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The Real Reasons Phones Are Kept Off Planes 642

jcatcw writes "Mike Elgan argues that the the real reason that cell phones calls are not allowed is fear of crowd control problems if calls are allowed during flight. Also, the airlines like keeping passengers ignorant about ground conditions. The two public reasons, interference with other systems, could easily be tested, but neither the FAA nor the FCC manage to do such testing."
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The Real Reasons Phones Are Kept Off Planes

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  • by ILuvRamen ( 1026668 ) on Sunday April 08, 2007 @12:02PM (#18655533)
    Who wrote this article?! Of course the FAA and FCC tested it. And so did the Mythbusters on a recent show. They proved if you hold the cell phone close enough, the radiation if gives off can affect equipment that would definitely result in a plane crash. It's horribly unlikely that a cell phone way back in the passenger area would affect the equipment but it's still possible, which makes it about as good of an idea as when the gas station near me had an open grill brat fry about 15 feet from the pumps. Yeah it's probably far enough away but do you really want to risk it? Same thing on planes so stop complaining.
  • Re:funny (Score:5, Informative)

    by Quasar1999 ( 520073 ) on Sunday April 08, 2007 @12:09PM (#18655605) Journal
    Actually, ask anyone that knows how cell towers work, and your real explanation would become evident. Cell phones try to communicate with as many towers at once as possible, this is required so that you can walk from one cell's coverage to another's without dropping your call... a typical phone sees anywhere from 3 to 6 towers at once depending on geography and density of cell towers. Throw that phone up a few thousand feet, and I've personally seen my blackberry connect to 40+ towers at once. This eats up valuable bandwidth at each cell tower, not to mention the fact that you come in and out of a cell's coverage area so fast that it's impossible for your calls to be handed off properly between the cells.

    Oh, and good luck with the E911 crap... In the course of a minute, you've gone from the east end of a major city to the west end according to the cells.
  • Doubtful (Score:3, Informative)

    by grahamsz ( 150076 ) on Sunday April 08, 2007 @12:25PM (#18655739) Homepage Journal
    I manage to work on almost every business flight I take. Mostly by collecting and printing stuff that i need to read and learn, or by sitting with a notebook brainstorming technical problems. Occassionally (if i have a decent amount of leg room) then i'll pull out the laptop and do some actual coding.

    It takes a little planning to find something to do but it's really not hard to make semi-productive use of that time.
  • by ChaosDiscord ( 4913 ) * on Sunday April 08, 2007 @12:26PM (#18655751) Homepage Journal

    Mike Elgan, the article's author brushes off the problem of an airborne cell phone seeing a large number of cell towers at once. He claims it could be easy to fix with a software upgrade to the towers. Nonsense. The fundamental problem is that there is only a finite range of frequencies for cell phone calls. The more towers a given phone's signal is visible to, the more towers whose frequencies you're chewing up. Redesigning the system to support cell calls would be massively expensive. Is the value of being able to make cell calls from a plane really that valuable? Who is going to pay for the overhaul? Elgan is just whining.

    Elgan points out that Europe is working on making this work. Tellingly, they're not just letting the phones connect to towers normally; they're shielding the cabin and routing connections through dedicated on-plane hardware. This is reasonable as it means you have a single source (the plane's hardware) that can far more efficiently utilize tower frequency space. Furthermore, the cost of making the changes falls on the airlines, who will pass it on to the logical people: the fliers who want to use this service.

  • by Anonymous Coward on Sunday April 08, 2007 @12:27PM (#18655759)
    My 0.02 as an air carrier pilot... I've seen 3 actual instances of interference from not just cell phones,
    but also data cards. 2 were voice bleed over when the persons cell phone was transmitting in analog mode, and the other was an AHRS (attitude and heading reference system...VERY important) which took a dump when someone started using their data card..fortunately it was good weather and the AC had an iron gyro backup system. Filed NASA ASRS reports on each. I certainly wouldn't use "Mythbusters" as any source of certification data.

    You have to understand that in the avionics can be located anywhere in the plane, not just upfront. On top of that the FAA is VERY picky about figuring out the worst case and applying it to all situations. If a person is in back using an old analog brick phone on a older aircraft, say a 727 or DC-9, and there is the even a remote chance of interference, everything will be prohibited, because how in the world are you going to police every make and model of phone with all the variations of aircraft?

    The NTSB files are chock full of accidents that happened because something happened that someone said couldn't, so I'm perfectly happy with the ban. If it keeps them from chatting loudly in my ear as I try to commute home, well that's just a bonus.

