6 ms·

The Real Hazards of E-Devices on Planes

42 points by 001sky 14y ago

jkat 14y ago
The FAA is being ridiculous about this. However...there's literally nothing I find more aggravating than flying - because of other passengers. Every flight, there's always a handful of people who refuse to follow the simple rules. Their carry-on is too big. They switch seats or use the lavatories when they are supposed to be seated and buckled-in. They don't re-adjust their seats when landing. They grab their carry-on while the plane is taxiing. I always feel horrible for the flight attendants. It feels like they are running a day care. Why are people like that? Are they stupid and don't understand the rules? Or do they think the rules don't apply to them?
- yareally 14y ago
  Modus operandi for many people is to get away with whatever you can until you're told otherwise (or caught). Just most do this with petty things versus breaking major laws.
- swombat 14y ago
  > Why are people like that? Are they stupid and don't understand the rules? Or do they think the rules don't apply to them? Speaking for myself, I have no respect for authority that does not stem from experience, knowledge, wisdom, etc. Air hosts/hostesses have none of those attributes - they are merely parrotting rules handed down to them, without putting any thought into them. A case in point is the electronic devices rule - clearly nonsensical and stupid. I take it as a good sample of the sense in the other rules being imposed, and therefore revert to my default mode of operation, that applies in most circumstances, unless overridden by someone who appears to deserve to have the power to tell me what to do. In other words, I do what I think is sensible, reasonable. Therefore, yes, I do check my emails before the plane has finished moving and even (gosh!) before the passport gates. I do grab my bag at the first opportunity (though it's usually pointless to do so before the plane has stopped moving - but then it's reason that's stopping me, not rules). I do fit as much as I can get away with into my bag (which generally weighs more than 5kg - but is usually compact and easy to stow because I value those attributes). In other words, I act like the free, responsible human being that I am, and no, I don't care one whit for "the rules" except where I have analysed them and deemed them sensible myself. Here's some good news for you: "the rules" don't apply to you either - not unless you want them to.
  - jkat 14y ago
    I don't disagree with your premise in general....but...The silliness of one rule doesn't, in my mind, invalidate all the other ones. I mean, couldn't you reverse your logic? Find a rule that makes sense (say, no smoking on the plane) and thus summarize that all rules make sense? I keep thinking to myself that flying is a privilege, not a right. But that's probably more a reflection of my own authoritarian views than anything else. Cheers.
    - swombat 14y ago
      You're absolutely right, and I didn't say they were all invalidated. All that the silliness of one rule means is that we have to make our own minds up as to which rules are sensible and which are silly. Which was basically my point.
  - gnaritas 14y ago
    So you're a self centered inconsiderate jerk and you're proud of it, how typical. The rules do apply to you, I suggest you figure that out before someone decides to teach you the hard way that everyone else doesn't appreciate you ignoring the rules.
    - swombat 14y ago
      Jump to conclusions much? Got some passive aggressive issues perhaps? No one has ever had anything to complain about with respect to my behaviour on planes - not even flight attendants.
      - DanBC 14y ago
        > Jump to conclusions much? When many people make the same assumption you might want to consider whether there's a problem with your post. Your first post makes you sound like a jerk. Such a jerk that people have down voted you for it; called it disappointing; and called you a jerk.
        14y ago
- ninguem2 14y ago
  I agree with the rest, but the lavatory sometimes can't be helped. I've been there.
- GotAnyMegadeth 14y ago
  Pilots should do a barrel roll every now and then to catch seat-belt-sign-ignorers out.
  - epochwolf 14y ago
    Most large planes aren't designed to do aerobatic maneuvers. Doing a barrel roll could rip off pieces from the control surfaces, cause an engine to separate, or tear off an entire wing. That's assuming the flight control software will let you try that in the first place.
    - pedrocr 14y ago
      Barrel rolls are low G maneuvers so properly executed they shouldn't cause any of those things. My memory had the barrel roll as a 1G maneuver but wikipedia tells me it gets up to 2-3g (probably to enter/exit the maneuver). Were you thinking of an aileron roll? I mean, if a 707 could do it safely in 1955[1] modern airliners should do just fine. (not that I support routine barrel rolls on airliners...) [1] http://www.youtube.com/watch?v=AaA7kPfC5Hk http://www.youtube.com/watch?v=AaA7kPfC5Hk
      - epochwolf 14y ago
        You're right, I was thinking of an aileron roll. A barrel roll is definitely doable.
- minimax 14y ago
