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Comment by waterlesscloud | Hacker News Reader

"Disable aircraft-integrated passenger communications systems and services (phone, internet access services, live television programming, global positioning systems) prior to boarding and during all phases of flight."

Because you can't blow up the plane if you don't know where you are.

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I think you're missing the point. The idea is to make it more difficult to stage an attack around a specific location, such as a heavily populated area or landmark.

I didn't notice anything requiring that window blinds must be closed though; it doesn't really seem to me that it would be too hard to just look out the window and figure it out.

Closing all the windows is dangerous because the pilots have no way of seeing the wings. If there was damage, gas leak, fire on the wing a passenger or flight attendant needs to see it and alert the pilots.

For example: http://www.af.mil/news/story.asp?id=123149266

It would be pretty easy to slip a gps antenna behind the shade before you closed it as well.

Personally, I find it impossible to even venture a guess as to what my location is just by looking out the window at cruising altitude. It becomes much easier during final descent, but it still requires familiarity with the location. In any case, an attacker will have nowhere near the precision provided by GPS.

Passengers, beyond curiosity, have very little use for GPS during a flight. When I'm on a plane I could really care less what my location is. I'm more concerned with how much longer I have to wait before arriving at my destination.

The parts of the security directive that bother me most are the restrictions on access to carry-on belongings and items on your lap and not being able to get up from the seat.

Maybe he'll just use a chronometer.

Actually, I believe that it's an FAA regulation that the window shades stay open on emergency exit doors. I've never been on a flight where the flight attendants allowed those shades to be closed (even partially).

Do those doors still have shades if they're never allowed to be closed?

All planes that I've ever been on have had shades, likely for the same reason that you still occasionally see ashtrays (although slightly different since they're usually screwed shut) on planes. The price to disable/retrofit simply isn't worth it to the airlines. Again, I'm not 100% sure that it's an FAA regulation - do we have any pilots/flight attendants on HN who could weigh in?

The regulation isn't applicable to the entire flight; it's perfectly ok to pull your blind down midway over the atlantic on a red-eye, for example.

Or just buy a ticket to a major area, figure out what the transit time will be, and pop the cork at T-5 minutes or something....

Airplanes have windows.

Also, I could write a computer program to use my cell phone's GPS receiver to activate an electronic device at a given location. (Hell, I do this to turn off my ringtone at work.)

Stuff that into the overhead compartment along with your bomb, and the plane is finished... at exactly the location you pre-program. (You don't even need to be on the plane. Put your bags in the overhead compartment, stuff some other bags in front of it, "oh shit, I forgot $foo in the terminal", done.)

Have you ever tried to leave a plane after boarding?

This isn't fool proof but the FAA policy that my dad experienced years ago was that the passenger was dissuaded from leaving, the captain came out, and he was told that if he exits the plane they have to sweep it and because of that he'd be denied reentry. Passenger insisted. Argued a bit.

Long story short, the passengers all had to disembark with their luggage and go back through security screening. And the flight crew presumably did their standard pre-boarding sweep.

This was, oh, 2002 or so. I wouldn't be surprised if they even let you off the plane anymore, at least not until the 3-hours are up that the new regs mandate.

And similarly, there has long been double-checks to make sure that no checked luggage is on a flight that isn't matched to a passenger. My understanding is that luggage that is freight checked (like, they lose your luggage and throw it on a later flight to get it to you) has to be more thoroughly screened.

About a year ago they let me board the wrong plane.

I was flying LAN, and the first leg of the flight, in the US, was operated by American Airlines. When I got to Miami for my connection to Peru, I showed my ticked to an AA employee at the gate and asked which gate the flight would leave. She pointed me to a nearby gate, I went there, waited about an hour, and boarded when they called everyone. They manually checked my ticket and gave me the stub back.

When I reached my seat there was someone already there. He showed me his ticked stub and he had the same seat number as I did. As I was cursing the airline for overbooking, we noticed his ticket was printed by AA, mine was by LAN. Since I had just flown with AA with a LAN ticket, I thought it was OK. The flight attendant returned after a while telling me that LAN and AA both had flights to Peru at that same time and my flight was actually leaving from a completely different terminal.

