3 ms·

Are you an electrical engineer, or similarly educated in RF communications, and thus able to determine what is arbitrary? I have been in tech for 29 years, and

by bsg75 13y ago

Are you an electrical engineer, or similarly educated in RF communications, and thus able to determine what is arbitrary? I have been in tech for 29 years, and I am a licensed commercial pilot in both fixed wing and rotorcraft (but I don't work as a professional pilot.) I don't know what effect my iPhone would have on aircraft instruments, so I turn it off. Pre-flight and in-flight procedures are based on what is known, and what helps to prevent problems from the unknown. The safety of flight is in part about not taking unnecessary risks. For example, if I have to visibility into a cloud (radar, instruments) I do not fly through a cloud. I apply this logic to during the critical periods of takeoff and landing, if I am unsure a device that emits RF will affect my instruments, I shut it off. Inconvenience does not outweigh safety, even / especially if the effect on safety is unknown. The worst case scenario, although likely minor, is simple not worth the risk.

AnIrishDuck 13y ago
> Are you an electrical engineer, or similarly educated in RF communications, and thus able to determine what is arbitrary? CpE here. The vast majority of communications links on planes use twisted-pair differential signaling [1], which is extremely resistant to RF interference. I've also worked on test procedures for avionics equipment, and assure you that RF interference testing is a part of all test plans for such equipment. The types of interference we tested against were far more aggressive than those that any consumer electronics can emit. Keep in mind that the FCC also aggressively regulates RF emissions from all consumer electronics devices. Testing against FCC regulations is an involved and expensive affair, and the vast majority of devices are forbidden from any powerful RF emissions. > if I am unsure a device that emits RF will affect my instruments, I shut it off. Inconvenience does not outweigh safety, even / especially if the effect on safety is unknown. The worst case scenario, although likely minor, is simple not worth the risk. If phones or other complex electronic devices truly can interfere with avionics, their presence should be forbidden in the passenger cabin. It wouldn't be hard to detect them during security screening. I conjecture the reason that this hasn't happened is because the risk of such interference is a practical impossibility for the reasons stated above. 1. http://en.wikipedia.org/wiki/Differential_signaling http://en.wikipedia.org/wiki/Differential_signaling
- bsg75 13y ago
  Thanks for some actual information (vs speculation, and paranoid resistance to authority). That said, care to speculate why the prohibition on device use during takeoff / landing?
  - Steko 13y ago
    Speculation: legal liability ass covering. If they allow it and it ends up as the probable cause in a plane crash that kills x hundred people it's a major disaster and likely to lose everyone's involved jobs. If they continue with current policy it's a continued minor inconvenience that many people ignore anyway. Payoff matrix is pretty much locked on status quo for now, maybe it will soften to "up to the airline but we advise against it" at some point and some of the smaller airlines will differentiate by allowing it and after a couple years the dam will burst.
  - gnaffle 13y ago
    It's because those are critical phases of flight, with an especially high workload on the pilots. This is also why small talk between pilots is disallowed during takeoffs and landings. If an instrument acts up in cruise, the pilots have a lot of time to figure things out, while an instrument acting during landing is much more likely to lead to dangerous situations.
  - jessaustin 13y ago
    It's rooted in a superficial theory of crowd psychology. It doesn't really matter whether passengers obey the cabin crew in most situations, but the two you mention are exceptions. Particularly during landing, if some moron is dancing around in the aisle, she is likely to hurt herself or someone else. The airline is the only deep pocket in that situation, so it's considered very important that passengers submit at that time. The more random rules they can heap on (keep your windowshade up, keep all your items under the seat, no Gameboy-playing, etc.), the more cowed the passengers and the more rare the expensive injury lawsuit. It's like those religions that really depend on their congregants' obeying to the point of never really thinking: all of those ban the consumption of alcohol.
  - 13y ago
jerf 13y ago
You seem to be operating from the assumption that the rules actually mean anything and somehow the vast majority of flights are done with all electronics following the rules. This is laughable. I'm sure that every flight with more than 100 people has at least a dozen bits of electronics still fully powered on and transmitting. Why do I think it's safe? Because rules don't control reality, only people's behaviors do. In reality, we fly with our electronics on every single large flight, and they are not crashing or experiencing any particular problems. The only reason the rules are still there is that nobody wants to run the risk of being the one who gets blamed for some problem, because after some crash or something, somebody else who labors under the delusion that the rules actually mean something will pin the blame on the electronic devices, falsely, and by extension, the one who lifted the rules. That's it. That's the only thing keeping this rule in place. It sure isn't physics. I don't have to be an EE or anything else, we've run this experiments hundreds of thousands or millions of times already. That said, your little planes may have their own issues and this experience may not apply to your plane. But we're talking commercial flights here.
- gnaffle 13y ago
  There are two assumptions that people in these discussion make 1) If 30% of the passengers leave their devices on today, leaving 100% of the devices on won't cause any increase in problems, and 2) If something happens it's either a) nothing, or b) the airplane falls out of the sky. The fact is that an airplane is an incredibly complex machine. Instrument failures happen all the time, and pilots deal with this (they have redundant instruments and alternate procedures they can follow). If some of these problems happen due to interference from electronic devices, that's pretty much impossible to verify.
SilasX 13y ago
>I don't know what effect my iPhone would have on aircraft instruments, so I turn it off. And my buddy at work takes flying lessons from a pilot who leaves his on so he can check weather and use other cute apps. As do probably numerous other less-enlightened pilots. So where is the epidemic of anomalous readings?

