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Wireless Networking Communications

Bluetooth on an Airplane? 145

Posted by Cliff
from the listen-to-the-stewardess dept.
bblazer asks: "Since I travel quite a lot, I am very familiar with the warnings about cell phone use on an airplane (could be bunk, but I still respect it and those around me). But what about using Bluetooth? I just got off an Alaska Airlines flight where the flight attendant said that we were not permitted to use any device that sends or receives a radio signal. I often use the bluetooth features of my PowerBook and Treo while onboard a plane (you can have the Treo on without having the cell phone on), or I set up a mini-network with others I may be traveling with. Could Bluetooth cause any problems, or is this something I need not worry about?"
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Bluetooth on an Airplane?

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  • Are you (Score:3, Interesting)

    by Jeremiah Cornelius (137) on Tuesday April 19, 2005 @06:08PM (#12286640) Homepage Journal
    ...Less than 32 feet away from critical in-flight avionics?
    • Most passenger jets have microwave ovens on board for food service, so I'm sure the avionics are tollerant to 2.4Ghz interference. Of course I really have no idea. They might use some special super shielded micorwave ovens...
  • Personally I wouldn't use it. And if I was on a plan with you, and you were using it, I'd report you. Yes the odds of it causing the aircraft to crash are small, but do you really want to take that chance?

    Anything that transmits has a chance of interferring with the signals the plane's navigation equipment receive. As the quality of a lot of consumer electronics isn't very high, the possibility that some unit may be broadcasting some horrendous noise on an off frequency is realistic.

    Last of all, with thes
    • by Anonymous Coward
      major mishaps because their code stinks? Are you refering to Airbus by any chance?

      the parent poster is probably fine on a Boeing or (shudder) Tupolev bird, but airbuses are dangerous...
    • by Anonymous Coward on Tuesday April 19, 2005 @06:52PM (#12287064)
      My understanding as to why you're not allowed to use cell phones on planes has to do with cell phone technology. When you're on the ground, you're only within broadcasting distance of one or two cell phone towers. But in the air, your phone can broadcast to hundreds of different towers. I'm not an expert in cell phone technology, but my understanding is that the signal would use tower resources from every tower within range.

      Honestly, if a consumer wireless device can interfere with critical airplane functionality, we've got serious problems. It would be fairly trivial for a terrorist to boost the signal comming out of their cell phone or whatever was necessary to cause problems, yet we haven't seen anything like that.
    • by BrookHarty (9119) on Tuesday April 19, 2005 @07:09PM (#12287188) Homepage Journal
      *cough* bullshit *cough*

      First, the reason cell phones are banned was they cell sites couldn't handle the handoffs of cell phones in air. The wireless communications companies asked the airlines to stop in flight calls, and offered and created companies just for in fight service.

      2nd. Fly by wire isn't, fly by RF, there are actual wires, and these wires wont pick up RF from a device as you say. If you're simple phone could put it out of service, any plane flying over a guys house with a HAM radio would crash it. Planes don't crash from RF like that.

      And you say you worked for the industry, well guess what, so do I.

      BTW, did you want a cookie for reporting the big bad man to the air stewardess (HA, Fuck Political Correctness)...
      • And you say you worked for the industry, well guess what, so do I.

        What industry? Airlines? Baggage handlers also work "in the industry" but I wouldn't think of them especially suited to answer questions about RF interference.

        Fly by wire isn't, fly by RF, there are actual wires, and these wires wont pick up RF from a device as you say.

        So if by "in the industry" you mean have actuall experience testing for interference then you surely know wires are antennas. They *will* pick up RF signals. Chanc
        • by LWATCDR (28044) on Tuesday April 19, 2005 @08:08PM (#12287650) Homepage Journal
          "To the OP, yes it can happen, and if it happens at all it'll be at takeoff or landing when all of the instruments are being used. I prolly wouldn't worry about using Bluetooth stuff en route."
          The only instruments that require RF are navigation. Not used all that much at takeoff. Also all standard navigation instruments are VHF except GPS. Even if your GPS failed 100% the pilot would then use INS and or VOR/DME. As too a cell phone messing with FBW. If that ever happened the designer should be shot. A FBW system is well shielded from almost all RF if not then a good lightning strike or sunspots.
          Frankly the story about the cell phone I find iffy at best. It might have happened back in the day of analog phones and it might have caused interference with a VOR or comm radio. Any worry about interference would have nothing to do with navigation it would have to do with interfereing with plane to tower communications. The pilot really need to keep in touch with the tower during take off an landings a garbled transmition could cause a near miss or worse.
          Your bluetooth uses 2.4ghz and is so low power that you really do not need to worry about it. BUT they are so touchy these days I would shut it off just to avoid going to jail.

          • [...] a garbled transmition could cause a near miss or worse.

            What could be worse than a collision?

        • Really, so why are planes affected by the tiny transmitters inside cell phones but not the massive TV, Radio (commercial and amateur), radar, and other transmitters that blast them with many many times as much RF near the airports?

          The difference in power more than makes up for the proximity issue.

