Talk:Mobile phones on aircraft

Opening comment

The critical reason phones are banned on aircraft is when they search for a repeater station, they intefere with the electromagnetic NAV instruments such as NDB's, DME's etc. Most cells cannot be used even if turned on because of the heavy dampening effect caused by noise & wayward frequency cancellation technologies used in the aircraft's structure. This is the breifing given to pilots regarding cellphone use, for more technical info you should check with an engineering outfit. - Molloy —Preceding undated comment added 10:43, 29 June 2005

This is not the case. Aircraft of all types are immersed in cellular traffic during the most critical portion of thier flights, approach and landing, often over densely populated areas where they are within a few hundred feet of large numbers of cellular users, as well as many other types of electronic equipment, and of course cellular ground stationns as well. There have been no published reports in many years of such equipment interfering with aircraft navigation and control. — Preceding unsigned comment added by Danwoodard (talk • contribs) 21:51, 15 February 2018 (UTC)

Strong statement. However, any wanted mobile phone RF transmission -- no matter which standard -- is separate from the Aircraft NAV/COM spectrum. 84.144.109.235 (talk) 19:38, 3 September 2008 (UTC)

Everyone with even a passing familiarity with the technologies involved knows that. However, anyone with just a little more than a passing familiarity also knows that EMI doesn't have to be caused by transmitters on the same frequency, or even nearly the same frequency, as the desired signals. Note for example that GSM phones (which operate around 1 or 2 GHz) commonly, even famously, cause interference with baseband audio circuits. Note also that many of the incident reports in the referenced documents do not seem to have much to do with simple interference with RF NAV/COM signals, but rather with a more direct path into the avionics, avionics that in many cases have nothing directly to do with received signals. i.e. the signals from the mobile phone or other PED apparently don't have to be received via an antenna on the outside of the a/c to cause problems. Jeh (talk) 23:35, 3 September 2008 (UTC)

real engineers know equipment can be designed to be immune to EMI! — Preceding unsigned comment added by 130.76.64.121 (talk) 18:13, 12 December 2011 (UTC)

That is a nice theory; however, pilots often use cell phones during flight. FAA FAR's are legal requirements, but they may be ignored in times of emergency, though it is unlikely that using a cellphone in flight is the answer to an emergency. In the case of cellular phones, if the pilot is the only person with a cellular phone turned on, he can easilly turn it off if he or she notes interference.

From the first few paragraphs this article reads like it was written by someone with a personal vendetta against the banning of mobile phones on aircraft, i dont know enough about the subject to rewrite it, however. 195.172.220.162

The article should not start with a reference to the USA. The topic is supposed to be the use of phones on any plane.Royalcourtier (talk) 02:54, 16 March 2014 (UTC)

Explaining my reversion

I came to this page because I was looking through contributions from an anonymous IP address which had vandalized the Adolf Hitler article today. I saw an edit from 24 November, and accidentally clicked the rollback button, while intending to click the diff. I tried to stop my edit, but it was too late. I would not have rolled back without checking that it was vandalism, especially since the edit could be from a completely different person. I then rolled back my own edit. I am not familiar with this article, and have no view on whether or not the NPOV tag should be on it. Someone else should look into it. I simply rolled myself back because I had not intended to use rollback. Apologies. AnnH ^(talk) 15:26, 28 November 2005 (UTC)

New title?

Shouldn't the title be "Use of Mobile phones on Commercial Aircrafts"? As far as I can see the whole article deals with that rather than the actualy mobile phone on aircraft. --antilived ^{T | C} 22:57, 10 December 2005 (UTC)

Cleanup

I've done some limited NPOV editing of the article. What do you guys think? Werdna648^T/_C\^@ 07:09, 31 December 2005 (UTC)

I agree completely. I am a pilot and have used a cell phone in a Maul to call the tower for landing instructions. Works at low altitude and low speeds. No instument problems but then I was flying VFR so didn't care. About 1000 feet above ground and 80 NM/hr — Preceding unsigned comment added by 71.17.55.125 (talk • contribs) 20:32, 19 April 2007 (UTC)

Cingular Against Phone Use On Planes

While I'm not sure what their current policy is, this article from last June [1] says that Cingular is in favor of keeping the ban on cell phone use on airliners, due to the fact that people talking on their phones can be irritating to those around them.--Raguleader 18:38, 28 February 2006 (UTC)

Billing Idea

I can in no one verify this but I heard that companies can not properly bill people who use cell phones in planes.Tjb891 20:28, 1 June 2006 (UTC)

I work for O2 in the UK. I don't see why there would be a problem with billing. When your phone is connected to a service provider, it is connected, the billing is not affected. My other point is that because we don't know whether mobile phones interfere with sysetms, we should not use them until we know they DO NOT interfere. I accidentally left my phone swithched on on a flight from JFK to Heathrow and I am still here! But we should not play "God" with the lives of others and should be sensible.