I had to run all the way across the airport, get a new ticket printed, go through security again to get to the right flight. Since my bags had been checked to the final destination, if the AA flight wasn't full and they hadn't sold the seat I had I might have never noticed the mistake.

For future reference, if you were being bumped from the flight (due to overbooking), you would never have been allowed on the plane. They don't just assign two people the same seat and hope that you two will resolve it on board the aircraft.

It is strange that the agents were not following the correct boarding procedure, which is to scan the barcode on your boarding pass and to ensure that the computer's idea of your seat assigument agrees with what's printed on the pass. Usually, if they disagree, a new boarding pass is printed, and you board with that. (I like when they don't match, as the next words are usually, "oh, we had to upgrade you...")

Also, by not scanning the barcode, the gate agent ensured that you would not automatically be credited with frequent-flyer miles. Highly unusual.

lan and aa share flights - you can book a lan flight and fly on an aa plane, or vice-versa, so this isn't that surprising (in fact, i think i have been in the same situation, but the other person was on the wrong flight. perhaps it was you? :o)

I have done it a few times, no questions asked. (The key is to have an excuse, like "I guess I need to gate-check this.")

The don't need to be on a plane bit- if you end up leaving the plane once you've boarded, the plane isn't going to pull away from the gate till you're either back on the plane or everything you took onboard with you is deplaned.

Now, that doesn't mean to say that you couldn't hide a bag onboard with such a device, and then make some kind of excuse that you have to go back to your office because there's some kind of emergency, and you won't be taking the flight after all. But then, you'll have had to somehow get your device into the sterile area (requiring accomplices who work there, or some surprisingly good luck getting through the x-ray scanners and explosive detection machines).

In other words, the security we had pre 9/11, with a little bit of modernizing, does the job fine. The rest of it (shoes, liquids etc) are really just theatre.

Is that speculation, or have you seen that provided as an official rationale? It just doesn't make sense to me that someone would not blow up a plane just because it wouldn't be maximally effective.

Umm... We all saw it happen September 11, 2001?

You're right that an attacker probably wouldn't back out just because the attack wouldn't be maximally effective, but the result would still be reduced casualties. Ideally, you want to prevent all attacks, but even when you can't the next best thing is to reduce the severity.

So you're saying you don't think it's very effective as a deterrent, and you haven't seen it provided as an official rationale?

Because Detroit has landmarks.

Media have reported that the attacker was instructed to blow up the plane over US soil. It's possible there were even more specific instructions that we are not privy to. Pieces of a plane raining down over a major city could not only inflict significant casualties, but also creates a hell of a lot of fear.

Fear, probably. Damage/Casualties on the ground? Not so much.

Detroit jokes aside, Metro Airport is in Romulus. It'd take a staggering amount of either skill or luck to hit even one or two buildings with plane bits. And pedestrians essentially do not exist in Michigan.

http://maps.google.com/maps?f=q&source=s_q&hl=en&...

Detroit is not really a major city anymore.

Cripes, remember when Flight 587 went down over Queens? 5 people on the ground were killed and Queens is about 4 times as densely populated as Detroit is.

I did notice that the map was disabled on my flight back from Australia yesterday. Pretty annoying.

By the way - GPS watches work just fine in a plane.

By the way - GPS watches work just fine in a plane.

It sounds like they are not allowed to be used according to that document though. I would imagine that cell phones also work just fine (I've never had the urge to try), but that doesn't mean their use is allowed.

Edit: Misread the document, I stand corrected. This is just another one of the TSA's typical security illusions.

The document specifically mentions "aircraft-integrated" GPS devices.

Cell phones are a bit of a different story. Cell phones were designed to be operated somewhere around 0-100MPH from the surface (or very close to it). A plane violates those assumptions. That's important in a couple ways.