          As a further exercise, try finding a single verified instance of a cell phone affecting an airplane. I did some quick googling but all I can find are "friend of a friend" type stories.

          Finkployd
        • And you say you worked for the industry, well guess what, so do I.

          What industry? Airlines? Baggage handlers also work "in the industry" but I wouldn't think of them especially suited to answer questions about RF interference

          Yes, the baggage handlers post to slashdot during the work day.
      • Well, I work in the industry too, and guess what? Farting at the wrong time can cause a huge catastrophy. So, obviously, our gentle readers should believe me over you and the grandparent!
      • I don't know about planes, but my cel phone causes horrible static and buzzing around my PC speakers, car stereo as well as cheap analog phone sets.

        My cel phone on my computer desk is apparently interfering with the amp from my speakers under the desk. It has to be a good 5 feet from the amp before the noise goes away.

        So given that, my phone stays off on the plane.
    • Well, to get the facts straight you need to know what you are talking about. Mobile phones are prohibited because the GSM network can handle a mobile that connects to 1 or 5 GSM accesspoints (antennas) - they can figure out which one is the master recieve and the others will "ignore" the signal.

      When you are in an areoplane the signal from your mobile will travel up towards 50 miles (+/- depending on altitude) and you will connect with hundreds of GSM accesspoints. This is where the problems come in. The G

    • Notice the "fly by wire". This is not fly by RF. Although it is true that an RF field can generate current in a wire, the ammount of current generated by a 1W cellphone 5 feet from the wire is unmeasurable. Planes are over-engineered. They are designed to withstand lightning strikes, and major failures of all kinds of systems. They are certainly designed to handle a little bit of RF radiation. The meason the goverment keeps radio frequency devices off planes is the old fear that they will interfere wi
  • ...simply won't take down an airplane. Even if you're in first class right behind the cockpit. I've had a wireless scanner agressively scanning in the background for a number of hours before I realized it was actually doing it and never ONCE did a pilot, flight attendant ever come on the PA, or heard chatter when the cockpit door was open.

    Hell, I've even used my cell phone (with headset) to check voicemail. The things simply do not interfere with flight information systems etc.

    It took me by surprise, but
    • A wireless scanner doesnt transmit, it scans. It won't transmit unless it picks up a network to hitch on to. Unless you arent talking about a wireless network scanner, in which case i have no idea what a wireless scanner is.
      • Well, thats not quite true. Wireless receivers resonate back, the power being a function of the frequency, antenna and other stuff. Thats how rfid works, after all.

        I remember being told to turn off /all/ electronic gear during take of and landing (still?) because some of the various radio systems used during that phase are very close to commercial FM. FM receivers do resonate back in that range (which could cause a problem).
    • by Banner (17158) on Tuesday April 19, 2005 @06:42PM (#12286959) Journal
      As I said earlier, I used to work on the systems that are in use today. I am an industry expert. Yes the odds are against you causing a problem.

      But it CAN happen.

      The worst place for it to happen is when you're in the weather, flying on instruments, and the plane already has some kind of problem. Then you're going to crash and die. Or burn to death in the wreckage.

      You can quote your own ancedotal evidence, but again, I used to test those systems for a living. I'd rather not put a million to one chance against the lives of a plane full of people, or myself.
      • Speaking of ancedotal evidence, I was on a Cessna 182 long ago, and the Garmin GPS navigation/weather system would screw up whenever a cell phone was being used. The pilot semi-legally made two calls, both to FBOs at our destination. I remember big patches of yellow appearing on the Garmin screen, indicating a 100% chance of severe lightening on a crystal clear spring day.

        I know the larger IFR-capable planes use more robust systems, but I would agree, the risk is still there...And I assume anybody using a
      • Million to one chance an asteroid will fly hit your plane. Better not fly.
      • by node 3 (115640) on Tuesday April 19, 2005 @10:17PM (#12288681)
        So, exactly how many planes have crashed due to cellphone or WiFi usage?

        Planes don't crash when they fly in areas that have radio towers, they don't crash when flying under satellites, they don't crash when people "accidentally" leave their cellphone one. But, of course, in the lab, when you turn on a cellphone right next to a radio receiver, you get little blips, oscillations, or otherwise see some minor effects. Yet it's absolutely clear that these effects aren't important in the real world. Is it because the radio sources are located tens of meters from the equipment? Is it because the effects are minimal (the device doesn't need the tolerances that the variations on your scope shows)? Is it because you cherry pick your results (well, if the system is hit by lightning and there are four cellphones equadistantly distributed around the plane at 25m, and they ring in order, the plane will think its headed backwards for 300ms)?

        When people believe a theory that contradicts reality, we call it superstition.

        You can quote your own ancedotal evidence

        And you quote yours. Who wins in this discussion? How about the person whose claims actually match reality?

        Now, if you have examples of planes being downed by a cellphone, I'm all ears. Let's hear some facts that turn your superstition into reality, if you're so convinced.
        • I'm not quoting acedotal evidence. I've worked on these systems. I've seen what stray RF can do.