--81.152.245.125 23:19, 13 July 2006 (UTC)

Frequency Reuse

DylanW removed the following section from the article a few months ago:

==Frequency Reuse==

Perhaps the greatest issue is, however, the principle of frequency reuse. Mobile phones are designed to transmit only as far as the closest cell tower. This allows the same frequencies to be used by different phones in any non-adjacent cells, a key component in allowing tens or hundreds of thousands of people to use their phones at the same time in a given metropolitan area. From an altitude, distant cells are visible to the mobile with no line-of-sight attenuation from intervening obstacles. Because the cells are in some cases several tens of thousands of feet below the aircraft, the phone will transmit at its maximum power (also increasing the risk of interference with electronic equipment on the aircraft), which will also significantly shorten its battery life. Since the phone is occupying its frequency and channel in all of the cells its signal reaches to (which could be many cells over many miles), that frequency and channel cannot be used by any other phones in any of those cells because of interference, resulting in an overall decrease in the cellular system's capacity. This is the primary reason the U.S. Federal Communications Commission prohibits the use of mobile phones in the air. (The U.S. Federal Aviation Administration is more concerned with interference to aircraft systems.)

I had added much of this paragraph to the original mobile phones article (which was subsequently moved to this article) based on several news articles as well as information from people inside the aviation community. A quick Google search for the topic brings up several sources for the info I posted. Here's a clip from a CNET article discussing the subject:

Why the cell phone ban?

The cell phone ban went into effect in 1991, mostly to eliminate the possibility that cell phone calls on airplanes would interfere with cell conversations on the ground, as well as with the airplane's radio communications.

The FCC cited effects of "frequency re-use," which is a fundamental cell phone principle that's helped mobile phones proliferate worldwide. The signal from a cell phone doesn't go on forever; the energy to propel it dissipates after a number of miles, and it dissipates more quickly if it bounces off buildings, hills and other obstacles. This allows the same frequencies to be re-used by operators in different markets sometimes just a few miles apart.

A cell phone signal falling to Earth from a phone aboard a plane encounters no significant obstacles to slow it down, so it's strong enough to reach the ground and find a network on its particular frequency. But if the airwaves belong to a different operator, there's likely to be "noise" and other forms of interference for everybody, the FCC believes.

DylanW put the reason for his edit as "rm section: its basis for its conclusions, "the phone is occupying its frequency and channel in all of the cells its signal reaches to", is false)." Perhaps the idea that using cell phones from the air reduces the overall cellular system's capacity IS a falsehood. Regardless, that argument is the primary one the FCC is basing its decision on, so regardless of whether it is true or not, I believe it deserves discussion in this article (albeit perhaps modified from the original version above--perhaps to indicate that this is the FCC's argument, not necessarily reality). Unless someone can show that the FCC has since rescinded that argument, I plan to add back that paragraph (with some edits). I will attempt to search for a verifiable source (perhaps a paper published by the FCC) quoting their argument to lend credence to my edit.

I'm not saying that the idea is true; I'm saying that as long as the FCC says it believes it is true, it should be discussed, even if it is false. The reality of the principle is a separate issue that can also be discussed by someone more knowledgeable about radio frequencies and electromagnetic interference (and/or studies and reports that discuss the principle).

I'm not disputing that many are against cellular usage in aircraft due to potential disturbances to navigational equipment, etc. There are TWO major federal agencies that have enacted bans on cellular usage onboard aircraft: the FCC and the FAA. The FAA implemented the ban because of concerns of interference; the FCC's ban is due to what I've said above. Both agencies (and perhaps others as well) will need to modify their regulations regarding cellular usage before mobile phones will be able to be used on aircraft. The FAA could find that cellular frequencies do NOT cause interference, but as long as the FCC believes that frequency reuse will be harmed, mobile phones will not be allowed on aircraft in the U.S.

This is my interpretation of the case based on my reading and research. As always, you are welcome to show where I am wrong--just support your challenges. I also believe it is in the spirit of Wikipedia to provide a detailed explanation/argument before removing an entire substantial paragraph, which DylanW did not do.

Sorry for being cranky--I'm a bit tired at the moment! Perhaps I'll be more cheerful come morning... cluth 02:23, 18 July 2006 (UTC)

I think this is well written and what I have heard from my aeronautics professors at college. So why is there no mention of this in the actual article? If I don't see any good reasons in the next day or so, I am going to just add it back. Like CLuth mentioned, even if the conclusions are false, we should mention what the FCC says.

