Is it really dangerous to keep your cell phone on while the plane is landing or taking off?

Factual Questions
21

First, there’s a difference between takeoff/landing, and flight in general. The rules are more strict for the former, since they’re more dangerous. You couldn’t even play a CD or non-wireless electronic game, according to the rules. Flight mode is for in-flight, not takeoff and landing. Antibob explains why, above.

That said, the rule is uninforceable. I wouldn’t be surprised to find that more than 10% of phones are on during takeoff and landing, simply because people forget or can’t be bothered.

If cell phones were a serious danger, they’d test for rf noise in the cabin. The current policy is a good balance between safety, convenience, and lack of hard data.

22

I’ve been flying several times a year since I’ve owned a cell phone and never turned it off during the flight. I’m willing to bet good money I’m not the only one. It just doesn’t make a difference.

The ban on electronic devices rests on anecdotes, not on hard evidence—because there isn’t any.

23

Missed the edit window:

Reading over the last few posts, it seems some posters aren’t fully aware of the types of noise electronics can produce, and it might be good to go into a more full discussion of this.

“Flight Mode” shuts off wi-fi and communication to cell towers. That’s not the only kind of electronic noise that can potentially affect communications between an aircraft and the tower.

Pretty much all electronics put out some kind of RF noise. It doesn’t matter if they’re designed for communication or not. Televisions, VCRs, DVD players, blenders, computers, electronic clocks, and any electric appliance will put out RF noise.

Mostly, the combined RF noise of all your stuff is at a pretty low level and won’t affect human health (though there are always nuts who claim any level of EM radiation is bad). If you bought new consumer electronics anytime in the last several decades, it should have included some kind of safety information (which nobody really reads), which lets us know that the device has been determined to output below the FCC minimum level of RF noise and poses no known threat to human health.

As it turns out, enough RF noise can affect communications. It’s a problem Ham radio operators have seen increasing over the last few decades, as we use more and more home electronics.

That noise can also affect communication between an aircraft and a control tower. As mentioned above, this can cause a low level of noise in the audio channel that some pilots have heard. It’s also possible (though rare) that such RF noise can be bad enough to affect avionics.

It’s important to note that it’s not only cell phones that create RF noise, but everybody happens to carry a cell phone with them. If everybody happened to be wearing a battery powered radio player, we’d be getting notices about those.

So even stuff like battery operated watches and pacemakers put out this type of noise. But they typically put out an incredibly small amount that is generally negligible.

On the other hand, stuff like wi-fi and cell phones, put out regular RF noise and ALSO blast high energy narrow band signals.

Various groups have been trying to determine the safety of leaving electronics on. It’s still not entirely understood. That said, it’s be shocking if there wasn’t at least one phone left on during any given flight. Here’s an IEEE spectrum article from a while back that delves into the topic of active cell phones. Mostly, it’s a 1 in a million shot that anything is significantly affected. Of course, it also completely sucks to be that 1 in a million.

Airlines, the FCC, the FAA, and manufacturers have been trying to figure out how much noise an aircraft can experience safely, but the safest policy is to shut down as many electronic devices as possible, especially during landing and takeoff when the flight crew is in direct contact with the control tower. Of course, I’d also like a unicorn and rainbows, too. Better shielding of sensitive aircraft components and more study may lead to relaxing of the rules in the future, though.

24

It doesn’t make a difference 99.999999% of the time. How do you know, for sure, that it never makes a difference?

I took a flight to Mexico 20 years ago. They take a different approach. They did not allow batteries in the passenger cabin, period. If there ever is a crash in the USA because of that 0.000001% of the time, the TSA will probably add batteries to the list of forbidden items in the cabin.

25

See here how a cell phone can make a Fluke multimeter crap out:

26

The last time we flew (a few months ago), the flight attendant said phones had to be off, and NOT in Airplane mode. I remember thinking, then what is Airplane mode for?

27

Emirates Airlines have permitted in flight cell phone use for a few years. Can’t remember whether they needed to be off for take off or landing.

Google also says Virgin Atlantic are cool with it too.

28

That’s just for takeoffs and landings. After you pass 10000 ft, you can have your phone on, but it has to be in airplane mode.

29

The last time I flew Charlotte to St Martin, my phone was in my bag, inadvertently left on the entire time. I had a mini seizure when I realized, as we deplaned.

30

If leaving a cell phone ‘on’ during takeoffs or landings could cause a plane to crash do you really think they would let anyone on a plane with a cell phone?

They tell you to turn them off because they want you paying attention to the crew and not yakking on the phone in case there is an emergency.

31

Frequent flyer here. Not an engineer.

I am not aware of a single incident determined to be caused by a cellular radio or toy and reproducible. And the airplane engineers have certainly tried. It’s true that they emit RF. It’s true a relatively unshielded instrument might pick up that noise. That’s it.

It’s not true it’s ever caused a reproducible problem in a commercial airplane, and instruments behave erratically all the time without explanation. Once the airlines realized they could make money off of inflight internet, we suddenly were encouraged to turn on our laptops and phones, and hook up to GoGo and increase their revenues. An amazing about face for such a previously dangerous behavior.

As the WSJ above cites, a large proportion of the population do not turn off their cellular devices. Nobody cares when a phone rings, unless the FA is in a bad mood.