          There have also been several published studies that support me, one was even posted here on Slashdot about 9 months ago.

          You do know that an aircraft is basically a faraday cage, right? So that charges and signals outside the aircraft have much less of a chance of effecting anything inside it, then say a much weaker signal being generated inside it.

          As for planes being affected by cellphones: http://www.listener
    • ...simply won't take down an airplane.

      Neither can a set of toe-nail clippers, but see it they don't play 'how many fingers can I get up this guy's ass' with you for trying to sneak em on-board.

      What do you have to gain, and what do you have to lose?
      Do you want to be right, or do you want to be happy?

      The way I look at it, I'm generally not on the plane long enough to get anything done; at best the electronic toys are a nice distraction to pass the time. Read this month's Wired or LinuxWorld or whatever,
      • The way I look at it, I'm generally not on the plane long enough to get anything done


        That all depends on the length of the flight. Most flights I have been on spanned the country or the Atlantic, and they both exceed 6 hours. Are you saying that 3/4 of a work day is not enough time to get anything done? (assuming 8 hour shifts)
        • Ahhh - I was talking typical travel within the US with at least one layover (ie, less than 2 hours total in the air.)

          The other concerns I have are machine empathy - I can almost hear the laptop hard drive scream every time the machine is moved while running, and battery life (even the best laptops run maybe 3 hours on a normal workload.)
    • ...simply won't take down an airplane

      Try telling that to the relatives of those who died in Crossair flight LX498. The Swiss investigatory authorities concluded that cellphone interference was a factor.
  • by Turmio (29215) on Tuesday April 19, 2005 @06:15PM (#12286710) Homepage
    Average member of Slashdot crowd isn't fully proficient in commenting flight safety. Your local air line representative is. So why don't you pick up your phone and make a call and have your question answered in no less than 30 seconds by a professional?
    • by Anonymous Coward
      Because they'll obviously say that you shouldn't use Bluetooth on the plane, and we don't want that answer.
    • Average member of Slashdot crowd isn't fully proficient in commenting flight safety. Your local air line representative is. So why don't you pick up your phone and make a call and have your question answered in no less than 30 seconds by a professional?

      Most flight safty rep's will just read of a list of things they dont allow. They dont or have not tested RF in planes. Manufacturers do.

      So, since a large group of engineers who do read Slashdot and design electronics for RF gear, or work in the RF industry
      • So, since a large group of engineers who do read Slashdot and design electronics for RF gear, or work in the RF industry might know a thing or 2.

        You're being too optimistic. Most posts are actually written by self-absorbed nerds who think they're experts in RF because they saw Maxwell's equations sometime during college. If that.

        A lot of misinformation goes around in these discussions, and even though most posters want to sound authoritative, they certainly aren't competent engineers.

    • When was the last time you encountered a first-level phone person who was a professional at anything other than reading from scripts?
    • Because when I did talk with a pilot for Delta, he didn't know what Bluetooth was....
    • I tried calling but the call was outsourced to India and I could not understand the customer service representative. But on the upside I was able to provide him with all my credit card and banking information so I know I will be safe flying.
  • by glarvat (753298) on Tuesday April 19, 2005 @06:16PM (#12286723)
    Here's a 2002 article [mobile-review.com]from Mobile Review that discusses that studies regarding cell phones and avionics. And they are seriously considering permitting cell phone and wifi usage in flight, as indicated by this article [com.com] from December.
  • They used to.. (Score:2, Interesting)

    They used to say this alot for portable CD players too, though I doubt the average discman would output more RF noise than a walkman or other audio device.
    Also AFAIK (dredging through my old basic electronics training and sometimes dodgy memory) RF interferance needs to be at the same or a harmonic of the broadcast frequency to generate problems.
    This last part is only things I have heard, and isn't verified truth, however I have been told that the reason they don't like you using mobile phones in aircraf
    • RF interferance needs to be at the same or a harmonic of the broadcast frequency to generate problems.

      This isn't really true. Any RF signal can induce current in nearby electronic devices, and those devices don't even have to be radio devices for interference to result. Even purely digital systems with no radio component whatsoever can be affected by strong nearby sources of RF. I don't know much about airplane instrumentation, but I would imagine some of it is pretty sensitive and could be fairly susce

    • It doesn't need to be a harmonic (radio term loosely related to multiple) of the freq the transceivers are transmitting/listening on. The wavelength of the radiation emitted from the offending device just needs to match (or be a harmonic of) any length of electrical conductor used in an important system to cause noise.
  • ever seen someone use a laptop ?

    these things are EMF monsters
    compared this to bluetooth which is pretty low grade and moves freq's

    ok look at what airlines do... switch everthing off at takeoff and landing

    thats the time to switch off otherwise if they let you use a laptop then just use it...

    personally use the time for downtime and read somthing good like
    lookup the book airframe
    http://www.amazon.com/exec/obidos/redir e ct?tag=zot tmann-20&path=tg/detail/-/0679446486%3Fv%3Dglance

    or

    http://www.amazon
  • by Anonymous Coward on Tuesday April 19, 2005 @06:31PM (#12286846)
    I'm on an airplane right now, over the Atlantic. Sure, THE MAN doesn't want you to turn on your devices because he thinks they will interfere with flight electronics, but you know better right?

