Slashdot Mirror
The Real Reasons Phones Are Kept Off Planes
jcatcw writes "Mike Elgan argues that the the real reason that cell phones calls are not allowed is fear of crowd control problems if calls are allowed during flight. Also, the airlines like keeping passengers ignorant about ground conditions. The two public reasons, interference with other systems, could easily be tested, but neither the FAA nor the FCC manage to do such testing."
this is funny because he missed the obvious and actual reason. most planes ive flown on have had a phone on the arm rest with a little slot to swipe your credit card.
The war with islam is a war on the beast
The war on terror is a war for peace
There are already enough planes that have satellite television (including news channels) along with air phones (at a very high cost - yes but still a source of information.
The real reason? Its bad enough when people are yapping on their phones constantly on the ground. Getting stuck on a plane near someone who won't shut up on the phone is MUCH MUCH worse due to the duration and the captive audience. For that reason I hope cell phones are never allowed (and if they are it should be a cell phone only section kept reasonable sound proof from the rest of the plane).
It might be easy in theory, but you need to think of scale. Take all of the cellphone manufacturers, during the course of a year a lot of cellphones are released. So each year you have a lot of cellphones to test. Then, the test itself isn't so clear-cut. Sure, that 1-year-old 737 might run fine, but what about the 7-year-old 737? It might have less around the electronics, or casual wear-and-tear might have left an opening. Put both factors together, and testing isn't so easy. Sure, it's possible but is it really worth the effort?
Congratulations on coming up with the exact opposite meaning to the one that the statement obviously is supposed to convey.
The only thing that could make my flights even more stressful than they already are (babies screaming, kids behind me hitting my seat, the person in front of me immediately putting their seat back, giving me no room to lean forward, etc...) would be someone sitting next to me, who does not apparently have the ability to control the volume of their voice, chatting away for the full 2 hours while I try to sleep. And to make matters worse, they'll probably be eating at the same time.
I'd be ok with the cellphone/no cellphone section division, though. That would be cool. Or maybe a special room for people talking on the phone. That way, I could use it without bothering anyone else if I absolutely have to make a call.
Bingo!
however:
you know, I'd rather the government (of whichever country) err on the side of caution, actually: "Well, we can't tell whether cellphones might cause crashes, so we'll just allow them and see what happens"?
Bottom line for me: people are annoying with cellphones. Now imagine sitting next to the guy talking shite for all 12 hours of a long haul flight. I'd hijack the plane just to shut him up. Keep the ban, people can surely live without cellphones for the duration of a flight... surely?
If gadgets can't crash planes, then the ban is costing billions of hours per year of lost productivity by business people who want to work in flight.
What the author completely fails to address is the noise that ensues if you have ten businesspeople in first class all "doing business" on a cell phone at the same time. Are they supposed to wander the aisles and pace as they talk? Or merely talk over one another in increasingly loud voices?
There's something about a long tube that seems to suggest to people that maybe conversation should be kept to a minimum. Not only planes, but buses and subways and trains too. In my experience riding public transit, most people do not chatter on their phones endlessly. In part, I think, because there's an unconscious realization that the guy standing 6 inches away (that you can't move away from) does not want or need to hear your prattle.
I was always under the impression that a mobile phone travelling at 500+ mph on a plane would be hopping from network cell to cell fairly regularly (once every few seconds?). This sort of frequent handover would then a) make it difficult to make, receive and conduct a call and b) cause issues for the phone networks if you've got num_people_per_plane * num_planes_in_sky_over_country people's phones all doing the same hops fairly regularly. Meh.
There is nothing interesting going on at my blog
I have a cell phone because it is a cheap and convenient way to have a phone number. It costs me $20 and it works in most of the places I go. I can turn it off whenever I want. There isn't anyone who can call me and make me do anything. So at best, they are *probably* another servant on a leash!
Nerd rage is the funniest rage.
With no players anymore in the US, Verizon out and aircell now offering Wifi instead of phone calls, this is not a reason.
Also the only phones still avaliable on planes are run by ARINC and SITA, which both now have a picocell replacements under testing for installation this year.
There is no technical nor marketing reason you can't have a cell phone on board, if cell phones were a real danger then they would not be in carry on allowance anymore.
FAA is very conservative, and the FCC is a political body.
That is all
-- email me @ 30,000 ft
This is a technical reason for a regulatory body to ban a technology? ... I hate the stupid people on the internet and so I think the internet should be banned too!
Next
-- email me @ 30,000 ft
It's worse than just the combinations of phones and planes. An aircraft makes a nice enclosed resonant space for cell signals to bounce around inside. Anyone who has looked at simulating or measuring RF fields would know that the field strength can vary by orders of magnitude depending on the exact location, orientation, and frequencies of the emitter and the exact orientation and location of the susceptible wiring or instrument. A tall person sitting in seat 6B with a CDMA phone may cause no problems, but a short person with a GSM phone in seat 32F could interfere with the automatic landing system. The field strength won't necessarily drop with distance inside the plane and may be focused to high levels anywhere inside the aluminum tube.
And testing individual phones isn't sufficient. What happens when 100 people all use their phones at the same time.