  Getting out of your seat on a taxiway is a bad idea. Planes do occasionally bump into one another. How'd you like to be standing up looking for your carry-on inside this CRJ when this happens: http://www.youtube.com/watch?v=ayCWSm1f9qk http://www.youtube.com/watch?v=ayCWSm1f9qk
- zobzu 14y ago
  Yeah it pisses me off when people don't follow those rules. None of the rule is even remotely annoying, but when not followed, annoys everybody else. Besides, most of those are actually useful. When you take the plane enough times, there's always one that will shake very heavily without warning due to unexpected turbulences that the stabilization software couldn't counter and pilots didn't foresee. Heck during those, all the stuff flies around and if you're walking around (or even sitted without seat bealt) you wont only hurt yourself but others as well.
- cglace 14y ago
  "I always feel horrible for the flight attendants. It feels like they are running a day care. Why are people like that? Are they stupid and don't understand the rules? Or do they think the rules don't apply to them?" My wife is a flight attendant and she defenately feels like she is running a day care. She says it has gotten progressively worse each year. It does seem to be regional though. She has some flights where the people are always nice and some(Pittsburg) where the people are always rude.
aw3c2 14y ago
Linkbait (original) title, a relevant quote right from the beginning of the text is "The F.A.A. has no proof that electronic devices can harm a plane’s avionics, but it still perpetuates such claims."
GotAnyMegadeth 14y ago
I don't think I've ever turned my phone off/to aeroplane mode during a flight.
- macspoofing 14y ago
  That's the ridiculous part (well, one of many). If wifi, or cellular signal could detrimentally interfere with an airplane's operation, shouldn't a more thorough check be done to make sure all devices are "off" rather than the current polite warning? After all a terrorist could be watching YouTube...on purpose!
  - lostnet 14y ago
    Of course it is harmless. But don't do it! It is part of a disinformation campaign/honeypot. The flights to area 51 are full of people secretly renditioned for watching youtube on commercial flights...
bmuon 14y ago
Well, the Mythbusters showed that the reason is that old planes without shielding on their wires and instruments did get interference from cell phone calls[1]. But no modern plane should have that issue. [1] http://en.wikipedia.org/wiki/MythBusters_(2006_season)#Episode_49_.E2.80.93_.22Cell_Phones_on_a_Plane.22 http://en.wikipedia.org/wiki/MythBusters_(2006_season)#Episo...
- jkat 14y ago
  Best. Show. Ever. Wouldn't make an important decision based on them. They are good, but a lot of what they do isn't nearly rigorous enough to risk lives.
  - bmuon 14y ago
    In this case the interesting part was that they actually showed that a cellphone can cause interference with some instruments. They dug up some old instruments, put them in a Faraday cage, called a cellphone and the needles in the instruments moved like crazy. So we now know the root of the problem. Then they showed that in a modern plane that shouldn't happen. And that wasn't scientific at all. But the point is that we know what the issue is and how to solve it (shielding), that modern planes already implement the solution and that the only thing left is to explore the issue a little further and publish it in a way that both the public and the regulatory agencies can digest and apply.
yock 14y ago
I have always wondered what the FCC must think of the FAA for this policy. I don't know a lot about the FCC certification process for electronics that contain radios, but I know that it involves both minimizing the amount of harmful emissions and operating safely under some harmful emissions. That the FAA could cite interference from radios as a reason to ban their use seems to this layman as a textbook example of the left hand not knowing what the right hand is doing. Typical contradictory policy making that we've come to expect of large governments.
dhruvmittal 14y ago
I don't think I've ever been more appreciative of any single Senator than I am now for Claire McCaskill and her comments in this article. A plane I was on just last week had a flight attendant that made the claim that he could check some sensor and tell us which mobile devices were on within the plane at any time. After the flight, I checked in with my family (Two teenagers, myself, and my older parents) and discovered that every one of us had taken that as a challenge and left our devices on.
wglb 14y ago
