Contrary to popular belief, it is perfectly legal to carry a folding pocketknife through airport security in the United States. Federal Aviation Administration (FAA) regulations state simply that pocketknives with blades of longer than 4 inches must be transported in checked baggage. The FAA also states that Alaskan Ulu knives of any size may not be passenger-carried.

The FAA has set a minimum standard and individual airlines are free to implement stricter standards if they so choose. Generally, you should contact your airline before attempting to fly with a questionable pocketknife to inquire about their guidelines. With that warning, here are the most common guidelines followed by US airlines today:

  • Blades must be no longer than 4 inches (some airlines specify a 3-inch maximum).
  • Blades must not be serrated.
  • Some airlines ban knives with black colored blades on the grounds that these knives are menacing.

Recently, ceramic knives have become all the rage with the crowd of people who like to carry knives covertly. There are several major knife companies (Boker, for instance) that manufacture folding pocketknives with ceramic blades and non-metallic handles (usually plastic) that could theoretically make it through airport security undetected. This is probably not a good thing to try however, since most of these knives may contain enough metal in the bolt and locking mechanism to be detected, and if you are detected with a "stealth" knife of this sort you will most likely have a few questions to answer.

From personal past experience, ceramic knives will easily get through airport security if they're non-folding and do not use metallic rivets. I used to carry a ceramic boot knife when I was in Thailand, and I was so used to wearing it, I left it on when I flew from Bangkok to Singapore. I was wearing Doc Martens with the steel tips. When I went through the metal detector, it lit up like a Christmas tree. I pointed at my boots, they nodded and swept me with a hand-held metal detector. It was only after I was sitting in my seat when I realized that I was wearing that knife. I left it in my boot, since I figured it would be easier to spot in my carry-on luggage.

If that wasn't stupid enough, I wore it when I went back to Thailand. Unfortunately, I chipped the blade when I dropped it off of my 12th story balcony, so I didn't get the chance to test it out on the US metal detectors.

Oh, that reminds me. Metal detectors do not detect a duffle bag full of fireworks. I bought a bunch in Tennessee, and when I flew to New York, I discovered that my bag full of clothes was actually full of fireworks. I had snagged the wrong bag... that could have been an ugly scene. I figure I've used up my nine lives when it comes to air travel.

I worked as the IT Manager for Aviation Security Service (abbreviated to AvSec, as the acronym isn't that flash) in bonnie New Zealand for a couple of years. It is their role to pass all luggage through an x-ray unit, and search passengers setting off the metal detector you walk through when leaving the country. There are also several other roles they perform (regular searching of aircraft for explosives and weapons, ground security, etc).

Each of the main international airports has display cabinets in the AvSec offices of confiscated dangerous items. You would be astounded at the items people try to carry aboard an international flight - many of which are covert weapons, designed specifically for the "protection" of the holder.

Such items include:

So it is for this reason that in the storeroom where I kept computer bits there was always a large supply of rubber gloves for the security workers. The next time you consider attempting to get through an airport security stop with a weapon onboard, try practising bending over and touching your toes with your pants around your ankles first...

I carry a Spyderco Delica, a folding pocketknife which has about a 3" blade, but is serrated, has one hand opening thanx to the thumbhole, and basically looks mean as hell.

I've travelled quite a bit the last few years, and I carry my knife with me out of habit, since I wear it everyday. When I don't wear it, I find myself slapping my right hip a good bit, which is a kind of nervous tic the habitual Spyderco user finds himself developing.

The inevitable happens, which is I forget I'm wearing it, and walk right onto the aircraft. When I land, I realize that I made it through, most likely due to the low ferrous content of the stainless steel blade and plastic handle. So I wear through on the return flight, without a hitch.

This is until I encounter the brand spanking new metal detector at the Columbus, Ohio airport. I set it off like a pinball machine, where the very zelous and motivated security personnel quickly locate it with a wand. I have to leave it at the customer service desk. Luckily, I was only picking someone up, or I'd have been S.O.L..

Living in LA now, where I would describe the equipment as somewhat sophisticated and the people as wholly unmotivated, I unclip and tuck it into the cellphone pocket of my carryon bag, so that it's sandwiched between the LIon battery of my phone and laptop. Both batts are radio-opaque, so this works out. I guess this might be foiled by a 3-d cat imaging xray machines like the one at CHI, but otherwise I'm good-to-go.

