Loren Pechtel

If you can get weapons on board it's not a barrier. Linear shaped charge.

Loren Pechtel

Back in 2010 there was a report based on an attempt to reconstruct how the AIT scanners worked that made two predictions:

1) Metallic objects held away from the body would be undetected.

2) Explosives that were feathered on the edges would be undetected. The scanner can't see thickness, only edges. Deny them the edge.

Since that time we have seen #1 demonstrated against the real machines. I see no reason to think they weren't just as accurate with #2.

Bttc

Wait, we discussed this in another thread. An FA sits in when the copilot goes to the bathroom.

Loren Pechtel

It will alarm. The side approach is only for metal. That's where you hide the cap, the explosives go on your belly with the edges carefully feathered.

Agreed on both of these.

LarryJ

Thanks for the link. That discusses false positives, not false negatives. Obviously, you'd want to minimize false positives, as they result in unnecessary procedures to resolve the alarm, but false negatives are the bigger problem.

You might remember that the MMW AIT scanners were originally read by an operator in a remote room instead of by the automated software. At the time, one European country (Denmark?) was already using the automated software and there was a good bit of criticism of the TSA for not using it as well. The software available at that time had a false-positive rate higher than the TSA would accept so they set them up with operators. Eventually, improved software lowered the false-positive rate and all MMW scanners have now been upgraded and the remote operators removed. I don't know which software was in use in the tests references by the article.

Your argument sounds like Clinton saying that the answer depends on what the definition of the word "is" is.

The AIT will alarm from concealed explosives. That meets the definition for detection.

de·tect/diˈtekt/
Verb: Discover or identify the presence or existence of.

By your definition the AITs, x-ray, and CTX scanners don't detect anything at all because none of them ever identify the substance that triggers an alarm. That would leave us with the WTMD and hand-searches of all carry-on and checked luggage.

There are no 100% foolproof security measures. There never will be. The doors are a big improvement over what we had before but only a fool would think that they make it impossible for a group of hijackers to take control of the airplane.

They do. You must always have two people in the cockpit in flight so that one can view the person requesting access through the peep-hole before the door is unlocked.

Wouldn't be hard for one pilot to overpower the other, though. The crash axe, which is required to be in each cockpit, would make it a rather lopsided battle.

Caradoc

Hardly. With that many false positives, a true positive gets lost in the signal-to-noise.

So you've got someone who goes through the AIT and it shows an "anomaly." The anomaly is resolved, and the search stops...

Keep in mind that we've seen multiple reports of "Red Team" efforts that succeeded by simply leaving a water bottle on top of everything in the bag. The TSA drones found the water bottle and stopped looking.

ANY system that provides false positives creates such a problem, on top of the massive waste of time and money involved in simply resolving the "true" false positives.

The body scanners are a boondoggle, with the twin purposes of enriching the manufacturers and providing the illusion that people are safer as a result of their use.

WillCAD

AIT will NOT "alarm from concealed explosives." It MIGHT alarm from SOME poorly-concealed explosives, but it will definitely not alarm from internally-carried explosives (rectally or swallowed), nor will it alarm to the presence of explosives concealed on the soles of the feet. Loren has stated that explosives with carefully feathered edges might also get through, and this seems plausible to me, though unproven AFAIK.

Baggage x-ray scanners with ATR actually do detect guns, though they're not, according to what I've read, setup to detect explosives (trace detection swabs and manual searches are relied on for those). Carry-on x-ray scanners don't even have ATR, so they don't detect anything, either; it's the operator who detects things, by looking at the image on the scanner screen.

WTMDs definitely detect the presence of metal. That is a definite. They identify it as metal. They don't identify which metal, and they don't localize the position of the metal; that must be done with either a manual search or a HHMD. HHMDs will not only detect the presence of metal, but will localize it and tell you exactly where it is on the body.

Even ETD can't actually detect explosives; it merely detects the presence of trace amounts of specific chemicals, which are components of common explosives. In other words, a positive on an ETD test means, "This person has been exposed to glycerine"; whether that glycerine was a component of explosives or a component of hand soap doesn't matter. To determine whether explosives are actually present, the ETD operator conducts a physical search of the person who tested positive for glycerine. Ditto for all of the other chemicals that ETD tests for.

"That would leave us with the WTMD and hand-searches of all carry-on and checked luggage."

DUH. That's exactly what we want! The rest of it is a bunch of smoke and mirrors that does little or nothing to make us any safer or catch bad guys, while actively sucking money and resouces away from equipment and methodologies that might actually have some positive impact on security.

Now, truthfully, I do support the use of ETD technology, including the portals (if they could ever make the darn things work reliably in an airport environment). It's a non-invasive methodology that, while not perfect, is effective when used by properly trained personnel and adds genuine benefit to the process.

AIT, on the other hand, is worse than useless.

exilencfc

Actually I think you can get non metallic detonators, one of the problems bomb detection teams are having in Afghanistan is the Taliban making metal free bombs.

Pesky Monkey

Great, are those really a problem here?

VelvetJones

Wow, that will work. I'm sure the 90 pound FA sitting in would really carry her own against some deranged captain. The whole scenario is ridiculous, but putting a FA in a position to guard the plane is even more ludicrous(Yes, I know not ALL FAs are 90 pounds women. The one on my recent Southwest flight looked like a MMA fighter who could bench 400 pounds. Odd career choice he made).

Pesky Monkey

What airline are you flying where the flight attendants are 90lbs? Sign me up!

RadioGirl

Netherlands (AMS). I saw it in use in ~Feb 2010.
In all likelihood neither you nor I will ever know, but I would bet $4700 that the software being used by TSA today is exactly the same software being used in AMS a few years ago when TSA claimed that the false-positive rate was too high. The hardware for detection (MMW) hasn't changed in that time, and there's only so much that software can do with the output of the hardware. It wasn't that the software improved to meet TSA's standards for false-positive (look at the reports of false-positives using ATR even now), but they were catching so much grief about the pervy booths that they had to do something.

As I say, we will probably never know, but that's my (informed) guess.