    In fact I think I'll turn on my PDA and hook it up with my powerbook via bluetooth right now, just to show them how it's done.

    There, see? I'm still here! Still humming along! Plane didn't fall out of the sky!

    Y'know, I don't remember the ocean being so
  • by nneul (8033) * <nneul@neulinger.org> on Tuesday April 19, 2005 @06:40PM (#12286938) Homepage
    There is no FAA restriction on the use of any electronics in flight. It is totally up to the pilot/flight crew. A pilot flying a private 747 owned by a sports team for example can freely allow use of any electronics at any time.

    There are specific restrictions imposed by the FCC depending on the band in use, such as cell phones, and that is on it's way out.

    Unless the FCC has applied restrictions to the band - you can freely use whatever you want subject to the requirements of the flight crew.

    Now, that's not to say any pilot is going to approve - in the world of lawyers, it's far easier to say no than to take any risk, even if it's practically nonexistent. Think about it - the first accident that occurs after a pilot allows it - it's going to get blamed, even it it has nothing to do with the real reason for the event.
    • This must be new. Because back when I was flying the restrictions applied to all planes, even private ones, even private ones I was flying by myself, alone.
      • Re-read my post... The FAA doesn't have any restrictions other than what is deemed acceptable by the flight crew. The FCC (not FAA) has a very specific restriction against cell phone use in the air.

        If you look at the regs, pretty much all of the places it's referenced, you can see this exception to any restrictions: .....
        (5) Any other portable electronic device that the operator of the aircraft has determined will not cause interference with the navigation or communication system of the aircraft on which i
      • Because the Unided States FAA does not restrict any PEDs at all on private aircraft operating under VFR. The actual regulations at 14 CFR 91.21, 121.306 and 135.144 prohibit the operation of any electronic device (with a few exceptions for things like pacemakers) unless the airline determines that the device will not cause interference.

        In 1993, the FAA published an Advisory Circular (AC) 91.21-1 that recommended PEDs be prohibited during takeoff and landing below 10,000 feet, but there is no actual regulat

  • by imsmith (239784) on Tuesday April 19, 2005 @06:41PM (#12286943)
    it is my understanding that there are two issues with cellphones and transmitters on commercial airplanes - neither of which were issues with military arcraft when I was on active duty (the 1990s).

    Issue one is that airplanes move through cells too fast for most cellphones to deal with it, and that causes them to ramp up their RF signal strength and the frequency of their outbound conenction traffic in an attempt to maintain a conenction to the network. (cell phones weren't allowed on transports but our UHF, SHF, and VHF radios worked fine)

    Issue two is that avionics packages are not always shielded to spec in older airframes and there is the outside chance that 'something' could go wrong. (just like the outside chance that 'something' could go wrong at the gas pump) (military airframes are emissions shielded by guys who make the tinfoil hat brigade look sane)

    The technical problems are exaserbated by the social problems - namely that there isn't a lot of significant science on the validity of the fears, that there are issues of profit to be had by airlines for 'owning' connectivity onto and off of a plane in flight, and that the technology landscape is a too fluid for the legislative response to be valid. Add to this the blanket of "security" as a catch all excuse for anything feasable but hard, and you begin to get a real picture of the situation that results in the "no transmitters" rule.

    The bottom line is that, while there may be no compelling technical reason to ban transmitters (my opinion) no one wants to be responsible for making the call and then have an NTSB report come back naming cell phones as the cause of a airline crash.

    Until that changes, it is illegal, just like replicating digital instances of copyrighted material, carrying a disposable lighter or wooden matches through security, making jokes about something being "da bomb", asking to see the regulations on presenting ID at the gate, or telling your less geeky pal how to defeat the ROT-13 encryption on his e-book.

    Turn off your wifi and bluetooth before you get on the plane.
  • by nathanh (1214) on Tuesday April 19, 2005 @06:44PM (#12286978) Homepage

    It has nothing to do with "interference" with the electronic systems on the plane. Rather it's a social engineering trick. You see, when you're at 10,000 feet all the mobiles are out of reception range. So any calls or SMS are temporarily diverted to voicemail or messagebank. When the plane lands, suddenly every phone is in reception and all the stored voicemails and SMS flood through to every mobile on the plane. Simultaneously every mobile starts that stupid BEEP BEEP BEEP noise that lets you know about your stored messages. Imagine 700 mobiles all going BEEP BEEP BEEP in unison! It's enough to drive you mad. The flight attendants got pissed off at the noise and cleverly invented this cock and bull story about "interference". Now the mobiles are turned off until you reach the baggage claim area where everybody turns on their mobile phones and annoys the baggage claim attendants instead. You see, the flight attendants have this secret war going on with the hated baggage claim attendants; you and your mobile phones are merely pawns in their devious mind games. Muahahaha.