I don't know what happened to the above plans for restoring this, but I went ahead and did it. More to follow... Jeh 16:15, 9 March 2007 (UTC)

There are 3 potential reasons for the non-use of mobile phones in aircraft

mobile phone types

GSM TDMA phones cause more problems to sensitive equipment than CDMA phones. This is because the GSM phones actually transmit quite high powered "pulses" of RF energy, typically several watts. A CDMA phone will only produce a maximum output of +22dBm (slightly less than 200 milliwatts). This will explain why a GSM phone will cause a loud buzz if placed near any audio equipment while being used on a call. Due to its much lower power output, a CDMA phone is less likely to cause this problem.

There are 3 primary concerns related to the use of mobile phones in aircraft.

1. The potential high energy pulses from some phones will effect the sensitive navigational and audio equipment on an aircraft.

2. A mobile phone situated thousands of feet in the air could have an effect on the phone carriers network of base stations on the ground. This is primarily because of frequency re-use as mentioned in the above information from cluth.

3. The antenna systems used on the phone carriers base station networks are designed to work with signals from either down or out from the base station (and not up). As the base stations often use very high gain and/or directional antennas, not much of the signal from the base station is radiated up towards aircraft flying above (or received at the base station from a mobile in an aircraft). As a mobile phone in an aircraft would be receiving a weak signal, it will automatically "turn" its transmit power up to maximum in an attempt to connect to the base station on the ground, hence creating the worst effect on the aircrafts sensitive systems.

While CDMA phone technology is more capable of dealing with frequency re-use, the base stations are mainly on the same RF channel (frequency), the base station antenna situation mentioned above will prevent the phones from working effectively. --Ericdog 03:38, 27 July 2006 (UTC)

3a. It's also the case that a phone moving at over 100 mph to or from a base station is going to have problems due to Doppler shift. This sounds far-fetched, as the frequency shift is not that many Hz -- but all digital phone systems use a modulation scheme that includes phase shift keying, and the Doppler shift is more than enough to corrupt the incoming data by changing its phase. The towers do have Doppler shift compensators that are good to about 100 mph but they can't begin to cope with 500 or 600 mph! Of course, just because the a/c is moving at 500 mph doesn't mean you're necessarily moving to or from the tower you're hitting at that speed; if the tower is abeam of the aircraft and at a moderate distance the relative speed may be quite low (of course, the distance is a problem too). The point though is that it's yet another reason why mobiles are just not going to work reliably at cruise speed and altitude.

The systems that are being experimented with do NOT involve letting pax just fire up their phones in flight; they work by installing a "microcell" in the a/c. So the pax's phones communicate with the microcell (using extremely low transmit power since everything is inside the a/c metal shell), and the microcell's external radios communicate with its own ground network or satellites using links that aren't bothered by the a/c's movement, just is done for the seatback phones today. Jeh 07:29, 1 August 2006 (UTC)

Aeroplane Mode

Not sure how relavent this is, but on all the flights I have been on recently (from the UK to Cyprus) the cabin crew have request that all phones be switched off even if they do have an 'In-flight mode'. --82.37.34.177 17:57, 16 August 2006 (UTC)

This is very interesting, as, when "in flight mode" is selected on a mobile phone, the whole RF (radio frequency) section is disabled and the phone can not transmit any signals. It would seem like an over-reaction on the part of the airline company.. Ericdog 12:30, 19 August 2006 (UTC)

Or perhaps not. A lot of electronic devices (even those not designed to transmit radio signals) generate quite a lot of radio frequency noise (try listening to some weaker AM stations with a radio beside your computer any youll see) Maybe some models of cellphone generate a lot of RF noise even when being used as an music player, camera or whatever ? 80.229.222.48 17:31, 22 October 2007 (UTC)

I don't have any references for my statement at this time, simply because I'm too lazy to perform more research at this time, but 7 years as an electrician (substation technician) and plain old common sense tells me that something as small as an MP3 player, such as an iPod or iPhone on airplane mode, could never create enough EMF, noise, RF interference or whatever else you want to call it, to affect the planes on-board electronics. I agree with switching your phone to airplane mode for the whole flight, even if there is no hard evidence of a danger caused by them, but why must we spend that whole period of time during take off and landing without our little electronic treasures? Especially when some flights have TV screens in the back of every seat running the whole flight (including take off and landing!). I understand it is slightly safer and easier for the airline to request ALL electronic devices be switched off during take off and landing. It avoids confusion and is probably easier than people trying to figure out how to find airplane mode, but I personally keep my iPod running as long as I am getting away with it. If something so small caused any REAL danger they would search you and confiscate such items before the flight, as they do with any other potential dangers. — Preceding unsigned comment added by 64.46.14.76 (talk) 01:49, 28 July 2011 (UTC)