Two wrongs don't make a right, but three lefts do.
At least based on this site, there is absolutely no GSM reception above 650m (2100ft). So I guess the plane would need an own GSM base station for the cell phones to work.
I manage to work on almost every business flight I take. Mostly by collecting and printing stuff that i need to read and learn, or by sitting with a notebook brainstorming technical problems. Occassionally (if i have a decent amount of leg room) then i'll pull out the laptop and do some actual coding.
It takes a little planning to find something to do but it's really not hard to make semi-productive use of that time.
Mike Elgan, the article's author brushes off the problem of an airborne cell phone seeing a large number of cell towers at once. He claims it could be easy to fix with a software upgrade to the towers. Nonsense. The fundamental problem is that there is only a finite range of frequencies for cell phone calls. The more towers a given phone's signal is visible to, the more towers whose frequencies you're chewing up. Redesigning the system to support cell calls would be massively expensive. Is the value of being able to make cell calls from a plane really that valuable? Who is going to pay for the overhaul? Elgan is just whining.
Elgan points out that Europe is working on making this work. Tellingly, they're not just letting the phones connect to towers normally; they're shielding the cabin and routing connections through dedicated on-plane hardware. This is reasonable as it means you have a single source (the plane's hardware) that can far more efficiently utilize tower frequency space. Furthermore, the cost of making the changes falls on the airlines, who will pass it on to the logical people: the fliers who want to use this service.
Search 2010 Gen Con events
My 0.02 as an air carrier pilot... I've seen 3 actual instances of interference from not just cell phones,
but also data cards. 2 were voice bleed over when the persons cell phone was transmitting in analog mode, and the other was an AHRS (attitude and heading reference system...VERY important) which took a dump when someone started using their data card..fortunately it was good weather and the AC had an iron gyro backup system. Filed NASA ASRS reports on each. I certainly wouldn't use "Mythbusters" as any source of certification data.
You have to understand that in the avionics can be located anywhere in the plane, not just upfront. On top of that the FAA is VERY picky about figuring out the worst case and applying it to all situations. If a person is in back using an old analog brick phone on a older aircraft, say a 727 or DC-9, and there is the even a remote chance of interference, everything will be prohibited, because how in the world are you going to police every make and model of phone with all the variations of aircraft?
The NTSB files are chock full of accidents that happened because something happened that someone said couldn't, so I'm perfectly happy with the ban. If it keeps them from chatting loudly in my ear as I try to commute home, well that's just a bonus.
Chuck them overboard?! Could we make them walk the plank aswell?
Seriously, if that was really the reason then you'd have to ask why planes have reclining seats and music via headphones. Each of those is equally capable of being annoying.
TFA's "they don't want testing because testing costs money" argument doesn't stand up to scrutiny either. Just because planes could be allowed to tested for phone usage doesn't mean planes would have to allow phones to be used. It would be up to the plane manufacturers to decide to have their plane designed and tested for that "feature" and then up to the airlines if they wanted to pay the inevitable extra cost for such a plane, and then of course pass that on in extra cost to the passengers.
Spelling mistakes, grammatical errors, and stupid comments are intentional.
If you are commenting about the fear of conflicts due to rude behavior, the AirFones are fine because no one uses them. I may have seen this phone used 1-2 times in the last 10 years. The fact is they are HUGELY expensive so people either don't use the service or use it for 2-3 minutes at most.
Now, compare that with a plane full of people with cell phones that have cheap plans where they can gab on for hours and, with power adapters, the phone can last the entire flight. Awful right? Even the nicest person would be hard-pressed to not start telling the person to hang the damn thing up.
I already see this on Amtrak between Boston and NYC. People gab loudly and for HOURS. Amtrak had to make a QUIET CAR because the amount of noise had gotten so awful due to impolite cell users.
I posted this to the original article as well, but I felt the slashdot community might derive some value from it as well. The interference issue is a VERY real one. I can't emphasize this enough. It's easy to debate this issue on the ground, but try debating it 2 miles above the ground when your only lifeline is a thin needle on a panel that is controlled by a radio transmitter on the ground. I have a personal experience with cellphone nav interaction. I've also watched the mythbusters episode. Everyone here knows that mythbusters, while entertaining, is not entirely scientific. I certainly am not willing to stake my life on the thoroughness of their conclusions.
Without further prefacing, here is my original post:
You mention in your article that "Many headsets used by private pilots come with jacks for using them with cell phones. The manufacturers say they're for use on the ground only. But many private pilots use them in the air without incident."
I fall into this category. However, I've also seen the dangers of airborne cell phone use. I carry a Nextel branded Blackberry. From my experience, it's not a very good phone to use on board an aircraft. About every 20 minutes or so, the phone goes into a signal frenzy. It's as if it finds multiple strong towers to connect to and is unable to choose. This results in a barrage of beeps and lights while it tries to figure out what's going on.
