Research: Mobile Phones Disrupt Aircraft

threeturn writes "Another contribution to the ever-popular "mobiles on planes" topic. Every time this is discussed on /. lots of people say "there is no danger - its just the airlines trying to make a buck on their skyphones". Well, now the UK Civil Aviation Authority has done some research which shows mobiles on planes do disrupt safety systems and interfere with compass readings and other navigation equipment. Also reported by the BBC. So do us all a favour and switch your mobiles off next time you fly."

Comments

I think this is good

[xmda]

Well, when it comes to airplanes and flying I think the expression "better safe than sorry" fits the bill quite nice.

Re:I think this is good

[VCAGuy]

"better safe than sorry"

Yes, it's generally not an indicator of common sense to compromise the very safety systems that are keeping you alive whilst you are being propelled at mach ~0.78 at 30,000' MSL...but, that's why common sense isn't all that common!

Re:I think this is good

[anshil]

If airplanes are already sensitive to the not so dramatic electromagnetic impact of simple little mobil phones, what would that mean to somebody who in act of terrorism wants to make strong em. impact on purpose?

Re:I think this is good

[TopShelf]

Not only that, but have you ever sat next to some schmuck who feels he has make a call as soon as the wheels hit the ground? And we're not talking some urgent business communication - it's more like "yeah, we just landed... I think I'll grab a burger and be there in an hour... yada yada yada..."

I say, install automatic detection systems for wireless devices, identify the location of the phone and put it on the screen for all passengers to see. Let them then decide what to do about it - I think after a few blanket parties the message will get around!

Re:I think this is good

[xmda]

Err... That is like saying that the sefaty belt in my car cannot save me from a bomb planted in the car. I'll say it again, better safe than sorry.

Re:I think this is good

[_Swank]

no, i'm offended that my seatmate thinks that the 5 minutes he's saved by calling at touchdown is more important than respecting the people around him and not disturbing them.

i've heard a very large number of these touchdown calls (i fly at least twice a week) and not a single one has yet been urgent enough to warrant the abuse of everyone in the vicinity.

Re:I think this is good

[los furtive]

I think they are more concerned with the potential of a sustained disruption caused by a pool of 300 passengers affecting the performance of the compass and safety systems throughout the flight.

In your scenario you'd expect a burst, which might temporarily disrupt performance but would not (I'm assuming here) have a sustained effect.

Re:I think this is good

[Anonymous Coward]

What you are failing to take into account is that there will ALWAYS be a way for terrorists to screw things up. No amount of police will stop it, because sometimes the police are corrupted as well. To put it in EE terms, a filter does not block noise, it changes the amplitude of certain frequencies. The ration of signal to noise may go up, but noise will still exist...

Re:I think this is good

[Drakonian]

Well, now you have a secret weapon when the terrorists have hijacked the plane. Just whip out your cell phone.

Re:I think this is good

[rifter]

Well consider that plane #4, which crashed into a field, had nearly all the passengers on their cell phones simultaneously...

Re:I think this is good

[spakka]

"yeah, we just landed... I think I'll grab a burger and be there in an hour... yada yada yada..."

They make calls about free NY Times registration?

Re:I think this is good

[anthony_dipierro]

Except for the fact that bombs aren't allowed on planes, but electronic devices are. Maybe we should think about disallowing mobile phones as well. Better safe than sorry.

Re:I think this is good

[goofballs]

uhh, no, no i don't. do you have a source for that? keep in mind that:

a) fit people can hit speeds faster than that relatively easily. ~11.25s in the 100m dash is ~20mph.

b) people have been riding horses that can go faster than that for a long time. Kentucky Derby winners in the 1870's were running at about 35mph.

so basically i think you're full of it. =)

Re:I think this is good

[The_K4]

Ok, i'll ask it.....why is a plane like a movie thearter? Why do you need complete silence from the other passangers? Think of it more like a bus or a subway, it's loud, people make calls, people do buisness, they talk (and if your in NYC screaming profanities and masturbating occur fairly reguarly). They are another form of mass transit, and as long as the person follows the rules, for when it's SAFE to use the phone why should it be a problem if they call as soon as it's allowed.

Re:I think this is good

[h4x0r-3l337]

If I am stuck next to random stranger X, then certain courtesy guidelines come into place. Among them are not picking my nose and eating it, screaming profanities, masturbating, and talking on a cell phone, listed in my own order of rudeness rating.

So next time the guy next to you makes a phonecall, show him you can do better and start masturbating. If he counters by screaming profanities at you, pick your nose.

Re:I think this is good

[werfele]

There was excellent empirical evidence to dispute this idea in 1900, since many trains traveled near 100 miles per hour at the time, and on most trips the passengers were just fine. On the other hand, the trains did have more of a tendency to explode, and they had fairly frequent nasty derailments.

Re:I think this is good

[matth]

Same "principal" applies to two way radios.. Like in a car... for some reason people feel if they can't hear themselves (ie over the roar of an open window in a car) that they need to talk louder into the mic.. which actually just distorts them to the end listener. Just talk normally, even if you can't hear yourself and everything will be fine.

Re:I think this is good

[rifter]

I have noticed that people tend to talk much louder on their phones than they normally talk. This is what ticks me off - when I am in a quiet setting like maybe a restauraunt and then someone uses their at-a-soccer-game voice.

This is because their phone/service sucks. On many phones if you do not yell no one can hear you (and even then it is sometimes problematic. This was the case with my previous Samsung/Sprint combination. With my nokia 3590 and at&t using gsm I can speak with a normal voice even with the phone slightly away from my face (like while taking down a number) and the other person and I have no problem hearing each other.

I think it is silly when cell phones do not have a higher range for their volume controls, since this is the cheapest thing to change and dramatically changes the customer experience w/r/t how the reception is perceived (if you can turn it way up and hear, then you will think you have ok service as long as you aren't cut off). Too bad everyone can't have phones designed by Spinal Tap! :)

Re:I think this is good

[Cramer]

An antenna aimed at the metal skin of an airplane will have zero effect inside the tin can. (that's basic physics) The best (or worst) one could do is damage the radar and radio equipment that has exterior antenna.

I was wondering why the electronics inside aircraft would be such insanely sensitive devices seeing how almost nothing else on earth even notices the RF from a pager/cellphone. But after considering the RF cage all that equipment lives in and the age of the entire system design... I'm really not surprised it's so easy to screw it up.

(fwiw, there's a Lucent notice hanging on our 5ESS phone switch(es) warning about RF problems from cellphones within 5ft of the equipment. I think I'm the only one who's bothered to read it in years.)

Re:I think this is good

[rifter]

Actually, I was mostly joking. I have read the actual research (well, I am reading through it now) and it seems that this is another example of bad science turning out an irresponsible academic paper with skewed results which are then sensationalized by "journalists" who don't even read the paper they are reporting on (but write at length out of their ass). Pretty much SOP.

What *should* have been the headline was "Researchers find it is impossible to affect airplanes with cell phones" though even that is kind of innacurate. They found that if you could get a device to transmit continuously on cell phone frequencies at the maximum power that a cell phone might be known to operate at and then put that device 30cm from the equipment in a cockpit there could be minor disruptions in instrumentation. Maybe someone who is more of a radio geek than I am could come up with a much more nefarious and effective device (effective from a longer range, for instance), but a cell phone does not fit the criteria of the device they used to disrupt service.

Re:I think this is good

[nomel]

Uhh...it would only be able to find something harmfull after it was turned on. If it was extremely high power, it would be too late by then. Also, when they did detect something, they would have to get someone to run over, find it, and take it away and destroy/disarm it. I guess it's doable.

I would rather see them not allow anything electronic...that way, they woludn't have to worry about it. BUT, this would be controlled by the people at baggage claim, which everyone mostly consists of idiots. They could just force the people to put them in the non carry on luggage, which could then be put in a metal box or something.

As an occasional airline passenger

[Vengeance]

I'd REALLY REALLY REALLY like to see Boeing, Airbus et al. installing avionics and comms systems that can't be disrupted by ubiquitous and nearly free techno-gadgets.

Re:As an occasional airline passenger

[bmongar]

My impression is that newer avionics are 'more imune' to the interference. It's all the electrinocs pre 1989 that are prone to interference. It's just that there are a lot of planes out there that pre-date 89 and there will be for a while.

Re:As an occasional airline passenger

[mhotas]

Seriously... the system as it stands couldn't be any more broken, as it depends for its safe operation on the active opting-out of every cell carrying passenger. I mean, phones ring in college lectures all the time -- I've seen it happen to professors who have very clear policies about turning them off.

