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Cell Phones and Air Safety

Cutie Pi writes "On the heels of this recent Slashdot story discussing Wi-Fi use on airplanes, the BBC is reporting about new evidence indicating that cell phones can interfere with airplanes' navigation systems. From the article: "In tests, compasses froze or overshot, navigation bearings were inaccurate and there was interference on radio channels." Look like like Wi-Fi and airplanes just don't mix."

36 of 295 comments (clear)

  1. Um... by autopr0n · · Score: 4, Informative

    Wifi uses far less power then cellphones do.

    --
    autopr0n is like, down and stuff.
    1. Re:Um... by Beryllium+Sphere(tm) · · Score: 3, Informative

      Cell phones, maximum around 0.6 watts. Typical WiFi, on the order of 50 milliwatts.

      Furthermore WiFi is direct sequence spread spectrum, so the amount of energy at a given frequency is even lower.

      What could cut either way is that WiFi equipment is at a different frequency from cell phones.

      I don't expect anyone to pay for the careful and expensive research and testing to prove whether passenger-operated uncertified radios can be used safely. You'd have to test every position in the cabin, to allow for multipath effects, and you'd have to check every operating mode of every safety-related piece of built-in electronics, and you'd have to repeat for every make of consumer radio, and even then you wouldn't be up to aviation safety standards because a consumer products company might let equipment come off the line with "minor" deviations. There's a totally different mindset in aviation safety, where equipment is guilty until proven innocent.

      Then come the combinatorial problems. Passenger A uses a GSM phone at 890-915 MHz. Passenger B across the aisle uses a WiFi card at 2.4GHz. Both induce currents in the aluminum structure, including the corroded joint in the 20-year-old airplane. The corroded joint is nonlinear and mixes the signals, retransmitting sum and difference frequencies and higher order combinations.

  2. Aren't they already banned? by cascino · · Score: 3, Interesting

    Aren't cellphones already banned on commerical airliners?

    1. Re:Aren't they already banned? by Verence · · Score: 5, Informative

      Cell phones are banned from gate to gate. You are not allowed to use them during flight.

      I recall an anecdote of a lady. She used her phone while approaching the airport (coverage in the air would be absolutely amazing) and was met at the gate by law enforcement.

      They are *not* allowed in the air.

      --

      ... that's all i wrote...
  3. Cells by CptChipJew · · Score: 3, Insightful

    Cell Phones don't mix with anything.

    Cell + Driving = Death
    Cell + Extended Use = Brain Tumor -> Death

    Although they've done wonder for the Tiny-Blue-LED Industry.

    --
    Vonal Declosion
    1. Re:Cells by cybermace5 · · Score: 3, Funny

      Cell + Extended Use = Brain Tumor -> Death

      All the times that urban legend is repeated + One more = Brain aneurism -> Death

      --
      ...
  4. compass? by Faust · · Score: 5, Funny

    I sure hope they are using more than a compass to navigate a commercial plane.

    1. Re:compass? by rbbs · · Score: 5, Informative

      In answer to your question: Civil Aircraft navigate using a variety of methods. Depending on where in the flight programme these are, this could be anything from VOR (Very High frequency Omni Directional Range) system to a Heading Select system ILS system or ADF. The Nav system itself functions using a variety of inputs including VOR (Military systems operate on TACAN (Tacital Area Navigation) which uses UHF rather than the mid band frequencies that VOR uses), Compasses, Accelerometers, Gimballs, Gyros as well as Ground Mapping RADAR fixes, GPS (these days), JTIDS (Joint Tactical Information Distribution System -Military again), On-Top fixes, HUD fixes and Offset fixes in addition to ADF (automatic direction finding) These inputs are used for comparison within the autopilot which uses a triplex (usually) voting system to decide what to show and what to do. (obv this various from system to system) So, finally, in response to your question, yes the plane does use a compass to navigate and whilst all these sub-systems are designed to promote redundancies within the larger system, they are taken into account and in the event of a larger systems failure, may be relied upon more than the pilot may realise - hence one of the major problems in over reliance on redundant systems...your perceived level of safety increases thereby causing you to change your actions accordingly and hence reducing the overall safety of the craft. - But thats another story. Incidentally, the reasons for not using cell phones on planes are neatly put at this link Airborne operation of PEDs [PDF] (I am not a pilot)

