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> but it drives me absolutely insane that flight attendants gripe at me about turning off my Kindle I agree BUT you've got to remember that there are a ton of

> but it drives me absolutely insane that flight attendants gripe at me about turning off my Kindle I agree BUT you've got to remember that there are a ton of different devices in the world. You can't expect every flight attendant to know what the difference (visually) is between an iPhone and an iPod Touch is, let alone how to set every device to their equivalent "airplane mode." Of all the rules I disagree with, this is the one that I understand the most. > If they were actually that dangerous, we wouldn't be allowed to carry them on board. My understanding (from a pilot friend of mine) that it is really about radio interference with the pilots' radios. Recall the older Edge (for ATT, whatever else for other providers) devices being put up near speakers and that sound made[0]. The rules are still there mainly to protect the pilots' ears from that noise and possibly dropping communication, though I don't know how possible that is. Yes, that isn't common place anymore now that radio frequencies have moved on but how is a flight attendant going to know the difference between an Edge device that causes interference and some 4G device that doesn't? [0] http://www.youtube.com/watch?v=R0O1_FYzbjw http://www.youtube.com/watch?v=R0O1_FYzbjw

wpietri 13y ago
Yeah, I feel the same way. If the FCC thinks it's fine, great. Otherwise, I can read a magazine for a few minutes. The case that I suspect worries them isn't the well-manufactured, brand-new device on a shiny new plane. It's the older, banged-to-hell, third-rate Chinese knockoff against the oldest avionics in service. The question they have to answer isn't, "Should it be fine?" but "Can we prove it will never cause a glitch at the worst possible moment on the most problematic flight of the 10,000,000 we have each year?" I'm astounded at the arrogance of random people who are sure they know the answer to that based on zero data and a strong sense of entitlement.
- snom380 13y ago
  Agreed. And there's been a few cases of (presumably poorly shielded) laptops in the 90s causing interference, to the point where the pilot would see the effect appearing/disappearing when the passenger turned on/off the laptop. The ban came about as a proactive measure because of these reports.
- CamperBob2 13y ago
  I'm astounded at the arrogance of random people who are sure they know the answer to that based on zero data and a strong sense of entitlement. I keep getting back to what was already said above: if there was any actual risk whatsoever, we wouldn't be allowed to carry them on in the first place.
  - npc 13y ago
    That's dumb, just because someone isn't willing to go to an extreme measure to prevent something doesn't mean that more moderate measures are unreasonable. Banning all electronic devices on airplanes would be a major headache for everyone involved and would probably be overkill, but the risk is still non-zero and asking passengers to turn devices off for a few minutes during the two most dangerous times in a flight is perfectly reasonable.
    - CamperBob2 13y ago
      Banning all electronic devices on airplanes would be a major headache for everyone involved I think we've seen that this is not a problem for the Powers that Be. It's not as if the TSA chairman ever has to fly coach. and would probably be overkill I'm certain that we've seen that this is not an obstacle for implementation by the government. but the risk is still non-zero (Shrug) Zero accidents out of tens of millions of flights in which you can be pretty sure that at least one passenger has left their phone on. Close enough to zero risk for me.
      - snom380 13y ago
        You're still welcome to get a PPL and have as many cell phones as you wish turned on while you fly. If you think anything that doesn't directly cause accidents aren't worth regulating, you don't truly appreciate why we have such good air safety. Letting he pilots chit-chat when landing can't hurt either, right? Millions of successful flights before the sterile cockpit environment idea came about, would perhaps seem like close to zero risk for you, yet we are all safer now because of it.
- jrockway 13y ago
  Remember that a radio is useless if you can't tune it to a certain channel. If the avionics can tune to various navigation channels, then they can probably reject noise from shitty electronics. I wonder how much power it takes to desense a GPS receiver, however.
  - CamperBob2 13y ago