  • by div_2n ( 525075 ) on Sunday April 08, 2007 @12:28PM (#18655765)
    People tend to talk louder on cell phones than regular phones. [] There is no feedback of their own voice.
  • by Himuanam ( 852822 ) on Sunday April 08, 2007 @12:39PM (#18655883)
    From the IEEE's Spectrum magazine last year, they actually measured RF signals on flights and reported on the results. No smoking gun where an accident was caused by a cell phone, but still interesting nonetheless (and no ads!). []
  • by ffejie ( 779512 ) on Sunday April 08, 2007 @12:43PM (#18655911)
    You are indeed correct. JetBlue landing gear mishap [].
  • Has been tested (Score:4, Informative)

    by DaveAtFraud ( 460127 ) on Sunday April 08, 2007 @01:02PM (#18656049) Homepage Journal
    The effect has been idependently tested and confirmed: []

    I think I'll trust real research from CMU over a vapid so-called journalist who probably just can't stand not yapping on his cell-phone.

    BTW, it doesn't matter if some or even nearly all cell phones don't cause interference with flight controls. All it takes is one person using one that does and things get ugly. Likewise, most airplanes have a mix of avionic equipment. Some of it is new where the cost/benefit makes it worth it for the airline to upgrade and some of it is old. Rather than test each airplane independently, it makes more sense to just say "no" until someone comes up with a way that is known to be absolutely safe regardless of the equipment on the airplane.

  • Re:funny (Score:5, Informative)

    by LordEd ( 840443 ) on Sunday April 08, 2007 @01:15PM (#18656131)
    I would rather insert actual satellite phone rates. Iridium is a satellite network provider. Their phone airtime rates can be found here []

    Looks like the cost is about $1.29 / minute. I don't know what kind of phones they might use, but a basic phone costs about $1500 according to here []
  • Re:Not quite (Score:3, Informative)

    by interstellar_donkey ( 200782 ) <> on Sunday April 08, 2007 @01:53PM (#18656411) Homepage Journal
    I don't know exactly what's going on when a cell phone is transmitting data, or what or how that may interfere with instruments. I have, however, noticed something with my most recent phone which gives pause. In October of last year, I purchased a new Sony Ericson telephone. At the beginning of telephone calls (both incoming and outgoing) or when the phone connects to the Internet, some of the electronic audio devices in my house emit a low 'dee dee dee dee' tone. This has never happened with any other phone I've had.

    It occurs with my home theater, computer speakers and desktop radio.

    Now, if that can happen, I'm somewhat reluctant to accept that cell phones can't interfere with avionics equipment, if only to a small degree.

    Then again, i kind of like the fact that I have at least one place where I have a valid excuse to not answer my phone.
  • Believe it or not, but it's not the FAA or the airlines doing the cellphone testing.
    It's the aircraft manufacturers.
    Boeing and Airbus both run tests, and there IS interference with some of the more sensitive systems on the plane, like, duh, navigation. GPS is better at high altitudes, but when you have to get 6 data values from GPS, you need many more satellite receptions than for just location. Modern planes don't use just gyros for roll/pitch/yaw rates, they confirm it with GPS data. As one might expect, the radio antennaes receiving those can become jammed.
    That's the reason you can call on your phone when you're on the ground, but not in the air.
    That post is just another Rosie-style conspiracy theory about the FAA and the FCC. I have no respect for people that don't try to understand the sensitivity of avionics and then reject every technical argument as "political cover-up".
    Wifi isn't so much of an issue because it is lower power, and on a narrower and very different radio range.
    Gees people, stop seeing evil everywhere, there's enough already that we don't need to paint the world as COMPLETELY depressing!
  • Testing Isn't Easy (Score:4, Informative)

    by Helmholtz Coil ( 581131 ) on Sunday April 08, 2007 @01:59PM (#18656459) Journal
    Speaking as someone who's tried to get gear flight certified, I can tell you that testing is never easy. Granted, it's definitely easier to get something approved that isn't going to be part of the plane but rather just another carry-on, but there's still a lot of work involved.

    I think it probably boils down to cost and caution. The testing is expensive, and nobody wants to be the one that approved cell phones if they end up causing a plane crash.

  • Re:9-11? (Score:3, Informative)

    by hedwards ( 940851 ) on Sunday April 08, 2007 @02:02PM (#18656483)
    I don't think so. My recollection was that some of the people aboard the flight which crashed in PA called loved ones. And had awareness from those phone calls of what was going to happen. I am pretty sure though that calling 9-11 wouldn't have worked as it is the number in a huge number of places. If the call got to two different towers straddling areas codes, it would probably have not gone through.
  • Re:funny (Score:5, Informative)

    by SerpentMage ( 13390 ) <[ ] ['' in gap]> on Sunday April 08, 2007 @02:29PM (#18656693)
    If a Russian plane flies into the US it has to be certified by the US. That usually means either Airbus, or Boeing or some other smaller plane manufacturer that has already been certified. If you want an interesting flight (my brother tells me this) fly in Russia using a domestic airline.