    • Now I finally understand why cell phones are banned in the immigration area at least at Detroit Metropolitan Airport, it has never made sense to me before...
    • thats funny, most people i know, including myself, turn their cell phone on as soon as they land.
    • They make cells that are more than 6 miles wide, and cell have to deal with hills and trees. 5280 feet are in a mile. A plane at 30,000 feet is within normal range of some tower. However the plane has line of sight, so 40,000 feet is likely to still be in range, even though that distance on the ground might be just out of range.

      • The cell phone towers broadcast a signal perpendicular to the tower. While some of the signal goes up, most of it just goes straight towards the horizon. Under ideal circumstances, if you were directly above the cell tower, you wouldn't get a signal. If you're 5 miles above a tower in an airplane (which is almost a Faraday cage), you probably wouldn't get a signal.
        • So it is just a little farther because the tower you are reaching is one you are on the horizon for, not the one directly below you. Either way you still have clear line of sight, with no hills or trees in the way. (They are called towers for a reason)

          They can aim antennas down, but most antenna designs that are aimable shoot a signal in the opposite direction of what they are aimed as well. (but not to the side, and generally a narrower and weaker signal)

          Planes might seems like a good Faraday cage, bu

    • You got modded up funny, and do seem to have put a largely humorous slant on it, but I think you do kinda have a serious point there. At least when it comes to the "700 mobiles all..." idea.

      It may not be so much the message-alert tone, but there is that annoying buzz that can affect radios and stuff. Now one phone putting out interference as it searches for a signal then gets a backlog of messages may not pose too much of a risk... (Yes, I know that sometimes it can just be the one small signal in the wro

  • So you're in the air. The pilot comes on and tells everyone to put the air mask on and brace for impact. Do you really want to find out at that point that, YES this crash was your fault, or Possibly that this crash was your fault. When I'm in the air I read a news paper.
    • You would know far in advance of that. If there was any type of problem with interferance, the Flight Crew would make an annoucement asking people to double check their cell phones/other electronic devices, or simply tell everyone to shut them off (such as taxi, takeoff, climbing, descending, and landing procedures require.)
  • I've been talking to my dad about this (who's degree is in electrical engineering but has worked for 20+ years as a commercial airline pilot) and he says that there is no documented situation, ever, where a cell phone has caused unsafe interference with the navigation equipment onboard the plane. The interference that these devices cause is an interference with signals that are already coming from outside the craft, there is no possibility of creating such a garbage signal that it would cause the plane to
    • by Detritus (11846) on Tuesday April 19, 2005 @07:00PM (#12287124) Homepage
      Tell your dad to check NASA's Aviation Safety Reporting System database. He should be familiar with it. There are many, many, reports of passenger electronics devices causing problems with aircraft systems.
      • Tell your dad to check NASA's Aviation Safety Reporting System database.

        hee hee.. maybe he can ask his mommy to check back issues of the RISKS listserv, where the discussion of electronic interference has been discussed to death by professional avionics engineers.
      • While setting the compass position off kilter, or slightly ebbing the coordinates of the plane may be annoying, these malfunctions are in no way 'unsafe' to the operation of the airplane, and are easy to correct. I'm not claiming that the cell phones don't do anything, I'm just saying that they aren't going to do anything seriously harmful to the plane or its occupants.
        • If cellphones really were effective in taking out planes, you'd see them banned as an anti-terrorism measure. That they're not strongly implies to me that cellphones have only irritating effects on flying.
  • As Toby on The West Wing put it, "This aircraft rolled off the production line 18 months ago, and you're telling me I can flummox it with a gadget I bought at RadioShack?"
  • by Grounded0 (703575) * <admingz@luukku.com> on Tuesday April 19, 2005 @07:18PM (#12287255) Homepage Journal
    ...take this [neisg.org] into consideration. :-)
  • Well. (Score:5, Interesting)

    by ColaMan (37550) on Tuesday April 19, 2005 @07:22PM (#12287279) Homepage Journal
    I don't know about you, but I was on a flight out of Singapore once...

    Casual Pilot: "Good evening everyone, we're ready to taxi, estimated flight time to Sydney is 8 hours, (blah ,blah, casual pilot chatter). Turn off all your cellphones for the duration of the flight, please."

    Plane begins to taxi.

    Plane abruptly stops taxiing.

    Grumpy Pilot: "Whoever's using their cellphone, please turn it *off*. Crew, search the cabin."

    After a pause of a few minutes, Plane begins taxiing again.

    So, hell, maybe they've got a few blinkenlights that blink when someone's got the phone on. As for bluetooth, yes, the power is miniscule. But as a pilot, you'd be pissed off if the plane you're flying lost some crucial function, because of eg. an overload of some very sensitive preamp that happens to be in the roof just above some passenger using bluetooth.

    So, I think they (and I!) would rather just leave the unknown variables out of the whole flying equation as much as possible, thanks very much.
    • Re:Well. (Score:1, Insightful)

      by Anonymous Coward

      Grumpy Pilot: "Whoever's using their cellphone, please turn it *off*. Crew, search the cabin."