Links to reports and other information

I'm not going to get into editing this article, but here are some links to relevant reports - make of them what you will. Jeh 20:17, 20 July 2006 (UTC)

http://asrs.arc.nasa.gov/report_sets/ped.pdf

http://www.avionicswest.com/myviewpoint/airlinecellphone.htm

http://www.airnig.co.uk/emi.htm

http://aviation-safety.net/database/events/ped/ped-case.htm

http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/Research/Rvs/Article/EMI.html

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20010066904_2001108092.pdf

http://www.caa.co.uk/docs/33/capap2003_03.pdf

http://web.archive.org/web/20031218092141/http://md-l.amulation.com/archive/199708/msg00020.html

http://www.aviationnow.com/avnow/news/channel_awst_story.jsp?id=news/VIEW04136.xml

http://www.airlinecrew.net/vbulletin/archive/index.php/t-168185.html

http://asrs.arc.nasa.gov/callback_issues/cb_237.htm (last two items)

http://eep.burdell.org/tech/ped2.php

"Some airlines do allow use of mobiles phones in flight"

A previous edit claimed

Some airlines do allow use of mobiles phones in flight, only restricting their use (and use of all other electronic devices) during take off and landing when communications with the ground are most critical.

Yeah? Name three. I'm moving this text here; if anyone stands up for this statement, please provide documentation. Almost all airlines allow the use of 'approved electronic devices' such as laptops during cruise... but not mobile phones. Jeh 22:43, 9 March 2007 (UTC)

Ryanair, Emirates, and Malaysia Airlines... —Preceding unsigned comment added by 195.222.2.22 (talk) 09:39, 20 February 2009 (UTC)

Hmmm. All of these use picocells aboard the aircraft. The proximity of the picocell allows the mobile phones' to work with very low power output. I believe the question here is rather, how many (or do any) airlines permit you to just use a phone in flight even though the airline has installed no equipment to support their use? Most of the time they won't even work at cruise altitude and speed. Jeh (talk) 04:08, 5 January 2013 (UTC)

That's somewhat different from what your original question was. — Preceding unsigned comment added by 89.126.57.115 (talk) 22:34, 15 June 2013 (UTC)

9/11

Can you talk about the calls received by relatives of the passengers of the Pennsylvania (?) flight on September 11th, the "Let's roll" ones? --84.20.17.84 08:17, 10 April 2007 (UTC)

All but one of those calls, not excepting Todd Beamer's, were made using the seatback phones. Not much to say there. Jeh 23:08, 10 April 2007 (UTC)

"Controversy Remains" - chaosfreak's edits

To explain my wholesale reversion... Perhaps "controversy remains", and in fact chaosfreak raises some valid points. But the rules on NPOV and OR require that you not post your own personal opinions on the matter, nor your own criticisms of other parts of the article. If you wish to present an opposing point of view you must find sources of that point of view OTHER THAN YOURSELF, such as newpaper articles and published reports, and cite them. n.b.: Writing your personal opinions on a blog page and then citing that doesn't count. Jeh 17:45, 26 August 2007 (UTC)

Mobile phones on mountains

RE: The frequency reuse issue What is the maximum recommended height for using a cellphone ? If someone on top of a high mountain (or even on the top floor of a skyscraper in a densly populated city) uses one could it cause problems ? 80.229.222.48 17:36, 22 October 2007 (UTC)

Interesting question. I have an industry expert I can ask. Stand by. Jeh 08:55, 23 October 2007 (UTC)

IEEE Spectrum Report's Conclusions

I have removed the text that claims that the 2003 IEEE Spectrum report shows that cell phones and other electronic devices "can and do interfere with avionics systems." The IEEE Spectrum report is deeply flawed in its methods... they use dubious statistics and inference based on trends from other industries. At no point do they ever prove any actual interference. The only concrete conclusions from the report is that several cell phones are left on on most flights in the United States.