There are two issues going on simultaneously. I suggest the following experiment. Take your hand-held two-way radio transmitter to Dayton Ohio during the annual ham convention there. Tune it to a 2 meter frequency, and just listen for half an hour. You will hear vast quantities of intermodulation--signals that aren't really there, and signals that are there that are hopelessly garbled. This is happening because there are hundreds of similar transmitters all over the hamfest that are transmitting simultaneously. The intermodulation distortion comes about because when a radio receiver, half of your two-way radio, receives multiple signals these signals combine in the receiver and produce distortion signals that are the sum and difference of two frequencies. So with many multiples of frequencies that are rather strong, there are a host of fake signals going to your earphone. Each device, such as an iPad, iPhone, android device, has multiple radio transmitters. Some of them are deliberate radio transmitters, such as the wi-fi or the cellular radio. Others are the side effect of the receivers that are built in to the devices, such as the GPS. Receivers themselves actually transmit, albeit at a smaller level. Similarly, if you have a transistor am/fm radio receiver, it generates (transmits) a signal as well. Other unintentional transmitters are the clock for any CPU that might be there. So on an airplane, if there are tens or hundreds of devices, you get a real mass of interfering signals. How does this affect the avionics of the airplane? Well, you won't hear a heterodyne, as there is no audio output--just some instrument reading. What happens when the avionics hears intermodulation distortion? As to the idea that two hundred ipads are just like one, the claim that “Electromagnetic energy doesn’t add up like that,” said Kevin Bothmann, the EMT Labs testing manager doesn't square with simple physics. Another article quoting this lab study suggested that he was confused by the difference between decibels and power levels. I argue that it adds up worse. Check out Dayton. The article says None of those episodes have produced scientific evidence that a device can harm a plane’s operation. Reports of such interference have been purely speculation by pilots about the cause of a problem. The thing is, that speculation about problems in the air by experienced aircraft operators is the only clue that we have just up to the point where people die. As was the case in the Tenerife air disaster, three second long whistling sound (or heterodyne) blocked a very key bit of information. The way we learn if a pilot's suspicion is true is for people to die in aircraft accidents. So the second problem is for the cellular phones. Keep in mind that cellular phones depend upon line-of-sight. If you are walking down Jackson avenue to meet a friend at Intellegensia for coffee, your line of sight to the cellular towers is limited. So how far is the line of sight away if you are at 20,000 feet? Quite a ways. Possibly the next state. For every cell tower that your phone can "see", there is the possibility of a connection. Not a good idea to tie up that many cellular tower channels. It will be interesting to see how this battle plays out. If the current FAA rules are right that passengers should not be transmitting during take off and landing and the social pressure causes the rules to change, the only way we will know is when a plane falls out of the sky, since we aren't giving pilots complaining about heterodynes any credibility.
DanielBMarkham 14y ago
I think the FAA is acting like an idiot, here, but it'd be good to look at this from their side. This falls under the "stuff that might make me look bad" category. You can be the guy who prevents electronic devices on planes for 50 years and it doesn't matter. But if you're the guy that approves them and then there's a crash? Better get your Senate suit out of the cleaners, because all of those politicians writing you letters to "do something" will be the first ones asking you the tough questions on national TV. They'll be first in line to take credit if the result is good, but it's all on you if the result is bad. It's very difficult to set up a politically-derived organization that can deal with risk effectively. Instead on manageable risk, it's much safer and easier to push for situations with no risk at all -- take the TSA, for instance. No bureaucrat gets fired for being too careful. This is an issue that might very well end up requiring legislation to fix. ADD: One more note. Every day there are millions of passenger miles flown on airlines. Surely the law of large numbers says that we're already performing an experiment on electronic device radiation and the cockpit. There's no way you can get 100% of the devices off. Somebody left their phone in the carry-on. Somebody's PC refuses to shut down. Somebody forgets to turn his kindle off. Dozens, if not hundreds of times each day, planes are flying in difficult weather with all kinds of electronic devices transmitting all kinds of garbage. Yet we've never seen a flight failure due to electronic interference. And of course the pilots are up front using all sorts of consumer devices as well. We've already done the experiment, at least in smaller numbers. Whether or not there's a problem when hundreds of devices are on is certainly an open question, but whether or not a few of them are going to take down a plane is already settled.
- bradleyland 14y ago