UPDATE: 9.13.2001

No more knives on planes. Not mine, not anyone's. If I see you with a knife on a plane, I'm going for your windpipe. I don't want to possibly provide a knife to someone on board - I don't want to figure out how to get through the new security, and if I do, I'm sure not going to post it on the internet. I'm serious - if I see you on a plane with me, and you're carrying a knife, I will seek to disable you first and ask questions later. Maybe this is chest thumping, locking the gate after the horse has run, but it's my position now. I leave the above as a demonstration of how we got into this mess in the first place.

This info. is slightly outdated; I stopped working at this airport about a month before Sept. 11, so I dunno how the laws have changed since then, except that knives are now a total no-no.

I work at an airport. I'm not going to say which one, for reasons that will become obvious. We get our fair share of stuff coming through the mag (walk-through magnetic metal detector) and the X-ray (three guesses what that is); so far, we've had a pretty good record safety-wise.
We are trained to look for bombs, guns, knives, opaque items (i.e. big thick metal stuff, lots of batteries on top of each other, leaded-crystal items -- we can't see behind these, and so they need to come out so we can look past where they were with the X...) and glass bottles (can you say Molotov cocktail?)

However, in the six months that I've worked there, I've figured out how to carry an entire bomb past security without any problems.

The first thing to know is this: don't put any of the stuff I mentioned in the second paragraph in your bag or we will have to get into it, and then you're screwed. If you put a bottle in, we will have to check it; if you have a laptop (rather thick, but OK) with a lot of batteries sitting on top of it and a military beer coin in a pocket above that, you're gonna get checked.

That said, I'll move on to the meat of the essay. There are five elements to a bomb: the timer (slightly optional if you're the suicidal type), the detonator, the explosive, and the wires and battery (for the detonator and timer).
Timers can be easily constructed from an analog clock with electrically conductive metal hands: drill holes in the face and side that correspond with the required position of the hour and minute hands, respectively, and insert wires into them in such a way that the hands complete an electrical circuit when they touch the wires. The X-ray operator will not have your bag checked as long as you have the clock by itself without any other components near/attached to it.

The detonator cannot, to my knowledge, be made by hand; you must purchase a real one. Fortunately, it's easy to get past security: just get a pair of cowboy boots (or any boot/shoe that's hard to get off and has a metal shank), place the detonator inside, on the bottom, and put your foot on top of it. You _will_ set it off; allow the security people to wand you down (wand: handheld metal detector), when they get to your boots, the wand will beep. Make a rueful face and say something to the effect of "Oh, it's the shanks in my boots." They might have to squeeze around your ankles to ensure you aren't wearing a knife or gun in a boot holster, but will let you go.

The explosive is a bit more difficult; you'll need to be careful. The key is not to let anything that touches the explosive touch the bag or anything inside the bag. The best way I know of to accomplish this is to use plastic explosives:
Wearing two pairs of disposable plastic gloves over rubber gloves, mold the plastic into small (golf-sized) balls. Take off one pair of gloves. Using some type of gripper (scissors, pliers, what have you) carefully pick up the balls and put them into baby-food jars.1 Be extremely careful not to let them touch anywhere near the rim of the jar; imagine that they are made of acid and you don't want it to melt the other things in your bag. Squish them down flat so they fill the jar completely; no air spaces at all. You want to present a solid object to the X-ray operator. Take off the second pair of plastic gloves. Screw the lid of the baby-food jar on with your off hand (left if you're a righty, vice versa) then hold it with that hand and get a plastic bag with the other. Holding the bag as wide-open as you can with your good hand (right if you're righty etc.), put the jar as far inside the bag as possible without touching the bag with your off hand. Then withdraw that hand slowly and pull the bag upward with your good hand, sliding the jar to the bottom. Remove the last set of gloves, then tie the bag shut, making sure that there's no holes or cracks in it anywhere. You don't even want to squeeze it to let the air out. Put it in the middle of a wet, dirty, diaper bag, and they won't even run a random test on it because it's very easy to get a false positive with dirt/water etc.

Whew, that was exhausting! Now for an encore, the wires and battery: these should be easy. A cell phone battery ("A spare, just in case I run out...") and the wires for a power adapter should be sufficient. No problem there; even I would let somebody through with those.

Well, that about wraps it up for "Sneaking A Bomb Through the Airport Security"...
until next time, this is Bathail Klenath saying "That'll make a nice front-page blowup!"

1Why baby-food jars? Because we're only required to check glass bottles that look like they're for alcohol i.e. wine bottles, burbon bottles; also metal hip flasks. Another thing not to have in your bag...

A word for those who wish to carry knives through BWI Airport, since Baltimore is to the rest of the world as peanuts are to gravy:

I often end up driving to BWI to pick up a certain E2 noder from the airport - just me, Elwood, his girlfriend, and her spyderco pocketknife. Our mission: to get safely past security without having to surrender any of our possessions or bend over and cough.