Some years ago I researched this topic. There is nothing there. It is not possible to have a cite for a negative event. There have been occasions (I recall one of the avenues I pursued was a Boeing engineer and pilot blog site) where an electronic device was suspected of interference and confiscated, but the interference couldn’t be duplicated.

It’s just absolute crap, basically, with banners determined not to lose face, and demanding proof that something CAN’T happen.

I have heard an explanation that the takeoff and landing ban has to do with anti terrorism. No idea if that’s true. It makes sense that you don’t want a cell phone guy on a plane mentioning where his specific plane is when it’s close enough to the ground to be a target (say, based on a passenger or whatever).

Reminds me of a presentation (this time related to hospitals and monitoring devices) where a presenter I saw showed how a cell phone sitting on a chest lead could make the monitor look like V fib, “possibly resulting in a dangerous unnecessary countershock.” No, pal. We’d take the cell phone off the guys chest and tell him not to park it there…

32

That’s brilliant. I’ll have to use that in the future.

33

you might make use of any kiosks or vending machines selling flight insurance, just in case.

34

I don’t think “crap out” is a helpful phrase. The Fluke is doing what it’s supposed to be doing: measuring voltage. It’s picking up 5-20 milivolts which is next to nothing considering the meter’s 10 meg ohm input impedance.

I just took my fluke and waved it around a few things nearby:

External hard drive: 17 mV
Printer (turned off): 9 mV
Printer (turned on): 16 mV
LED lamp: 24 mV

Strangely, it registered nothing (0-2 mV) when placed on my Samsung Note while it was on a call.

Of course the power isn’t what we’re concerned about as much as how any nearby sophisticated instrumentation might interpret the signals coming from the device. But the signal has to be strong enough to get picked up in the first place.

35

It is not simply measuring voltage, it causes the screen to turn off and some people have reported that the multimeter was bricked after that (the firmware was erased or something).

Fluke acknowledged that the problem exists and they have revised the design of newer models.

36

No.
I won’t bother with the Wikipedia link, but this is one I found amusing:
Myth Busters

I still support the Cellphone ban, just because of the assholes on the ground who can’t keep from telling the world what the are doing now, right this moment, loudly, but other PEDs shouldn’t be banned.

37

Cite? My guess is every single plane that takes off or lands has at least one mobile phone switched on inside it. The damn things should have been falling out of the sky.

38

Whether it’s dangerous or not, I dread the day when they lift the ban and the cabin is filled with idiots yapping about their boring lives & businesses through the whole flight.

39

No one is saying that a cell phone will always cause problems. What is being said is that in rare circumstances, they can cause problems. Just because it doesn’t happen often doesn’t mean it doesn’t happen. And the reason it doesn’t happen often is that aircraft systems are specifically designed to be as immune as possible from interference.

Saying cell phones are perfectly safe because planes don’t fall out of the sky every day is a lot like having a room filled with a thousand guns, only one of which is loaded. You can walk into the room and pick up a random gun and point it at your head and pull the trigger, and most of the time, nothing will happen. But it’s rather foolish to say that it’s a perfectly safe thing to do based on the fact that it usually doesn’t turn out bad.

As for actual cites, I can’t find a cite for either specific case I mentioned. The loss of communication incident was a yahoo news story about a year or two prior to 9/11. It’s probably not archived anywhere on the net. I don’t recall exactly where I read the story about the thrust reverser deploying. The evidence for the thrust reverser was admittedly a bit circumstantial. An incoming call was being set up at the exact time the thrust reverser deployed, and there was no other reason found for its deployment. Admittedly it’s not anywhere near 100 percent proof of cause and effect.

But, for cites that cell phones can cause problems, those are easy to find.

For example, see this report, from the UK’s Civil Aviation Authority (CAA) (warning, PDF):
http://www.caa.co.uk/docs/33/CAPAP2003_03.PDF

That’s a six year period, and only 35 incidents were reported. As you noted, just about every plane these days takes off and lands with a cell phone turned on. So it’s clearly not something that happens often.

On our side of the pond, there’s this report from NASA (again, PDF warning):

This covers a longer time period, and includes interference from any “PED” (personal electronic device). It lists a total of 130 incidents. 39 of those are rated as “critical”, and 40 were rated as “less severe” (the rest were unrated). In other words, half of those rated weren’t just minor annoyances. They were things that really could have led to major problems.

A chart on page 16 of that document lists the following equipment affected (I’m only showing totals since I can’t easily copy and paste the entire chart):

Navigation: 112
Communication: 7
Autopilot: 7
Yaw Dampers: 1
Engine Fuel Controller: 1
Speed Brake Auto Deploy: 1
Autothrottles: 1

A chart on page 20 lists the type of device responsible for the incident. Laptops and cell phones were both tied for the top two spots (I personally would have expected cell phones to rank a lot higher).

The paper mentions an ASRS database of incidents. You can probably hunt that down and get more recent data. NASA may have a more recent version of that report available somewhere as well.

40

I’ve read articles on this before, and what I fail to see is any conclusive evidence that the particular device was at fault. “We’re getting noise in our headsets, umm, it must be someone has a personal electronic device on.”

With the energy of the device following the inverse square law, I have a really hard time seeing how a cell phone in row 43 having anything to do with what happens in the cockpit.

I would like to see some hard science (OK, hard engineering) on this.