Re:As an occasional airline passenger

[Anonymous Coward]

True, but you're forgetting that back in the 60's and 70's, GHz-based transmissions were pretty much unheard of at 30,000 feet so various electronic packages aren't shielded adequately. Lots of these planes have a range of systems onboard that may have been built at any point in the last 30 or so years, retrofitting all of them will take time and a lot of money, something the airline industry is not too keen on right now.

I'd expect to see newer planes kitted out in such a fashion though. What better way to ensure aircraft sales than to say "yup, business class passengers can still use WiFi and their mobiles... on our new jets..."

Re:As an occasional airline passenger

[scsirob]

You are right of course, but this is why the danger exists. Many aircraft have been certified with way-back technology, and it doesn't pay to re-certify these airliners with hot, new goodies that are designed to live in peace with mobile phones and other wireless toys.

Avionics system designs are very conservative, it's all designed to work forever. Latest-and-greatest simply doesn't fit their books. With the track record of modern software, I don't think we should be sorry for that..

Besides the danger to the aircraft, the mobile networks are also not designed to handle mobile phones moving between cells at 500mph and 'visible' to every cell in a 100 mile radius.

Re:As an occasional airline passenger

[bhsurfer]

I see your point. I do think it would be cool if the avionics folks had some sort of testbed set up for mobile phone developers, etc. I mean, just because the phone folks are capable of moving as quickly as they do doesn't mean that they have no responsibility to ensure that their devices don't muck up systems that are already in place. I really think that the responsibility lies on both parties. Given that there are decades of avionic system documentation and error logs / fixes (presumably via IV&V or a similar mechanism) you'd think that the involved parties could slow down and communicate a little bit. Neither aircraft nor telephones are going away anytime soon, so at some point they need to work this out.

Re:As an occasional airline passenger

[trout_fish]

So to prevent the airlines having to spend money, we have to be put at risk everytime we fly? If mobile phones really pose a risk to the safety of an aircraft then something more needs to be done than simply asking people to turn off their phones.

Re:As an occasional airline passenger

[Arker]

I'd REALLY REALLY REALLY like to see Boeing, Airbus et al. installing avionics and comms systems that can't be disrupted by ubiquitous and nearly free techno-gadgets.

I'll second that.

Having read the article, there are some interesting points. First off they aren't alleging that using your cellphone will make the plane crash, but rather that it might cause some sort of distracting noise in the crews headsets and at worst could conceivably cause a false alarm on one of their warning lights. Sounds a little iffy to me, but ok, better safe than sorry on a plane... then I read on.

Turns out it doesn't matter on new jets - only ones certified pre-'89. So why don't they let people use their mobiles on the newer planes where it's not an issue? Back to the old 'conspiracy theories' on that one. Controllers like control. And the high prices on the sky phones can't hurt either.

Plus, as you kind of hinted at, if a cellphone can really cause even minor systems disruption on a pre-'89 jet, just imagine what someone that was seriously trying to cause a problem could do. It's absurd. If those jets really do have systems that can be so easily disrupted, they should be grounded until they're fixed. So either way, something doesn't add up here, either they're lying (or maybe just stretching the truth very far and very consciously) or they're not even trying to do their job, take your pick.

In an age when we know there are people trying to bring jetliners down, it's absolutely absurd to be flying jetliners that are so poorly insulated against EM interference that a mobile phone is a threat to them. Period.

Re:As an occasional airline passenger

[arivanov]

Bollocks.

They are immune as well.

At least to a phone you can get on the plane (one that fits in your pocket).

The British Civil Aviation authority tested with a transmitter that was constantly transmitting at 5 watts. That is the maximum allowed power of a car phone (anyone seen a GSM car phone?). And they barely got some interference in some parts of the aircraft. If they would have tested with real mobile power and with real transmission (which is not contiguous) they would have been unable to show interference even with pre-1989 avionics.

Re:As an occasional airline passenger

[Cecil]

Mind you this is under the assumption that the avionics are not held to Part 15.
They're not. They fall under the category of "authorized radio station". You need a license to operate a plane's radio.

Re:As an occasional airline passenger

[PetiePooo]

But you don't have to worry about this while at 30,000 feet. Up there airplanes are separated by miles.

Not true. There can commonly be as little as1000' separation with a combined horizontal velocity of 1400mph or higher.

Flight levels above 18,000' alternate between easterly directions on the odd-thousands and westerly directions on the even-thousands. The altitudes are determined by pressure altitude and monitored carefully by radar. The altimeters are precision instruments and frequently calibrated.

So, a 767 flying at 250 degrees at flight level 280 (28,000 ft) can meet a 757 flying at 70 degrees at flight level 270 (1000 feet below) along a published airway, and it would not be unusual circumstances. ATC (and their onboard collision detection system) would keep them aware of each other.

Re:As an occasional airline passenger

[Thurn und Taxis]

"yup, business class passengers can still use WiFi and their mobiles... on our new jets..."

Great, so you can pay extra to spend six hours next to someone yelling into their phone:

Yeah, Jack? Listen. About those latest sales figures - can you CC them to me ASAP? Oh, and FYI, the head honcho up in corporate really wants to grow this business, so I'd like you to get up to speed on the ISO9002 requirements for the Peterson accou - dammit, Frank, how many times do I have to tell you, we don't sell PRODUCTS, we sell SOLUTIONS! What? Yeah, I know you're Jack. Hey, we're golf buddies, right? No, I didn't just call you Frank! Listen, Alan, I can tell you're upset - why don't you take five minutes to think about your situation while I touch base with some clients. Can you do that for me? Greaaat."

I think I'll stick to economy class, where people are less likely to use their laptops as speakerphones.

Re:As an occasional airline passenger

[mduell]

Flight levels below 18000 also alternate altitudes. Even thousands for westbound IFR trafffic, even thousands plus 500 ft for westbount VFR traffic, odd thousands for eastbound IFR traffic, and odd thousands plus 500 for eastbount VFR traffic. But above 18000, you dont have to worry about the pesky VFR traffic.
Additionally, once you get up really high (~32000, maybe 36000), they start seprating by 2000 or 3000 ft.

Re:As an occasional airline passenger

[rifter]

Unfortunately they spend a substantial amount of their money on Congresscritters. Probably more than they would spend on retrofitting, but the point for them is not to have to listen to you ;).

How much is your bribery budget? Feed a Congresscritter today! :)

Re:As an occasional airline passenger

[DonGar]

What about the cumulative effect of a hundred phones at once? If you don't ban them, then almost all passengers will leave them on.

I'm not sure if this really matters or not.... I'm asking.

Re:As an occasional airline passenger

[rnturn]

``Additionally, once you get up really high (~32000, maybe 36000), they start seprating by 2000 or 3000 ft.''

And if get very much above those sort of altitudes, chances are that you're much more maneuverable than a typical airliner, and usually armed, so if you can't avoid the collision you could just should at the risk until it goes away.

No, just like always

[yatest5]

the slashdot posters are always right. Mobile phones don't interfere with planes. It's just MS using their monopoly position to interfere with Linux developers mobile phone calls the only place they can - in the air!

In this way, they hope to stifle Linux's development - as we all know, Linux developers are all high flyers in the world of business and are always on the move, meeting new people.

Re:No, just like always

[halftrack]

as we all know, Linux developers are all high flyers in the world of business and are always on the move, meeting new people.

That's if they can decide how to put the plane together.

Cell phone towers are the problem

[ShwAsasin]

The biggest problem when flying and using mobile phones is the phones themselves. When you are flying, the phone may try to communicate (roam) with many towers which causes cell network problems. Imagine the area of towers you could hit at 30,000ft in the sky.

Re:Cell phone towers are the problem

[trapdoor]

> Imagine the area of towers you could hit at 30,000ft in the sky

Quite a few, if the signal was strong enough to travel 30,000 feet. That's 10,000 yards. Which in (British at least - don't know about US) miles, is about 5.5 miles. This might work along the ground, but straight up in the air???

I worked for a while almost at the top of the new HSBC building in London's Docklands. It's only a little shorter than Canada Tower (Britain's tallest building), but above about the 40th floor, you lose your phone signal and can only intermittently make calls.

Therefore, I think that the danger comes not from communicating with cells, but the phones continually searching for cells (which does involve transmission I believe). They do this every few seconds. An unscientific way of showing this is when you are out of range, the battery life of phones left on standby reduces dramatically, due to all the extra transmissions.

Re:Cell phone towers are the problem

[doctor_oktagon]

Eh Hullo?