by bsg75 13y ago

AnIrishDuck 13y ago

> Are you an electrical engineer, or similarly educated in RF communications, and thus able to determine what is arbitrary? CpE here. The vast majority of communications links on planes use twisted-pair differential signaling [1], which is extremely resistant to RF interference. I've also worked on test procedures for avionics equipment, and assure you that RF interference testing is a part of all test plans for such equipment. The types of interference we tested against were far more aggressive than those that any consumer electronics can emit. Keep in mind that the FCC also aggressively regulates RF emissions from all consumer electronics devices. Testing against FCC regulations is an involved and expensive affair, and the vast majority of devices are forbidden from any powerful RF emissions. > if I am unsure a device that emits RF will affect my instruments, I shut it off. Inconvenience does not outweigh safety, even / especially if the effect on safety is unknown. The worst case scenario, although likely minor, is simple not worth the risk. If phones or other complex electronic devices truly can interfere with avionics, their presence should be forbidden in the passenger cabin. It wouldn't be hard to detect them during security screening. I conjecture the reason that this hasn't happened is because the risk of such interference is a practical impossibility for the reasons stated above. 1. http://en.wikipedia.org/wiki/Differential_signaling http://en.wikipedia.org/wiki/Differential_signaling

bsg75 13y ago
Thanks for some actual information (vs speculation, and paranoid resistance to authority). That said, care to speculate why the prohibition on device use during takeoff / landing?
- Steko 13y ago
  Speculation: legal liability ass covering. If they allow it and it ends up as the probable cause in a plane crash that kills x hundred people it's a major disaster and likely to lose everyone's involved jobs. If they continue with current policy it's a continued minor inconvenience that many people ignore anyway. Payoff matrix is pretty much locked on status quo for now, maybe it will soften to "up to the airline but we advise against it" at some point and some of the smaller airlines will differentiate by allowing it and after a couple years the dam will burst.
- gnaffle 13y ago
  It's because those are critical phases of flight, with an especially high workload on the pilots. This is also why small talk between pilots is disallowed during takeoffs and landings. If an instrument acts up in cruise, the pilots have a lot of time to figure things out, while an instrument acting during landing is much more likely to lead to dangerous situations.
- jessaustin 13y ago
  It's rooted in a superficial theory of crowd psychology. It doesn't really matter whether passengers obey the cabin crew in most situations, but the two you mention are exceptions. Particularly during landing, if some moron is dancing around in the aisle, she is likely to hurt herself or someone else. The airline is the only deep pocket in that situation, so it's considered very important that passengers submit at that time. The more random rules they can heap on (keep your windowshade up, keep all your items under the seat, no Gameboy-playing, etc.), the more cowed the passengers and the more rare the expensive injury lawsuit. It's like those religions that really depend on their congregants' obeying to the point of never really thinking: all of those ban the consumption of alcohol.
- 13y ago

jerf 13y ago

You seem to be operating from the assumption that the rules actually mean anything and somehow the vast majority of flights are done with all electronics following the rules. This is laughable. I'm sure that every flight with more than 100 people has at least a dozen bits of electronics still fully powered on and transmitting. Why do I think it's safe? Because rules don't control reality, only people's behaviors do. In reality, we fly with our electronics on every single large flight, and they are not crashing or experiencing any particular problems. The only reason the rules are still there is that nobody wants to run the risk of being the one who gets blamed for some problem, because after some crash or something, somebody else who labors under the delusion that the rules actually mean something will pin the blame on the electronic devices, falsely, and by extension, the one who lifted the rules. That's it. That's the only thing keeping this rule in place. It sure isn't physics. I don't have to be an EE or anything else, we've run this experiments hundreds of thousands or millions of times already. That said, your little planes may have their own issues and this experience may not apply to your plane. But we're talking commercial flights here.

gnaffle 13y ago
There are two assumptions that people in these discussion make 1) If 30% of the passengers leave their devices on today, leaving 100% of the devices on won't cause any increase in problems, and 2) If something happens it's either a) nothing, or b) the airplane falls out of the sky. The fact is that an airplane is an incredibly complex machine. Instrument failures happen all the time, and pilots deal with this (they have redundant instruments and alternate procedures they can follow). If some of these problems happen due to interference from electronic devices, that's pretty much impossible to verify.

SilasX 13y ago

>I don't know what effect my iPhone would have on aircraft instruments, so I turn it off. And my buddy at work takes flying lessons from a pilot who leaves his on so he can check weather and use other cute apps. As do probably numerous other less-enlightened pilots. So where is the epidemic of anomalous readings?