  > One more note. Every day there are millions of passenger miles flown on airlines. Surely the law of large numbers says that we're already performing an experiment on electronic device radiation and the cockpit. I couldn't agree with this more. At one point, I was flying very frequently for work, and I used to make a hobby out of watching to see what people did with their electronics when prepping for take-off. Laptops usually got turned off, but rarely did I see someone turn their phone off completely. I'd see a lot of people switch to airplane mode, then put their phone to sleep (a short press on a button). I'd even see a lot of people who simply put their phones on silent (usually when I'm sitting next to them; this is difficult to observe from a distance). Behavior on landing is pretty telling as well. When you see people texting and making calls immediately after landing, you know that their phones weren't off completely. When you watch the person next to you take out their phone and begin texting immediately, you know that the phone wasn't even put in to airplane mode. These scenarios were far more common than observing someone actually power down/up a device. I'd imagine that it is possible to get an estimate of the number of RF emitting devices within range. I really wish the FAA would do a study of what actually happens on planes, rather than what the rules say should happen on planes, because I suspect the results will be much different than they expect.
mmariani 14y ago
Two days ago I flew VIE-MXP. I didn't turn off my iPad, nor my I put my iPhone on flight mode. Yet, I'm still here typing this.
- polyfractal 14y ago
  An asteroid didn't destroy civilization yesterday. Therefore, it follows that an asteroid will never destroy our civilization. I'm not a fan of "turn off all electronics" policy either, but your statement is just plain silly.
  - mmariani 14y ago
    Did you read the article? They cite reliable sources that say this ban on electronics on airliners is nothing but baloney. Anyway, I'm honestly curious... Where's your favorite place, under your bed?
    - polyfractal 14y ago
      Did you read my comment? "I used an iPad and I'm still alive!" is just about the worst argument possible (for anything), for similar reasons that saying an asteroid won't destroy the earth because it hasn't yet is a terrible argument. It had nothing to do with the article (which I read) and my personal opinions (which, you'll notice in my comment, I express agreement with the article). This is just turning pedantic now, so apologies. I should have just down-voted your comment instead of replying.
      - mmariani 14y ago
        No harm, no foul. Happy new year! :)
ricardobeat 14y ago
I found this 2005 paper from NASA's Langley Research Center [1]. The report says that the data "confirms this expectation [of interference] with alarming clarity", though it is completely based off crew reports attributing a problem to a device in use. It also uses data from 1986-1999, both airplanes and devices have improved a lot since. In addition, most of the incidents in the annual report on electronic devices [2] are of the kind "passenger X refused to turn off his mobile phone / [random problem here] crew suspects passenger in the bathroom using his laptop as culprit". Why can't gov. agencies or airplane manufacturers create an test that mimicks real-world conditions and put a definitive end to the question? [1] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050232846_2005233838.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2005023... [2] http://asrs.arc.nasa.gov/docs/rpsts/ped.pdf http://asrs.arc.nasa.gov/docs/rpsts/ped.pdf
- dhimes 14y ago
  Why can't gov. agencies or airplane manufacturers create an test that mimicks real-world conditions and put a definitive end to the question? Agreed. Just to a broadband jamming experiment to see what leaks in. A mil-spec style shielding might be expensive (this is the argument a pilot made to me- as if planes are cheap), but we could at least test, and possibly approve some designs. OTOH, turning off devices for a few minutes isn't really a big concern for me. But I dislike the "it's ok to be ignorant" attitude by the rule-makers.
deleted 14y ago
[deleted]
oakwhiz 14y ago
There are two main classes of electronic devices: 1. Devices that are unintentional radiators 2. Devices that are intentional radiators The concern is that people may not know which class their device falls into, and also that they may not know how to fully disable their device as well. The problem with intentional radiators is more obvious - it could potentially jam other circuits by producing energy at specific frequencies. However, many people seem to ignore the other class of unintentional radiators. Many circuits require the use of clock generators and phase-locked loops, which can actually radiate a fair distance away if not designed correctly. One of the problems with this is that noise generated by a PLL could intermodulate with the PLLs in the plane's navigation systems (i.e. GPS or ADF) and cause the pilot to use an inaccurate position report in determining the location of the plane. An example of one such interference case: Someone wanted to launch a high-altitude balloon with onboard GPS and an amateur radio transmitter. They added a small keychain camera manufactured by a Chinese company, but when the camera was powered on, it completely disabled the GPS from locking on to any satellites.