Furthermore, the risks of interference are very real. When I'm using the phone, I never notice the interference. I recently let someone else use my phone and was very surprised. My headset (flight radio headset) emitted a horrible scratching noise. I was totally unable to hear anything on the radio. I quickly looked at my VOR (radio navigation, NOT a gps) , and noticed that it was off coarse as well. Now, had I not been certain that I was on the right course, I might have well thought I was off course and corrected in an ultimately wrong direction.
I'm not sure if you're familiar with VOR technology, but it's the primary aviation navigational aid. GPS is wonderful, but it's still not the primary navigation mechanism. GPS is considered a "non-precision" navigation tool. VOR and ILS are still the primary mechanisms and they are dependent upon terrestrial radio transmissions. This is where the cellphone interference comes into play. Most cell phones operate in the 800mhz range. I'll save you a lesson in radio technology by simply stating that they can often have harmonic emissions in the same bands as used for aircraft navigation.
While you state that countless numbers of phones are left on during flights, this is not particularly dangerous. A phone ranging a tower is only actively transmitting for a very short period of time every 20 minutes or so at regular speeds. A phone that is in active use is a source of radio emissions that is in VERY close proximity to the aircraft communications and navigation antennas and is operating on a frequency that can have interfering harmonics. I have personal experience with the reactions a nav needle can have to a cellphone.
Imagine if the weather was bad (instrument meteorological conditions or IMC) and you were trying to land a large passenger airliner using nothing but a small needle on the panel to align with the runway. Then, a passenger starts talking to their uncle Bill about his bypass surgery and that needle jumps even 10 degrees off position. Now, instead of aligning with a runway, you're aligning with a corn field.
To answer your thoughts about shielding, that's not a viable solution. You would either have to shield the passenger cabin from radio emissions or shield the comm/nav antennas from it. In either case, the shielding to protect them from each other would seriously impair their usefulness. A passenger cabin shielded from RF emissions wouldn't allow your cell signal to get out, thereby negating the purpose. Shielding the comm/nav antennas sounds like a good idea until you realize that oftentimes nav aids and aircraft controllers a
From the IEEE's Spectrum magazine last year, they actually measured RF signals on flights and reported on the results. No smoking gun where an accident was caused by a cell phone, but still interesting nonetheless (and no ads!). http://www.spectrum.ieee.org/mar06/3069
My father is a retired Pilot (Air Force, then the American Airlines). Since I used to work for Jeppesen, we have had some interesting conversations about this. He has said that he has seen nav equipment messed with that the FAA said was cell phones. Now it was early 90's, and likely to be one of the analog phone, but they were not certain. But some of his old co-pilots (now all senior captains for American), says that several instruments will be interfered with from time to time and they believe it to be cell phone. In general, they claim that most of the interference occurs on the ground (i.e. as soon as the phones are turned on). Now, I do not know why that is, but I would want to make certain before allowing them to be used. It is possible that it is just one frequency or type of phone that is causing the issue. My question is, why has the FAA not determined where the issue is? ALPA is actively pushing against allowing the phone usage until FAA or FCC can explain what is causing this.
I prefer the "u" in honour as it seems to be missing these days.
The effect has been idependently tested and confirmed:
http://www.post-gazette.com/pg/06060/662669.stm
I think I'll trust real research from CMU over a vapid so-called journalist who probably just can't stand not yapping on his cell-phone.
BTW, it doesn't matter if some or even nearly all cell phones don't cause interference with flight controls. All it takes is one person using one that does and things get ugly. Likewise, most airplanes have a mix of avionic equipment. Some of it is new where the cost/benefit makes it worth it for the airline to upgrade and some of it is old. Rather than test each airplane independently, it makes more sense to just say "no" until someone comes up with a way that is known to be absolutely safe regardless of the equipment on the airplane.
Cheers,
Dave
They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty.
Ben
They should ban kids from carryon luggage and make parents check them.
Infuriate left and right
You obviously never heard about this. I believe this level of fear and response would be greatly increased if people were hearing stuff from the ground or using it for web surfing. The idea is that it would give people a lot of people information that might cause panic, and a mass panic on an airplane is not exactly a good place to have one.
Also, this fear the web thing is a bit over-stated on your part, considering some planes are going to begin having internet access, which short of shoots down the entire argument of this guy. There is far more information available via the internet then in any phone call. I think the real reason is they do not want to have any people chattering away and people complaining about them talking too loudly.
As for your terrorists comment, you simply ignore what the author is trying to say. He is saying this lack of wireless devices on airplanes is bullshit, because if they would take down planes, terrorists would have tested every device possible to try to interfere with equipment and see if you cannot bring a plane to the ground. You really should spend less time at Digg.
Learning to spell "the" correctly: two years of elementary school.
Learning to spell "retarded" correctly: two years of high school.
So I guess that puts you somewhere in the grade 9 range? LOLWTFOMG pwnage!!!11!1! (I kid, I kid).
Godless heathen.
I just flew on a bunch of different planes in the past week, and a couple of them had the control tower chatter actually broadcast on one of the channels of the in-flight entertainment system.