    Cell phones are already tested for interference because otherwise they would interfere with other devices. Cell phones are certified to use regulated bandwidths. It's walkie-talkies and cordless phones that you need to be worried about since they use uncertified spectrum's.

    The reality is that most of these things have already been verified as that is why you have little stickers on the back of the device indicating that they have been certified. And interestingly enough most countries have similar certifications because otherwise they would have wireless nightmares.
  • by wik ( 10258 ) on Sunday April 08, 2007 @02:40PM (#18656771) Homepage Journal
    I read somewhere (too lazy to find the reference) that part of the reason is because cell phones don't locally play back your voice on the speaker. Hence, to the person on the phone, it feels as if (a) their ear is blocked and (b) the phone is not capturing their voice. By contrast, landline phones apparently do leak some of your voice back over the speaker and so you feel as if you're talking loud enough.
  • by fm6 ( 162816 ) on Sunday April 08, 2007 @02:41PM (#18656777) Homepage Journal

    I have no respect for people that don't try to understand the sensitivity of avionics and then reject every technical argument as "political cover-up".
    People like conspiracy theories. They're more emotionally satisfying than banal technical explanations. Take a popular urban legend, find somebody who believes it, and try to pick hobs in it. You'll get nowhere.

    My favorite example is the one about the bodies of all the dead construction workers buried in Hoover Dam, supposedly to conceal the high rate of accidental deaths on that project. Construction engineers have no patience with that one -- the builders went to a lot of trouble to control the consistency of the concrete. But that little fact does nothing to deter people who like the story -- which seems to he most people.
  • Don't ask a pilot (Score:2, Informative)

    by ZoOnI ( 947423 ) on Sunday April 08, 2007 @02:46PM (#18656845)

    I used to work on Aircraft avionics in my earlier days. Unless a pilot has an electrical engineering degree, Pilots generaly don't know to much about the actual working of the electronics on board that they use. The FCC alots frequencies to civilian and gouverment agencies. A hug chunk of the available frequencies go to Avionics/Gouverment leaving only a few frequencies for civilian use (Notice how overused 2.4 GHz is). When frequencies are assigned the useable ones are far enough away from each other so no interferance happens. The electronic equipment is also designed to filter out any other frequency outside its selected range. Example if you talk on one VHF channel you don't hear the VHF channels beside it.

    The strongest source of the cell signal is the cell tower which planes fly through all the time. So how would a cell phone effect other systems on a plane? They would not.

  • by Anonymous Coward on Sunday April 08, 2007 @02:58PM (#18656931) les/viewarticle.jsp?id=37150/ [] as well as plenty of other reviews mention it (though not many use the phrase "sidetone" to name Motorola cellphones' behavior of having the speaker echo anything picked up by the mic.

    For some weird reason, Nokia's don't (didn't -- I suppose its possible their newer phones diverged from this years-old Nokia characteristic).
  • by beeblebrox ( 16781 ) on Sunday April 08, 2007 @03:07PM (#18656973)

    Disclaimer: I have absolutely no pilot training, however I do write software for mobile phones as well as networking apps in general.

    While you state that countless numbers of phones are left on during flights, this is not particularly dangerous. A phone ranging a tower is only actively transmitting for a very short period of time every 20 minutes or so at regular speeds.

    With the "legacy" cell app - voice - that is true. However, with wireless broadband becoming more common and affordable, applications with more chatty idle-mode traffic patterns - email and IM for example - break this assumption.

    This way an Exchange email download can still give you that nasty ILS deviation for a few critical seconds during a bumpy IMC approach.