    I wonder how much power it takes to desense a GPS receiver, however. Terrifyingly little, it turns out. Signals from the GPS constellation are about as 'bright' as a light bulb several thousand miles away, and the modulation format usable by civilian receivers is not exactly jam-resistant. Thankfully there's no reason for a GPS antenna on an aircraft to look anywhere but straight up. It can be well-shielded against interference from within the cabin. Still, GPS interference is a real, reproducible and documented issue, unlike the cargo-cult science being discussed here.
- patio11 13y ago
  If "older, banged-to-hell, third-rate Chinese knockoff against the oldest avionics in service" is, indeed, a threat scenario, then "Things which resemble a Gameboy" would rate at least as high as water on the "Stuff we will not let you take on a plane" list. Al Qaeda can procure old Chinese electronics, or custom-modded Arudinos in casings which resemble iPhones, for that matter. [Edit for background: The case against water is "Water is difficult to tell, by cursory visual inspection, from a binary explosive. We've never actually lost a plane to a binary explosive, but we know they were pretty serious about trying that, and we wargamed it out and it looks like one liter of binary explosive applied to the right part of the right airplane means we have a very bad day." ]
  - wpietri 13y ago
    I don't think so. The threat scenario that worries me for cheap electronics isn't "flying along in the blue sky and suddenly the plane crashes". Its "distraction of pilot or minor technical disruption during a difficult landing at a moment that has become crucial because of other issues." Al Qaeda can't afford to put terrorists with custom electronics on an appreciable fraction of our 10m flights a year hoping they get one of the 10 most vulnerable ones. But those flights will have hundreds of electronic devices on them. Being 100% sure that there will be zero problems is tricky. And given that the tradeoff is, "people have to read a magazine for a few minutes" versus "fiery death for hundreds", I'm perfectly ok with them being conservative here.
kpao 13y ago
> My understanding (from a pilot friend of mine) that it is really about radio interference with the pilots' radios If it was the case, this would be a complaint we hear from pilots every day. Think of how many people simply forget to turn off their cell phones...
- hanley 13y ago
  In the past few years I've noticed this pattern more and more - flight attendant asks passenger to turn off iPhone, passenger simply pushes the top button to turn off the screen, flight attendant accepts this. So flight attendants either don't know or don't care that turning the screen off doesn't turn off the device. I'd be willing to bet that most people don't bother to actually turn off devices / switch to airplane mode. On a flight last month I even watched a guy turn off the screen on his iPad when asked to shut it off, then as soon as the attendant walked away he turned it on again and continued to use it throughout take-off.
- snom380 13y ago
  Not necessarily. Avionics fail all the time and it's pretty much impossible for pilots to pinpoint a specific incident to cell phone interference. I've had at least one incident where the pilot came in the PA and asked us twice in flight to make sure all electronic devices were off, because they had problems with the instruments.
dchichkov 13y ago
As far as I understand it [studied electronics engineering and a private pilot] the main problem is with faulty devices. Although it is very unlikely, a faulty device potentially can act as nasty source of interference at _any_ frequency. Effectively blocking this frequency. And although it is not a problem for a pilot in normal conditions, it could be a factor that complicates things for a pilot. If the visibility on a takeoff/landing is bad, there is traffic congestion, air traffic control is stretched to the limit you'd definitely don't want a faulty cell phone suddenly jamming an ILS approach system ;)
- hexedpackets 13y ago
  Not any frequency, the radios have physical limitations that only allow them to transmit on a small range of frequencies. They can certainly cause interference outside of the bands they were designed to operate on, though.
  - dchichkov 13y ago
    Yes, any frequency. Remember we are talking about a faulty piece of electronic. With some pretty weird fault. Not just a transmitter operating in an almost normal mode. Take an ILS (instrumental approach) frequency 108Mhz. Any piece of wire of around two feet (half dipole) can be a pretty effective antenna at that frequency. Say, headset cable + an output cascade of the amplifier self-excited at this frequency? Doesn't happen in real life, but still...
    - jrockway 13y ago
      Remember that your faulty headphones are inside a big faraday cage, and the nav antennas are outside. I am not sure how much effect this has, but it's something to keep in mind.
      - kalleboo 13y ago
        Are airplanes really that effective as faraday cages? If they were, it wouldn't be possible to use a cellphone inside one at all, and this wouldn't have been a debate to begin with.