  5. No Immunity Requirements? by LinuxInDallas · · Score: 3, Insightful

    For commercial and medical products we have to design based on certain electromagnetic immunity requirements. What's the deal with the equipment on airplanes? I realize that wireless lans probably produce a fair amount of radiation that has to be handled but that's no excuse. I would think EVERY piece of electronics in an airplane would be designed to handle far worse. Why is that stuff so fragile?

    1. Re:No Immunity Requirements? by DarkBlackFox · · Score: 4, Insightful

      Most airliners in use today were designed and built well before cell phones became mainstream, and well before WiFi standards were adopted. When they were built, there was no need for concern over something that for all intents and purposes, didn't exist.

      I'd imagine an overhaul to "cell proof" all commercial planes would cost the already struggling air industry more than they can handle.

    2. Re:No Immunity Requirements? by Detritus · · Score: 3, Informative

      A perfectly shielded communication or navigation receiver is still a radio receiver, which can be jammed by passenger electronic devices. Consumer electronics equipment is designed to be cheap, not to minimize spurious emanations. Radio transmitters commonly have spurious emanations. They may be suppressed by a reasonable amount, but that may not be enough if they are near a receiver that is receiving a weak signal. Then there is interference caused by intermodulation. All you need are several strong signals and a nonlinear junction.

      --
      Mea navis aericumbens anguillis abundat
  6. Doesn't make sense by SeattleDave · · Score: 3, Insightful

    Planes are bathed in cell phone radiation just sitting at the gate and certainly during take-offs and landings in busy metro areas. People in the airports and surrounding areas certainly don't curb their use of cell phones. It doesn't make sense to suggest there's a serious danger to airplane navigation. Would we not have seen them before.

  7. Well, that's comforting by ryanr · · Score: 4, Funny

    I can't do my nails on an airplane, but they let me take all the cell phones and WiFi equipment on that I want. In fact, they make sure that they work before you can take them on.

    As long as they're not pointy.

  8. ok, but... by dwgranth · · Score: 5, Insightful

    The article does NOT mention the age of these airplanes.... which does make a big difference since Boeing and Airbus have started shielding their equipment better in their recent airplanes

  9. BT plans wifi on its planes.. by wfberg · · Score: 3, Informative

    According to the register,
    British Airway is set to introduce on-board broadband services next month.
    and Connexion By Boeing has received to go ahead from the US Federal Aviation Administration to use WiFi networks with satellite links aboard planes, after satisfying the authority that the technology is safe.

    Anyway, your cell phone won't work on a plane, it goes to fast to do hand-offs between cells properly.

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  10. Re:I guess I really should shut off my cell phone by MeerCat · · Score: 4, Informative

    because I think it's ridiculous that it could really be harmful. I guess I was wrong?

    Do you leave it on in your pocket when you fill up with "gas" (petrol) too because it's ridiculous that a spark could cause an explosion of fumes ? Do you smoke while filling the car up too ?

    Put your phone next to your car antenna and turn the radio on, and turn the phone on - hear that "dut-dut-der-dut-dut-der-dut" pulsing ?? Notice how you get the same effect when you drive to the airport (from their radar) ? Do you figure maybe a cell-phone that can't get a signal so has upped its power output to max to try and get one, about 20 feet away from the plane's antennas is going to providea stronger pulse than the radio signal being transmitted from 5 miles away ?

    I was standing on the tarmac waiting to board a flight in Pakistan, next to a 747 that was being re-fuelled (which was freaking me out anyway - the av-gas fumes were really strong), and the people behind me decided this would be a good time to light up a cigarette... (they were german, said something about being ridiculous when I told them to put their lighters away and put their "f*ckin fags out").

    --
    I spent a lot of money on booze, birds and fast cars. The rest I just squandered. - George Best
  11. long range wifi? by SHEENmaster · · Score: 3, Funny

    Maybe I could solder a signal amp onto my airport card and wap to get longer range?

