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"Disable aircraft-integrated passenger communications systems and services (phone, internet access services, live television programming, global positioning sys

"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.

timcederman 17y ago
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.
- mrduncan 17y ago
  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.
  - rufo 17y ago
    The document specifically mentions "aircraft-integrated" GPS devices.
  - mdasen 17y ago
    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_Channel_reuse 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.
    - johns 17y ago
      I think he was referring to cell phone GPS
      - mrduncan 17y ago
        For the record, I was referring to transmitting information with another party (either text or voice) - should have been more specific.
    - mrduncan 17y ago
      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.
      - mdasen 17y ago
        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.
- lallysingh 17y ago
  By the way - a departure time, and arrival time, and a wristwatch all work fine in a plane.
jm4 17y ago
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.
- jrockway 17y ago
  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.)
  - imajes 17y ago
    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.
  - encoderer 17y ago
    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.
bmm6o 17y ago
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.
- waterlesscloud 17y ago
  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.
  - ojbyrne 17y ago
    Nor is it difficult to look out the window and see that you're over an urban area.
- dagw 17y ago
  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.
  - shin_lao 17y ago
    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.

timcederman 17y ago

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.

mrduncan 17y ago
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.
- rufo 17y ago
  The document specifically mentions "aircraft-integrated" GPS devices.
- mdasen 17y ago
  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_Channel_reuse 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.
  - johns 17y ago
    I think he was referring to cell phone GPS
    - mrduncan 17y ago
      For the record, I was referring to transmitting information with another party (either text or voice) - should have been more specific.
  - mrduncan 17y ago
    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.
    - mdasen 17y ago
      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.
lallysingh 17y ago
By the way - a departure time, and arrival time, and a wristwatch all work fine in a plane.

jm4 17y ago

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.

jrockway 17y ago
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.)
- imajes 17y ago
  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.
- encoderer 17y ago
  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.

bmm6o 17y ago

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.

waterlesscloud 17y ago
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.
- ojbyrne 17y ago
  Nor is it difficult to look out the window and see that you're over an urban area.
dagw 17y ago
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.
- shin_lao 17y ago
  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.