wpietri 13y ago

Yeah, I feel the same way. If the FCC thinks it's fine, great. Otherwise, I can read a magazine for a few minutes. The case that I suspect worries them isn't the well-manufactured, brand-new device on a shiny new plane. It's the older, banged-to-hell, third-rate Chinese knockoff against the oldest avionics in service. The question they have to answer isn't, "Should it be fine?" but "Can we prove it will never cause a glitch at the worst possible moment on the most problematic flight of the 10,000,000 we have each year?" I'm astounded at the arrogance of random people who are sure they know the answer to that based on zero data and a strong sense of entitlement.

snom380 13y ago
Agreed. And there's been a few cases of (presumably poorly shielded) laptops in the 90s causing interference, to the point where the pilot would see the effect appearing/disappearing when the passenger turned on/off the laptop. The ban came about as a proactive measure because of these reports.
CamperBob2 13y ago
I'm astounded at the arrogance of random people who are sure they know the answer to that based on zero data and a strong sense of entitlement. I keep getting back to what was already said above: if there was any actual risk whatsoever, we wouldn't be allowed to carry them on in the first place.
- npc 13y ago
  That's dumb, just because someone isn't willing to go to an extreme measure to prevent something doesn't mean that more moderate measures are unreasonable. Banning all electronic devices on airplanes would be a major headache for everyone involved and would probably be overkill, but the risk is still non-zero and asking passengers to turn devices off for a few minutes during the two most dangerous times in a flight is perfectly reasonable.
  - CamperBob2 13y ago
    Banning all electronic devices on airplanes would be a major headache for everyone involved I think we've seen that this is not a problem for the Powers that Be. It's not as if the TSA chairman ever has to fly coach. and would probably be overkill I'm certain that we've seen that this is not an obstacle for implementation by the government. but the risk is still non-zero (Shrug) Zero accidents out of tens of millions of flights in which you can be pretty sure that at least one passenger has left their phone on. Close enough to zero risk for me.
    - snom380 13y ago
      You're still welcome to get a PPL and have as many cell phones as you wish turned on while you fly. If you think anything that doesn't directly cause accidents aren't worth regulating, you don't truly appreciate why we have such good air safety. Letting he pilots chit-chat when landing can't hurt either, right? Millions of successful flights before the sterile cockpit environment idea came about, would perhaps seem like close to zero risk for you, yet we are all safer now because of it.
jrockway 13y ago
Remember that a radio is useless if you can't tune it to a certain channel. If the avionics can tune to various navigation channels, then they can probably reject noise from shitty electronics. I wonder how much power it takes to desense a GPS receiver, however.
- CamperBob2 13y ago
  I wonder how much power it takes to desense a GPS receiver, however. Terrifyingly little, it turns out. Signals from the GPS constellation are about as 'bright' as a light bulb several thousand miles away, and the modulation format usable by civilian receivers is not exactly jam-resistant. Thankfully there's no reason for a GPS antenna on an aircraft to look anywhere but straight up. It can be well-shielded against interference from within the cabin. Still, GPS interference is a real, reproducible and documented issue, unlike the cargo-cult science being discussed here.
patio11 13y ago
If "older, banged-to-hell, third-rate Chinese knockoff against the oldest avionics in service" is, indeed, a threat scenario, then "Things which resemble a Gameboy" would rate at least as high as water on the "Stuff we will not let you take on a plane" list. Al Qaeda can procure old Chinese electronics, or custom-modded Arudinos in casings which resemble iPhones, for that matter. [Edit for background: The case against water is "Water is difficult to tell, by cursory visual inspection, from a binary explosive. We've never actually lost a plane to a binary explosive, but we know they were pretty serious about trying that, and we wargamed it out and it looks like one liter of binary explosive applied to the right part of the right airplane means we have a very bad day." ]
- wpietri 13y ago
  I don't think so. The threat scenario that worries me for cheap electronics isn't "flying along in the blue sky and suddenly the plane crashes". Its "distraction of pilot or minor technical disruption during a difficult landing at a moment that has become crucial because of other issues." Al Qaeda can't afford to put terrorists with custom electronics on an appreciable fraction of our 10m flights a year hoping they get one of the 10 most vulnerable ones. But those flights will have hundreds of electronic devices on them. Being 100% sure that there will be zero problems is tricky. And given that the tradeoff is, "people have to read a magazine for a few minutes" versus "fiery death for hundreds", I'm perfectly ok with them being conservative here.

kpao 13y ago

> My understanding (from a pilot friend of mine) that it is really about radio interference with the pilots' radios If it was the case, this would be a complaint we hear from pilots every day. Think of how many people simply forget to turn off their cell phones...

hanley 13y ago
In the past few years I've noticed this pattern more and more - flight attendant asks passenger to turn off iPhone, passenger simply pushes the top button to turn off the screen, flight attendant accepts this. So flight attendants either don't know or don't care that turning the screen off doesn't turn off the device. I'd be willing to bet that most people don't bother to actually turn off devices / switch to airplane mode. On a flight last month I even watched a guy turn off the screen on his iPad when asked to shut it off, then as soon as the attendant walked away he turned it on again and continued to use it throughout take-off.
snom380 13y ago
Not necessarily. Avionics fail all the time and it's pretty much impossible for pilots to pinpoint a specific incident to cell phone interference. I've had at least one incident where the pilot came in the PA and asked us twice in flight to make sure all electronic devices were off, because they had problems with the instruments.

dchichkov 13y ago

As far as I understand it [studied electronics engineering and a private pilot] the main problem is with faulty devices. Although it is very unlikely, a faulty device potentially can act as nasty source of interference at _any_ frequency. Effectively blocking this frequency. And although it is not a problem for a pilot in normal conditions, it could be a factor that complicates things for a pilot. If the visibility on a takeoff/landing is bad, there is traffic congestion, air traffic control is stretched to the limit you'd definitely don't want a faulty cell phone suddenly jamming an ILS approach system ;)

hexedpackets 13y ago
Not any frequency, the radios have physical limitations that only allow them to transmit on a small range of frequencies. They can certainly cause interference outside of the bands they were designed to operate on, though.
- dchichkov 13y ago
  Yes, any frequency. Remember we are talking about a faulty piece of electronic. With some pretty weird fault. Not just a transmitter operating in an almost normal mode. Take an ILS (instrumental approach) frequency 108Mhz. Any piece of wire of around two feet (half dipole) can be a pretty effective antenna at that frequency. Say, headset cable + an output cascade of the amplifier self-excited at this frequency? Doesn't happen in real life, but still...
  - jrockway 13y ago
    Remember that your faulty headphones are inside a big faraday cage, and the nav antennas are outside. I am not sure how much effect this has, but it's something to keep in mind.
    - kalleboo 13y ago
      Are airplanes really that effective as faraday cages? If they were, it wouldn't be possible to use a cellphone inside one at all, and this wouldn't have been a debate to begin with.