I've been lurking here for most of this year, but haven't had anything to really add to the discussion.. I'm new at the game, but flying regularly, so I've been learning a lot in anticipation of being among the elite, like the rest of y'all.

However, I have seen something that I'm really curious about, and was curious if more enlightened minds had an idea.

Recently, while waiting in SFO for a United flight, I was chatting with an elderly gentleman, who mentioned a strange device at the security checkpoint. Basically, he said that they ran a white cloth pad across the handles and zippers of his carry-on, and put it into a machine. He said that the security people told him that "Each person has individually different sweat, and we're checking to make sure no one else has been handling your baggage, for security reasons." [now, I'm pretty sure that the technology exists, but I'm also pretty sure that doing this analysis takes a wee bit longer than the time you can afford to spend in the Security checkpoint]

A few weeks later, I was going through the security checkpoint, and my carry-on bag was taken from the x-ray machine rollers, and I was told that they were doing spot checks for security. The security lady ran what looked like one of those round cloth face cleanser pads across the handle and zipper of my carry-on, and fed it into a machine. I asked, and was told that it was an explosives detector. [Now, if I were lunatic enough, and I'm not, to put explosives in my carry-on, would I really rub them across the handles and zipper of my carry-on? I suspect not, but that's a side issue]

Now. Does anyone know what those things actually are, and what they're really checking? It doesn't really matter, but I'm curious as all get-out, and I don't ususally have time when I get to the airport to wander around, looking for supervisors to get an answer..

--Vird
(Almost up to 25k miles on United in the past two months!)

These devices have been around for a while, and have been discussed on FlyerTalk, see:

http://www.flyertalk.com/forum/Forum1/HTML/000589.html

They are detectors for explosives residue.

If an explosive device were in your bag, trace amounts of the explosive agent would likely still be around. They are most likely to come out through the airspace in the seam or through the zippers. (So they rub those areas.)

Also, the possibility is fairly high that the person who manufactured the device also handled the bag after the device was put together. (And they rub the handles).

It's not too hard to tell who they target with these detectors, if you encounter them often enough.

I usually travel with a college-looking bookbag, and it gets checked using this machine 8 out of 10 times...

The first time I saw the swab test was in PHX a year or two ago, and the security person said that it was a test for explosives (my readout said 0/500 or something like that), which I accepted and thought not much more about; but at BWI-UA gates, where one particular bag has been tested almost every time, the security person said it was for drugs. I've never been stopped at BWI-any other gates with this bag, which is kind of odd.

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Cheers
Michael *G

These "security" guards get paid around $6/hour. Due to the extremely low starting wage, chances are good that even they don't know what the machine does or what to do if the machine alerts! BTW, my source on the pay is the classified ad section of the Arizona Republic.

I have had my bag checked once using this procedure at JFK. The agent apologized over and over saying he was required to check every tenth person period!

I have been checked twice, and the explanation was that it was for explosives. iI think that it checks for the presence of nitrates.
FWIW, since it is for OUR safety, I don't mind one bit.

DD

No, don't get me wrong- I'm not complaining- I was just insanely curious. (yesterday, the guy in front of me was told that they were lifting prints to see if it had come in contact with known felons.)

My apologies for not having seen its mention in my search of the history- I must have been glazing over that far back!

--V

Vird,

Sorry, I did not take it as a complaint - just a comment.
Sometimes, when we are delayed due to a "mechanical problem" I get angry, frustrated, etc. until I remember that I would much rather fly a "good" plane than a "broke" one. I'm sure the pilots feel the same way (at least I hope so!).

DD

As someone previously noted, the device is specifically checking for traces of nitrates.

I've have had them check my carryon 2-3 times in the last few months. Guess I just look suspicious.

BTW, if you use/carry sublingual nitroglycerin tablets; these will sometimes set off the detector.