Q. Why is it such a hassel?
A. Because if you are caught with a knife that is unallowable, you have two options: either leave the airport immediately (under your own power or no), or Throw Your Knife Away! They do NOT hold, or allow you to go back and check items. You can't leave them at a service desk. There are no luggage lockers. So, basically, if you don't get your knife through, you're SOL.

Here is how to tell if your knife will hack it in Bawlmer:

1. If the blade of your knife is longer than 3.5 inches(8.89 centimeters), forget it. The security personnel at BWI carry ruled plastic cards exactly 3.5 inches long, with which they measure the blade of your knife - if the knife is longer than the card, you do not pass go, do not collect $200.

2. If your knife is double-bladed, leave it at home - they don't even measure those, they just kick you to the curb. P.S. Double bladed knives of any length are illegal to carry in Maryland (everything's a crime in Maryland!), so good luck if you're caught concealing one of these.

3. If your knife is a single-bladed, 3.5" or under in length, go ahead and carry it - provided that you're traveling during the day. If you're going at night, the security is tighter, and you won't get through. ( I know it makes no sense, but that's how they are.)

4. Oddly, they don't care if the blade is serrated.

5. Don't forget to show security the knife when the mag goes off Before you tell them that it's just your belt, which is made from a seat belt and very difficult to remove, and to just wand you. Oh, yeah, and don't make this mistake when your ride, who is going goth clubbing later, is lurking about wearing a black lace sheath, knee high boots, and wet n'wild 508 lipstick.

Jedi mind tricks, however, have not been tried.

As ZenZagg points out in his (her?) node on this subject, BWI security is, generally speaking, kinda lame. But they're uptight about knives: I guess it's much easier to say "Knife! Bad!" than to actually ponder what could be built out of all that stuff. It's on par with their 'Terrorists only fly at night' theory.

Update: After mulling it over, I've decided to leave the content of my inital write-up for this node intact, although I wanted to delete it after September 11, 2001, since I figured it would no longer be accurate. However, I'm going to leave it up for now, to remind myself and anybody who comes across it just how lax airport security used to be, which was really the point of this node all along. But now I have this to it or not, you can kill someone with just about anything, if you put your mind to it. Although I'm totally in favor of tightening airport security, taking away everything that might be used to hijack a plane is pointless, because someone will always be able to think of something new. The only real thing we can do to stop it, is follow igloowhite's example, and take down anybody foolish enough to try.

Update: This node is now a little creepy when you think of what happened Sept. 11, 2001, seeing that this was originally made Jun 13 2001. If I could get a 6-inch serrated blade through, in my CARRY-ON luggage, then what's stopping a box-cutter from getting through?

A few summers ago I visted a friend who lives in Pennsylvania for two weeks. It was a round trip flight from ATL to BWI and back. Having recently completed Revision B of the WaffleBox, I decided to bring it, along with my electronics scrap box (the significance of this will come later) and a few choice gadgets to keep me from succombing to boredom in the wonderful town of York,PA.

From my experience, airport security is fairly poor. For example, my carry-on luggage contained:

  • One (1) 2500 degree butane lighter with 4oz. fuel capacity (full).
  • One (1) Portable handheld color TV with headphones (those 'air phones' eartubes things just dont cut it.)
  • One (1) Sharpened, 4-point, heavy, stainless steel shiruken *gleam*. (great conversation piece with my seat mate, "They let you come on with THAT?")
  • One (1) Large, analog multimeter.
  • Several (2-5) Screwdrivers of various styles. (this is all still carry-on, folks)
  • One (1) Large Swiss Army knife.
  • One (1) WaffleBox, which has several metal toggle switches, a flashing orange light, several high voltage capacitors, 4 batteries, and it basically looks like a Hollywood bomb...not to mention that at 350v@several amps it could also function as a detonator.
  • My electronics scrap box, which contrains spools of wire, 20 high voltage capacitors (all stacked together) various circuit boards, wires, mercury switches, regular switches, flash bulbs, a soldering iron, speakers, bits of odd shaped metal, and tons of other random electrical objects, all compacted into a relatively small cardboard box.
  • Some clothes. *yawn*

I carried this stuff through both Atlanta and Baltimore's airports, with nary a hitch. It went through X-Ray each time and God only knows what they saw in there. I'm not sure how strict BWI's policies on knives are, but you'd think either Atlanta or Baltimore (or both) would have checked my luggage which was seething with potential destruction. I was let on with a smile, with everything I needed to assemble whatever I wanted on the plane. Just something to think about...especially in the light of the recent rise in terrorism. Those security measures are only as good as the humans behind the screens, you know.