Your first point seems fine. But re. "deeply flawed," that is your opinion. We have there three degreed professionals in the field, writing in a peer-reviewed journal of the field. If you can find a credible source critiquing the study on that basis, then absolutely, please cite it in the article. But to put your own critical opinion in the article here is OR. Jeh (talk) 13:16, 8 December 2007 (UTC)

IEEE Spectrum is a magazine published by the IEEE for its membership, and not a peer-reviewed journal like the various Proceedings titles, and thus has review standards more in line with journalistic magazines. If the article's authors have peer-reviewed papers on the topic, cite those instead. 146.6.200.182 (talk) 18:32, 9 October 2008 (UTC)

OK, but my primary point is that the description of what the report proves is inaccurate. The report does not prove that cell phones interfere with avionics systems, nor was it designed to do so. That is where removed this mischaracterization. While I disagree with their method for concluding that cell phones will one day cause an airplane accident, unfortunately I cannot afford to fund a study to refute their conclusions. ChaosFreak1 (talk) 17:48, 29 December 2007 (UTC)

Allowed in the EU

Do we not add the fact that they now allow mobile phones inside the EU's airspace? —Preceding unsigned comment added by 87.119.164.117 (talk) 13:13, 11 April 2008 (UTC) http://news.bbc.co.uk/2/hi/technology/7334372.stm —Preceding unsigned comment added by 84.50.183.116 (talk) 12:53, 31 July 2008 (UTC)

Why no "Signal propagation / antenna radiation pattern" section in the main article?

In the main article, in the technical section, there are only 2 sub-topic (channel re-use, and EM interference).

Why is there not a third section - pertaining to cell tower antenna radiation patterns (and why it is, or is not the case, that cell towers are, or are not, optimized to transmit and receive signals from several miles ABOVE the ground-plane of the tower).

And possibly, why is there not a 4'th sub-topic, pertaining to the differences between the increasingly defunct analog cell-phone technology (and tri-mode phones) vs digital phone technology, and how that could impact using a cell phone in a plane at 10k to 35k feet.

The section on channel reuse already needs references. I was going to write the stuff on tower rad patterns, but at first I didn't have refs and I didn't want to add yet another unref'd section. Since then I've collected some refs for the tower radiation patterns but just haven't gotten around to writing the text.

And yes, the tower patterns intentionally do not cover the sky. The reason is simple: Antenna directionality is how you get antenna gain. Eliminate half of your possible "directions" and you have a 3dB power gain in the directions you are covering. There is no point wasting transmitter power or receiver SNR on an entire hemisphere in which you do not expect any phones to be.

And since I thought about it, a 3dB reduction in the above-horizon signal isn't really enough to say "the phones won't work". In practice of course the patterns are not perfect, so you don't even get all of that 3dB. And I can't find a reliable source that says "the phones won't work" because of the tower directionality. I can find refs for the directionality, but not for the "phones won't work" conclusion, so the conclusion would be "original synthesis", which is disallowed here along with original research.

Making an antenna directional, in your example to gain 3 dB of received signal strength, decreases the signal strength in the undesired directions by much more than 3 dB; attenuations of 20 or 40 dB would not be unusual. What is more likely to happen in this scenario is that the strongest signals at the cell phone will not be towers directly beneath it, but farther off towers which are at shallower angles and thus lower attenuation. This can exacerbate the channel-sharing problem. The best data would be call-trace data for a phone call made from an aircraft, showing which towers it was in contact with vs. the aircraft's position. 146.6.200.182 (talk) 19:48, 9 October 2008 (UTC)

Your point about analog vs. digital is well taken. There's actually yet another reason for doubting that digital phones will work at jetliner cruise speed and altitude: All digital mobile phone systems (CDMA, GSM, i.Den) include phase shift modulation and this can be thrown off by very small frequency errors... such as would be caused by Doppler shift due to the airplane moving at ~500 mph wrt to the tower. In fact even the movement of a car is problematical. The tower software can compensate for this at up to about 100 mph, but not faster. But I need refs for that one. This btw is why in some of the discussions of 3G and faster data speeds you will frequently see a lower spec for "if in motion", they mean in a car, not walking. Jeh (talk) 08:04, 4 August 2008 (UTC)

I looked up the Doppler effect math and found that you get a Doppler shift of 1.5 kHz when using the 1.9 GHz band in your example assuming worst-case aircraft movement (diving at the tower). The aircraft traveling directly toward or away from the tower may be the rare case; the windows on the aircraft will likely block towers that are not to the aircraft's sides, for whom Doppler will be minimized. That all said, there was an article on this, but the server's down right now so I looked at the Google cache. They cover the Doppler issue, but seem to miss the possibility that Airfone systems are probably designed to deal with larger Doppler shifts than the 480 Hz that cell phones use. 146.6.200.182 (talk) 19:48, 9 October 2008 (UTC)

Is it possible to get a signal if it was allowed?