    Better yet, I mercilessly slaughter ever 2.4ghz cordless phone for causing interference with my wifi.

    --
    You can't judge a book by the way it wears its hair.
  12. load of bull by gobbligook · · Score: 3, Insightful

    What about all the planes that are taking off from the airport in the middle of a city? Are people required to turn off their cells in the airport terminals? Are telcos not allowed to place towers near airports?

    I bet those 30+ incidents reported blamed cells because they needed a scapegoat for their lack of good equipment checks.

    I once heard a cell phone was blamed for starting a gas station on fire. Perhaps that would be true, except the last I checked circut boards arn't a good source of spark. Next thing you will see is women being baned from wearing makeup and good looking clothing because it is a distraction for the pilots. Give me a break

  13. ok some dumb questions.. by zogger · · Score: 3, Interesting

    ...if it's all this bad, why don't planes fall out of the sky from all the existing thousands of cell phone towers all broadcasting, and tv and radio stations and other sorts of radio wave emitting places? Why not? Is it *really* that bad, or is this FUD? Seems like if it was really that bad we would have seen mass crashes and various huge numbers of fubars by now, yes?

    I am skeptical, but readily admit I don't know.

  14. Re:I guess I really should shut off my cell phone by wfberg · · Score: 3, Informative

    Do you leave it on in your pocket when you fill up with "gas" (petrol) too because it's ridiculous that a spark could cause an explosion of fumes ?

    Ridiculous.

    Do you smoke while filling the car up too ?

    Not ridiculous.

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  15. fix the airplanes by g4dget · · Score: 4, Insightful

    If navigation and other electronic systems on airplanes malfunction because of consumer devices that are tens of feet away, then there is a problem with the design of airplane electronics that needs to get fixed. Otherwise, airplanes are just way too vulnerable. And transmitters can masquerade as just about any kind of electronics--if they don't get fixed, then pretty much all electronics will have to be banned for security reasons. Just more deterioration of service--"we won't fix it, we'll just make things even more uncomfortable for our customers"--and people wonder why airlines are going bankrupt.

  16. Wait, am I reading this wrong? by dethl · · Score: 3, Insightful

    Look like like Wi-Fi and airplanes just don't mix.

    And yet you link to a story about Cell phones! Cell phones != wi-fi!

    /end rant

    --
    "Some fight for law. Some fight for justice. What will you fight for? One day, you will see."
  17. 35?? by c1pher · · Score: 3, Interesting

    "Since 1996, pilots have reported 35 mobile phone-related safety incidents, including false warnings in the cockpit, distractions causing aircraft to stray accidentally onto runways or fly at the wrong altitude, interrupted radio communications and multiple safety systems malfunctions."

    35 cases in 7 years?? How many planes fly each day??

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  18. Cell Phone Interference Report by B3Geek · · Score: 4, Informative

    Here's a report (pdf) that discusses the interference effects of cell phones on aircraft: Interference Levels In Aircraft at Radio Frequencies used by Portable Telephones An html version is available on google.

    Executive Summary

    Measurements made on two types of civil transport aircraft confirm that transmissions made in the cabin from portable telephones can produce interference levels that exceed demonstrated susceptibility levels for aircraft equipment approved against earlier standards. Since aircraft equipment in this class is currently in use, and can be installed, and is known to be installed, in newly built aircraft, current policy restricting the use of portable telephones on aircraft must continue. Recommendations are made to reduce the interference risk and for further studies to understand more precisely the effects of interference to aircraft equipment arising from the use of portable telephones.

  19. Difference between "VFR" and "IFR" by Maxwell'sSilverLART · · Score: 3, Interesting

    The navigation instruments in question are extremely sensitive; that precision is required when operating in the terminal area (particularly on the approach) in clouds or other visual obstruction. Operating in such conditions is done under Instrument Flight Rules (IFR). Particularly in the terminal area, IFR operations depend on precision, with less error tolerated the closer the airplane is to landing. On final approach (200' above the ground, 1/4 mile from the touchdown zone, moving at 150 knots, for a typical airliner; some approaches can be flown entirely by instrument, without ever seeing the ground, all the way to touchdown), precision is very important; a very small error could have significant consequences.