42 points by 001sky 14y ago

jkat 14y ago

The FAA is being ridiculous about this. However...there's literally nothing I find more aggravating than flying - because of other passengers. Every flight, there's always a handful of people who refuse to follow the simple rules. Their carry-on is too big. They switch seats or use the lavatories when they are supposed to be seated and buckled-in. They don't re-adjust their seats when landing. They grab their carry-on while the plane is taxiing. I always feel horrible for the flight attendants. It feels like they are running a day care. Why are people like that? Are they stupid and don't understand the rules? Or do they think the rules don't apply to them?

yareally 14y ago
Modus operandi for many people is to get away with whatever you can until you're told otherwise (or caught). Just most do this with petty things versus breaking major laws.
swombat 14y ago
> Why are people like that? Are they stupid and don't understand the rules? Or do they think the rules don't apply to them? Speaking for myself, I have no respect for authority that does not stem from experience, knowledge, wisdom, etc. Air hosts/hostesses have none of those attributes - they are merely parrotting rules handed down to them, without putting any thought into them. A case in point is the electronic devices rule - clearly nonsensical and stupid. I take it as a good sample of the sense in the other rules being imposed, and therefore revert to my default mode of operation, that applies in most circumstances, unless overridden by someone who appears to deserve to have the power to tell me what to do. In other words, I do what I think is sensible, reasonable. Therefore, yes, I do check my emails before the plane has finished moving and even (gosh!) before the passport gates. I do grab my bag at the first opportunity (though it's usually pointless to do so before the plane has stopped moving - but then it's reason that's stopping me, not rules). I do fit as much as I can get away with into my bag (which generally weighs more than 5kg - but is usually compact and easy to stow because I value those attributes). In other words, I act like the free, responsible human being that I am, and no, I don't care one whit for "the rules" except where I have analysed them and deemed them sensible myself. Here's some good news for you: "the rules" don't apply to you either - not unless you want them to.
- jkat 14y ago
  I don't disagree with your premise in general....but...The silliness of one rule doesn't, in my mind, invalidate all the other ones. I mean, couldn't you reverse your logic? Find a rule that makes sense (say, no smoking on the plane) and thus summarize that all rules make sense? I keep thinking to myself that flying is a privilege, not a right. But that's probably more a reflection of my own authoritarian views than anything else. Cheers.
  - swombat 14y ago
    You're absolutely right, and I didn't say they were all invalidated. All that the silliness of one rule means is that we have to make our own minds up as to which rules are sensible and which are silly. Which was basically my point.
- gnaritas 14y ago
  So you're a self centered inconsiderate jerk and you're proud of it, how typical. The rules do apply to you, I suggest you figure that out before someone decides to teach you the hard way that everyone else doesn't appreciate you ignoring the rules.
  - swombat 14y ago
    Jump to conclusions much? Got some passive aggressive issues perhaps? No one has ever had anything to complain about with respect to my behaviour on planes - not even flight attendants.
    - DanBC 14y ago
      > Jump to conclusions much? When many people make the same assumption you might want to consider whether there's a problem with your post. Your first post makes you sound like a jerk. Such a jerk that people have down voted you for it; called it disappointing; and called you a jerk.
      - 14y ago
ninguem2 14y ago
I agree with the rest, but the lavatory sometimes can't be helped. I've been there.
GotAnyMegadeth 14y ago
Pilots should do a barrel roll every now and then to catch seat-belt-sign-ignorers out.
- epochwolf 14y ago
  Most large planes aren't designed to do aerobatic maneuvers. Doing a barrel roll could rip off pieces from the control surfaces, cause an engine to separate, or tear off an entire wing. That's assuming the flight control software will let you try that in the first place.
  - pedrocr 14y ago
    Barrel rolls are low G maneuvers so properly executed they shouldn't cause any of those things. My memory had the barrel roll as a 1G maneuver but wikipedia tells me it gets up to 2-3g (probably to enter/exit the maneuver). Were you thinking of an aileron roll? I mean, if a 707 could do it safely in 1955[1] modern airliners should do just fine. (not that I support routine barrel rolls on airliners...) [1] http://www.youtube.com/watch?v=AaA7kPfC5Hk http://www.youtube.com/watch?v=AaA7kPfC5Hk
    - epochwolf 14y ago
      You're right, I was thinking of an aileron roll. A barrel roll is definitely doable.
minimax 14y ago
Getting out of your seat on a taxiway is a bad idea. Planes do occasionally bump into one another. How'd you like to be standing up looking for your carry-on inside this CRJ when this happens: http://www.youtube.com/watch?v=ayCWSm1f9qk http://www.youtube.com/watch?v=ayCWSm1f9qk
zobzu 14y ago
Yeah it pisses me off when people don't follow those rules. None of the rule is even remotely annoying, but when not followed, annoys everybody else. Besides, most of those are actually useful. When you take the plane enough times, there's always one that will shake very heavily without warning due to unexpected turbulences that the stabilization software couldn't counter and pilots didn't foresee. Heck during those, all the stuff flies around and if you're walking around (or even sitted without seat bealt) you wont only hurt yourself but others as well.
cglace 14y ago
"I always feel horrible for the flight attendants. It feels like they are running a day care. Why are people like that? Are they stupid and don't understand the rules? Or do they think the rules don't apply to them?" My wife is a flight attendant and she defenately feels like she is running a day care. She says it has gotten progressively worse each year. It does seem to be regional though. She has some flights where the people are always nice and some(Pittsburg) where the people are always rude.