  • Re:funny (Score:3, Informative)

    by multimediavt ( 965608 ) on Sunday April 08, 2007 @03:24PM (#18657087)
    To add to your comment, because you are jumping towers so quickly (if you were even at an altitude where you could connect to one at all; cell towers have at most a 2km to 5km range folks, do the math) you would bring entire cell networks down as they tried to keep up with your (and everyone else on the plane's) signal traveling in excess of 300MPH. The whole "interfere with the airplane instruments" thing is bunk. The only thing critical that a cell phone *might* interfere with is the ILS system on approach, and that would only be a problem in bad weather. Altitude, location, etc. are all GPS-based today. Aircraft communications are in frequency bands well out of reach of the common GSM or TDMA cell phones, and all the remaining instruments and controls are mechanical or hardened, redundant fly-by-wire systems that are shielded. So, the real reasons you can't use your cell phone on an airplane? 1. You can't get a signal that high up in the air (30,000+ feet) from a cell tower, and 2. if you could get a signal you are traveling too fast for the system to keep up with you and will be bringing down cell towers and networks as you went jet-setting across the sky while not ever being able to make a call stay connected for more than a few seconds.
  • by King_TJ ( 85913 ) on Sunday April 08, 2007 @03:26PM (#18657103) Journal
    I've seen that same explanation stated several times before when this discussion came up. But the last time I read about it, I believe it was a message thread on - a site specifically made to discuss cellphone technology. Many users there work in the industry in one capacity or another. One of the guys who claimed he worked on engineering the cell tower infrastructure said that this is really not a true statement. Yes, the phones are designed to communicate with any towers within range. BUT - the cell towers have the ability to handle situations such as a phone suddenly "appearing" on 40 towers at the same time. They have software that knows such things aren't possible in normal cellphone operation at ground level - so it ignores the signals on all but a few towers at a time.

    He claimed that in reality, this process doesn't "tax" the towers inordinately at all. The "bandwidth" tied up is no more than a regular call would tie up, since the towers are rejecting the extra instances of the connection to the phone. There's simply a small amount of overhead involved in the towers passing along the information to each other about the status of your connection.

    (I believe this type of software also comes into play for handling problems of "cloned" cellphones. If a connection shows up simultaneously on towers that are spread far apart, they know they're dealing with not just 1 legitimate phone, but also a duplicate in service elsewhere.)
  • Re:funny (Score:3, Informative)

    by rv8 ( 661242 ) on Sunday April 08, 2007 @03:30PM (#18657143) Homepage

    The problem is much more difficult than simply certifying every cell phone design as safe. The problem is that a small number of cell phones might have shielding that becomes ineffective, either through a problem during manufacturing, or something that happens in service (dropped cell phone, cell phone disassembled and reassembled by curious geek, etc).

    And, it is possible that the avionics or coax cabling in some aircraft might be not quite up to snuff. So, most aircraft of a given design are OK, when coupled with most cell phones. But put a defective cell phone in the right place in the right aircraft, and you could have a problem.

    Several years ago I spoke with the captain of a Challenger business jet who told me an interesting story. They were in cruise, when suddenly the VOR indications in the cockpit started doing very strange things. He sent the copilot back in the cabin to see if anyone was using an electronic device. He found that the CEO's son was playing with a Game Boy. The Game Boy was turned OFF, and the VOR indications returned to normal. The Game Boy was turned back ON, and the VOR problems returned. Game Boy OFF for the rest of the flight.

    Also see another report of problem caused by Game Boy [].

  • Re:funny (Score:3, Informative)

    by Mike McTernan ( 260224 ) on Sunday April 08, 2007 @03:40PM (#18657205) Homepage

    Which technology are you describing? It doesn't sound accurate to me, but I'm familiar in only 3GPP standards.

    A GSM handset may monitor many cells at one time, basically reading some broadcast data (BSIC etc...) and monitoring the signal level, but it will only be transmitting to one cell at any one time. The broadcast channels from cell towers are constantly on, and an accepted overhead that makes the system work - monitoring these broadcast channels takes no bandwidth from other users.

    A WCDMA FDD handset may actually communicate with more than one cell tower at a time, and hence use more bandwidth, but this is a decision made by the network as it assigns the resource, not the handset. Also WCMDA has a tight power control loop, so it is careful not to be wastfull. Again, like GSM, other cells maybe monitored and some information decoded (CellId etc...), but this is again broadcast data that takes no bandwidth from other users.

    The problem I think of is more that a lot of network activity would be caused by a plane load of people moving quickly between cells. The network has to tightly co-ordinate the allocation and re-allocation of resource as a person moves between cells, as well as updating databases that record the location area in which the user can be reached. I could believe that planes filled with people quickly moving across the network could cause some critical parts of the network to receive very high loading - especially as I would imagine these bits to have been dimensioned according to models that assume things like the average user is travelling at less than 50 kph.

    I've personally seen my blackberry connect to 40+ towers at once. This eats up valuable bandwidth at each cell tower

    As described, your Blackberry is merely observing large numbers of cells, and not using all their bandwidth.