It was actually pretty cool to hear the various airplanes yak with the tower. O'hare is a busy airport (to say the least), and it was astounding to listen to them juggle all the incoming planes. What was particularly funny was listening to them berate our pilot - the guy mumbled a bit, so the flight number kept getting cut off. The tower had to repeatedly ask him to repeat, and eventually they started making fun of him. Things like "well, this particular pilot doesn't feel he's important enough to respond to us". Tres droll.
Also cool was listening to the tower give directions (turn left, etc) and feel the plane immediately respond. All in all, it sounded pretty much exactly like it does on TV/movies. I'm sure if there were any actual flight emergencies, it would have been broadcast for the passengers to hear - unless there's some protocol to shut that channel down when things go amiss - which would just alert passengers to a problem anyway.
Endless arguments over trivial contradictions in books written by ignorant savages to explain thunder in the dark.
IEEE Spectrum had an article about this last year ( http://www.spectrum.ieee.org/mar06/3069 ); the authors actually sampled in-flight RF data and reviewed some related publications. They also discussed the current reporting methods for HED interference and discussed some of the reports. Bottom line for those that don't want to read the whole article: some cell phones and other devices emit innocuous signals that pose no significant danger, while _other_ cell phones and devices pose significant risks of interfering with avionic electronics, depending on the frequencies they use. This inconsistency alone is a problem. "Sure, you can use your AT&T phone, ma'am. I'm sorry sir, you have to turn your Sprint phone off or we're all going to die". The FCC and FAA do not work with each other (as a rule of thumb), so both the technical and regulatory issues can conflict with one another.
It's a good article for the layperson, I'd encourage reading it.
TFA says:
Real testing has been done. Unintended emissions from the phone have been identified as the culprit, not a deficiency in the navigation equipment. The aircraft's receivers are doing exactly what they are supposed to, responding to signals of certain frequencies arriving at the antenna. Once the phone pollutes the spectrum with spurious signals, nothing can protect the receiver. The shielding and filtering must be applied at the problem, which is the phone. Since the competitive consumer phone market demands the lowest possible cost, once a phone meets the minimum legal requirements they won't add another dime of product cost for further interference control.
Intereference does not occur every time, but when it does occur there has been a demonstrable cause and effect relationship. Start with this NASA case study(long pdf warning).
Then consider this article from Spectrum. On page 3:
And from page 4:
It's no conspiracy, and no urban lege
So this is like.. tangentially OT.
But, how much money could I make if I started a business that installed Faraday cages into movie theaters? Could I completely block all cell traffic with one? And could I install the cages relatively cheap and keep them invisible? See, I know there's been talk amongst movie theaters of using jammers to stop cell phone use. But the FCC is against that and it doesn't look like it's going to happen. But can the FCC stop me from constructing a faraday cage around my theater to 'ensure the highest degree of fidelity of the digital projection equipment, thereby ensuring the best viewing experience'?
I'll tell you what, if I know one theater in town has faraday cages and the others don't.. I'm goin to the one with the cages.
A lot of people argue that they need their cell phones during a movie in case of emergency situations. I think that's bullshit. For decades people managed to go to movie theaters without cell phones. They accepted there might be emergencies happening that they weren't aware of until after they left the theater. They accepted this because whenever an emergency happens and you are twenty minutes from the scene you are 99% of the time too late anyway.
Someone enlighten me here, what kind of emergency can you really expect to respond to fast enough to make a difference by racing out of a theater to the scene of the emergency? By the time you get there either the emergency is over or people who are supposed to handle that sort of thing (you know, EMT, Firefighters, professionals...) have already done so. But please, give me an example of how I could be wrong. I'm curious. There has to be something.
TLF
I do not respond to cowards. Especially anonymous ones.
IIRC a cell tower covers a geographic area of 36 sq mi, and assuming that's a circle (I know they effectively chart them as hexagons, but...) if that's true, the radius, given pi r ^2 for area, sqrt(36/pi) = 3.64 miles. That's only 19,000 ft. Sure, straight line would be better than terrestrial terrain, but above 19,000 you're heading out of range anyway, not to mention rapidly switching cells (400 mph = 6+ mi/sec)
If that were the case, it'd be torches and pitchforks for the cellcos if they allow it and then it sucks.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Everybody here has entirely too much faith in the electronics that are in place in commercial aircraft.
The wiring on board is all exceptionally thin and shielded poorly - per spec, and on a great deal of commercial planes the wiring has significant corrosion.
An industry wide test for interference factors may not indicate a great deal of problems with cell phones, but it would end up resulting in the requirement for replacing the wiring in a great deal of airplanes, at an impressive cost - because planes would have to be grounded (losing revenue from air travel), gutted, re-wired, and re-certified.
If they thought it was one or two planes, the airlines might suck up the cost (assuming crowd control and airphone revenue were not factors), but we're talking hundreds of planes, if not thousands.
The fear of having hundreds of planes grounded in order to allow cell phones is the primary factor pushing against it. Everything else is window dressing.
Believe it or not, but it's not the FAA or the airlines doing the cellphone testing.
It's the aircraft manufacturers.
Boeing and Airbus both run tests, and there IS interference with some of the more sensitive systems on the plane, like, duh, navigation. GPS is better at high altitudes, but when you have to get 6 data values from GPS, you need many more satellite receptions than for just location. Modern planes don't use just gyros for roll/pitch/yaw rates, they confirm it with GPS data. As one might expect, the radio antennaes receiving those can become jammed.