aw3c2 14y ago

Linkbait (original) title, a relevant quote right from the beginning of the text is "The F.A.A. has no proof that electronic devices can harm a plane’s avionics, but it still perpetuates such claims."

GotAnyMegadeth 14y ago

I don't think I've ever turned my phone off/to aeroplane mode during a flight.

macspoofing 14y ago
That's the ridiculous part (well, one of many). If wifi, or cellular signal could detrimentally interfere with an airplane's operation, shouldn't a more thorough check be done to make sure all devices are "off" rather than the current polite warning? After all a terrorist could be watching YouTube...on purpose!
- lostnet 14y ago
  Of course it is harmless. But don't do it! It is part of a disinformation campaign/honeypot. The flights to area 51 are full of people secretly renditioned for watching youtube on commercial flights...

bmuon 14y ago

Well, the Mythbusters showed that the reason is that old planes without shielding on their wires and instruments did get interference from cell phone calls[1]. But no modern plane should have that issue. [1] http://en.wikipedia.org/wiki/MythBusters_(2006_season)#Episode_49_.E2.80.93_.22Cell_Phones_on_a_Plane.22 http://en.wikipedia.org/wiki/MythBusters_(2006_season)#Episo...

jkat 14y ago
Best. Show. Ever. Wouldn't make an important decision based on them. They are good, but a lot of what they do isn't nearly rigorous enough to risk lives.
- bmuon 14y ago
  In this case the interesting part was that they actually showed that a cellphone can cause interference with some instruments. They dug up some old instruments, put them in a Faraday cage, called a cellphone and the needles in the instruments moved like crazy. So we now know the root of the problem. Then they showed that in a modern plane that shouldn't happen. And that wasn't scientific at all. But the point is that we know what the issue is and how to solve it (shielding), that modern planes already implement the solution and that the only thing left is to explore the issue a little further and publish it in a way that both the public and the regulatory agencies can digest and apply.

yock 14y ago

I have always wondered what the FCC must think of the FAA for this policy. I don't know a lot about the FCC certification process for electronics that contain radios, but I know that it involves both minimizing the amount of harmful emissions and operating safely under some harmful emissions. That the FAA could cite interference from radios as a reason to ban their use seems to this layman as a textbook example of the left hand not knowing what the right hand is doing. Typical contradictory policy making that we've come to expect of large governments.

dhruvmittal 14y ago

I don't think I've ever been more appreciative of any single Senator than I am now for Claire McCaskill and her comments in this article. A plane I was on just last week had a flight attendant that made the claim that he could check some sensor and tell us which mobile devices were on within the plane at any time. After the flight, I checked in with my family (Two teenagers, myself, and my older parents) and discovered that every one of us had taken that as a challenge and left our devices on.