  • by Anonymous Coward on Sunday April 08, 2007 @03:44PM (#18657223)
    You need to understand how an antenna works. An antenna isn't just a passive bulk of metal picking up signals passing thru it. You would need huge antennas for your radio equipment if it was so. Consider the old style antennas which were made of huge lengths of copper cable. Modern antennas create an electric field that is much larger than the metal itself and measure the fluctuations in the field due to radio signals passing thru. This electric field causes the interference with other equipment. So, yeah. You can safely watch TV on an aircraft if you can carry your 100m passive antenna with you :)
  • by nbritton ( 823086 ) on Sunday April 08, 2007 @03:55PM (#18657293)
    Back in season 3:

    "It was found that cell phone signals, specifically those in the 800-900 MHz range, did interfere with unshielded cockpit instrumentation. Because older aircraft with unshielded wiring can be affected, and because of the possible problems that may arise by having many airborne cell phones "seeing" multiple cell phone towers, the FCC (via enforcement through the FAA) still deems it best to stay on the safe side and prohibit the use of cell phones while airborne." -Wikipedia

    You can read more about it here: phones_on_plane.html []
  • Re:What I want... (Score:3, Informative)

    by 0100010001010011 ( 652467 ) on Sunday April 08, 2007 @04:40PM (#18657597)
    Or just buy a few of these and install them: []

    Pay some kid to walk around the place and sit in every seat with a cellphone from carrier to see if they still get signal.

    Much easier than putting a copper mesh over the entire theater and worrying about holes.
  • Re:funny (Score:1, Informative)

    by Anonymous Coward on Sunday April 08, 2007 @05:15PM (#18657789)
    Although I too came by my method by working at RIM, it's hardly something you need to work there to use. I just would never have owned a BlackBerry otherwise (not from lack of wanting to, I assure you, just for the price)

    Options >> Advanced Options >> Host Routing Table

    Depending on your line of handheld code, you may not have the "Advanced Options" menu. If so, just go straight to the next one.

    The bold one is the tower you are currently connected to. If you click the trackwheel/menu button and select "Register Now" it will connect to the tower you have highlighted, as opposed to the default.
  • Re:funny (Score:3, Informative)

    by SnowZero ( 92219 ) on Sunday April 08, 2007 @06:30PM (#18658203)
    You're making a faulty assumption that airplanes are uniformly distributed. On an approach to LAX, for example, a not-insignificant fraction of the population is in the air. Also, over a densely populated area (such as around LAX), your mobile phone might be able to connect to something like 50x the towers as a phone on the ground. The result would be that phones would barely work around airports, which nobody would like.

    Now, the real solution is to have picocells onboard the airplanes. In the mean time, is it that hard to not use your phone for a few hours on a domestic flight? On real long flights over oceans and completely unpopulated areas, you wouldn't be able to use them anyway.
  • by w9wi ( 162482 ) on Sunday April 08, 2007 @09:39PM (#18659357)
    On any kind of cell phone, you're only connected to one cell at a time.

    Let's say your phone is connected to Cell A and is talking on channel 375. You aren't using Cell B. But you are using channel 375. If Cell B tries to assign channel 375 for someone else's call, your phone is going to interfere with theirs. If you're flying at 15,000 feet, you're only going to tie up one cell at a time -- but you're going to tie up channel 375 for as far as 100km or more.
  • by BlueStrat ( 756137 ) on Monday April 09, 2007 @03:20AM (#18660619)
    Also: since 9/11, most of the cockpit doors are very strong, which means lots of metal, which means lots of shielding for the instruments up front

    Most of the electronics on an aircraft are located either in compartments in the nose or tail, or in bays below central fuselage areas (depending on specific aircraft).

    What you see in the panels in the cockpit are 'control and indicator' heads, which house only display and switching to conserve precious cockpit panel space. They are linked by cabling to the actual devices they control or display the output of. Add to that, the cabling required to link sensors back to the devices in the bays from wings, nose, tail, control surfaces, antennas, etc etc.

    Even if that cabling is shielded, shielding breaks down with age and mechanical vibration and friction caused by vibration between the cable and the guides through which they are run on their twisting path through the aircraft.

    A particular aircrafts' resistance to radio/EMF interference to its' avionics degrades in a non-linear and hard-to-predict manner. Cabling may wear or be damged in areas where it's impossible to inspect without major airframe dissassembly.

    I worked for over 25 years as a Rockwell/Collins Avionics-trained and FAA-certified senior avionics technician on a wide range of aircraft, so I'm not talking out of my ass here. I've actually seen with my own eyes this cabling degradation and wear, and had it cause weird, unpredictable, intermittent, and hard-to-isolate problems *without* any nearby interference to make things worse. Adding strong local RF fields to this scenario, especially to aircraft that have been in service for years, is asking for trouble.



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