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Heathrow scraps liquid container limit

bbc.com

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Re: Heathrow scraps liquid container limit

#241

Post by Fervicus »

closewith wrote: post #192
bruce511 wrote: post #147

Earlier quoted context omitted.

To answer the parent question, no not even close. TSA direct costs, passenger time wasted, flights missed, items confiscated. All so no bombs on planes. But somehow also no bombs at sports events or music concerts, or on trains or subways, or courthouses or.... So the TSA is either stunningly successful or a complete waste. I'd argue a complete waste, but hey, everyone in a TSA uniform drawing a paycheck us entitled…

> But somehow also no bombs at sports events or music concerts, or on trains or subways, or courthouses or.... Boston marathon? The Madrid train bombings? 7/7? Ariana Grande? Airport security has been stunningly successful.

But we don't have intense security checks at concerts, trains, or at marathon events as a result, do we?

Re: Heathrow scraps liquid container limit

#242

Post by alibarber »

lmm wrote: post #95
PcChip wrote: post #78

Earlier quoted context omitted.

How did they force you to do that?

Anything a border official says is implicitly backed with the threat of, at a minimum, detention without trial and without basic humane treatment like access to drinking water. Heathrow has well publicised cases (and is not unusual in this).

It's probably much more boring. The choice was likely between leaving the whole water bottle and its contents in a bin of forbidden/discarded items, going home and missing the flight, or chugging it, or arranging a courier for said bottle.

Probably the act of defiance of pouring the contents onto the floor where there was no drain was implied to be disruptive and would have lead to harsher sanction for no reasonable payoff.

Re: Heathrow scraps liquid container limit

#243

Post by littlecranky67 »

jandrewrogers wrote: post #185
wyldfire wrote: post #128

Earlier quoted context omitted.

Here's an article that talks about Dual-energy CT [1]. And another one talking about material discrimination using DECT [2]. [1] https://en.wikipedia.org/wiki/Spectral_imaging_(radiography) [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC2719491/

Neither of those articles seem to support the idea that you can do molecular analysis with x-rays. They are all about elemental analysis, which is not useful for the purpose of detecting explosives.

Not sure if they use dual-energy x-ray as in [0], but you don't need to if you take x-ray shot from different angles. Modern 3D reconstruction algorithms you can detect shape and volume of an object and estimate the material density through its absorption rate. A 100ml liquid explosive in a container will be distinguishable from water (or pepsi) by material density, which can be estimate from volume and absorption rate.

https://en.wikipedia.org/wiki/Dual-energy_X-ray_absorptiomet...

Re: Heathrow scraps liquid container limit

#244

Post by FatalLogic »

necovek wrote: post #64
nlawalker wrote: post #15

Let me get this straight. If the article is correct, the new capabilities are related to better detection of large liquid containers, not determination of whether or not the liquid is dangerous. So - you couldn’t take large amounts of liquids previously because some liquids in large amounts might be able to be weaponized. If you were caught with too much liquid (in sum total, or in containers that are too large) they…

It's not just large amounts of liquids: it was my understanding that this is both a restriction on large amounts of liquid, but particularly on large containers needed for an explosive of sufficient destructive power. You could always easily work around the liquid amount restriction (multiple containers over multiple people), but if you still need a large container, it becomes harder. I don't know if this is true or…

>particularly on large containers

It's common for people to carry large metal equipment cases (for cameras, etc.) onboard

Re: Heathrow scraps liquid container limit

#245

Post by fc417fc802 »

reeredfdfdf wrote: post #187
closewith wrote: post #167

Earlier quoted context omitted.

> they don't stop bombings (there are much better targets for that, which don't involve killing the bomber), I think you should read: https://en.wikipedia.org/wiki/Timeline_of_airliner_bombing_a... The only reason you believe aircraft bombings aren't being stopped is because you live in a world where rigourous security has stopped all aircraft bombings.

Yeah. The "security theater" absolutely does play its part in stopping attacks. Without it, airplanes would be an extremely easy target for any nutjob to commit mass murder in. They wouldn't even necessarily need a bomb, anything that can cause a big enough fire mid-flight could be potentially catastrophic. Over past few decades many airliners have crashed because out of control fire in the cabin / cargo hold. I real…

> Without it, airplanes would be an extremely easy target for any nutjob to commit mass murder in.

They still are, but I'm not comfortable spelling out details. The 95% TSA failure rate should lead you to this conclusion naturally.

> They wouldn't even necessarily need a bomb, anything that can cause a big enough fire mid-flight could be potentially catastrophic.

