Is using electronics on planes dangerous?

[BadBilly]

Originally Posted by JGB

My understanding, and this comes from a pilot though he could have been pulling my leg is that it is very simple.
The first part of the flight is where problems are most likely to occur, and any sort of crash etc. They want people paying attention during the safety briefing and able to respond to instructions if any are given, not really to do with interference anymore.

While there MAY be the slight possibility from interference from some devices (they can't test them all when they're designing the systems), the real reason is to try to save the flying public's asses when the crap hits the turbofan. All kinds of unsecured objects, be they iPads, laptops, or other devices, connecting with a skull at 100 knots can be fatal. Furthermore, if you're zoned out listening to the latest One Direction hit on endless repeat through those $300 headphones and emergency instructions need to be given, you won't hear them. It's the same reason the seats and tables need to be up. They get in the way if an evacuation is needed.

[BWinmill]

Originally Posted by SteveEisenberg

Is there a remote possibility that the RF shielding on a aircraft could experience a partial failure? If so, they should keep the current rule. If that's utterly impossible, they should lift the rule. Up to now, there has been a legitimate scientific difference of opinion on this question. Probably they will lift the rule eventually, and I hope it's not because of public pressure.

I'm guessing that the whole RF interference explanation comes from the days when electronics used far more power and operated at frequencies much closer to aviation communications frequencies. That being said, there are still huge liability concerns if modern device should interfere with the communications or instrumentation of a modern airplane so nobody wants to go out on the limb and say that using the stuff during take-off and landing is okay. I would also suggest that anyone who can't put down their electronics from the time that the plane leaves the gate until the seatbelt light turns off are probably thinking about themselves when they say that there are no safety concerns, rather than about the potential safety concerns themselves. (That is especially true as others have also pointed out other concerns: distractibility while giving instructions to passengers and loose objects in the cabin.)

[Pinecone]

The reason for the 10,000 foot requirement is there is a LOT more air traffic below 10,000 feet. The airlines run what is called a sterile cockpit below 10,000. NO talking, except for thing directly related to the flight. NOTHING. There were several incidents that occured when due to chatting, radio call were missed.

As for interference, I can hear my phone ring, before it rings, in several cars. Multiply that by up to 550 people (A380) and you can have an issue.

As for the rules, the FAA doesn't ban their use. The FAA requires the that the operator (airline) determine what is safe and what is not safe. So with airlines running near 0 profit (or at a loss) who do you think is going to pay for the testing required? The reason the pilots (only on some airlines) can use iPads instead of paper charts is that it is easy to test two specified devices in a specific places on the aircraft.

[SeaKing]

Let me talk about the difficulties of making certain that nothing is being interfered with on the plane by people's electronics.

A device may be designed and tested to operate on a certain frequency that causes no problems. Then because of failure in the device, other frequencies including harmonics are produced that weren't expected.

The best way to prevent something in the passenger cabin from interfering with the cockpit is to electrically shield them from each other, but then there might be cables in the body of the plane that could be affected by signals from the passengers or for that matter from the cargo area. Radio interference isn't what it used to be but it hasn't gone away.

Some of you may have experienced some of it when you heard another caller on your house phone or cell phone. Likewise, you might have heard a CBer or a Radio Telephone on your TV or radio.

Sometimes this is called "cross talk." These same signals might interfere with devices that aren't powering audio circuits and then you might not know about it immediately.

[SteveEisenberg]

I think the most influential article on the limit-device-use side is this one from the Institute of Electrical and Electronics Engineers Spectrum magazine:

http://spectrum.ieee.org/aerospace/a...t-any-airspeed

This certainly is a controversial article. But its existence shows that reasonable people can have a safety concern here.

[JSWolf]

Originally Posted by pidgeon92

During takeoff on one flight I was told by the flight attendant to stow my paper book.

That is so you will pay attention to the emergency directions instead of your book.

[Anabana]

A few years ago, I was a juror on a burglary case where the 3 men accused were driving through suburban neighborhoods using a remote device to open garage doors. Amazing how many could be opened!

Naive on my part, perhaps, but it seems perfectly reasonable to me that today's electronics could interfere with 'yesterday's' airplanes.

[Edward M. Grant]

Originally Posted by Anabana

Naive on my part, perhaps, but it seems perfectly reasonable to me that today's electronics could interfere with 'yesterday's' airplanes.

Modern electronics is designed not to interfere with anything. Avionics is designed not to be interfered with. I've only worked on military avionics, not civil, but the idea that an iPad or cell-phone could interfere with the hardware I worked on just makes me laugh.

Perhaps something actively transmitting like a cell phone could interfere with a radio, but it would have to be pretty badly designed to put out that much power on a frequency well away from where it's supposed to be transmitting.