Airports aren't the only place you have to deal with security and metal detectors.

I have on my key chain a knife I use to open all the boxes I get in the mail at work containing cool computer parts. This knife is one of those imitation miniature swiss army knives that they pass out at conventions with somebody's logo on it that rubs off in a few weeks if you carry it all the time.

Anyway, this knife is not nearly quite as sharp as your average dull letter opener, and about two inches long (the case, the blade is shorter). It does a good job on cellophane tape, though.

Anyway, I got called on jury duty. They had installed metal detectors at the courthouse about a year earlier because an annoyed defendant decided that the judge and lots of other people deserved the contents of his gun after the jury convicted him.

The first day, anticipating a long boring day in the waiting room, I brought a bag full of books to study, and for some reason dumped my keys in with the books. The whole thing went through the X-ray machine when I came in, when I went out for lunch, when I came back for lunch, etc... Towards the end of the first day, I was put on a panel and then actually selected for a jury.

So, the second day, I came without the book bag. I go through the metal detector, without emptying my pockets, since my wallet full of change hadn't set it off the previous day. BEEEP BEEP BEEP!! Ho boy. I get converged on by three bailiffs, for whom this obviously was the high point of their day. No, silently walking through the detector without my keys wasn't good enough. Out come the wands, one each. Meanwhile, here I am, emptying my pockets (a little late) into their basket. Of course, the wands show nothing. But then they see the stupid two inch knife on my key ring that would bend and break if I tried to cut myself with it. Boy did they freak!! You'd think I brought in a machine gun or something. For a moment there, I thought they were going to cuff me or something. I was a juror, not a suspect!! I had even brought it in (through the x-ray machine) repeatedly the day before.

Anyway, one of the bailiff's very reluctantly confiscated it (rather than destroying it or arresting me, which they would have liked better, I'm sure), and I got it back on my way home. Since then, I've always been extremely paranoid about what's on my key ring when I anticipate metal detectors.

I suppose this is nothing in comparison to the reaction my Uncle got when he accidently brought his tools of the trade into a court house to pay a traffic ticket. (He worked for a meat packing plant. What he didn't give a second thought to was probably not close to street legal, let alone accepted in a court house.)

IMHO, the airports should have a vending machine full of prepaid mailing tubes right next to the metal detectors. If they find something they won't let you take, you should be able to pop it in a mailing tube, address it to yourself, and drop it in the mailbox next to the vending machine. No fuss, no loss. It would make everyone happy, and probably give the airport a few more pennies.

2004 update: I saw an article in the paper that someone is now doing exactly this. Vending machine full of postage pre-paid padded envelopes next to the metal detector. Hmmf. And they didn't even give me credit.

Back when I worked as a passenger agent at Cardiff-Wales International Airport, September 11th was still somewhat fresh in people's minds (and here we are now a week from the third anniversary) and so we were very, very strict about what went into your cabin bags: no knives or stabbing weapons, but also bizarre things like:

  • hairdryers or similar electrical appliances - we were told this was because of the strangulation potential of the cord, but given your belt or shoelaces would do just as well, this restriction didn't last
  • nail clippers, for some unfathomable reason (although I did get myself a nice brand-new pair after someone handed them in to me)
  • metal nail files, for slightly more obvious reasons
  • gas-powered hair curlers, unless the only fuel cylinder was already inserted into the curlers
  • corkscrews and bottle openers
  • tools, such as screwdrivers, hammers and the like.

All fairly obvious things, with potential for harm. This also explains why virtually all airlines now give plastic cutlery to eat with (so cutting meat that's been a 'steak' far longer than it was a cow is doubly hard) and don't offer sewing kits. I took a few days off and took a flight out from Cardiff to stay with a friend in Glasgow. I brought my laptop.

Typical procedure is to make you turn it on (so it's not just a bomb in an empty casing) but they didn't care. On the flight back to Cardiff the security guy asked if he could inspect the contents of the back. I happily obliged, and as he rummaged through my mouse, power adaptor, I noticed the top pouch. Just visible was the corner of my (like ssd's) mini Swiss Army Knife/corkscrew/thingy from a Christmas cracker.

Somehow, the guy didn't see it, and I was on my way, shaken both by the risk I'd inadvertently run with a 'weapon' in my cabin bag both ways, but also that it had been missed twice despite being in an easily-accessible location. So many things struck me: how pointless confiscating nail files was, how poor security still was despite the terrorist attacks, and how if you were really determined you could get something truly dangerous onto a plane... when I was working and the guard called me over and pointed to the rather large power tool some woman had in her suitcase, clearly visible on the x-ray machine.

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