That's the reason you can call on your phone when you're on the ground, but not in the air.
That post is just another Rosie-style conspiracy theory about the FAA and the FCC. I have no respect for people that don't try to understand the sensitivity of avionics and then reject every technical argument as "political cover-up".
Wifi isn't so much of an issue because it is lower power, and on a narrower and very different radio range.
Gees people, stop seeing evil everywhere, there's enough already that we don't need to paint the world as COMPLETELY depressing!
---- I am certain of only one thing : I know nothing else.
I think it probably boils down to cost and caution. The testing is expensive, and nobody wants to be the one that approved cell phones if they end up causing a plane crash.
I don't think so. My recollection was that some of the people aboard the flight which crashed in PA called loved ones. And had awareness from those phone calls of what was going to happen. I am pretty sure though that calling 9-11 wouldn't have worked as it is the number in a huge number of places. If the call got to two different towers straddling areas codes, it would probably have not gone through.
Many large cities have these things called mountians and tall buildings in the middle.
If this was a serious problem they would at least have signs telling us not to use our cell phones in high places. Even if they could not enforce it it would help.
As someone who regularly flies across the Atlantic, I thank them.
My favorite example is the one about the bodies of all the dead construction workers buried in Hoover Dam, supposedly to conceal the high rate of accidental deaths on that project. Construction engineers have no patience with that one -- the builders went to a lot of trouble to control the consistency of the concrete. But that little fact does nothing to deter people who like the story -- which seems to he most people.
I think the plane crashed because they all used their cell phones.
Heh, it's the exact reason Snakes Are Kept Off Planes
I used to work on Aircraft avionics in my earlier days. Unless a pilot has an electrical engineering degree, Pilots generaly don't know to much about the actual working of the electronics on board that they use. The FCC alots frequencies to civilian and gouverment agencies. A hug chunk of the available frequencies go to Avionics/Gouverment leaving only a few frequencies for civilian use (Notice how overused 2.4 GHz is). When frequencies are assigned the useable ones are far enough away from each other so no interferance happens. The electronic equipment is also designed to filter out any other frequency outside its selected range. Example if you talk on one VHF channel you don't hear the VHF channels beside it.
The strongest source of the cell signal is the cell tower which planes fly through all the time. So how would a cell phone effect other systems on a plane? They would not.
"Never say Never."
That is the way I interpreted the fear of crowd control problems if calls are allowed during flight. cited in the summary. I assumed it was the fear of controlling the crowd of fellow passengers from bludgeoning blabbermouth fellow passengers to death.
Until there is a mechanism on each plane to jettison the bodies of cellphone users who have been thrashed to death by fellow passengers, I don't think the planes are ready. I can't see passengers having to endure long 9-12 hour flights with the bloody mess. And I certainly don't want to discourage anybody, anywhere, from smacking the viscera out of public cellphone blabbermouths.
I fully believe that cell-phones can interfere with aircraft nav systems (the fact that they interfere with PC speakers and conference-call microphones is plenty of evidence for me).
However, there's also a restriction on hand-held TVs/radios and GPSs, and I've always wondered why, since they're all receive-only. I don't see how it's possible for them to cause any interference (or at least no more interference than a laptop computer) since they're only picking up on signals that are already passing through the plane from an external source.
So, does anyone have any info on why those are banned as well?
Jet Blue offered live on-plane television programming, which allowed the passengers of the plane with the stuck landing gear to watch the news coverage of their problem live while on the plane.
United often allows you to hear the flight deck communications.
Some airplanes still have in-plane phones using something similar to a cell network (with much bigger cells). So not all phones are banned.
If this was the real problem, these things would also have been banned, or never allowed but they are not.
The real reasons for banning phones are:
1) Paranoia by the FAA about malfunctioning devices (which is valid, BTW-- it doesn't usually cause a problem but I have seen radio intererence from many other devices that you wouldn't expect).
2) Concern by the FCC about the effect on ground-based cell systems. I.e. if you use your cell on a flight high above New York, how many cells are you reserving bandwidth on?
This article was largely typicall Slashdot incite....
LedgerSMB: Open source Accounting/ERP
I mean, they don't allow you to sit in the cockpit anymore. Another thing islam has ruined.
--
vi VS emacs arguments are pointless and a waste of time.
vi is the best.
Attacking a religion like that is just pure flamebait.
You probably shouldn't have brought up Islam either.
Oh, goodbye karma.
"I realise this is not a very popular opinion but it's the truth, and there for needs to be said" -Bill Hicks
I've seen that same explanation stated several times before when this discussion came up. But the last time I read about it, I believe it was a message thread on HowardForums.com - a site specifically made to discuss cellphone technology. Many users there work in the industry in one capacity or another. One of the guys who claimed he worked on engineering the cell tower infrastructure said that this is really not a true statement. Yes, the phones are designed to communicate with any towers within range. BUT - the cell towers have the ability to handle situations such as a phone suddenly "appearing" on 40 towers at the same time. They have software that knows such things aren't possible in normal cellphone operation at ground level - so it ignores the signals on all but a few towers at a time.