Is it possible to get a signal if it were allowed? When did it become possible to make a call easily on a commercial airliner flying at high altitude at full speed? --Rolec Dubbing (talk) 16:47, 11 December 2009 (UTC)

At cruise altitude and speed it isn't impossible but it's quite difficult. Jeh (talk) 23:04, 11 December 2009 (UTC)

I used the local picocell facility on an Emirates Airbus between South Africa and Dubai in December 2009 and January 2010. Over South Africa, which has a good gsm network, I made high quality gsm calls via the onboard picocell by Aeromobile. SMS also worked perfectly. Clearly the picocell receiver in the plane was getting a good strong signal. Though the Aeromobile website refers to Inmarsat L as the transmission channel I have my doubts - the system seems to depend on ground facilities not satellite, as there was no coverage over wilderness areas in northern Mozambique and no signal at all over Somalia. Tanzania and Kenya reception worked perfectly as we overflew Dar-es-salaam (TZ) and Mombasa (KE), otherwise the signal was intermittent. Craigallan.za (talk) 20:09, 10 January 2010 (UTC)

That's fine, but it doesn't say anything about the ability of a mobile phone to get a signal without a picocell. If the system is using ground facilities then it is contacting them with high gain antennas on the outside of the aircraft - the success of that is not relevant to whether an unassisted phone inside the a/c would work. Jeh (talk) 22:00, 10 January 2010 (UTC)

Cell towers transmit primarily horizontally. At low altitude cellular phones work normally. At high altitude, certianly above 10,000 feet, the aircraft may be above the rediated pattern of the cell towers. — Preceding unsigned comment added by Danwoodard (talk • contribs) 21:55, 15 February 2018 (UTC)

Copy Edit Notice

For anyone who may be interested, I will be doing a major copy edit of this article over the next couple of days. This will probably involve cutting some of the content, where I believe cutting will help to make points more clearly. At present I think that the article is very long for its content. If I cannot locate sources for some statements or sections which at present appear to be opinion or unattributed original research, I will probably delete them as being in violation of Wikipedia's policies (either WP:NPOV or WP:NOR).
I will keep an eye on this page, so if you disagree with any of my edits on this article please feel free to raise the issues here rather than simply reverting them. I am approachable, willing to be corrected, and will not take issue with rolling back if need be.
I will also post updates on progress here. David_FLXD (Talk) 20:50, 1 January 2013 (UTC)

Interesting. Do you consider yourself at least familiar with RFI/EMI issues? How many relevant ASRS reports have you read? Jeh (talk) 07:31, 2 January 2013 (UTC)

Competency is required, but expertise isn't. A good copy editor can certainly improve an article even if he or she knows little to nothing about the subject at hand. Better to wait and criticize edits that are made instead of discouraging them altogether. --BDD (talk) 02:41, 3 January 2013 (UTC)

For Jeh - I have the good English! I watch the Air Crash Investigation show on the tellyvision! Seriously? I know enough about electronics to repair a radar set, and enough about flying to have flown solo. I have no particular axe to grind here, and am more concerned about clarity, intelligibility and quality of spelling and grammar. David_FLXD (Talk) 03:57, 3 January 2013 (UTC)

Follow-up on {{GOCEinuse}} tag: I am going to take rather longer than normally expected; however, I expect to finish by 5th January. (A few days rather than a few hours; I can't work on this for hours at a time). David_FLXD (Talk) 04:05, 3 January 2013 (UTC)

I am nearly done; some referencing and wikifying to do still. David_FLXD (Talk) 05:58, 7 January 2013 (UTC)

I am done. I trust I have made an improvement. David_FLXD (Talk) 06:54, 9 January 2013 (UTC)

Proposed move to Portable electronic devices on commercial aircraft

Much of the source material seems to deal with wider issues than just mobile phones, and it seems that other devices have greater potential for hazard than the yet uproven dangers of mobile phones alone. However, the present content of the article is largely about mobile phones. Is the purpose of the article only to address the specific issues of mobile phones on aircraft, or is the purpose of the article to address the issue of electronic interference aboard aircraft? Which should the purpose and thrust of the article address? And, if it is more about portable electronic devices (PEDs) in general, then should the article not be moved to the above proposed title? Naturally, if it primarily concerns mobile phones, it should stay where it is. Comments please. David_FLXD (Talk) 04:41, 4 January 2013 (UTC)

Oppose move. Mobile phones are sufficient for this article. If we can find sources discussing the general issue of portable electronic devices on aircraft, that could be its own article with the details about phones left here. --Wtshymanski (talk) 05:38, 4 January 2013 (UTC)

Oppose at least in this exact form. As a proposed move (rather than a parallel article) then the new title as suggested is inappropriate, as not only commercial aircraft are involved. In the US, FCC regs prohibit the use of mobile phones on particular bands aboard any aircraft that isn't touching the ground. Even non-commercial aircraft, and even things like hot-air balloons. Yes, this reg is routinely ignored by e.g. hot air balloonists; nevertheless, it does exist. And the technical considerations of interference to avionics are relevant to non-commercial a/c. Jeh (talk) 21:43, 4 January 2013 (UTC)