I'm sure the Airlines couldn't care less that their passengers are screwing up the Telco systems - they are far more concerned about the effect on their planes!

Hence the biggest problem is the interference with the avionics, NOT the telco problems it creates!

Re:Cell phone towers are the problem

[trapdoor]

> cell phones are different than mobile phones.

No. They are the same thing. In Britain, what you call a cell phone, is called a mobile phone. The CAA mean cell-phones not walk-around-the-house style things.

Re:Cell phone towers are the problem

[pixelpusher220]

Exactly. A friend of mine who is a pilot, has forgotten to turn his off a few times when he goes flying. His battery is just about gone after only an hour in the air.

No problems getting reception up to 3000 ft, but you get LOTS of extra transmissions switching from tower to tower.

Re:Cell phone towers are the problem

[Lumpy]

Imagine the area of towers you could hit at 30,000ft in the sky.

not many at all.

First Cell site antenna array's are high gain and therefore squeeze the signal to the horizon, second they tilt the antennas downward to limit the cell sites coverage in regards to adjacent cell sites.

It amazes me how many times this comes up on cellphone doscussions and how suprising it is to find how many people have no clue as to the basics of how a cellsite operates.

Re:Cell phone towers are the problem

[cruppel]

You're right, cell phones were never designed to work at that altitude with so many towers in sight. Three towers is basically the magic number (the least number of points to make a cell). Also, the cell phones were designed for day-to-day activity, such as walking or driving around. The sheer number of cells within the phone's sight in a plane coupled with the speed at which you are traveling makes it pretty difficult for the phone to behave.

This has no bearing on whether or not it's OK for a phone to operate on a plane. Shit, the old planes may not have shielding for transmissions of that frequency (old ones at least), but I've been asked to put a four-function calculator away during the middle of the flight at cruising altitude... they just don't want to worry about technical problems like that I guess.

Re:Cell phone towers are the problem

[wowbagger]

True, a cell site puts most of its signal out horizontally, and receives horizontally.

That only makes the problem worse.

Consider: You are at 30000 feet, and your phone is on. Its listening for a control channel, and finds one. It does a registration.

Now, several factors are reducing the signal strength of the control channel to the phone: distance, the gain pattern of the site's antenna, and the fact the phone is in a big metal box with small holes in it. So the phone will have a very low RSSI (received signal strength indicator), and will put out maximum power to reach the site.

Now, because the altitude, the angle the signal comes in at and the distance are not going to be very much different for many cellsites - each is going to receive the phone about equally well. This actually tends to EXPAND the range of sites affected - the sites under the plane suffer from the gain pattern of the signal and the emission pattern from the plane (most of your signal is going out horizontally from the windows, modulo knife edge scattering), but get a boost from proximity. The sites far from the plane lose signal due to distance, but now the signal is coming from a lower angle and is in the higher gain portion of the antenna pattern.

Now, cell sites are laid out in a pattern - usually in most urban areas it is a hexagonal pattern, with adjacent cells using different frequencies and DCC (digital color code - basically a number that helps the phone tell the difference between sites). So there WILL be several sites that will match the frequency and DCC the phone is using.

Now, for CDMA systems ALL those sites have to swap data about the signal they are receiving (this is to implement "soft handoff" where the phone gradually changes which site it uses - for a time the phone is actually using 2 sites at once.) This GREATLY increases the data bandwidth used between sites.

For GSM it's a little different - but the upshot is you are STILL confusing the sites and forcing them to talk to each other over the landline connections.

Meanwhile, here is your phone blasting out bursts of RF at maximum power to try to register to the cell site it hears - only to have to register AGAIN a few seconds later because it has moved out of range.

So, your battery will go flat very quickly (the way these new phones keep battery life up is by not being on all the time - they only listen during their assigned time slot, normally. However, when the phone detects that is has changed sites, it must re-register and listen to ALL time slots until it gets one assigned.)

Also, you are tying up resources in the cell system.

Lastly, you are pumping out a fair amount of RF power inside this big metal box full of wires. What is another term for "wire" - ANTENNA. Each of the wires in that plane is detecting some of your radio's signal, and any non-linear element (corrosion, a semiconductor, etc.) can act as a detector to convert the RF into DC. (Think about the old style crystal radios, or the foxhole razor blade radio).

When you do EMI complience checks, you will be amazed at what can act as a receiver and make things go screwy. All sorts of things that you might think "this cannot interfere - it's gigahertz away!" start interfering.

Re:Cell phone towers are the problem

[p4ul13]

It amazes me how many times this comes up on cellphone doscussions and how suprising it is to find how many people have no clue as to the basics of how a cellsite operates.

The general public doesn't study up on how cell towers work?!?! This is an outrage, somebody call James Earl Jones the verizon wireless guy!

Re:Cell phone towers are the problem

[mesocyclone]

There are two aspects to this observation - one sort of reasonable, one not.

First of all, the phone signal is easily strong enough to reach hundreds of kilometers from high altitude. Cell phones transmit several hundred milliwatts of power. I once used a 100 mW ham radio mountaintop-to-mountaintop at a distance of 175 miles. Since 30,000 feet is onloy 6 miles, signal strength per se is not going to keep your cell phone from working.

Then there is the issue of antennae. The cell system antennas are oriented to maximize signal towards or below the horizon. Thus a signal from a high angle will be somewhat attenuated. Also, the shielding of the aircraft body will also attenuate the signal.

Overall, if you operate a cell phone in an aircraft, it is likely to interfere with a number of cell sites.

Then there is the problem of cities with hills or mountains in them. I live about 500 feet above average terrain in the Phoenix, AZ area. I have had a number of weird cell phone effects as a result. Cell service at my house is sporadic. I can start a call from down on the flat and it will carry most of the way home and then be lost. If I start a call at home it will be lost very quickly!

The reason appears to be that as I drive to my home, my signal is first strongest towards cell towers far to my southeast, and then I go around a corner and they are suddenly only good to the southwest. I don't think the system can handle a switch from a cell to one several cells away.

Odd

[EyesWideOpen]

It seems odd to me that there would be this much discussion on the topic. While it may not be a cut-and-dry issue it would seem that it could be determined rather quickly via research whether mobile phones cause interference or not.

Why go back and forth on the issue?

Note: Of course I don't know all of the facts on the subject so I could be missing something (different plane models are affected differently, etc.)

Even worse...

[Mostly Monkey]

Better not play a flight sim on a 802.11 equipped laptop or the plane will REALLY be in trouble.

Terrorist use?

[Anonymous Coward]

Are they giving ideas to wannabe-terrorists?

But even if they aren't, now "the bad guys" don't even need a gun or knife, just a small electric device to cause much damage...

Re:Terrorist use?

[weicco]

Take this plane to Cuba or I turn on my Sony Ericsson P800!!!

Re:Terrorist use?

[belroth]

No way dude, it's in flight mode!

(NB: you can turn of the 'phone electronics and leave the PDA active on a P800)

A little too late here

[Ores]

A text message sent to a passenger is one theory for a crash that happened last Friday.

News link

I'm sure I read somewhere though that an airline was going to use wireless for flight attentents.

802.11[a|b|g]?

[kipsate]

Can anyone explain why apparantly 802.11b wireless connections do *not* pose a problem in planes?

Re:802.11[a|b|g]?

[monkey_tennis]

Frequency and power - GSM units utilise 900, 1800 and 1900 MHz (depending where you are) 802.11a/b/g uses 2.4 and 5 GHz. In terms of power - just look at the distances involved WLAN tops out at 300 feet without obstructions, phones can manage a bit more :)

Re:802.11[a|b|g]?

[VCAGuy]

I think it's because the only other thing in the 2.4GHz spectrum for aircraft is the WX radar. And since it points forward through the aircraft's nose, anything behind it won't affect it. Also, those transmissions are all within the Faraday cage that is the aircraft's skin--none of those transmissions have to leave the plane (and won't anyway, because of the frequency). Aircraft have onboard microwaves, so I don't think that 802.11b|g poses a problem (don't know about .11a, though).

do you even get reception?

[mydigitalself]

um, on the point of it being a plot to make you use their expensive sky phones...

would one even get reception up there? not only up there - but in there (metal cylinder)?

Re:do you even get reception?

[Vengeance]

Of course. Remember the cell phone calls from the Pennsylvania flight on Sept. 11, 2001?

Re:do you even get reception?

