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.

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

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

That said, care to speculate why the prohibition on device use during takeoff / landing?

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.

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.

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.

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.

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.

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?

That's why people are so resistant; the whole thing has the stench of unsubstantiated BS about it. Kinda like the TSA.

But there are thousands of models of phones, tablets, wifi cards, 3g cards, bluetooth accessories, LTE/WiMax cards, gps devices, etc., etc., etc.

Then we get into the wide variety of planes in the air with varying amounts and types of avionics, radios, etc. And those systems are in different places in different planes.

And don't forget aftermarket alterations both in software and hardware (i.e. custom firmware, different batteries) to those devices.

So your test wouldn't be too hard, but the result it seems you want (i.e. a definitive answer on the safety of electronics use by passengers on aircraft) takes a hell of a lot more legwork.

Likewise, you can test your database server for all known exploits and it might come up clean, but if you open your firewall you can still be hacked if someone later on finds a new exploit. A security minded person would ask you: "Was it _really_ necessary to open that port, of could you have inconvenienced your developers a little bit and made them use a VPN instead?"

Trust me, this isn't the only rule in aviation that seems stupid, but the mindset that results in rules like this has had a positive effect on aviation safety.

So, our defense against potentially dangerous future electronics devices is a generic safety announcement at the beginning of the flight with only cursory verification that it was followed?

Likewise, airlines have a "clean cockpit" policy disallowing small talk during landings. Do they monitor the CVRs and fine pilots who break this rule? I don't think so. Will some pilots find the rule exessive and make exceptions? Maybe. But the rule still has an effect, and is in place because of previous accidents where distracted pilots have been a contributing factor.

While I think this rule about electronic devices might be too stringent, and that it will eventually change, I don't think the airlines have overblown it. Pilots will handle instrument failures gracefully in 99.99% of all cases, and then there's the fatal accident where some stupid malfunction caused the pilot to screw up (AF447, and many others before). Because they know this is a "numbers game", they try to minimize potential problems, even though they may not be able to eliminate them altogether.

If somebody told me not to fart during takeoff and landing (because it might change trajectory of the plane — you never know…), then I'd still protest even though it _might_ be safer not to fart.

Phones are supposed to pass FCC EMI tests and I expect planes' electronics to be properly hardened/shielded from EMI even stronger than tiny consumer devices can produce.

The best argument I've heard is that its about distraction (EDIT: and in-cabin projectiles), and takeoff/landing are more prone to harsh landing situations.

The argument is similar to subjecting yourself to radiation in the off chance that it (scanner) might detect yourself as a terrorist.

Also this is not a security issue (one of persons with malicious intent). It is a safety issue, one of incompletely studied electronic effects.

>incompletely studied electronic effects.

Are you an electrical engineer, or similarly educated in RF communications, and thus able to determine whether the EMI testing that's been done is incomplete?

Flying on a plane is already far and away the most miserable way for me to travel, don't take away my goddamn ipod.

And I would reiterate, this is during the brief period of takeoff and landing.