wglb 14y ago

There are two issues going on simultaneously. I suggest the following experiment. Take your hand-held two-way radio transmitter to Dayton Ohio during the annual ham convention there. Tune it to a 2 meter frequency, and just listen for half an hour. You will hear vast quantities of intermodulation--signals that aren't really there, and signals that are there that are hopelessly garbled. This is happening because there are hundreds of similar transmitters all over the hamfest that are transmitting simultaneously. The intermodulation distortion comes about because when a radio receiver, half of your two-way radio, receives multiple signals these signals combine in the receiver and produce distortion signals that are the sum and difference of two frequencies. So with many multiples of frequencies that are rather strong, there are a host of fake signals going to your earphone. Each device, such as an iPad, iPhone, android device, has multiple radio transmitters. Some of them are deliberate radio transmitters, such as the wi-fi or the cellular radio. Others are the side effect of the receivers that are built in to the devices, such as the GPS. Receivers themselves actually transmit, albeit at a smaller level. Similarly, if you have a transistor am/fm radio receiver, it generates (transmits) a signal as well. Other unintentional transmitters are the clock for any CPU that might be there. So on an airplane, if there are tens or hundreds of devices, you get a real mass of interfering signals. How does this affect the avionics of the airplane? Well, you won't hear a heterodyne, as there is no audio output--just some instrument reading. What happens when the avionics hears intermodulation distortion? As to the idea that two hundred ipads are just like one, the claim that “Electromagnetic energy doesn’t add up like that,” said Kevin Bothmann, the EMT Labs testing manager doesn't square with simple physics. Another article quoting this lab study suggested that he was confused by the difference between decibels and power levels. I argue that it adds up worse. Check out Dayton. The article says None of those episodes have produced scientific evidence that a device can harm a plane’s operation. Reports of such interference have been purely speculation by pilots about the cause of a problem. The thing is, that speculation about problems in the air by experienced aircraft operators is the only clue that we have just up to the point where people die. As was the case in the Tenerife air disaster, three second long whistling sound (or heterodyne) blocked a very key bit of information. The way we learn if a pilot's suspicion is true is for people to die in aircraft accidents. So the second problem is for the cellular phones. Keep in mind that cellular phones depend upon line-of-sight. If you are walking down Jackson avenue to meet a friend at Intellegensia for coffee, your line of sight to the cellular towers is limited. So how far is the line of sight away if you are at 20,000 feet? Quite a ways. Possibly the next state. For every cell tower that your phone can "see", there is the possibility of a connection. Not a good idea to tie up that many cellular tower channels. It will be interesting to see how this battle plays out. If the current FAA rules are right that passengers should not be transmitting during take off and landing and the social pressure causes the rules to change, the only way we will know is when a plane falls out of the sky, since we aren't giving pilots complaining about heterodynes any credibility.

DanielBMarkham 14y ago

I think the FAA is acting like an idiot, here, but it'd be good to look at this from their side. This falls under the "stuff that might make me look bad" category. You can be the guy who prevents electronic devices on planes for 50 years and it doesn't matter. But if you're the guy that approves them and then there's a crash? Better get your Senate suit out of the cleaners, because all of those politicians writing you letters to "do something" will be the first ones asking you the tough questions on national TV. They'll be first in line to take credit if the result is good, but it's all on you if the result is bad. It's very difficult to set up a politically-derived organization that can deal with risk effectively. Instead on manageable risk, it's much safer and easier to push for situations with no risk at all -- take the TSA, for instance. No bureaucrat gets fired for being too careful. This is an issue that might very well end up requiring legislation to fix. ADD: One more note. Every day there are millions of passenger miles flown on airlines. Surely the law of large numbers says that we're already performing an experiment on electronic device radiation and the cockpit. There's no way you can get 100% of the devices off. Somebody left their phone in the carry-on. Somebody's PC refuses to shut down. Somebody forgets to turn his kindle off. Dozens, if not hundreds of times each day, planes are flying in difficult weather with all kinds of electronic devices transmitting all kinds of garbage. Yet we've never seen a flight failure due to electronic interference. And of course the pilots are up front using all sorts of consumer devices as well. We've already done the experiment, at least in smaller numbers. Whether or not there's a problem when hundreds of devices are on is certainly an open question, but whether or not a few of them are going to take down a plane is already settled.