[Make]

I am glider pilot, flying in heights of only up to 3000 metres.. it's quite difficult to make a call in 1000 metres or above. It happened once that my phone rang in 1500 metres, but I've never managed to call someone from up there. Signal indicator says signal is great, but no calls possible. Strange.. (I have tried that on GSM nets in Germany and Sweden)

Longer term solution

[monkey_tennis]

As a frequent flyer I'm more than happy to comply with requests to turn off my phone on planes, but recently air-crew have not been tech savvy enough to recognise a P800 'smartphone' in 'flight' (phone bits off) mode. In these cases I offer an explanation and then comply if they insist it goes off, but as all kinds of wireless tech gets built into PDAs, laptops and watches how will they know? Just because it doesn't look like a phone doesn't mean it isn't...

My guess is aircraft will need better shielded systems.

Re:Longer term solution

[codefool]

It's been a few years, and I'm not up on all the specs anymore, so please bear with me...

When I was working on wireless tech, and had to sit on industry consortium meetings on various initiatives for this type of stuff. One idea that was being passed around was to have an access point on the aircraft that would broadcast a 'forbidden' command to all the wireless devices which would tell them to play nice. iow - the plane would be a 'forbidden zone' where the device would know that it was not allowed to broadcast certain signals. IR would be okay, but bluetooth, 802.11[abg], cell phones, etc. would be right out. This could also be used in signal sensitive places like hospitals, etc.

Re:Longer term solution

[codefool]

As I recall, we couldn't get much momentum on the idea. Mainly because it wasn't a revenue point - which contrary to popular belief is what drives these types of projects. Anyhow, the ap would only need power from the aircraft to function. And since they airframe-strip planes every so often (can't recall the number of flight hours), its a simple matter to install them. And yes, the protocols would have to be augmented to either adopt the function, or a new protocol would have to be defined. I lobbied for the latter, since it would be easier for existing products to support 'friendly wireless protocol a', than having to upgrade to 802.11b.1, or whatever. Also, you avoid problems with IEEE, ISO, etc. having to augment their protocols.

Full report here

[Quixote]

The full report can be viewed here .

From the executive summary:

In October 2002, a set of avionic equipment was tested under controlled conditions in a test chamber for susceptibility to cellphone interference. General aviation avionic equipment, representative of earlier analogue and digital technologies, was used. The equipment, comprising a VHF communication transceiver, a VOR/ILS navigation receiver and associated indicators, together with a gyro-stabilised remote reading compass system, was assembled to create an integrated system.

The tests covered the cellphone transmission frequencies of 412 (Tetra), 940 (GSM) and 1719MHz, including simultaneous exposure to 940 and 1719MHz. The applied interference field strengths were up to 50 volts/metre for a single frequency, and 35 volts/metre for dual frequencies.

The following anomalies were seen at interference levels above 30 volts/metre, a level that can be produced by a cellphone operating at maximum power and located 30cms from the victim equipment or its wiring harness.
snip

I am wondering: how realistic is a test which assumes that the phone will be 30cm from the equipment?

Re:Full report here

[Lumpy]

The applied interference field strengths were up to 50 volts/metre for a single frequency, and 35 volts/metre for dual frequencies.

ok now how about running the same test with REALISTIC amplitudes... no cellphone on this planet can generate 50V per Meter.

Cripes, my ham gear transmitting at 25 watts is only at 11 volts per meter as measured by a field strength meter...

Sheesh I might as well report that cellphones make cars unsafe because when I put the car's computer in my microwave oven and set it for 10 minutes the electronics fry out..

Call me when they perform a real test.

Re:Full report here

[bobs2pacsvegaswirled]

The field strength appears to be reasonable.
First a quick calculation for the power density at 30 cm from a 1 Watt transmitter transmitting isotropically:

Power_density = 1 Watt / (4 * Pi *(0.3 meters)^2)
= 0.884 Watts/m^2

Field_strength = Sqrt(Power_density * Z_o)
= Sqrt(0.884 Watts/m^2 * 120 * Pi Ohms)
= 18.26 Volts/meter

This is in the ballpark. Once the factor for the phone's antenna gain (~2 dB) is included, it's close to the stated 30 V/m. I'm guessing that you are not measuring your ham rig from 30 cm while you're transmitting (of course is wouldn't make sense to try and measure HF from that short distance anyway).

After reading through the test results, there is some room to question the applicability of the results to a real aircraft, namely:

1. The avionics used in the test are not the newer models that are required to have better EMI rejection. They are certified to an older standard that is more susceptible to interference.
2. A passenger is very unlikely to approach within 30 cm of the avionics equipment without any obstruction that would mitigate the interference.

Additionally, no further attempts are reported to determine the mechanism for the interference. In the test, the navigation signals the instruments use are injected directly via cable into the devices' antenna ports. The interfering signal is transmitted at the devices using a horn antenna. Therefore one can presume that the interference is not entering the device via the RF section but instead through the housing, power connections or some other route. But which is it? Are the power connections poorly sheilded?

This is probably about right...

[irving47]

I tend to agree in that I find the wisdom of flying aircraft that can be interfered with by an every day gizmo a little questionable. I talked to a pilot about this a while back and he said that yes, it's true, the cabling is not very shielded, so sometimes even laptops in mid-flight can cause instruments/radio to flake out a little, since the EM tends to bounce all around inside the metal hollow cylinder you're in.
Has anyone ever left their phone on anyway and checked their signal strength at 35,000 feet?

Damn! It doesn't say 'Ashcroft'

[Surak]

For a second there, I thought it said "Mobile Phones Disrupt Ashcroft." And I was ALL SET take my cell phone down to the White House! :-P

Foil Hat

[dfn5]

We could build a really big aluminum foil hat to put on the cabin and block those signals.

Upgrades do need to happen, although...

[Vengeance]

Granted, it takes the airlines forever to agree to small safety changes like, oh, I don't know... Installing non-flammable seat cushions?!? I guess we can't really expect too much in the way of retrofits, particularly in today's economic climate.

We bail 'em out, they waste it, we'll just bail 'em out again.

Whether or not it's a safety issue...

[Jay Maynard]

...using your cellphone on board an aircraft is a Bad Idea. Even if you disregard the safety issues, there's another issue: the cellphone system depends on each phone being seen by a small number of cell sites. This works fine on the ground, but at 37,000 feet, one cellphone can activate literally hundreds of sites. The cellular network cannot deal well with this situation.

The cell network can, however, detect this condition, and report the number of a phone that's on use in the air (by the sheer number of sites it talks to). The FCC has issued fines before to people who have used their cellphones inflight. Want a fine? Then turn yours on.

why?

[adamruck]

who needs to use there cell phone... IN AN AIRPLANE?? If you need to call someone.. just wait a couple hours until your plane lands then hit the nearest pay phone.. if its an emergency... your on a friggin plane anyway..theres nothing your going to do.

Besides.. alot of the larger planes have phones built into the seats anyway, why not just use those?

And for those of you who need to play nibbles or whatever... you need to unplug and get more fresh air or something.

we should punish those people who try to use cell phones by taking thier cell phone away and making them use satalite phones(when they get off the plane that is)

Re:why?

[feepcreature]

And for those of you who need to play nibbles or whatever... you need to unplug and get more fresh air or something.

On a plane????

Have you ever tried winding down the windows?

They are not meant to work on planes anyway

[earthforce_1]

Because of the high dopplar shifts. They are only meant to work when the base station and mobile are moving less than 100 KPH relative to each other. (I think it is higher for GSM, it is meant to operate on high speeed european trains) I was amazed that people on one of the Sept. 11th hijacked planes were able to even use their phones. Your call would also be handing off from one base station to another and a very high rate.

Re:They are not meant to work on planes anyway

[SpikeSpegiel]

Not the case for GSM or TDMA. They will have problems over 100KPH. I work in sales for wireless phones, and people who have GSM or TDMA based handsets will always drop calles when they are on the highway ~75-85MPH/120-130KPH. The network handoff cannot handle it.

On the other hand, you have CDMA. It can handle much higher speeds. I am not sure as to the upper limit, but travelers around those same speeds do not report the same problems.

This is probably due to CDMA using a soft-handoff system, where all towers monitor the call. If one fails, if it is out of range, another instantly picks it up. While this is great for ground communications, I am sure that if thousands of towers start monitoring a CDMA signal, that could be a problem for the carrier's network.

Oh, as a side note to an earlir post, 30,000 ft (5.5 mi) is within range for most cell phones. Average ground range is around 7 miles, with 800MHz CDMA reaching an astonishing 15. with no interfearance from ground based objects, you would see a lot of signal in most parts of the US.

Need for standards

[panurge]

This really emphasises why there is a need for standards, and why vendors alone cannot be allowed to create them. The various bodies concerned with EMC seem to have failed to cooperate to ensure that one set of widely available systems (avionics) is compatible with another (mobile phones).