    Navigating from city-to-city is usually done with the aid of instruments regardless of conditions, but doesn't require quite so much precision--consider that, in trying to find New York, you're looking for a target several hundred square miles in area. A half-mile here or there is irrelevant.

    How did they hit the buildings? Well, if you saw any video at all of any of the crashes, you might have noticed the color of the sky: blue. As in, no clouds. Without clouds or other visual obstructions, operations can be carried out under Visual Flight Rules (VFR). In short, the terrorists steered the airplanes toward the targets that they could see, visually, from many miles out!

    Duh.

    --
    Moderate drunk! It's more fun that way!
  20. Re:cellphones being used in hijacked planes on 9/1 by moonbender · · Score: 3, Informative

    Cell phones can work in planes. When you zip over the country, your cell phone antenna has an enormous range due to the fact that there are basically no obstructions compared to the walls and trees present on the ground. But the service providers really hate it, because you leave old and re-enter new cells at an extremely high rate, which generates a huge amound of traffic in the respective cell towers.

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  21. Re:Physics by Maxwell'sSilverLART · · Score: 4, Interesting

    DME, VOR and ILS are based on ancient technology.

    I believe you meant to say "DME, VOR and ILS are based on ancient technology that is well-proven and works.

    Seriously, the reason the ILS hasn't changed in half a century is that it has a wide installation base (so changes would affect hundreds of thousands of airplanes around the world). We have a technology with incredible inertia; lots of people use it, and it is ungodly-expensive to replace avionics. (Nav/Comm radio? $2K for a nice one. GPS? Try $10K for some of the nicer models, equivalent to what you find in nicer cars these days. And that's in the light aviation market--radios in jets start closer to fifty grand apiece, and most airplanes have three or four comms, three or four nav radios, GPS, etc.) Changing technology requires exhaustive testing to gain certification, and an enormous investment from all parties; if a new system is going to "take off" (pun intended), it will have to be available in a wide area, or else nobody will want to pay for it.

    The ILS has seen some incremental improvements; standard (Category I) ILS typically guides the airplane down to 200' above ground level (AGL). Cat II ILS, which requires special equipment on the ground and in the air, and special pilot training, reduces that to 100' AGL. Cat III ILs (which is actually subdivided into IIIa, IIIb, and IIIc), can provide guidance all the way down to the runway, in zero-zero conditions (zero foot cloud ceiling, zero foot forward visibility). The technology is proven reliable, relatively simple (always nice), and has the capability to go to zero-zero; what more do you really want from it?

    VOR is "good enough" for most purposes; it has a nominal accuracy of four degrees (if memory serves), which is only four miles' error when you're sixty miles from the station. In most parts of the US, you would be hard-pressed to get more than sixty miles from a station. Four miles' error may sound like a lot, but it's really quite inconsequential--all of the other airplanes on VOR are seeing the same error, so it's a simple transposition, and you're in controlled airspace anyway, with a guy watching a radar screen to keep an eye on things. On top of that, the absolute error decreases as you approach the station. Given that most VORs are either on or near airports, the problem takes care of itself; as you get close to the airport (where precision is more important), the error decreases. Distance Measuring Equipment (DME) is plenty accurate at low altitude[0], and at high altitude, errors are less critical; on top of that, when using DME, everything is referenced to DME readings, so again, it's a transposition error. As long as everybody's on the same page, it's not a concern.

    If you really need that degree of positional accuracy, there's GPS, which is being adopted with great enthusiasm by the aviation community. If you need more precision, use WAAS/LAAS, or inertial nav, or all of the above into a flight management system; if you need that kind of precision, though, you're probably referencing yourself to something specific on the ground. If that's the case, there's a wonderful navigation technology that can give you all kinds of precision. It's called "eyeballs."