He claimed that in reality, this process doesn't "tax" the towers inordinately at all. The "bandwidth" tied up is no more than a regular call would tie up, since the towers are rejecting the extra instances of the connection to the phone. There's simply a small amount of overhead involved in the towers passing along the information to each other about the status of your connection.
(I believe this type of software also comes into play for handling problems of "cloned" cellphones. If a connection shows up simultaneously on towers that are spread far apart, they know they're dealing with not just 1 legitimate phone, but also a duplicate in service elsewhere.)
If cell phones and two-way pagers indeed had the ability to interfere with aircraft to a point where it compromises safety then the TSA should be confiscating them rather than bottled water and toothpaste. At least it's a more plausible threat than "liquid explosives". Perhaps the fact they are *not* confiscating them is telling.
Actually I'd like to see that. Confiscating a bunch of inexpensive water bottles in the name of security is a relatively benign way of maintaining the appearance of security. Being willing to risk massive public fallout by confiscating expensive cell phones would show they are actually serious.
I can verify from personal experience that MY cell phone does cause interference with radios. I'm a Private Pilot and I have a two year old Sony Ericsson. If I forget to turn the phone off, I can hear a cycling beep sound in my headset every time the phone is transmitting (i.e. ranging to a new cell tower or checking my email etc.) The VHF set also shows that it's receiving, so its actually picking something up through the antenna.
It's not particularly loud, and I haven't had any trouble hearing ATC over it. On a commercial jet... with several hundred cell phones, and the much higher importance of ATC calls under IFR... I can see where it could be a major problem.
Are there ways to solve the problem? Sure. Is it really worth spending the resources to test and resolve in light of the social factors? I'd say no. I personally consider time spent on commercial flights as downtime. I don't want people to be able to get ahold of me, I want to read a book or watch a good movie.
If you really are important enough you HAVE to be in communication 24/7... well buy your own jet =)
"42"
Back in season 3:
l phones_on_plane.html
"It was found that cell phone signals, specifically those in the 800-900 MHz range, did interfere with unshielded cockpit instrumentation. Because older aircraft with unshielded wiring can be affected, and because of the possible problems that may arise by having many airborne cell phones "seeing" multiple cell phone towers, the FCC (via enforcement through the FAA) still deems it best to stay on the safe side and prohibit the use of cell phones while airborne." -Wikipedia
You can read more about it here: http://kwc.org/mythbusters/2006/04/episode_49_cel
I can't believe it...Everyone knows that the passengers on United 93 never actually spoke to anyone on the ground it was all part of the elaborate hoax by GWB part of his plan to get more oil.... GOSH.....
j/k i just really can't stand people who say that you can't make phone calls as if that even supports their ridiculous argument.
You must be new here.
I can tell you the TRUE reason cell phones are not allowed on airplanes.
I fly on Air Force flights, which are not subject to FAA regulations, and the main problem with cell phones on airplanes is the fact that they DO NOT WORK. The transmitter in your phone is not powerful enough to reach more than say, 1000m. Your phone will go dead at less than 10,000 ft of elevation. Add this to the fact that cell towers are not powerful enough to reach the average cruising altitude of ~30,000 ft.
Fear of instrument interference was due to older, analog units with less defined spectrum. With ALL equipment in aircraft being shielded these days there is almost NO possibility of a disturbance in flight.
Besides, your 50mW transmitter is no match for, oh, the sun. And all the other background noise that is present in our atmosphere these days. I would bet that the electric motors on the landing gear ( or hydraulic pumps that may power them) put out more EMF in just about every frequency known to man than all the cell phones that might be in call at once.
I'm fighting The War on Drugs!
I need to point out that VOR navigation has gone the way of the DoDo bird. I cannot imagine anyone in a modern aircraft spending the time to fiddle around with triangulating VOR's when the GPS is sitting there telling the pilot the current position within 10 meters, current groundspeed, and the exact distance to any point on the planet (within 10 meters). The nav radios are now used as a backup to the GPS, if at all. (Autopilots rely solely on GPS.)
I suppose one could make an argument that VOR's are useful in case the GPS fails, but I would retort that one would be much better off with a second redundant GPS on a separate power supply. Which system sounds more reliable: one based on a collection of a couple dozen satellites with no moving parts located *above* the aircraft where there is no weather or terrain and cannot be vandalized, or a system based on hundreds of rotating VHS radios scattered around on the ground, subject to weather, terrain, vandalism, and maintenance problems? Also, it is a simple and prudent matter to mount the GPS receiving antenna so that it is looking up and shielded from RF radiated from below. (A secondary receiver can be located below for extended inverted flight, if that is a concern.) GPS is in all ways better than VOR.