      I'm gonna go ahead and say that, with no formal knowledge of electronics, and years of people telling him that cell phones do bad things, he attributed whatever bad thing was happening to the cell phone without any particular evidence. I could be wrong, but I dare you to prove it.

      But as a pilot, you'd be pissed off if the plane you're flying lost some crucial function, because of eg. an overload of some very

      • As a pilot, I'd be really annoyed that a professional engineer decided to use a really sensitive op-amp in my plane, and to leave it unshielded.

        Read through the Risks Digest [ncl.ac.uk] some time. Stupider things happen - and they happen a lot more often than you would like.

        As I mentioned, it's all about removing unknown variables. Has anyone does any rigourous testing of the effects of bluetooth devices on avionics? Yes? No? Don't know? Then lets just keep all the bluetooth activity to a minimum, to be on the safe
    • (puts on tinfoil hat)
      What an awsome application of social engineering to get everyone to turn their phones off :-)
  • yeh? (Score:1, Funny)

    by Anonymous Coward
    I often use the bluetooth features of my PowerBook and Treo while onboard a plane

    So why are you asking us NOW? You could have crashed long ago!

  • I've seen numerous legitimate studies and reports, originating in organizations from Boeing to the FAA, that found no verifiable or repeatable interference from any PED (personal electronic device) tested, including many which intentionally transmit.

    Argue any conspiracy theory you like, whether financial or otherwise, but rest well assured that the device prohibition is NOT about interference.

    $0.02,
    ptd

    • Re:It's all FUD (Score:4, Informative)

      by YrWrstNtmr (564987) on Tuesday April 19, 2005 @08:52PM (#12288007)
      Uh huh.

      A quick stroll through the ASRS database [faa.gov], searching on "RF Interference" or "EMI"

      Report # 541518
      DEPARTING SFO WE WERE ADVISED THAT ATC WAS NOT RECEIVING OUR TRANSPONDER. THE ATC FAIL LIGHT WAS ON AS WELL AS NUMEROUS TCASII FAULT MESSAGES. WE SWITCHED TO TRANSPONDER NO 2 AS PER THE OPERATING MANUAL AND ATC WAS ABLE TO RECEIVE IT. THE AIRPLANE HAD ONLY ONE MODE S TRANSPONDER SO WE HAD NO TCASII AT THIS POINT. THE FLT CONTINUED NORMALLY FOR ANOTHER HR OR SO WITH NO CHANGE IN THE STATUS OF THE NUMBER 1 TRANSPONDER AND TCASII. IT WAS AT THIS POINT THAT I DISCOVERED THAT I HAD INADVERTENTLY LEFT MY PCS PHONE ON. AND THAT IT WAS IN SEARCH MODE. I TURNED IT OFF. IMMEDIATELY, ATC NO 1 AND TCAS WERE RESTORED TO FULL FUNCTIONALITY. NO FURTHER ANOMALIES WERE OBSERVED DURING THE FLT.

      Report # 536654
      NAV INTERFERENCE. OVER CHT, CLRED '10 DEGS R INTERCEPT LOC RWY 31L PLAN CIRCLE RWY 22L.' UPON TUNING LOC FREQ AND SETTING COURSE, IT APPEARED WE WERE ON THE LOC, ALTHOUGH VISUALLY WE APPEARED S OF COURSE. ATC ASKED IF WE HAD INTERCEPTED AND SAID WE WERE S OF COURSE. THE CDI THEN SWUNG FULL SCALE TO THE OTHER SIDE INDICATING WE WERE N OF COURSE. I TURNED TO CTR THE CDI AND WE SWITCHED TO TWR. MY CDI SWUNG R INDICATING WE WERE S OF COURSE. I NOTICED THE FO'S CDI WAS SWINGING THE SAME DIRECTION AS MINE, BUT MOVING ABOUT HALF AS FAR. WHEN WE SAW THE RWY, WE WERE N OF COURSE WITH CDI'S INDICATING WE WERE S OF COURSE. WE WERE HIGH AND WELL N OF COURSE WHEN TWR ASKED IF WE COULD GET DOWN FROM THERE. WE ASKED TO BE TURNED OUT TO RE-ENTER THE PATTERN. UPON TURNING OUTBOUND WE MADE A PA ASKING PEOPLE TO PLEASE MAKE SURE THEIR CELL PHONES AND OTHER EQUIP WERE TURNED OFF. THE CDI'S IMMEDIATELY BECAME STEADY AND WE COMPLETED A NORMAL ILS RWY 31C CIRCLE RWY 22L WITH NORMAL INDICATIONS AND THE FLT ATTENDANTS RPTED THAT A WOMAN IN THE FORWARD LOUNGE WAS TALKING ON HER CELL PHONE. AS SOON AS SHE TURNED HER PHONE OFF, OUR CDI INDICATED NORMALLY.