    Voice (and other stuff) is done using AM instead of FM because AM has lower power requirements for equivalent service; less power means less weight in the airplane, and better service for the ground station. Jam-resistant modulation? Again, we run into the problem of paying for the upgrade (unless, of course, you're offering), testing (and lots of it), and the fact that we have no real need. If we get into a situation where we're in that much trouble, the civilian fleet will no doubt be grounded (again!), and the military already has encrypted, jam-resistant communications and navigation technology. What we really need is more bandwidth, and we're getting that by reducing the channel spacing (comm channels have gone from 50kHz to 25kHz, and are moving to 8.33kHz)

    --
    Moderate drunk! It's more fun that way!
  22. Re:Now, if the radiation is baking the electronics by anonymous+loser · · Score: 4, Informative

    You get 50 times as much radiation from background sources like the sun, the earth (plants & minerals),etc. than from any man-made source like consumer electronics.

    But don't take my word for it, read the CDC study.

  23. Not really all that funny. by Nick+Driver · · Score: 4, Informative

    I sure hope they are using more than a compass to navigate a commercial plane.

    They do.
    The compass is there to fall back on in case the sophisticated stuff quits working for whatever reason. And yes, a cellphone can interfere with the magnetic compass. I know, I'm a private pilot and own a small aircraft. Every bit of electrically operated gear in the cabin jacks with the compass's reading. Since I *know* how the electrical equipment that's installed and certificated as part of my aircraft affects my compass, I can deal with and compensate for that since I'm intimately familiar with all that gear.

    It's all the *unknown* electrical devices that are brought on board an airliner and operated by passengers, that an airline pilot doesn't need to be made to worry about and wonder how to compensate for because if the situation has deteriorated to such a bad point that he's having to use the mag compass, you want nothing to interfere with it.

    Now you might want to say,"How often does everything really go wrong and the pilot have to use the old fashioned mag compass to navigate?" Well, not very often at all in fact extremely rare, but I have to ask you, "How many times have you needed the spare tire in your car"? Well, I've driven my current vehicle over 150K miles in the past 11 years and never needed it, but that still doesn't mean I'm going to remove it or let the air out of it, or not check to see if it is in roadworthy before embarking upon a long trip, so why should the airline pilots risk the integrity of their last backup spare navigation instrument just because some selfish passengers want to play with their toys on board. Hell, the passengers should consider themselves lucky they are still allowed to fly at all and not having to make do with only ground and water transportation.

  24. WiFi vs. cellphones on planes by frdmfghtr · · Score: 4, Informative

    OK, so cellphones cause trouble...I've read stories in airplane magezines where cellphones affected small-plane avionics.

    BUT...to say "planes and WiFi" don't mix is inappropriate, since:

    (a) the article makes no montion of WiFi

    (b) WiFi is lower power

    (c) Wifi is in the 2400MHz range. CDMA is 1900GHz, GSM is 900/1800/1900MHz, depending on where you are.

    CLearly, if Lufthansa felt that WiFi was no threat to avionics, they wouldn't be testing it on international flights OVER WATER.

    --
    Government's idea of a balanced budget: take money from the right pocket to balance...oh who am I kidding?
  25. It's mostly GSM that's at fault. by Chmarr · · Score: 4, Interesting

    I'm a recreational pilot, and I've had first-hand experience with mobile phone that interfere with the avionics on a light aircraft. I've not witnessed any issues with nagivation instruments being affected, but I've certainly had interference on the communication systems (radio) from the mobile phone, when, for example, I've forgotten to turn my own mobile phone off (quickly remedied, thankfully :)

    However, it's mostly GSM phones that are the problem. When the phone detects that it's losing contact with the cell, it makes a short burst of very high energy transmissions that, on the radio, sound like 'dt-dt-dt dt-dt-dt dt-dt-dt' (morse code for SSS? :). It's very annoying.

    However, I've NEVER noticed this with a CDMA (okay, technically IS-95) phones, which are a lot more common in the USA (vs England and Australia which primarily use GSM now). So, the UK's test is probably more accurate for GSM phones. However, I'm also sure it's not a black/white issue, but rather a matter of proportions.