There are already compatibility problems between cell phones and cordless phones (at least, I and others I know can't use both simultaneously because of interference)and I'm sure other problems will surface with the flavors of 802.11. But wireless technology just keeps advancing without much assessment of the risks, and the FCC seems more concerned with spectrum selloff and taxing modems than with the actual effects of the technology.

I also wonder, given the apparent senstivity of aircraft to the weak signals from cellphones, how safe are they really when powerful radar systems lock onto them? In the past, I have come across (ground-based) cases where directional radar caused severe interference and the military simply denied the existence of the radar (sorry, guys, panoramic receivers and signal strength meters are more reliable than base spokesmen.)It looks like this whole issue needs a lot more transparency and joint investigation. It isn't good enough just to say "OK, can't take this, switch them off". If there is an EMC problem with current aircraft, it needs to be investigated properly and we need to be told about it.

my own experiment...

[Anonymous Coward]

I used to be firmly against the interference argument - until one day at work I heard my hardline phone making all kinds of weird buzzings and beepings. Oddly enough, they sounded identical to the noise I occasionally get on my cell phone. The cell phone, not surprisingly, was sitting right next to my hardline phone. After moving my cell to various positions, I discovered that it does indeed interfere with my hardline phone. When I moved the cell away the periodic noises stopped, and when I placed it next to the phone the noises began again.

Now, I seriously doubt my phone operates anywhere near the band that my cell uses, but for some reason the cell manages to interfere. Based on the outcome of this little experiment, I would definitely believe that cells could interfere with other systems - including aircraft systems - even though it may seem counterintuitive.

Re:my own experiment...

[Xibby]

Try putting your magnetic security badge or one of those credit cart hotel keys under your cell phone while you sleep. I've loocked myself out of a hotel room and my office doing that.

I guess Boeing got it wrong!

[EvlOvrLrd]

In a Discovery Wings program (self described Discovery geek with a VFR rating), they showed the build and testing cycle for new aircraft. Even their engineers said (while standing in front of a electronics emissions testing array) that at least on their aircraft, that nothing within the 'consumer bandwidth' can affect the installed electronics.

But to put an argument to those that say that the airlines are prohibiting cellphones to promote skyphones... 'Most' cellular services utilize directional antenna that completely terminates at the ground within 3 - 5 miles. Just ask anyone who works in a building above the 4th floor and can see the cell tower in the distance. Plus, even for those companies that still use large arrays of omni-directional antenna, skipping from tower to tower at 400mph (3 - 6 miles over them) would be difficult for the MTA to keep the call terminated at the handset.

Bah!

[Greyfox]

They're probably just saying that to give the air marshalls an excuse to rough up those self-important assholes who can't shut the fuck up for four goddamn hours. Face it, if you're riding in someone else's plane, your life just isn't important enough to warrant you jabbering on a cellphone to anyone, anyway.

Talking on a cellphone while any vehicle is moving should be a crime punishable by a severe power stapling. Or caning, as they do in Singapore. Yeah... I've had 3 suvtards in the last month nearly take me out while driving their Maibatsu Mostrosities with cellphones glued to their ears. You may as well just down a fifth of Jack Daniels before getting behind the wheel of that thing. Shut up and drive!

Re:What about EMP bombs then?

[delcielo]

I'm sure not every airplane is susceptible to interference from every phone; but it's obvious that some airplanes and some components are susceptible. As a pilot, if the compass swings or the autopilot tracks off in some weird direction, it would be difficult with the equipment currently installed on most aircraft, to determine that it was because of the phone call going on in first class.

Cell phones are worse for this sort of thing than say, a Gameboy, because the cell phone is built to be a transmitter. Sure, other devices will emit some rf; but the cell phones are designed to do so.

I remember my first cell phone came with a warning to turn it off when driving by construction sites where blasting was going on. There was some fear that a signal from the phone could cause problems with the equipment they were using to set off dynamite.

I'm not sure I buy the whole thing about cell phones causing fires at gas stations; but I also wouldn't call it impossible.

As for the airplane, it certainly can swing the compass; and its effects on VOR/OBS equipment are demonstrable.

I don't get why it's so hard to believe. Most of these airplanes were designed long before cell phones and laptops were the norm. It wasn't a danger anybody had conceived of. If we want to build the new airplanes to be immune to these effects, that's great (and I suspect we already do so with the new airplanes); but retrofitting the wiring harnesses, etc. on old airplanes is not tenable. All you have to do is take that already obnoxious thing out of your ear for a while. Consider the airplane sanctuary from your phone. You not only have a reason for turning it off, you have a responsibility.

They proved nothing ...

[binaryDigit]

at least according to the bbc article.

It found evidence that calls produced interference levels which could disrupt aircraft systems. Faults that could be attributed to mobile phones use include ...

I see a lot of "coulds" and not a single "did". So what they found was that they have no better information now than they did before. Did they observe a single instance where there was interference? It's seems highly dubious that they couldn't construct a scenerio where they could conclusively show this "error".

And it's been stated before but I think it's worth mentioning again. By god, if cell phones are really capable of such chaos, why on earth do they allow them on the planes to begin with? Just what I need is to have someone bring down my plane because they forgot their phone was on in their briefcase, or 6 members of some terrorist org only need to start sms'ing each other to take down a 747 full of people. There is a severe disconnect between what the FAA is claiming and their actions taken. What, I have 5 people make sure I don't bring finger nail clippers onto the plane, but no one cares that I can bring the entire thing down with my Nokia?

Re:They proved nothing ...

[Imperator]

6 members of some terrorist org only need to start sms'ing each other to take down a 747 full of people

If those terrorists are using anything like my wireless plan, that would be prohibitively expensive! Cheaper to build a nuclear bomb or something.

Re:GPS Recievers

[phylus]

Well really, even receiving signals causes you to generate a signal. The VFO, or whatever kind of fixed-oscillator that is being used to tune and receive the frequencies that the GPS satellites use causes a sort of EM leakage that is detectable.

Is this a problem? Probably not, but just so you know... receiving does generate an electromagnetic field that could theoretically interfere with the most poorly designed electronics on the planet.

The more research the better

[salimma]

Right now some airlines like Emirates take a 'better safe than sorry' option and ban any electronic device during the flight.

No discman, no PDA, no notebook... nasty. More research like this would show exactly which electronic equipment can cause disruption and which are safe.

Feasible way to identify cellphone use?

[dpbsmith]

Taking the article at face value, which I do, cellphone use really is a hazard. But simply asking people to turn of their cell phones probably isn't good enough.

I'm perfectly cooperative, but on my last plane flight I had put my cell phone in my backpack, put the backpack in the overhead luggage, honestly thought it was turned off, and after landing discovered I had left it turned on.

What does a cell phone do when it's powered on but not being used to make or receive calls? Does it transmit occasionally and spontaneously?

So the next question is: without suggesting any draconian measures, is there any good way that flight staff can _detect_ that there's a powered-up cell phone on board--so that they can politely tell the flyer to turn it off?

A related thought re:9/11

[LittleGuy]

It would be interesting if one of the mitigating factors how passangers on UAL 77 overpowered their hijackers was because of the cell phones used to call loved ones, hence interfering with the instrumentation and/or guidance controls, enough to distract the highjackers.

Hmmmmmm.....

Re:DILDOS: "portable electronic devices" ???

[Havokmon]

My electric razor causes enough interference to screw up the television set, so dildos could theoretically do the same.

You idiot, the tv doesn't get screwed up, that's the razor making your face vibrate.

Just turn them off....

[wrero]

The rules regarding portable electronic devices predate cell phones and the air-phones in aircraft. While I don't disagree that perhaps part of the reason they haven't been approved is because the airlines don't want them approved for use, perhaps part of the problem is that the airlines actually DO want to make things as safe as possible without dramatically over-inconveniencing people. If there is any chance at all that cell phones MIGHT screw up something once out of every 10,000,000 flights, what's wrong with them being that tiny tiny bit safer? Or even having the perception of being slightly safer?

It *is* up to the airlines to decide if a particular device is or is not to be used. What I mean by that is that although rumor has it that cell towers get screwed up if a phone "sees" too many of them, it's under the FAA's and the airline's discretion. Although I could be wrong, I am unaware of any FCC rule that says that cellular telephones are not to be used on planes.

