5 ms·

> 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 comm

> 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.
- lawnchair_larry 13y ago
  Well that's an interesting and seemingly arbitrary characterization. You see, I did not need to know what he said in order to know that the rule didn't make sense (although I do appreciate the info). There are a few problems with your default position of "minimize risk because we don't know". If you don't know, how is it different from the 13th floor being bad luck? Something bad might happen if you visit that floor. To minimize risk, we should just avoid it? Generally, the burden of proof has to be on whoever makes a claim that something exists. The existence of the rule is essentially that claim. The creation of the rule was not backed by any particular study or data. You speak dismissively of what you perceive to be speculation, yet that is entirely what the rule is based on (you also said not being afraid of these ghosts is the paranoid behavior, but I digress). To introduce a little logic - we know that this has more than likely been tested. The fact that it's a concern at all means it's a safe bet that experiments have been done. If said experiments found anything at all that causes danger to a flight, it defies reason that they would not implement a hard ban on the devices and screen for them. There would be penalties and fines. Instead, a polite attendant asks that they be turned off. Does this make sense to you? It tells me that they aren't very serious about it. There is no way that anything potentially dangerous would be trusted to "the honor system". Once a rule is in place, it's difficult to change it, so it remains the default. Wireless signals are the modern day version of ghosts. They might cause cancer, they might crash planes, they might microwave your lunch. Of course, we have no reason to believe that they do any of these things - we just don't have a reason to believe that they don't. As a scientist, it is your duty to reject this invalid line of reasoning.
Steko 13y ago
"If ... their presence should be forbidden in the passenger cabin" It bears mentioning here that the FAA approves ipads in the cockpit itself as a replacement for flight charts[1]. And many airlines give their pilots ipads. [1] http://en.wikipedia.org/wiki/Cockpit_iPads http://en.wikipedia.org/wiki/Cockpit_iPads

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.
lawnchair_larry 13y ago
Well that's an interesting and seemingly arbitrary characterization. You see, I did not need to know what he said in order to know that the rule didn't make sense (although I do appreciate the info). There are a few problems with your default position of "minimize risk because we don't know". If you don't know, how is it different from the 13th floor being bad luck? Something bad might happen if you visit that floor. To minimize risk, we should just avoid it? Generally, the burden of proof has to be on whoever makes a claim that something exists. The existence of the rule is essentially that claim. The creation of the rule was not backed by any particular study or data. You speak dismissively of what you perceive to be speculation, yet that is entirely what the rule is based on (you also said not being afraid of these ghosts is the paranoid behavior, but I digress). To introduce a little logic - we know that this has more than likely been tested. The fact that it's a concern at all means it's a safe bet that experiments have been done. If said experiments found anything at all that causes danger to a flight, it defies reason that they would not implement a hard ban on the devices and screen for them. There would be penalties and fines. Instead, a polite attendant asks that they be turned off. Does this make sense to you? It tells me that they aren't very serious about it. There is no way that anything potentially dangerous would be trusted to "the honor system". Once a rule is in place, it's difficult to change it, so it remains the default. Wireless signals are the modern day version of ghosts. They might cause cancer, they might crash planes, they might microwave your lunch. Of course, we have no reason to believe that they do any of these things - we just don't have a reason to believe that they don't. As a scientist, it is your duty to reject this invalid line of reasoning.

Steko 13y ago

"If ... their presence should be forbidden in the passenger cabin" It bears mentioning here that the FAA approves ipads in the cockpit itself as a replacement for flight charts[1]. And many airlines give their pilots ipads. [1] http://en.wikipedia.org/wiki/Cockpit_iPads http://en.wikipedia.org/wiki/Cockpit_iPads