    Personally, if *I* was in charge of the safety of a passenger-carrying flight, I'd want to make damn sure there wasn't ANYTHING that could adversely affect navigation, even if the chance was remote. Flying around IFR at night is /scarey/ :)

    Further studies need to be done. Operators need to weigh the costs of shielding the navigation instruments against the benefit of allowing passengers to use bluetooth/WiFi on the aircraft. And, passengers need to damn well obey flight crew instructions :)

  26. rules against cellphones by cronian · · Score: 3, Insightful

    During takeoff and landing, all electronic devies are banned, because they can intefere with airplanes. However, cell phones are banned from the air by the FCC, because they work too well. They don't cell phones on airplanes tying up its frequency in range of 30 base stations, which would cause interference with ground cell stations.

    Have you ever heard of an airplane crashing from cell phone usage? If it was really that easy to create safety problems, I'm sure it would happen all the time. Besides, terrorists could easily bring a much more powerful brodcaster onto an airplane. The real reason cell phones are banned, is that airlines don't want competition to their really expensive phones.

  27. Selfish by JimPooley · · Score: 3, Informative

    Remind me never ever to board a plane with any of you selfish fuckers who are so afraid of going without using their precious toys that they'd put the safety of their fellow passengers at risk.
    The world's aeronautical authorities don't do this sort of thing for fucking fun you know. This is serious business, and some of the responses coming from know-nothing fuckwits on this forum fill me (as occasional plane passenger and as a pilot) with horror.

    --

    "Information wants to be paid"
  28. Wireless Technology Aboard Aircraft by BenFranske · · Score: 4, Informative

    I have a friend who used to work for Motorola and another friend who is a pilot and have disscussed this many times with both of them. The pilot friend has confirmed that in reality there are no issues with cell phones, or almost any other consumer wireless technologies aboard aircrafts. It does introduce some risk when flying under instrument flight only, but cause no problems during normal cruising. With this information I was left wondering why they are banned in most commercial planes. My friend from Motorola explained that when the cell phone system was designed it was not designed to hand off calls from one tower to another tower for a phone traveling at such great speeds. In fact if you drive too fast on the road (something over 140MPH in testing) you will also have problems. Planes are flying high causing you to access multiple cells at once and you are moving to fast for the handoff to occur from one tower to another. For this reason cell phones have been restricted on commercial planes. In fact amateur radios which put out far more power than a cell phone or wifi cards are allowed to be used on planes pending the pilots permission, this confirms that it's not an issue as it is not prohibited by FCC rules. It's not reallly an interference problem, it's a policy and cell technology problem.

  29. What's with the attitude? by CausticWindow · · Score: 3, Insightful

    Why are everybody going "no damn way, you'll pry this cell phone from my cold dead hands, I need scientific evidence". What about being a bit cautious, or are you all leet electrical engineers?

    I have experienced cell phones interfering heavily with electronic equipment on the ground and also in flight, so this isn't a complete fabrication.

    While I was flying in a dash8, the fire alarm went off, which was pretty damn scary, I tell you. Later it turned out that a cell phone recieving a call would almost always trigger the fire alaram system in a dash8.

    I really don't understand why you are so negative towards this. Do you think it's some kind of airline conspiracy, forcing you to use their expensive phones?

    --
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  30. I'm a private pilot by transient · · Score: 4, Insightful
    I think this preflight briefing between my sister and I sums it up pretty well:

    Me: Kat, is your phone off?
    Kat: Will my phone really mess up the plane?
    Me: I don't know. Do you want to find out?
    [Kat turns off her phone.]

    My point is that almost none of us are qualified to determine whether mobile phones cause problems for aircraft. (Raise your hand if you're a certificated avionics technician.) Unless you were on one of the September 11 flights, there is not a single phone call so important that it's worth jeopardizing the safety of the flight. All of the people who are getting indignant about not being able to use their precious phones on an aircraft should step back and get some perspective. I'm an instrument-rated pilot, and if you're in my plane when I'm shooting an ILS through a 200 foot ceiling, you damn well better turn that shit off.

    --

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