      Report # 283948
      CLBING THROUGH 13000 FT MSL, RADIO ALTIMETER INDICATED 900 FT. GPWS SOUNDED 'TOO LOW TERRAIN.' THIS WARNING CONTINUED FOR SEVERAL MINS. HAD FLT ATTENDANT CHK CABIN FOR ELECTRONIC DEVICES. PAX WAS FOUND WITH CELLULAR PHONE 'ON' BUT NOT IN USE. PAX SHUT OFF CELLULAR PHONE AND PROB STOPPED. NO FURTHER PROBS DURING REST OF FLT OR RETURN LEG (ORD-LGA-ORD).

      • The reports I read mentioned anecdotal observations like these too. But none were repeatable or deterministically linkable.

        If PEDs were the cause of those incidents, did anyone prove it measurably or repeatedly, or did they simply invoke post hoc reasoning to incite fear?

        Let's face it, people leave their cell phones on during flight all the time, whether accidentally or obstinantly. If there was even a statistically remote likelihood of causal interference, wouldn't that be sufficient reason to not even a

    • In one of the many mobile comunications journals I get I get spammed with I read that one of the largest problems with inflight GSM trafic was not the interference - which is a semi serious problem - but the fear that Airlines would have to face litigation if they travel over multiple GSM masts at high speeds with many passengers with GSMs trying to connect to each of the masts.
      As with wifi, GSM to AP communication can take some time, this is even more problematic if you take into account that the telco may
  • by noahbagels (177540) on Tuesday April 19, 2005 @08:08PM (#12287652)
    Dear /. readers.
    I'm an FAA certificated private pilot of several years. I work in the aviation industry and have had some interesting experiences with this exact issue.

    I do not know that, or pretend to know that operating any RF devices will "crash" an aircraft.

    I DO know that even leaving a cell phone on during flight can interfere with avionics and communications. This is from real experience - and it was *very* distracting.

    Here's the story: Flying closed traffic touch & goes at Oakland International Airport, my instructor (CFII) and I were both hearing a loud static noise at two places in the pattern. This was pretty darn distracting to say the least. Here we are, doing proficiency drills (landings / pattern / emergency landing without power, etc) and there's a darn buzzer in our ear shortly after takeoff and at midfield. What was it? I had left my cellphone on accidentally and buried deep in my flight bag. It was soo annoying that I asked my instructor to fly the plane while I akwardly tried to twist around the seat of the C172 and find the cell, and only was able to after several painful moments - but it was worth it for how annoying the buzzing was.

    Now, this was a Day VFR (visual flight rules) flight under nearly ideal conditions. Most major aviation accidents that occur have some level of human factors that play into the incident. Further, the NTSB establishes a "chain of events" that leads up to the accident - any one of which being broken would likely have prevented the accident.

    Let me ask you this. You are cruising at night in IFR conditions (in the clouds, no horizon) 30,000 feet in a commercial aircraft and the pilot loses his artificial horizon. Immediately, the pilot informs the copilot and the copilot starts flying the aircraft on his 'good' instrument. You land safely. This exact scenario was one of the more recent fatal airliner accidents in Asia, except that the pilot was distracted and did not properly give control to the copilot.

    Do you want the pilot of your aircraft to be distracted by frequent buzzing in his/her headset? Aircraft these days have the capability of flying and landing themselves. Pilots are largely there for two reasons (IMHO). One of these is to re-assure the public. The other, perhaps more valid, is to deal with emergency situations. Please - don't mess with them, once the autopilot is disabled/off, they're your only chance.
    • I've also seen the static effect when a cellphone was left near a speaker of any kind, I think what you were experiencing was caused more by the fact that your cellphone was near your radio system. I doubt it would have a smimlar effect if the cell phone was farther away.
  • Since I drive quite a lot, I am very familiar with the warnings about drinking while driving (could be bunk, but I still respect it and those around me). But what about using LSD? A police officer just told me that I'm not supposed to use any recreational drugs while driving. I often take LSD while driving my car. Could this cause any problems, or is this something I need not worry about?

    Ok, maybe I'm taking a few liberties in rewriting the question, but in all seriousness... you are required by law t
    • Of course here in Australia they are starting to implement random drug testing of drivers. So in fact you re-writing of the question is not as outlandish as you think.
  • by mbstone (457308) on Tuesday April 19, 2005 @10:56PM (#12288994)
    It wasn't so long ago that the airlines banned [slashdot.org] PDA-cellphone combinations such as the Treo. Now, many airlines including AA, Southwest and JetBlue allow you to use your Treo if you can show the flight attendant that the wireless feature is turned off (see, e.g., the back pages of American Way magazine). All it would take is one ***hole to be found interfering, say, with the intracabin communications system used by the Federal Air Marshals to have the policy revoked, and then I wouldn't be able to read ebooks or AvantGo on airplanes anymore. Thanks a lot.
  • Have you ever played with those science exhibits where two parabolic reflectors are seperated by a large distance in a room? You talk towards one, and someone at the other reflector can hear you clearly while others between you cannot.

    Have you ever driven a car that, at a certain speed or on a certian road, the car got *very* loud, and all you had to do was speed up or slow down to dampen the noise?