For what it's worth, here is the relivant FAR:

125.204 Portable electronic devices.
(a) Except as provided in paragraph (b) of this section, no person may operate, nor may any operator or pilot in command of an aircraft allow the operation of, any portable electronic device on any U.S.-registered civil aircraft operating under this part.
(b) Paragraph (a) of this section does not apply to --
(1) Portable voice recorders;
(2) Hearing aids;
(3) Heart pacemakers;
(4) Electric shavers; or
(5) Any other portable electronic device that the Part 125 certificate holder has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.
(c) The determination required by paragraph (b)(5) of this section shall be made by that Part 125 certificate holder operating the particular device to be used.


At any rate, and I know I will be slammed for this one: Why can't people play by the rules, ever? It seems that quite a few people don't turn off their cell phones on aircraft. It seems that these are the same people that get up before the airplane gets to the gate; the same people that don't turn off their cell phones when going to the theater. How much, really, does it harm your personal liberties to play by the rules occasionally, and turn off the damn things when on an airplane? This society seems to always be "me me me me", and this just seems to be a symptom.

So make the guy sitting next to you feel better. Put your seatback in the upright position when they tell you to, turn off the laptop when you should, and leave the cell phone off.

Power Failure

[msheppard]

When all the redundant power in an airplane fails, the hydralics and compass will still work. The pilots don't use the compass much whent he much more advanced electirc systems are working. So when the plane is hit but lightning (or something else which takes the power out) the pilot really needs the compass to know which way to go, and just then, every joey on the plane fires up his cell phone and the compass goes haywire.

I'm a private pilot, and I always thought the reason cell phone usage was restricted wasn't interferance (on a clear day, you don't need any electronics in the plane, just spark to the plugs) I thought it was becuase the massivly increased range of the phone screws up the cell to cell protocol.

M@

A Cell Vacation

[KFury]

I'm happy to hear this. Personally, what I hate most about cellphones is that some people don't know how to modulate their volume. I'm for any excuse that stops them from yelling a conversation right next to me for four hours (with an aircraft power supply charger so they don't run dry!)

Mobile networks

[Gordonjcp]

I got a letter from Orange once, complaining about my phone jamming six adjacent cells (two cells that normally can't see each other suddenly both get the same phone at the same time). This was from having my phone switched on in an aircraft at around 3,500 feet.

Re:Mobile networks

[rifter]

Was this a personal aircraft? You know it would be interesting to hear from pilots of small aircraft on the effects (or lack thereof) on their instruments. I bet their stuff is more robust in this case.

Re:Mobile networks

[mduell]

I was on a 2 mile final for San Luis Obispo airport in Cessna 172 and my pax phone went off, causing a lot of static on the radios (just ringing, he didnt actually answer) and causing the magnetic compass to oscilate a bit.

Re:Mobile networks

[felixsw4me]

I fly a Cherokee 235, and have received calls, and made calls. I never hear any unusual static, or see my compass swing. I read in a report that they took a cell phone, and had to hold it against the outside antenna of the airplane before the cell phone caused any problem. Same with a notebook! The FAA says in FAR/AIM, that we must follow the FCC, and what they say about electronics in the airplane. The FCC says dont use them. This is of course VFR operaions. IFR operations says that the PIC (pilot in command) can say what can be used and not used in the airplane. I belive it boils down to this: The cell phone people lobbied the FCC to ban cell phones because it was messing with the towers. period!

People will leave phones on

[exp(pi*sqrt(163))]

Clearly they need to install shielding. People taking phones onto planes and leaving them on is inevitable even if you tell them to switch them off. Having the safety of a plane rely on the goodwill of its passengers to follow instructions is ridiculous and is just a convenient way for airlines to shift the blame.

Re:People will leave phones on

[mesocyclone]

Clearly they need to install shielding

Much easier said than done! There are miles of wire. Any break in the shielding can be enough to cause problems. Any corrosion can too.

Furthermore, the phone can cause interference by other processes, for example:

Your phone starts transmitting. It is at high power because it is hearing a weak signal. It's signal gets into your walkman via the headphone cable. Another signal, perhaps from a radio on the aircraft or another cell phone or whatever, also gets into that same cable. The two mix because the walkman is non-linear at those frequencies. The result is on the radio communications frequency, the ILS (Instrument Landing System) frequency, or GPS band.

In general, this whole thing is about incrementally improving safety. The odds of a single cell phone on a single flight causing a crash are very low. But the odds get much larger when you are talking millions of cell phones on hundreds of thousands of flights.

Even then, the cell phone may just *contribute* to an accident. Most commercial air crashes are a result of a cascade of individually recoverable failures or events. The cell phone may simply take out a backup system at a critical time, or it may interfere with a primary system (say, glideslope) while the pilot is distracted by another urgency.

For those who comment about how the presumably more susceptible legacy systems on the aircraft should be replaced... the systems mentioned include such minor systems as the only air-to-ground communications mechanism used for air traffic control, and the only instrument landing system available for many airports. Replacing this "legacy" infrastructure would require replacing every aircraft radio in every aircraft, control tower, air traffic center, etc in the world, and replacing all of the Instrument Landing Systems.

This is not trivial. Furthermore, in aircraft, it is not a good idea to rapidly replace systems that have been working and safe!

They'll Get My Cell Phone When They Pry It...

[Nova Express]

...From My Cold Dead Fingers!

Assuming, of course, that they can find my fingers at the crash site.

(Actually, I don't own a cell phone...)

Opting out

[Glonoinha]

Anybody know what the penalty for actually having your cell phone ring while in flight is?
Know the penalty for actually answering it?

Just curious, this is a question (not a statement)

Re:Opting out

[squiggleslash]

You're required to continue your conversation outside...

Re:Opting out

[rifter]

It would be interesting to find out. In the US, with the advent of Air Marshals, even the smallest infractions are now enforced (a man was tackled and arrested by the Air Marshals for *wanting* to go to the bathroom while the seat belt sign was on. He had asked the flight attendant repeatedly to let him go, but never actually went...) The Article, which no one reads, talks about a man being sentenced to 12 months in prison in the UK for having his cell phone on (and not using it) during a flight.

I am annoyed to find out, however, that the whole thing is bogus. Once again "journalists" (what passes for them these days) misreport findings in an uncited study that was flawed in the first place. The study *did not* find that cell phones disrupt flights. They did not even use cell phones for their tests. So the science behind this simply is not there.

good, fix it

[Trailer Trash]

Fine, so cell phones really do disrupt airplanes. I still don't believe it, but, if it's true then we've identified an exploit that needs to be fixed. "Please turn off your cellphone" is not a fix.

"Software company X has identified a buffer overflow in our popular Y software, which can lead to a remote root exploit. Rather than fixing it, we're asking that you please don't connect to port yz and send a string that is 5000 characters long and ends with the binary sequence..."

Moronic. Fix the bug and quit boring us with the details.

Michael

Simple way to make it happen.

[Demon-Xanth]

Have a policy that if a cell phone rings, or if someone is caught talking on one during the flight, they will be immediately ejected.

Suddenly, people will double check thier phones.

We don't play by the rules because...

[crashnbur]

At any rate, and I know I will be slammed for this one: Why can't people play by the rules, ever?

...somebody got the silly idea that rules are made to be broken. It isn't our fault that we are compelled to (civil?) disobedience when we disagree with the reason behind a rule, but it is our fault when our ignorance (lack of understanding, specifically) of the reason perpetuates the larger problem.

cellphones

[ajs318]

A cellular mobile radio telephone includes a radio transmitter. It deliberately and unavoidably uses RF energy for its operation. In addition, modern mobiles transmit digital data, i.e. fast on-off switching of RF. This is the kiss of death for sensitive analogue circuitry.

An aeroplane carries many electrical signals around its wiring harness. These can act as antennas and pick up interference from RF sources. Many were designed when there was less requirement to be immune to RF, because no-one could have envisaged at the time that people would be carrying portable radio transmitters.

Aircraft engines are supposed to be stripped down and rebuilt every so often. I'm not sure whether the requirement applies to wiring harnesses. If so, it would be possible to stipulate that shielded cables be employed. But don't be tempted to think that would be an end to it.

The real problem is one of testability. Automotive electronics are tested by placing the vehicle in a Faraday chamber and bombarding it with RF from a signal generator, amplifier and antenna, and seeing what goes wrong. Obviously, parts can be tested this way too ..... My old employer used to make electronic modules for vehicles and domestic appliances, and we had to do this kind of testing throughout the development cycle to get the CE mark {for mains stuff} or the manufacturer's approval {for vehicle stuff}.

Getting a Faraday chamber big enough for an aircraft is a surmountable logistical problem. Actually doing the testing will take a long time.

