Cell Phones on Airplanes

Cell phones are perfectly safe on airplanes. So why can't we use them?

by Brian Dunning

Filed under General Science, Urban Legends

Skeptoid #14
December 15, 2006
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Today we're going to fly up to 40,000 feet, flip open our cell phone, and call the Twilight Zone to tell them we're doing something that's supposed to be deadly dangerous.

I love Mythbusters and it's my whole family's favorite show, but with their episode on the cell phone ban aboard aircraft, they did a disservice to those of us who hope to get this groundless ban dropped. In case you missed it, they did a test and concluded that cell phones can potentially interfere with an aircraft's navigation system. The only instrument they tested was a radio direction finder called a VOR, which detects a radio beam coming from a ground station and points its direction. In practice, VOR is on its way out, in favor of GPS. VOR stations are each assigned a unique frequency in the VHF range between 108 MHz and 117.95 MHz, which is right above the FM radio frequency range. By contrast, the lowest frequency used by any US mobile telephones is 700 MHz; and in European mobile telephones, 450 MHz. Since the frequencies are so incredibly different, the whole debate is ended right there, for all practical purposes. Mythbusters used an older VOR receiver that could be tuned to receive a much broader range of frequencies, which is why they were able to detect the mobile phone signal. To be more responsible, they should have admitted that this frequency was wildly different than what any aircraft might possibly tune to. As it was, they left viewers with an inaccurate, and alarmist, impression. Mythbusters called the myth "plausible". No, it's really not plausible; a cell phone cannot affect an aircraft's navigation instruments in the real world, and we'll have more on that in a moment. Maybe if you threw a cell phone really hard at the GPS, you could break something.

So this raises an obvious question: why aren't cell phone calls allowed on airplanes, if there's no harm in it? The real reason has nothing to do with the FAA; it comes from the FCC, the Federal Communications Commission. It has nothing whatsoever to do with safety or security. When you're seven or eight miles up in the air, your phone can hit any of hundreds of cell towers, and there is supposition that this could cause a problem. As we know from 9/11, cell phones work fine from the air, but nevertheless the FCC has enacted a law making it illegal to operate a cell phone in a commercial plane that's not touching the ground. I've used mine from general aviation aircraft on a number of occasions and never had a problem either. A non-profit called RTCA is the Federal Advisory Committee for the FAA, and their report finding that cell phones pose no risk to aircraft safety is detailed in their report DO-235A, Assessment of Radio Frequency Interference Relevant to the GNSS. The only law that the FAA has is in support of the FCC law.

Boeing and Airbus routinely bombard their aircraft to harden them against every conceivable type of attack, physical and electronic, certainly including cell phone signals. If cell phones had the potential to endanger an aircraft, you'd be allowed to bring them on board in the same way as you bring dynamite on board. Meaning, not at all.

All other devices that you're not allowed to use during takeoff and landing (PDA's, video games, iPods, laptops), are not restricted by either the FAA or the FCC. You'll find the authority for this in RTCA document DO-233, Portable Electronic Devices Carried on Board Aircraft. These rules are arbitrary and are invented by the airlines, without any legal authority. It is their plane and they're within their rights to make whatever rules they want, but travelers should know that there are no laws against using these devices at any time, and that the research has been conducted and the devices have been demonstrated to be safe. Feel free to put this on the comment card next time you fly.

When you listen to the flight attendants explain the rules, it's clear that their training includes a simple mention that portable electronics and cell phones represent a danger. The trainers probably believe it and the flight attendants have no reason to question what they've been told. If you've ever wondered how your 1.5 volt LCD Palm Pilot could be so dangerous, you were on the right track. When you hear something that sounds far fetched, be skeptical.

So what's the deal? Are Men in Black secretly going from airline boardroom to boardroom, handing out corporate welfare payments in exchange for the promise to support the government's evil plan to convince us all that we're on the brink of destruction? Are there paranoid, over-cautious, or ignorant policymakers in charge at all the airlines? Personally both of those are a little too conspiracy theory for my taste, but I also think there might be a small element of truth in each.

Take the example of the terrorist train bombing in Madrid in March of 2004. The bombs were set off by cell phone calls, since cell phones are easy to get and are reliable. One reaction, which thankfully has not been put in place so far that I've seen, was the immediate proposal to jam cell phone signals anywhere that was bombable. Airports, national monuments, stadiums, train stations. Was this a logical reaction? No. If the bombers couldn't have used cell phones they would have used walkie talkies from Radio Shack. If they couldn't have used those they would have used mechanical wind-up clocks attached to detonators. If they couldn't have used those, they would have used slow burning fuses. There are a million ways to set off a bomb and no law can prevent it from happening. Any reasonable person understands this. Unfortunately, our politically correct, alarmist, liability hysterical culture demands that government do something. The culture doesn't know or care whether it's logical, or makes any difference. Our culture sleeps better knowing that Big Brother is babysitting. Satisfy the public's emotions, and you have a happy population. I guarantee you that Osama bin Laden is not rending his garments in despair over all his plans being ruined, now that Americans aren't allowed to bring a bottle of water on board a plane. It's a useless and inconvenient law, but it shows that government cares, and our culture is willing to be walked all over and curtailed in any way necessary to feel protected.