Secondly, the whole interference argument is moot. It doesn't matter. Out of the 137 passengers on a 737, how many of them have mobile phones? I'll guess 30%, or 41. How many of them actually turn their phones OFF when told to do so? I'll guess 50%, leaving 20 phones actively seeking cell towers for the duration of the flight. As far as interference goes, there is really very little difference between a handset trying to negotiate with a tower and one that is locked on and transmitting data. In fact, the device typically radiates more power when negotiating. The only way to prevent this situation is to be absolutely positive all the devices are OFF (including the ones in the baggage hold) -- an impossible task, or move the devices out of range of the towers (five miles UP) -- an inevitable task. So the solution is either impossible or inevitable, neither requiring any action on anyone's part.
Furthermore, radio communication is most critical during takeoff and approach. This is precisely when the devices onboard are the most active -- low altitude over populated areas, within range and transitioning cell tower coverage at a rapid clip. And guess what? Not a single significant incident reported. There have been anecdotal reports, but nothing more than mild curiosities.
This whole argument is a bunch of hooey. The airlines just want to figure out a way to monetize the connections, others want people to just shut the hell up and let them sleep, and the FAA is (as usual) in a state of paralysis. (This is usually a good thing.) The only thing I am pretty sure about is that it has nothing to do with radio interference.
However, if passengers did want, and were allowed, to use mobile phones openly (as opposed to furtively ;) ) in flight it would require a system to relay the signals to the network in a way that overcomes the problems of distance and speed. This will most likely (must be?) a small cell tower (picocell) located on the plane that relays the signals to a satellite link, then down to a central terrestrial hub. Once all the onboard devices discover the very nearby cell tower, they all back off to their lowest power settings and contently sit in low-power mode for the duration of the flight. Even if the picocell were not relaying the signals I think it is the only viable method to control the user devices. But this is a few hundred thousand dollars per aircraft to install, ongoing maintenance costs, and additional regulations and contracts. Not to mention media headaches when some tech blog points out that the airline is now bathing the passenger cabin with microwave RF. So it does not surprise me that this is happening slowly, but I am confident that within the next five
If there is a 'real' reason for no cellphones on planes, I think its about time we found out the *real* reason people are not allowed to bring decent quantities of drinking water on planes.
It is, surely, trivial to test whether a given substance is H2O. I mean, how hard can it be?
It is, surely, trivial to test whether the container has got a false top containing water and the rest of it contains some other (possibly explosive) substance. Those xrays give pretty detailed views plus you could push a probe down the mouth of the bottle and wave it about. They do this to passengers all the time.
Therefore there has to be a reason why passengers are not allowed to bring *water* onto planes.
One theory is that the homeland security guys figured out a way to harm an aircraft by pouring enough water into or onto a certain area of the passenger compartment of the plane; flooding it with a conductive fluid.
Any other offers?
In the free world the media isn't government run; the government is media run.
If cellphones were really really dangerous, we'd have aircraft graveyards everywhere, especially around airports.
What do cellphones talk to? Cell towers. Where are those towers? EVERYWHERE, and they all operate at much higher power levels than any handset.
If there was some sort of danger, cell tower signals from the ground -particularly towers near airports where they are always A LOT of such towers- would be knocking planes out of the sky on an hourly basis from miles away. Every airliner in the sky flies over hundreds of these towers on every flight. It would be like the worst anti-aircraft fire ever devised.
But it doesn't happen.
And cell towers are hardly the most powerful transmitters in the wild. A cell tower throws out a couple watts. A TV transmitter can throw out a million watts and there are thousands of those towers too.
Aircraft operate happily amid a sea of RF and generally nothing goes wrong. So the idea that a wimpy little cell handset are threats are just overblown assumptions, unproven and unrealistic.
Sig for hire.
It's generated in the part of the phone called the "network", which, among other things, contains something called a "hybrid coil", which allows the single pair of copper wires to separate the outgoing and incoming voices. In addition to that function, there's also a "sidetone coil" that couples a sample of the outgoing voice into the receiver circuit.
In electronic phones, it's done slightly differently, but there is absolutely no reason it can't be done in cell phones, and it often is.
The explanation is correct in one respect, though. Increasing the sidetone will cause the talker to lower their voice.
Used to take phones apart for fun, have designed hybrid circuits.
I don't think "It was the airplane's problem for having faulty shielding, not the electronic device" would be much of a comfort to relatives. Can't we just be a little patient while the last of the analog phones (which really can interfere) disappear, and the FAA/FCC test out onboard picocells? People here talk like addicts -- as though somehow its impossible to not use your phone for a few hours.
This is more or less the case. I was watching CSpan as a bill considering the use of laptops which connect over the cell network on airplanes was debated, and the debate got straight to the point: We should allow laptops because they are not intrusive, but no one likes a cell phone call on an airplane so the nuisance should continue to be banned. At no point during the Senate debate did anyone show proof of serious harm to the airplane or cell network from cell phone use, and it's interesting that no one had any serious objections to laptops connecting wirelessly over that same network.
Although the cell network concern is somewhat legitimate, the truth is it's a simple software problem of anticipating this kind of broad network access and handling it appropriately. It's not a serious technical challenge, it's just a limitation of SOME cell networks, for now. If the law changes, so will the software, so it can't be taken seriously.