But the worst is that it takes only the tiniest alteration in a single parameter to completely alter the sensitivity of the whole system. You can do the test in the chamber, and it will pass; but out in the wild, things are different.

Crash investigators moved a step closer to understanding why the 797 literally fell from the sky with no warning. The passenger compartment voice recorder was recovered from the wreckage by a team of firefighters using breathing apparatus and infra-red cameras. The last words captured by recorder sounded like ".....urn that ..oody .obile phone off, for ...ist's .ake"

Aw, what the hell ..... Go ahead and use phones on planes. It's not as though you'd have to live with it on your conscience for long .....

From the BBC story...

[ader]

If the guy is typing "I love you" into his mobile, he doesn't need jailing, he needs help.

Other side-effects of mobile use I have noted:

• talking too loud;
  
• having nothing to say;
  
• limited awareness of surroundings;
  
• enhanced but illusory sense of own importance;
  
• long term brain damage;
  
• short term brain damage caused by people around you KICKING YOUR FUCKING YAPPING HEAD IN.
  

Ade_
/

Re: FAR 125

[AceyMan]

[Wrero wrote..] For what it's worth, here is the relivant FAR: 125.204 Portable electronic devices. (yada yada) [end snip]

However, the US majors and national airlines operate under FAR 121, not part 125, which is for charters, and the like.

Part 125 details are here.

Note that in paragraph (a) under 125.1 reads "..when common carriage is not involved". This excludes the type of ticketed travel most people make use of.

Nevertheless, the parts about portable electronic devices are the same in both, IIRC.

Yes indeed...

[mwood]

...but there are two stages to addressing this problem:

1) Passengers, do obey all instructions from the crew. Even if you don't get yourself and your fellow passengers killed, you can get in serious trouble for wilfully interfering with the operation of a vessel under way.

2) Airlines, FIX YOUR AVIONICS. Anything *that* fragile should not be associated with terms like "safety", except in a negative sense. No legally purchased electronic gizmo should be able to disrupt flight systems, period.

Experience (as a pilot) with GSM

[Alioth]

This is my experience with (accidentally!) left on mobile phones (GSM variety) in aircraft.

I fly light aircraft. On a dark, rainy night, a friend and I was approaching Ronaldsway. My friend was the 'handling pilot' (i.e. the guy who's waggling the stick), and I was in charge of the radios - setting up frequencies, identing navaids, talking to ATC etc. Although our aircraft (a Grumman Cheetah) only requires one aircraft, we fly together reasonably often and find this arrangement works very well.

My friend was at the time a very new instrument pilot. Ceilings (the bases of the clouds) were about 800 feet, winds were light, and it was pelting with rain. It was about an hour after sunset.

We were just intercepting the localiser (the horizontal guidance part of the ILS - instrument landing system), and we had been cleared for the ILS approach.

Suddenly, the radio was blotted out with:

'Bip-b b b bip b b bip b b bip b b bip' - the highly recognisable radio interference from a GSM phone. My friend had forgotten to switch it off when we had taken off an hour and a half earlier. His wife was phoning him.

It completely blotted out the COM radio with the extremely loud 'Bip-b b bip b b bip bzzzzzzzzzzzz' noise as the phone went off. However, it did not intefere with the nav radios nor the compass - the localiser needle continued to behave how it should have, as did the other instruments (the direction indicator, for example, is gyroscopic) and it did not affect the compass. However, the noise was extremely distracting, and if ATC had any further instructions, we had no chance of hearing them until we got the phone shut off or my friend's wife hung up.

Fortunately, with two of us on board, it was a non-event (I could fly whilst my friend turned the phone off).

An important point to remember: aircraft fly on the rules of Bernoulli and Newton, not the rules of Marconi! It's perfectly possible to fly without radios. The problem is in instrument conditions (i.e. in the clouds) where you can't navigate by looking out the windows. Even so, a prudent pilot always plans an 'out' in case of radio failure, and does not bet their lives on the continued operation of the com and nav radios!

IEEE Spectrum noted this too

[worldcitizen]

The IEEE had a very interesting article in Spectrum magazine on the issue of portable electronics and flight safety.

The conclusion was that there is little doubt about the interference and it is not just cell phones. The article relates an incident when too many people listening to the radio (there was some "important" sports match going on) did cause noticeable interference. It seems that in most cases the pilot can notice that some instruments are providing inaccurate readings (thanks to having redundant information around, different instruments would be affected differently) and it doesn't become a big problem.

So, by using your high-frequency electronic devices inside the plane you're making the pilot's job more difficult. During cruise flight it may be less risky and during takeoff and landing it is definitely not recommended. Personally I wouldn't even trust that much those skyphones. I'd rather err on the safe side. Read a book!

Re:What about EMP bombs then?

[untaken_name]

I'm not sure I buy the whole thing about cell phones causing fires at gas stations; but I also wouldn't call it impossible.

Well, I'm sure that there hasn't been a single reported case where cellular phones have been determined to cause a gas station fire. I'm also sure that Nokia attempted to cause a fire using a cellular phone in their labs, and were unable to. They kept a disclaimer about it because of public FUD and fear of being sued frivolously, say by a gas station fire victim that also happened to have a cellular phone. The best way to prevent gas station fires is to not have an open flame around the pumps (obviously) and to stay outside your car while filling up. (most people don't know this one) When people get into their cars to wait for the tank to fill, then get back out, they sometimes charge themselves statically. When they touch the metal pump handle, it may cause a small spark. In very rare cases, this can set off an explosion. Of course, you're more likely to have a rock fall on your head from space than to blow up at a gas station, but it *does* happen. Just hasn't happened due to cellular phones, and I for one would be extremely surprised if it *ever* did. Is it still *possible*? Sure, the same way that winning the powerball lottery 50 times in a row is *possible*. Don't spread FUD about this issue please. There's plenty of that in the world as it is.

I don't get why it's so hard to believe. Most of these airplanes were designed long before cell phones and laptops were the norm. It wasn't a danger anybody had conceived of.

yeah, interference only began with cellular phones! It was *never* a problem in electronics before that damned cellular phone was invented!
Look, I'm sure cost or laziness or 'we don't need it' or something prevented them from shielding the cables on commercial airlines. I'm sure it was a reason that looked good in the budget, or whatever. That doesn't get around the fact that it *could* have been done differently in the beginning, it just wasn't; now it's too expensive to retrofit. Does it matter whose fault it is? At this point a soultion would require not only retrofitting commercial aircraft, but also changing the way the cellular tower network is constructed, and possibly even the way the whole system works. That just isn't going to happen. Can't we just agree that even if you *could* use your phone without screwing up the plane, it would still be a very bad idea given our current cellular tower/network design, so it doesn't really matter?

I still contend there is no danger.

[kcornia]

It all came to me on 9/11, when I was watching the news. I'm a frequent flyer, so I know all about how they say you can't use your phone, disrupts frequencies, magnetic fields, blah blah blah...
But on the news, here's what they said that stuck in my mind. When the planes hit, Prez Bush was in the air on Air Force One. Security immediately went back to the press corps who were also on Air Force One and said turn OFF your cellphones NOW, we don't want anyone to be able to track us by the cellphones.

So ok, the MOST IMPORTANT PLANE IN THE COUNTRY can afford to have a press corps full of cellphones on during flight, but the plane I'm on is going to crash and burn if there's even one?

Riiiiight..

Re:frankly they shouldnt

[YrWrstNtmr]

If the airplane is designed to be used for 20 years, then *yes it should.* Otherwise, it should not be specced for a 20 year life span.

Ok...design shielding against any and all consumer products to be designed in 2023.

The military was shielding its cables back then, and I'd expect Boeing knew about it.

Well, since Boeing built many of those military aircraft, I'd expect they would have some idea about shielding against interference. Two things would seem to come into play. Weight and cost. It adds significant costs to harden all aircraft wiring against known and unknown interference. Evidently, they weren't willing to pay those costs back then.

Take an aircraft designed in 1975. Laptops were but a dream. Cellphones, CD players, GameBoys. Not even on the horizon. Much less what type of EM interference they would generate.

Making products forward compatible is incredibly hard. Making them backward compatible is much, much easier.

It seems hard to believe that cellular phones would be approved by the FCC for general use

Do your cell phone, WiFi, cordless phone, Bluetooth, microwave, TV, stereo ALL play well together? And all were 'approved' by the FCC.

Analogy: Should a wireless PCCard built today be designed so as to play nice with some unknown wireless device for your car built in 2023? Or should the future device be built so as not to interfere with, or accept interference from, the older equipment?