Unless there are any differing opinions expressed, I withdraw the suggestion! David_FLXD (Talk) 15:47, 7 January 2013 (UTC)

2013 was a long time ago. Many airlines now have in-flight WiFi, so once the cell connection is off, you can turn on WiFi. As well as I know, it is interference with the cellular network that is the primary reason for the rule. That might apply to some cell systems and not others. Older analog phones used narrow (relative to the carrier frequency) channels that could easily doppler-shift to another channel. The cell system wasn't designed for that. It might be completely different for newer digital systems. Gah4 (talk) 13:15, 3 February 2020 (UTC)

Note also that many airlines that allow in-flight WiFi disallow its used for voice (VoIP) connections. The might even block the ports commonly used, though one could likely find systems using a different port. Gah4 (talk) 13:15, 3 February 2020 (UTC)

Weeks later..."Doppler shift" caught my eye; but a jet doing 500 MPH would shift frequency by less than 1 ppm, far less than your phone shifts by taking it out of your warm pocket and exposing it to the cold air, so Doppler shift is not the reason. --Wtshymanski (talk) 22:04, 27 February 2020 (UTC)

In the analog cell phone days, they were about 10kHz channels and a 1GHz (or so) carrier, so about 10ppm. So 1ppm is about 1/10 of the channel width, or 10% overlap. That is as close as I know it. Obviously the phone has to have a way to accurately follow the carrier, which a PLL should be able to do. Now it gets more interesting. The phone will lock onto the Doppler shifted frequency, and then use this as the reference for the return channel. The return channel then gets shifted another 1ppm, so as seen by the cellular system, it is 2/10 or 20% off. That might be enough to cause problems. But now everyone uses digital phones, which I haven't tried to follow at all. I believe it is right that the phone locks onto the base carrier and uses that for the return, and that the effects add. It is interesting that airlines allow WiFi but not cell, when the frequencies are somewhat close. Ruling out voice use for phone wouldn't automatically rule out data, and as noted above, airlines that I know disallow VoIP phone connections on allowed WiFi systems. Gah4 (talk) 09:19, 28 February 2020 (UTC)

OK, looking it up as I haven't thought recently, AMPS is 30kHz channels. Digital_AMPS uses the same channels, but time division multiplexes three connections into that channel. But OK, 30kHz so about 7% channel overlap, which isn't so much, but still might be too much. And I still don't know at all about more recent systems. Gah4 (talk) 09:36, 28 February 2020 (UTC)

OK, this one says that it is due to the combination of Doppler and multipath causing fading (fast amplitude change) that the system can't follow. Cell towers and phones are supposed to adjust the signal amplitude as appropriate, but they can only do that so fast. Gah4 (talk) 09:55, 28 February 2020 (UTC)

Here is a reference from a university course so advanced that it needs a four digit course number. It has more details than I feel like following now. Gah4 (talk) 10:08, 28 February 2020 (UTC)

That looks like the sort of power point where the lecturer talks for 20 minutes on each slide. The sole numerical example makes it look like driving in a car is a challenge for multi-megabit/s data links. But the Doppler shift alone is not of a magnitude to cause changing channels. Analog voice communication with aircraft is well-known, even in supersonic fighters. The hams have to adapt tuning for moon bounce and satellite work, but the relative velocities are orders of magnitude higher. --Wtshymanski (talk) 18:08, 28 February 2020 (UTC)

References

Technical Discussion has an axe to grind

The last three paragraphs of Technical Discussion (surrounded, for some reason, by /* */) read like a rant on a blog. Even just the capitalization warrants rewriting, but the reasoning and math is specious, at best. — Preceding unsigned comment added by 207.198.105.24 (talk) 15:22, 31 October 2013 (UTC)

Requested move 19 March 2014

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: No consensus, not moved (non-admin closure) DavidLeighEllis (talk) 03:56, 27 March 2014 (UTC)

---

Mobile phones on aircraft → Mobile phones on aircraft in the United States – this article deals mostly with the United States, so it would be better to move this article to explicitly state that fact, and split off the international coverage back to "Mobile phones on aircraft" after the move (keep edit history with the US article), with a summary of the US situation at the new general article. This would balance the coverage in the article properly, while giving the US full coverage without having an unbalanced situation. Also provides enough precision to identify that the article is US coverage. 70.50.151.11 (talk) 07:36, 19 March 2014 (UTC)

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's policy on article titles.