I think the cell phone ban on airplanes is just another example of this. Big Brother has cultivated and nourished a supposed danger, and leveraged it into another opportunity to babysit. Now I promise you that I'm not a conspiracy theorist, and I'm not some paranoid anti-government guy who thinks the government is out to get us. But I can't think of a better explanation for the absurd inflight cell phone ban, than the one I've just given. If you can, I welcome your comments on the web site.

Tip Skeptoid $2/mo $5/mo $10/mo One time

Brian Dunning

© 2006 Skeptoid Media, Inc. Copyright information

References & Further Reading

Elgan, Mike. "Why cell phones are still grounded." Computerworld.com. Computer World, 6 Apr. 2007. Web. 14 Dec. 2009. <http://www.computerworld.com/s/article/9015839/Why_cell_phones_are_still_grounded?taxonomyId=15&pageNumber=1>

Ely, J.J., Nguyen, T.X., Koppen, S.V., Salud, M.T. "Electromagnetic interference assessment of CDMA and GSM wireless phones to aircraft navigation radios." Proceedings of the 21st Digital Avionics Systems Conference. 10 Dec. 2002, Volume 2: 13E4-1- 13E4-13.

Heussner, K. "Why Can't We Use Cell Phones On Planes?" abcnews.go. ABC News Internet Ventures, 9 Feb. 2009. Web. 15 Nov. 2010. <http://abcnews.go.com/Technology/AheadoftheCurve/story?id=6833039&page=1>

Koski, O. "Why Can't You Use Cell Phones on Airplanes?" Scienceline. NYU Journalism, 8 Feb. 2010. Web. 15 Nov. 2010. <http://www.scienceline.org/2010/02/why-cant-you-use-cell-phones-on-airplanes/>

RTCA Committee SC-159. Assessment of Radio Frequency Interference Relevant to the GNSS L1 Frequency Band (DO-235B). Washington: RTCA, Inc., 2008.

RTCA Committee SC-177. Portable Electronic Devices Carried on Board Aircraft (DO-233). Washington: RTCA, Inc., 1996.

Thomas, Cyndi. "FCC TERMINATES PROCEEDING ON THE USE OF CELLULAR PHONES ONBOARD AIRCRAFT." FCC News. FCC.gov, 3 Apr. 2007. Web. 14 Dec. 2009. <http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-272051A1.pdf>

Reference this article:
Dunning, B. "Cell Phones on Airplanes." Skeptoid Podcast. Skeptoid Media, Inc., 15 Dec 2006. Web. 25 Oct 2014. <http://skeptoid.com/episodes/4014>

Discuss!

10 most recent comments | Show all 135 comments

I lived in Spain for a while. Spain (like the rest of Europe) has an excellent train system and it's very convenient to travel by train. But it seems like half the passengers will be talking on their cell phones at any one time and it is a colossal pain, especially since most people shout when talking on the phone, or at least raise their voice considerably.

A plane full of yahoos shouting into their phones when I'm trying to sleep? NO NO NO NO NO!!!!!

As for laptop computers during takeoff and landing, I think there is a genuine, if small, safety issue, as in the event of a crash, anything heavy not properly stowed away would become a projectile. Is it really that big a deal to wait ten minutes after take-off before booting up your computer, or stowing it away a few minutes before landing?

I just wish the government would pass a law against those interminable advertisements for credit cards, in-flight-shopping, etc., over the P.A. system, which also make it impossible to sleep or even listen to music.

Daniel, Spokane, WA
March 4, 2013 10:57am

"I just wish the government would pass a law against those interminable advertisements for credit cards, in-flight-shopping, etc., over the P.A. "

So you're saying they should outlaw a business's right to advertise their business inside their privately owned space? That's, well, sort crazy.

Another Nick, Alexandria VA
March 4, 2013 2:25pm

AFAIK, there are indeed some good reasons not to allow cellphones in airplanes, and they may no have much to do with security, but are rather the same, why they aren't allowed in hospitals, libraries, lecture rooms or any other place, where human beings are jammed together for a certain time without the possibility to simply stand up and walk away... telling people it has security reasons, however, spares you a lot of discussion, since everyone is willing to accept this - if you talk in terms of "stress", "politeness" or whatever, there will always be the one customer, who starts a discussion about why he needs to be the exception from the rule etc. blabla... Telling people that the plane might hit the next mountain because of you using your cellphone makes a very quick end to that, no matter if it's true or not.