People have plenty of such things with them as it currently stands. Plenty more can be trivially brought on board in a checked bag or even pocket. But again I'm not going to spell it out.

> I really don't want it to be easy for any random person to cause such fire.

Well that's unfortunate because it already is. I think the primary things protecting passengers are the cost of entry (the true nutjobs don't tend to be doing so well financially) and the passengers themselves. Regarding the latter, the shoe bomber was subdued by his fellow passengers.

Re: Heathrow scraps liquid container limit

#246

Post by lagniappe »

Fervicus wrote: post #241
closewith wrote: post #192

Earlier quoted context omitted.

> But somehow also no bombs at sports events or music concerts, or on trains or subways, or courthouses or.... Boston marathon? The Madrid train bombings? 7/7? Ariana Grande? Airport security has been stunningly successful.

But we don't have intense security checks at concerts, trains, or at marathon events as a result, do we?

I don't know where you live, but where I live, we do.

Re: Heathrow scraps liquid container limit

#247

Post by don_esteban »

jandrewrogers wrote: post #185
wyldfire wrote: post #128

Earlier quoted context omitted.

Here's an article that talks about Dual-energy CT [1]. And another one talking about material discrimination using DECT [2]. [1] https://en.wikipedia.org/wiki/Spectral_imaging_(radiography) [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC2719491/

Neither of those articles seem to support the idea that you can do molecular analysis with x-rays. They are all about elemental analysis, which is not useful for the purpose of detecting explosives.

Hm, isn't it enough to just detect water and flag everything else as suspicious?

If your liquid is 80%+ water (that covers all juices and soft drinks), it is not going to be an explosive, too much thermal ballast.

Re: Heathrow scraps liquid container limit

#248

Post by fc417fc802 »

throwaway290 wrote: post #211
bruce511 wrote: post #140

Earlier quoted context omitted.

You gotta love the TSA. They serve no real purpose, but its a monster too big to kill, staffed by people who desperately cling to the notion they're doing something important. They don't stop hijackings (locking the cockpit door does that), they don't stop bombings (there are much better targets for that, which don't involve killing the bomber), they don't stop weapons (lots of airports outside the US have simple met…

> they don't stop weapons (lots of airports outside the US have simple metal detectors for that.) There are 3D printed guns.

Those tend to have extremely limited usefulness. Good enough to assassinate a single person at point blank range before they catastrophically fail but (unless something has changed) not much else. Plastic just isn't cut out for the job.

Re: Heathrow scraps liquid container limit

#249

Post by davedx »

jandrewrogers wrote: post #71

This just adds confusion as to the purpose of all this. The motivation behind the liquid limits is that there are extremely powerful explosives that are stable water-like liquids. Average people have never heard of them because they aren’t in popular lore. There has never been an industrial or military use, solids are simpler. Nonetheless, these explosives are easily accessible to a knowledgeable chemist like me. The…

On one hand, I think it's a valid criticism to say it's security theatre, to a degree. After 9/11, something had to be done, fast!, and we're still living with the after effects of that.

On the other hand: defence in depth. No security screening is perfect. Plastic guns can get through metal detectors but we still use them. Pat downs at nightclubs won't catch a razor blade concealed in someone's bra. We try to catch more common dangerous items with the knowledge that there's a long tail of things that could get through. There's nothing really new there, I don't think?

Re: Heathrow scraps liquid container limit

#250

Post by fc417fc802 »

edm0nd wrote: post #87
jandrewrogers wrote: post #71

This just adds confusion as to the purpose of all this. The motivation behind the liquid limits is that there are extremely powerful explosives that are stable water-like liquids. Average people have never heard of them because they aren’t in popular lore. There has never been an industrial or military use, solids are simpler. Nonetheless, these explosives are easily accessible to a knowledgeable chemist like me. The…

Correct. In the US, the TSA is just a government jobs program for the lowly skilled or unskilled. It's all security theater. TSA Chief Out After Agents Fail 95 Percent of Airport Breach Tests "In one case, an alarm sounded, but even during a pat-down, the screening officer failed to detect a fake plastic explosive taped to an undercover agent's back. In all, so-called "Red Teams" of Homeland Security agents posing as…

I find it interesting to contrast this with my experience flying out of China. I was taken to a private room and shown the digital colored X-ray of my bag on which a box had been drawn around an empty lighter, I was asked to remove it myself and hand it over, and I went on my way. All in under 5 minutes, no pat down, no fuss, and no one physically rifled through my belongings. (Granted I was a tourist so that might well not be typical.)

I'm not sure what their success rate is when tested by professionals but the experience definitely left me wondering WTF the deal with the TSA is.

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