The only possibility I can really see is someone actively broadcasting at high power to try to make it crash, but then they're hardly going to turn it off just because the cabin crew tell them to.

[jbjb]

Originally Posted by Edward M. Grant

Modern electronics is designed not to interfere with anything.

All non-trivial electronics radiates. There are legal restrictions on how much devices are allowed to radiate (e.g. FCC Class A/B in the US for unintentional radiators), but these limits aren't zero. Furthermore, in the real world devices can be faulty and may well radiate above these limits.

Similarly, the EMI immunity of avionics can be less than would be hoped for.

While it does seem unlikely that a problem could be caused, the range of unknowns involved in an unknown collection of unknown devices radiating unknown powers with unknown spectra makes it very hard to be sure.

It doesn't take much study to see that this is an area in which expert opinion varies - the answer isn't clear and requires more study. It seems perfectly sensible to me that until sufficient work has been done by experts to be confident that it's safe then playing safe is the right thing to do.

This is an area where the "weight of public opinion" needs to be ignored (other than in encouraging those with the expertise to do the research). No matter how much Joe Public may feel that he understands the science, he doesn't - this is an area for the experts to decide, not public opinion.

A couple of points which are frequently brought up to argue in favour of allowing devices:

1. "Some airlines allow pilots to use iPads, so it must be safe"
2. "If it wasn't safe, terrorists wouldn't bother with explosives, they'd just use cellphones"

In answer to (1) - there's a big difference between a known number of known devices being used in a known way at a known time and the free-for-all of unknowns above.

In answer to (2) - there's a big gap between the confidence that a crash would be caused required to make the devices an option for terrorists and the confidence that a problem won't be caused required to provide adequate safety for passengers. If (hypothetically) use of a phone caused a crash every 100,000 flights it would be useless as a terrorist tool but still present too much of a risk to be allowed.

Having said all that, it seems likely to me that at some point in the near future enough work will have been done to show that it is (in some form) sufficiently safe and more freedom will be allowed.

/JB

[tubemonkey]

Again, if these devices truly posed a safety risk, the FAA would ban them. After all, what guarantee does the flight crew have that all devices have been turned off?

[tubemonkey]

Originally Posted by jbjb

In answer to (2) - there's a big gap between the confidence that a crash would be caused required to make the devices an option for terrorists and the confidence that a problem won't be caused required to provide adequate safety for passengers. If (hypothetically) use of a phone caused a crash every 100,000 flights it would be useless as a terrorist tool but still present too much of a risk to be allowed./JB

Are there any documented cases of plane crashes or other problems caused by consumer electronics in use by passengers?

[jbjb]

Originally Posted by tubemonkey

Again, if these devices truly posed a safety risk, the FAA would ban them. After all, what guarantee does the flight crew have that all devices have been turned off?

It's down to statistics. While telling passengers to turn off devices doesn't ensure that they are all turned off, it seems fair to assume that it will significantly reduce the number of devices which are still on.

We have historical evidence to show that the current arrangement (where all are asked to be turned off and, presumably, most but not all are) yields an acceptable level of risk (i.e. the rate of accidents is still acceptably low). We have no such evidence about what would happen if there was freedom to use whatever gadget you wanted at whatever time.

Personally, if we're considering changing the policy from one which we have evidence is safe to one with no such evidence, I'd rather that was done once scientific tests have shown it to be safe.

/JB

[jbjb]

Originally Posted by tubemonkey

Are there any documented cases of plane crashes or other problems caused by consumer electronics in use by passengers?

There are documented cases where avionics issues could have been caused by consumer electronics - I seem to remember some have been quoted in other threads on this subject in these forums. If you can't find them I'll see if I can find them for you.

That's not really the point though. If we're talking about changing the rules then whether there are cases under the *existing* rules isn't the issue - we don't know how many cases there would be if devices *were* allowed as we haven't got a track record of operating under those rules to study.

/JB

[Edward M. Grant]

Originally Posted by jbjb

All non-trivial electronics radiates.

Uh, yes. But it's nowhere near the amount that an electronic device from the 80s would radiate.

Similarly, the EMI immunity of avionics can be less than would be hoped for.

Then someone really screwed up.

The simple reality is that, on any flight, there are probably half a dozen people who forgot to turn off their cell phone or other device and it's sitting in their bag or pocket doing its thing despite all the rules. So if your avionics can't handle that, you've got big problems.

[DianNC]

Originally Posted by jbjb

It's down to statistics.

Aha! So it's a bit like Russian roulette (just substitute rule-breaking passengers for the bullets)!

We frequent fliers can all feel so much safer now!!!