First, if you're in the air, you have line of sight to a lot more cell sites than you normally would. While there might be a couple sites at any give point that are a similar signal strength to you, here there could be hundreds. Basically, cellular wireless is based off the idea that your transmission only goes so far and therefore they can re-use the same spectrum in different locations (or, in the case of CDMA systems, not have every code talking over each other, but rather have a limited number of voices screaming). Being on a plane violates that. With a CDMA system, you'd either be drowned out by closer signals or you'd be causing a ton of interference for all towers within range and it'd be a lot of cell sites. With a TDMA system, you'd be transmitting on a frequency/time-slot that would be re-used on another tower that could similarly hear you. To explain that a bit more: in real life if you have:

  Tower FreqA :: Tower FreqB :: Tower FreqC :: Tower FreqA

in a linear fashion and you're transmitting to the first tower (using frequency A), your signal won't reach the last tower (which is using frequency A to talk to a different customer). However, if you're flying above all the towers, all of a sudden you have line of sight like you've never had before and if you're transmitting to the first tower on frequency A, your signal is also likely being heard by the last tower as well meaning that the entire theory of re-use goes down the drain.

Likewise, you're travelling at (potentially) 500 miles per hour. Travelling at 60MPH, you'll likely need a new cell site every few minutes (depending on geography and the like). At 500MPH, you could be getting new sites more often than not. Combined with the fact that you'd be in "range" of so many sites as noted above, it would become difficult for the network to determine which site you should be transmitting to/from.

And that is important. Cellular wireless only works because the same finite bandwidth can be reused since you aren't using that bandwidth in all locations.

So, unless microcells are used on the plane itself, wireless service is a terrible idea in the sky. A microcell in the plane would get the phone to transmit at a very low power (therefore not interfering with customers on the ground) and the cell site would be a constant distance from you. It's why even in countries where the aviation folk are moving toward cell phones on planes, they're doing so through microcells.

I'm not saying that it would't work. I haven't studied it, but it wouldn't be a wonderful experience and would cause havoc for the network.

EDIT: It seems that it's an FCC (in addition to FAA?) prohibition in the US (http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#USA_C...). The article on Wikipedia also mentions airlines installing microcells (although not by name) to allow people to call on planes.

I think he was referring to cell phone GPS

For the record, I was referring to transmitting information with another party (either text or voice) - should have been more specific.

Very interesting explanation, thanks!

I would imagine that text messaging probably wouldn't be subject to these issues since it's just a quick burst of data. It would also be a little easier to get away with using too.

Well, the issue is even having the phone on since your phone needs to been in communication to cell sites via the control channel (which determines how to send an incoming call to you, what tower you should be using, and allows for sending/receipt of text messages). So, you might not be causing problems for the traffic channel and the speed issue probably wouldn't be a problem, but you'd still be causing problems on the control channel even by having the phone on. Granted, if a few people did it, it might not matter, but if everyone did you'd have the exact same problem where you'd be defeating frequency re-use.

By the way - a departure time, and arrival time, and a wristwatch all work fine in a plane.

Yes, this is the part of the rules I find most confusing. Someone with the ability and desire to blow up a plane wouldn't do it unless they could be sure they were on approach to the destination? There would be more devastation if the plane crashed into a densely populated area, but he would give up if he couldn't maximize the impact?

The only thing I can think is maybe it has more to do with the altitude of the aircraft and the hour window is whether the plane is on its final descent or not. Perhaps the explosion is not too powerful, and the pilot could recover in time if the plane is high enough? I'm not sure that's plausible.

It's not too difficult to notice your plane is descending.

And you know the length of the flight, within a reasonable tolerance. So timing can't be too hard.

This rule makes no sense at all.

Nor is it difficult to look out the window and see that you're over an urban area.

Let's say you are a terrorist organizer and have found a novel way to get a bomb onto a plane. Assume also that if you abort the mission before detonation chances are good you'll get the bomb off the plane without detection. You probably also realize that any method you use will only work once, so you want to make sure that one use is used to best effect. Given this I can see the logic in aborting a mission which would give a sub-optimal result given that there is a reasonable chance you can try again for a better result later.

Being able to blow up the plane in the sky is terrorizing enough I think.

You don't care about the death toll, you just care about the fear.

I imagine a plane crashing into a major city will bring far more terror than bringing a plane down in a desolate forest. Not only will be people be afraid to fly, they'll be afraid every time they see a plane overhead. Also imagine the the epic problems that will be caused if the powers that be declare in response that no commercial flights can fly over cities.

As others have pointed out, you can look at the window and see where the city is. Also, while your argument may be otherwise logically sound, that's a long string of suppositions that I'm not convinced hold. Do you honestly think that what you've described is the rationale for the policy?

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