There is also some legitimate technical concern of radiation affecting internal plane signals. However, this kind of interference is only possible on unshielded cable on the plane, which presents a problem whether a cell phone is on or not.
There are many reasons rumored (even by the FAA!) for the cell phone ban and the above are the only 2 with any technical basis, and even they just take a little more investigation to reveal their lack of merit. What was enjoyable was that the Senate debate didn't spend more than a few minutes pondering the technical concerns - they accepted them all as crap and moved directly to the nuisance issue, and focused primarily on that for the entire debate.
Hmmm - I was on a flight last year which was struck by lightning on final approach - I'm stunned that the planes systems can take massive broadband interference spikes from lightning without missing a beat and yet they are threatened by the milliwatts of signal from a cell phone.
I mean, they don't allow you to sit in the cockpit any more.
What, Pilots have to stand nowadays?
I thought they were glorified bus-drivers, not glorified tram-drivers!
988738/12227 =~ 81
Just saying...
It IS an effect of the copper loop. Telephones contain a hybrid coil (hybrid network), the purpose of which is to separate / mix the sent & received audio. It's a clever application of balanced networks.
Unfortunately, the copper loop is a complex impedance and varies with line construction. There are various balance network options (e.g. TN12, etc) which try to approximate a 'best match' to the line, but they're not perfect. The end result is imperfect isolation across the hybrid - i.e. some microphone sound appears in the earpiece.
Oddly enough, it was found in the early days of telephony that this was in fact desirable; it made the phone sound more 'natural'. After all, when you speak normally some sound does reach your ears via the air - an effect which is reduced when you put a phone up to your ear. So, in fact, it's a happy accident that telephony hybrids are imperfect.
Mobile phones don't have this effect (separate transmit/receive frequencies or timeslots), and the electronic hybrid in some wired phones is too good at matching the line, so some mic sound is deliberately mixed back in to the earpiece audio to create sidetone. AFAIK, the only reason why this is less effective in mobiles phones is purely a power issue - the mixed audio is reduced to an absolute bare minimum in order to shave a few microamps/milliamps off power consumption, and so extend battery life.
(That's an overly simplified explanation - but, yes, I WAS a telephony engineer...)
What part of "a well regulated militia" do you not understand?
LOL, good burn. :)
There is a lot of talk about terrorists, but if memory serves, it was passengers using cell phones and in-seat phones on United flight #93 that clued in the passengers that 3 other planes had been hijacked and crashed, presumably giving them the will to fight back agaisnt the terrorists.
Only if you've got a first generation analog brick-phone using FDMA. Since G2, the handset/cell interaction has been digital (The cell network was always digital) using TDMA or CDMA.
TDMA on a moving target requires the handset ensure that the transmission occurs during its assigned timeslot. There is an acceptable amount of error built into the length of the guard interval between assigned timeslots. Violate the TMA assumptions of the code for calculating transmission timing significantly enough and the handset starts blabbing over into someone else's timeslot. Degradation of service occurs. This can be fixed by increasing the guard interval, but that reduces available bandwidth.
CDMA was created with the shortcomings of TDMA in mind and does not suffer from them for the most part. The "soft-handoff" the CDMA performs as a handset moves from cell-to-cell could present a problem for the handset if it transverses through many cells rapidly and simultaneously. How the network deals with a rapid string of handoffs is entirely up to the carrier. One carrier flogged "no connection charge for dropped calls" back in the day, kept the code around, and ended up with malicious users being able to get unbilled calls by forcing handoff back and forth between cells before the tab started. The same thing happens unintentionally if you fly across a city and are legitimately changing cells fast enough. Who knows what other weird implementation specific things happen... The problem isn't with the technology, though.
Simple Machines in Higher Dimensions
Well, not that I care one way or another, but...
It's pretty easy to determine that your navigation equipment may be unreliable when it's lightning out. Not so much when someone is fiddling with their electronic device.
Buckle your ROFL belt, we're in for some LOLs.
You can redesign every plane, but still, it moves at 500mph, and the fading and Doppler effects will kill the cellular signal. Your handset is not capable of operating at these speeds.
I was on a plane from Denver to Jackson WY.
The flight attendent told us that the pilot could not see the airport, being a plane full of locals who had flown in and out several times (including at least one pilot) we looked out the window and said, "no. Their it is."
She left, and came back and said "the tower won't let us land"...we all were silent. How could we land if the tower wasn't going to let us. She played the trump card...except we all knew that Jackson has no tower. Someone asked her to repeat herself. Someone else asked her to verify with the piolot. She went forward and came back, confirming that the tower would not let us land. We went nuts. It started out polite enough, but once she added that we would not be comped a room because the delay was weather related, she had a real revolt on board. She refused to to admit that she lied.
Eventually she went forward and we never saw her again. I think she hid in the cockpit while we disembarked. We did not land in Jackson, we flew to SLC Utah and were comped a room. I understand that the young guy on the plane who was still going bonkers when we landed got comped an additional flight voucher.
But the fact is it happens all the time. People lie. Being on an airplane does not stop that, it just means their is no place for you to run.
Twenty minutes befor us and fourty minutes after us a competing airline landed their jets.
You must be new here! :)