bradleyland 14y ago
> One more note. Every day there are millions of passenger miles flown on airlines. Surely the law of large numbers says that we're already performing an experiment on electronic device radiation and the cockpit. I couldn't agree with this more. At one point, I was flying very frequently for work, and I used to make a hobby out of watching to see what people did with their electronics when prepping for take-off. Laptops usually got turned off, but rarely did I see someone turn their phone off completely. I'd see a lot of people switch to airplane mode, then put their phone to sleep (a short press on a button). I'd even see a lot of people who simply put their phones on silent (usually when I'm sitting next to them; this is difficult to observe from a distance). Behavior on landing is pretty telling as well. When you see people texting and making calls immediately after landing, you know that their phones weren't off completely. When you watch the person next to you take out their phone and begin texting immediately, you know that the phone wasn't even put in to airplane mode. These scenarios were far more common than observing someone actually power down/up a device. I'd imagine that it is possible to get an estimate of the number of RF emitting devices within range. I really wish the FAA would do a study of what actually happens on planes, rather than what the rules say should happen on planes, because I suspect the results will be much different than they expect.

mmariani 14y ago

Two days ago I flew VIE-MXP. I didn't turn off my iPad, nor my I put my iPhone on flight mode. Yet, I'm still here typing this.

polyfractal 14y ago
An asteroid didn't destroy civilization yesterday. Therefore, it follows that an asteroid will never destroy our civilization. I'm not a fan of "turn off all electronics" policy either, but your statement is just plain silly.
- mmariani 14y ago
  Did you read the article? They cite reliable sources that say this ban on electronics on airliners is nothing but baloney. Anyway, I'm honestly curious... Where's your favorite place, under your bed?
  - polyfractal 14y ago
    Did you read my comment? "I used an iPad and I'm still alive!" is just about the worst argument possible (for anything), for similar reasons that saying an asteroid won't destroy the earth because it hasn't yet is a terrible argument. It had nothing to do with the article (which I read) and my personal opinions (which, you'll notice in my comment, I express agreement with the article). This is just turning pedantic now, so apologies. I should have just down-voted your comment instead of replying.
    - mmariani 14y ago
      No harm, no foul. Happy new year! :)

ricardobeat 14y ago

I found this 2005 paper from NASA's Langley Research Center [1]. The report says that the data "confirms this expectation [of interference] with alarming clarity", though it is completely based off crew reports attributing a problem to a device in use. It also uses data from 1986-1999, both airplanes and devices have improved a lot since. In addition, most of the incidents in the annual report on electronic devices [2] are of the kind "passenger X refused to turn off his mobile phone / [random problem here] crew suspects passenger in the bathroom using his laptop as culprit". Why can't gov. agencies or airplane manufacturers create an test that mimicks real-world conditions and put a definitive end to the question? [1] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050232846_2005233838.pdf http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2005023... [2] http://asrs.arc.nasa.gov/docs/rpsts/ped.pdf http://asrs.arc.nasa.gov/docs/rpsts/ped.pdf

dhimes 14y ago
Why can't gov. agencies or airplane manufacturers create an test that mimicks real-world conditions and put a definitive end to the question? Agreed. Just to a broadband jamming experiment to see what leaks in. A mil-spec style shielding might be expensive (this is the argument a pilot made to me- as if planes are cheap), but we could at least test, and possibly approve some designs. OTOH, turning off devices for a few minutes isn't really a big concern for me. But I dislike the "it's ok to be ignorant" attitude by the rule-makers.

deleted 14y ago

[deleted]

oakwhiz 14y ago

There are two main classes of electronic devices: 1. Devices that are unintentional radiators 2. Devices that are intentional radiators The concern is that people may not know which class their device falls into, and also that they may not know how to fully disable their device as well. The problem with intentional radiators is more obvious - it could potentially jam other circuits by producing energy at specific frequencies. However, many people seem to ignore the other class of unintentional radiators. Many circuits require the use of clock generators and phase-locked loops, which can actually radiate a fair distance away if not designed correctly. One of the problems with this is that noise generated by a PLL could intermodulate with the PLLs in the plane's navigation systems (i.e. GPS or ADF) and cause the pilot to use an inaccurate position report in determining the location of the plane. An example of one such interference case: Someone wanted to launch a high-altitude balloon with onboard GPS and an amateur radio transmitter. They added a small keychain camera manufactured by a Chinese company, but when the camera was powered on, it completely disabled the GPS from locking on to any satellites.