plenty of projects involved with making small
things (e.g. 20mm shells) go bang, and believe me, just because something's
small doesn't mean it can't wreak havoc.

Additionally, I suspect that having plenty of air around the explosive
device, and putting it all in a sealed tube (an aircraft) would amplify the
explosion. Fill a glass bottle to the brim with lemonade and drop it on a
concrete floor, and it'll go splat. Leave a half-inch gap at the top and
drop it, and you'll have an immense bang and absolute carnage. Now I'm not
versed in the physics of it all, but presumably it's because the gas is
given the opportunity to expand massively, as would happen when heating the
air in a fuselage.

Whether you could crash an aircraft by using explosives to sever the control
lines, hydraulics, etc, is an interesting question, since many systems have
multiple redundancy. My suspicion would be that the main hazard would be an
explosion causing sufficient damage to the structural integrity of the
aircraft so that (e.g. the fuselage doesn't have sufficient rigidity to
remain straight).

And even if it doesn't go bang, burning intensely would be a useful concept
to a terrorist. The company I worked for used to make "illuminant" mortars -
fire one in the air and it releases a flare on a parachute so you can see
who you're shooting at. From half a mile away, you could hear those things
sizzling - we're talking long-range roast pigeon. Remember that one of the
reasons put forward for the collapse of the World Trade Center was that the
intensity of the fire melted crucial support structures, causing their
separation and the collapse of the buildings; deform an aircraft
sufficiently and I suspect you'd get a similarly disastrous effect, as has
been exemplified by videos of water-bombing aircraft that have flown too low
when trying to extinguish forest fires.

David C

[lomcovak]

David Newman wrote:

There seem to be new developments:

<http://www.weeklyworldinquisitor.com>

[Peter]

Post by lomcovak
<http://www.weeklyworldinquisitor.com>

Very funny :)

On funny subjects, I found the juxtaposition of some of the reporting
on that airliner where the woman went berserk, which got escorted by
F16s to some U.S. airfield, quite funny:

She was tied up, had a jar of vaseline, and sniffer dogs were used :)

[M***@blueyonder.co.uk]

On Wed, 16 Aug 2006 00:43:14 GMT, David Newman

Post by David Newman
But the X-ray screening of hand baggage will pick up large strong metal
casings. Wouldn't that mean that bombers would, at best, be able to
improvise a small firebomb from their smuggled nitroglycerin, TNT or
whatever? So how could that cause the aeroplane to crash? I haven't
heard any explanation of how a strong enough blast could be produced to
structurally damage the skin or the control lines of the aircraft enough
to make it unflyable.

On a slightly different note regarding hand baggage I am prescribed a
liquid spray which is wholly made from nitro or contains nitro for use
during an angina attack and I know for a fact that this stuff does go
up with a bang if heat is applied to it been there done that:)).
So as it is a prescribed medicine would myself or more importantly
would a potential terrorist be allowed on to a plane carrying the
stuff I am sure there must be terrorist who suffer from angina!!.

[David Cartwright]

Post by M***@blueyonder.co.uk
On a slightly different note regarding hand baggage I am prescribed a
liquid spray which is wholly made from nitro or contains nitro for use
during an angina attack and I know for a fact that this stuff does go
up with a bang if heat is applied to it been there done that:)).

Yup - the label probably says something like "GTN", or "Glycerol
trinitrate" - nitroglycerine, in other words.

Post by M***@blueyonder.co.uk
So as it is a prescribed medicine would myself or more importantly
would a potential terrorist be allowed on to a plane carrying the
stuff I am sure there must be terrorist who suffer from angina!!.

There is, however, a far more entertaining use for GTN (see
http://www.patient.co.uk/showdoc/23069071/ if you're interested) - in this
case applied as an ointment for anal fissures (tears/scratches in your
sphincter). It gets better still, though, when you note one of the known
side effects of GTN cream - namely that it gives you a throbbing headache.

So if you get a sudden urge to blow up the plane you're on, and those pesky
security people wouldn't let you take your grenade on board, step one in
your search for raw materials is to look for the guy fidgeting in his seat
and popping headache pills.

David C

[Greg]

Post by David Cartwright
There is, however, a far more entertaining use for GTN (see
http://www.patient.co.uk/showdoc/23069071/ if you're interested) - in this
case applied as an ointment for anal fissures (tears/scratches in your
sphincter). It gets better still, though, when you note one of the known
side effects of GTN cream - namely that it gives you a throbbing headache.

Now I can't help but wonder how they discovered that the cure for a sore bum
is to insert nitro-glycerine...

Greg

[Umgall]

...or that the active ingredient in Preparation-H is "extract of shark's
liver". Was someone just walking along a beach with an arse full of piles,
when he saw a dead shark washed up on the shingle? "I know, I'll rip out
its liver and smear it on my hoop!"

Post by Greg
Now I can't help but wonder how they discovered that the cure for a sore bum
is to insert nitro-glycerine...

[Peter Twydell]

Post by Greg

Post by David Cartwright
There is, however, a far more entertaining use for GTN (see
http://www.patient.co.uk/showdoc/23069071/ if you're interested) - in this
case applied as an ointment for anal fissures (tears/scratches in your
sphincter). It gets better still, though, when you note one of the known
side effects of GTN cream - namely that it gives you a throbbing headache.

Now I can't help but wonder how they discovered that the cure for a sore bum
is to insert nitro-glycerine...
Greg

The world's biggest manufacturer of suppositories* is called Squibb**,
so it sounds like there have been some pretty bizarre experiments.







* Maybe not now, but they were several years ago
** I know there's only 1 b in squib