• Oppose I think it would be better to fix this article. And I doubt that such a split will magically make more contributions in the international arena appear, so the non-US article you propose will be quite scant for some time. Jeh (talk) 06:59, 20 March 2014 (UTC)
  • I would like the article "fixed" (i.e. its scope widened), too. However, the article has been around for nine years and it hasn't happened yet. Time have the title match the contents. —  AjaxSmack  01:40, 21 March 2014 (UTC)

• Support exactly what the nominator calls for (per WP:PRECISION) to accurately reflect the article's contents. —  AjaxSmack  01:40, 21 March 2014 (UTC)
• Oppose. I look forward to the expansion of the article to cover systems outside teh US. But it's silly to have an article on "Mobile phones in <countryname>". The techniques and issues are inherently trans-national. --Wtshymanski (talk) 18:04, 25 March 2014 (UTC)
• Oppose The only reason I can see for making such a move is impatience. --BDD (talk) 22:14, 26 March 2014 (UTC)

Discussion

Any additional comments:

• What should happen to the base title, then? There's WP:NODEADLINE on a potential expansion of the article's scope. --BDD (talk) 00:02, 25 March 2014 (UTC)
  • I mentioned what should happen in the nomination rationale. After the article is moved, we start developing from a stub. There is no deadline for improving the potential new stub either (should this get renamed). However if it is moved, it will no longer be greatly unbalanced, and thus counter systematic bias. Should we not fix bias, or just nodeadline things and never fix it because we are projecting that someone will expand something at some nodeadline future in lieu of fixing things is better than fixing things by renaming things in an expected future time that will definitely fix things and still allow nodeadline expansion to a neutral article? -- 70.50.151.11 (talk) 06:41, 25 March 2014 (UTC)

Will you or anyone else start work on that article right away? I hope we can all agree that Mobile phones on aircraft shouldn't redirect to Mobile phones on aircraft in the United States, nor would readers be well served to have the base title simply deleted. --BDD (talk) 22:13, 26 March 2014 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

I was going to since it was my nomination, and my rationale, but no point in doing so now, since this article has not been moved, so there's really no point in splitting the article in twain and making a new stub, when the name of this article remains "Mobile phones on aircraft" and contains the edit history for the US topic. So, this will remain a US-biased subject. -- 70.50.151.11 (talk) 04:47, 27 March 2014 (UTC)

Consider creating the article in Userspace and then resubmitting the move request. —  AjaxSmack  04:29, 29 March 2014 (UTC)

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Text messaging and hijacking

Does "mobile phone use" include text messaging? And is it (even technically) against the law to report a hijacking by cell phone, or to coordinate an anti-hijacking plan with these handy little devices? (I wonder if Todd Beamer knew he was breaking the law on 9/11.) --Uncle Ed (talk) 18:46, 28 January 2018 (UTC)

Airplane mode

This article never mentions airplane mode, which seems like a major omission considering that as far as I know every airline in the US (and many internationally) allows cellphones to be used in airplane mode. The article's policy descriptions seem to have been written before the smart phone era. Would somebody please find a source and fix the article? 73.138.3.167 (talk) 07:38, 22 January 2020 (UTC)

Airplane mode turns off the cell signal. Many airlines now allow one to turn on the WiFi signal above about 10,000 feet. I suspect that emergency use would get around any restrictions. Note, for example, that the restriction on cell phones and driving does not apply to the police for official use. Gah4 (talk) 09:45, 28 February 2020 (UTC)

Very confusing lead section, needs to be rewritten

Here is the current lead section:

In the U.S., Federal Communications Commission (FCC) regulations prohibit the use of mobile phones aboard aircraft in flight. Contrary to popular misconception, the Federal Aviation Administration (FAA) does not actually prohibit the use of personal electronic devices (including cell phones) on aircraft. Paragraph (b)(5) of 14 CFR 91.21 permits airlines to determine if devices can be used in flight, allowing use of "any other portable electronic device that the operator of the aircraft has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used."

Right now, the first part of the lead says the FCC bans phones on airplanes, then it says the FAA doesn't ban it, then it says the CFR bans it (not saying under what agency made this regulation). Not to mention it doesn't start out with a general worldwide overview of the topic, starting with the US then going to other regions after that.

It needs to be rewritten, with a starting sentence (with references) such as:

"Mobile phones on aircraft have been regulated since the early days of the mobile phone. Although originally banned on aircraft entirely due to concerns that phones would interfere with safe operation of aircraft, this has been shown to not be a significant risk. Although regulations in some regions have been relaxed, various technical and social factor make the issues more complex than a simple discussion of safety versus hazard." MarkiPoli (talk) 14:55, 12 April 2024 (UTC)