Doesn't sound right to me

[all_i_want_is_an_acc]

So, if I put 10 cell phones, left on, in my checked baggage, and I get someone to call these numbers, my flight will veer off course? I highly doubt it. If this were the case, they (the FAA or whoever controls your airspace) would NOT LET A CELL PHONE WITHIN 10 MILES OF AN AIRPORT. Think about it, if the FAA won't let you have so much as a plastic knife on a flight, do you really think they would let you have something on board that could seriously affect the operation of the aircraft? Is it possible that EM could mess up radio comms (like static), sure. That is why they politely ask you to turn these devises off. If there was the chance that a serious failure could be caused by a cell phone, they would not ask, they would search and destroy!

Despite my total lack of belief regarding the issue of disruption of flight operations, I do think that if you use a cell on a flight you should be beaten with a sack full of hammers. No one wants to listen to your stupid conversation with you boss/wife/frat buddy, that goes for buses, trains, theaters, bars ......whatever.

thats my .02

still suspect

[cr@ckwhore]

If you were engaged in the business of trying to "promote" the use of skyphones rather than allowing people to use their own cell phones, wouldn't you want the UKCAA on your side to back up the claims? I think they're in on it too ;)

You may now dawn your aluminum foil hat.

Home Experiment for Interference

[tekrat]

Want to see what your cell phone is doing? Here's something every one of you can do with your cell phone to witness the interference it creates:::

Place it upright, next to your computer monitor speakers. This will probably work best if you use the speaker with the amplifier built in (the speaker with the volume control on it).

Now wait to get a call -- or better, if you've got one of those fancy phone that updates the clock every hour or so. Before the screen lights up and it rings or before it updates the time, you'll hear an odd sound coming out of speakers. That's an example of the interference a cell phone can create.

Try it right now, and you'll see I'm not kidding.

FAA Regs

[KrispyKringle]

Every time this is discussed on /. lots of people say "there is no danger - its just the airlines trying to make a buck on their skyphones".

This is ridiculous. It's not an airline regulation that bans the use of mobile phones; it's an FAA regulation. This applies to general aviation as well as airline flights, too.

Whether the effect is very significant I wouldn't be able to guess (past what the article says) but many instruments are extremely sensetive to electromagnetic fields and thus tuned to precision in the exact field at the spot on the plain in which they are mounted.

For example, the actual compass (as opposed to the directional gyro, a high-speed gyroscope which allows easier reading and does not have turning-errors and the like) is mounted by a trained professional who then parks the plane in a compass rose painted on the ground and computes the deviation on the compass due to metal, electrical currents, and so forth throughout the plane. Adding to those currents and fields could be a minor issue, at the least. Even "E6B" circular slide-rule flight computers are typically made out of plastic or aluminum to avoid throwing off the compass of placed on the dash next to it.

For that matter, its entirely possible that radio navigation aids like VOR or ADF would be sensetive to certain electromagnetic fields.

Even if there were no significant need for this, I highly doubt that an accross-the-board ban would result from the airlines' desire to charge more for phone use. The FAA is incompetent, but not that incompetent. And they seem to err most often on the side of lax regulation, so its not really that bad to see them being strict about something.

Re:What about EMP bombs then?

[untaken_name]

I was once told by a gas station attendant who had come back from a safety course (it was EXXON. Ride the Tiger baby!) the cell phone fire scenario is also due to static electricity. The claim is that static from the antenna might cause a problem. There is the additional possibility of the electronics inside the phone igniting gasoline fumes which permeate the case, but I would think this is something that could be tested for. Gasoline fumes are volatile but I have to wonder if they are really volatile enough to be ignited by the amount of current running through a cell phone.

good link here

Nokia couldn't make gas fumes explode with their phones...but they concede that, though extremely unlikely, it is *possible*. Of course, I tell people that it's *possible* I'll become the world's richest yet most beloved benevolent tyrant, but that doesn't mean it's *likely*.

no joke

[_avs_007]

I get more irritated at:

1.) Those rugrats sitting behind me kicking the chair

2.) The lady next to me who keeps sleeping with her head on my shoulder.

3) The guy across the aisle who thinks I'm interested in his conversation.

4.) The screaming baby a few rows over.

5.) Those kids running up and down the aisles getting in everyone's way...

Same at a restaurant. I don't mind if someone is on the phone, so long as their ringer isn't loud and obnoxious. More often then not, I find more people in the restaurant who aren't on the phone, but talk/laugh really loud when talking to members at their own table...

And I can't believe how many times I go to see a movie at the theatre, and some moron brings their baby, and doesn't bother to leave when he/she starts crying. I also hate those kids that think its funny to point a laser pointer at the screen.

Believe me, chatting on the phone is the least of my irritations.... :)

Re:Disruptive interference, an example...

[panurge]

Er. no.
It's the tuned intermediate frequency amplifiers that create the EM waves - and they are effectively small radio transmitters.

But if you were building a military or avionics grade receiver, you would not only shield the case against those IF signals, you would filter them from being back-emitted via the antenna connection. The signals come out of the home radio because it's designed to be cheap and light, and proper shielding is expensive. In exactly the same way, well designed PCs have cases with spring connection fingers so as to shield them effectively, and ferrite beads on some of the ports to prevent the emission of radiation, while cheap ones or case mods with windows have large shielding holes and emit all kinds of crap.

Now, do you want to fly in an aircraft with cheap leaky avionics or well designed shielded wiring systems and boxes? I know which I'd prefer.

Better idea...!

[jbuilder]

If he counters by screaming profanities at you, pick your nose.

Better yet, pick his nose. That will be *sure* to make an impression he won't forget...!

two cents

[nomel]

I work in EMC (Electromagnetic Compliance), so we have two semi anechoic chambers (they absorb radio waves). In the 3 meter chamber, even with the radio absorption material, we have measured around 30v/m from a source signal strength of only 3v/m. How is this done? Well, the waves bounce off the walls where, at certain points in the room, they construct and destruct. This causes areas with very large signal strengths and some with extremely small signal strengths. Now remember, these walls are made to absorb the radio waves and this still happens. Just imagine if the walls weren't designed to absorb any!

There was a study some time ago posted here on /. (can't find via search engine) about the use of cell phones in passenger trains cars, about how the signals could add up to above the regulated levels. The same thing can happen in an airplane, but most likely worste because of the smaller windows. Now, just imagine if there was a sensetive piece of equipment that happened to be in one of the places where the signals added up very high...you would have a problem. I can understand why they don't want them in there. They could fix them by protecting the equipment more, or isolating the cabin from the equipment (which would most likely isolate you from your phone's network), but this would cost a lot. If I were them, there would be no motive for me since the planes already have usable phones that don't interfere (and create income).

Re:Bah!

[arkane1234]

I perfectly agree with you!

I know myself, when I talk on the cell phone I sometimes drive. I have no problem driving and talking at the same time... sometimes even avoiding other people attempting to swerve into my car at the same time. Company business is important, and if some people can't accept the fact that others have to speak with other people at certain times then I don't know what to say.

When a normal person talks on the cell phone, it's relatively silent, unless they are special or just rude. If people don't like hearing part of the conversation, then they shouldn't be listening in! it's worse than someone complaining about your diarehea sounds when your in the bathroom.

Anyone with a GSM phone can see this themselves

[Colitis]

If you've ever had your GSM phone sitting within a few feet of your stereo when it's contacting the cellsite and heard the horrible electronic noises that come through, or had it next to a monitor and seen the screen jumping, you must be pretty thick if you can't figure out for yourself that maybe, just maybe, your cellphone has the potential to mess with flight systems on an aircraft...

Re:What about EMP bombs then?

[rifter]

Ah, snopes. Yes, I ended up following a number of links today researching this topic. I also found information on the Exxon program referenced by the friendly attendant. It seems indeed to be the result of a series of urban legends which were believed by lawmakers and oil company execs who got scared and issued a bunch of warnings/laws/etc. Motorola also seems to have been trolled successfully.

Once again, like the cell phones + airplanes FUD, it seems to be a matter of bad/no science backing ridiculous regulations. Of course it is clear there is a growing prejudice against cell phone users which has resulted in a slew of nonsensical, reactionary laws that have nothing to do with real safety concerns.

NASA report on Electromagnetic Compatibility (EMC)

[zombieflesheater]

For those interested in information about actual incidents where Electromagnetic Interference (EMI) has caused failure or degradation in performance to aircraft systems, refer to the following paper:

Electronic Systems Failures and Anomalies Attributed to Electromagnetic Interference

Section 2.3 - Aircraft passenger carry on devices - is relevant to the current discussion and can be found on page 11.