    The first example has to do with reflection. The second has to do with resonance.

    In a flying tin can you cannot possibly know where the reflections and resonance will occur. You do not know what equipment may or may not be affected by your transmissions.

    While holding your cell phone next to an avionics box may have no effect, sitting in seat J23 with the cellphone in your pocket as it broadcasts at maximum power (because, see, you're in a tin can) may be just the spot to form a nice reflection which, coupled with a resonance, would put a very strong signal right at the wrong spot of an important piece of equipment.

    Your blue tooth has the same problem, though the frequencies are difference, and the power *should* be less. This doesn't actually make it any less dangerous, however.

    The plane you are riding in is likely very old. The equipment can easily be more than 20 years old, and if the equipment itself isn't, the design is.

    The long and short of it is: Planes are a bad place to use equipment that intentionally radiates (ie, transmits). They aren't so great for devices that unintentionaly radiate either.

    While "testing" does take place there is no way to ensure that everything will operate properly in real conditions - only a complete design analysis could come close to providing that information.

    -Adam
    • Agreed. I think that a lot of the hysteria surrounding cell phones (for example, the ability to turn gas stations into firebombs) is bogus. Likewise, a large reason behind aircraft cell phone bans seems to be that they cause problems for providers when attempting to peer with every single mast over the tri-state area at the same time.

      But as you state, you simply don't know what radio waves interfere with which electronics under what variations of a given condition. As for bluetooth, various implementati
  • In all seriousness, aren't the aircraft manufacturers more than a bit negligent for not building avionics etc in ways that shield them from unwanted RF?

    If every airliner has a couple hundred cel phones on it, and if in all likelihood at least couple will not be turned off, should airlines really be working to design the passenger compartment to keep that RF inside?

    Or, if you're a passenger, wouldn't you prefer to know that the plane had been designed to keep cel radiation from interfering? As it stands n
  • Considering some flights offer Internet access using 802.11b/g it seems the flight companies acknowledge it to be safe. Bluetooth is using the same frequencies (the ISM bands) as 802.11b/g, but at lower power. If the flight companies allow 802.11b/g, there really shouldn't be any problem with Bluetooth.

    But what do I know (IANAAirplane technician), maybe they have given the airplanes that allow 802.11b/b some special treatment? I find that unlikely though.
  • It's pretty simple. If you get on a commercial aircraft, you're implicitely agreeing to whatever rules they tell you. So don't be a schmuck and do what you promised to do. Don't turn on your cell phone. Don't use your laptop, game boy, whatever until after you're in the air for 10 minutes.

    You agreed to it, so do what you agreed to do.

    Second guessing them doesn't get you anywhere, it's just being shitty.

    By the way, the AOPA right now is working to get cell phone use from the air approved. If that's d
  • by DjReagan (143826) on Wednesday April 20, 2005 @05:42AM (#12290686)
    I doesn't really matter whether its a risk or not - the fact remains that failure to follow the directions of the airline crew is a federal offence.
  • What a bunch of crap. I mean serieously. I don't care if you are an electrical engineer with 20+ years of pilots experience, or a super tester avionics tester at NASA, because obviously you don't know shit. (with 'you' I mean everybody that thinks it could interfere or the like).

    More informed slashdot readers should remember [slashdot.org] these [slashdot.org] articles [slashdot.org].

    Yes Wifi on airplanes is a reality allready, and experiments with bluetooth and GSM are on the way aswell. (Actually that article was 'pre' lufthansa's wireless servi
  • Since virtually every laptop carried by a airline traveller has a wireless card, and I'm sure virtually every one of those has the wireless enabled by default, doesn't this mean there is plenty of wireless traffic inflight from people turning on and using their computers?
  • Really this is mostly BS. Any well designed system will have shielding and be fairly secured from interference. One of the real reasons this ban (and the existing bans in hospitals) was created was so they could charge you outrageous prices for using their in-flight phone services.

    If the problem was really that serious the FAA wouldn't be considering lifting the ban on cell phones in planes. I know that cell phones can put out tons of interference but most of the interference is in the short range (unde
  • They asked you not to use RF-transmitting devices on the plane. So why do you ignore them?

    Oh wait. You probably also ignore that big red octagon with the letters "STOP" written on it while you drive.

    Or, if you bike, you probably ignore traffic signals, stop signs, and every other rule that ALL vehicles are supposed to follow.

    Maybe you eat lunch on the public transit right under the sign that says "PLEASE DO NOT EAT WHILE ON THE TRAIN" (substitute bus, etc.).

    20 in a school zone? F that!

    Granted, some
  • In 2000, the UK version of the FAA, the CAA [caa.co.uk] carried out study [caa.co.uk] on mobile phone interference.

    The study, carried out in a laboratory, indicated [section 6.2]that cellphones can cause interference to VOR and ILS indicators and background noise to audio channels.

    Whilst section 6.2 does point out that the interference caused problems when the cellphone was very close to the equipment or wiring harness, its not inconceivable that someone using a cellphone on an airliner could be in relatively close proximity to

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