Plus: This general ban of certain (harmless and non-vital) devices has also a psychological effect - it is random, but does no harm to anyone, and is therefore - so I was told once by a former flight attendant - perfect for testing/ensuring the passengers' willingness to obey the orders of the flight personel, which might turn out vital in a crisis.
So there are in fact some good reasons for this ban, even if they don't have much to do with airplane security!

Markus, Neuss / Germany
April 26, 2013 1:13am

"The real reason has nothing to do with the FAA; " and "All other devices that you're not allowed to use during takeoff and landing (PDA's, video games, iPods, laptops), are not restricted by either the FAA or the FCC." and "These rules are arbitrary and are invented by the airlines, without any legal authority."

Once again, Brian you're running your yap about a subject on which you just don't have the knowledge to comment intelligently. I would direct your attention to Part 121 Federal Aviation regulations, which are the operating regulations for Airlines in the US. Specifically, 121. 306, which reads in part:

"Portable electronic devices.

(a) Except as provided in paragraph (b) of this section, no person may operate, nor may any operator or pilot in command of an aircraft allow the operation of, any portable electronic device on any U.S.-registered civil aircraft operating under this part. "

There is more, including some exemptions, but that's the essence of it, and it does apply to cell phones.

As far as the interference issue; I am a airline pilot, and I can assure you with 100% certainty that cell phones *do* cause interference with the VHF communications systems. It's a very distinctive sound. I've heard it many times. Another poster described it as a "galloping" sound, which is descriptive, it's a little bit bit like a monotone William Tell Overture.

Andrew, Anchorage
May 26, 2013 10:58pm

Is it possible that the Doppler Effect changes the cell phone frequency so much that it interferes with tower control communications (for instance)?

Douglas, Brazil
October 30, 2013 5:41am

Brian, you have a point of view, not facts. I've spoken with pilots who have said that they have been able to tell when someone was using a cell phone on the plane based on the response of their instrumentation. It's not a frivolous precaution; at least it has not been in the past. You are a computer guy who is a proponent of unlimited wireless--just admit it, and stop putting yourself out as some kind of expert on its bioeffects.

For those who want to get a less industry-influenced view, check out this roundtable for skeptics. My guess is that it will be broadcast or archived on the Commonwealth Club's website after it occurs.
http://www.commonwealthclub.org/events/2013-12-09/expert-roundtable-skeptical-about-cell-phones-and-health

M Glaser, Chicago
November 12, 2013 10:16am

Brian,

Having re-visited this again recently, I have some points against the arguments you make :-

1. Any receiver of radio frequency can be overloaded by a close proximity radio transmitter even thought thy may be operating on different frequencies. This may manifest itself as a decrease in receiver sensitivity to weak signals up to total receiver signal loss.

2. After reading about the amazing safe landing of a Qantas Airbus A380 after the catastrophic failure of one of its engines, I sought out the ATSB incident report http://www.atsb.gov.au/publications/investigation_reports/2010/aair/ao-2010-089.aspx
Section 1.12 Survival Aspects and 1.12.1 Portable electronic devices goes into detail the issues with passengers using electronic devices. To quote one telling point - "During an emergency situation, crew members provide instructions to passengers regarding their safety....It is important for the safety of all passengers that these instructions are listened to and understood. Human attentional resources are a single-channel, filtered and limited resource and PEDs have been shown in numerous research studies to have a significant distracting effect. In an emergency situation, such as an evacuation, actions need to be carried out quickly and there can be insufficient time for crew to be repeating information to passengers distracted by their PEDs."

Astro, Gosford NSW Aust
December 18, 2013 5:43am

What I notice is that most of the comments here assume a perfectly serviceable aircraft. Unfortunately, aircraft often aren't perfectly serviceable.

The trick about Radio Frequency emissions is you can't see them like you can a failed engine. The failure can be much more insidious with only minor interference causing undesired effects. One tool/process used by safety engineers is Failure Mode, Effects and Criticality Analysis (FMECA). When the FMECA is conducted, electromagnetic interference (EMI) is taken into account and potential combined effects of EMI on failure chains are calculated. Despite using Mil-Spec connectors and shielded boxes, if any connector on one of the double shielded cables vibrates its back-shell loose, it will no longer be properly grounded/bonded and will be susceptible to EMI. That ridiculously expensive double shielded cable essentially turns into an RF antenna with a lot of spurious loss. (You can verify this with a spectrum analyzer) When the bond is lost, unpredictable things happen. Maybe the failed connector isn't catastrophic on it's own, but it could (however unlikely) be part of a longer larger failure chain. There are many redundant systems and factors of safety built into all flight platforms since safety is all about probability: keep risk as low as reasonably possible. Turning random emitters off during take-off and landing is just one more minor safety precaution to reduce the potential combined effects of EMI.

Jag, Calgary
April 27, 2014 3:35am

You are pretty well spot on in my estimation Brian, although I have heard some interference through the radios on a flight once or twice. But that was a long time ago and I'd imagine the phones should be better now, and shielding on aircraft should be better as well. In fact, one airline I worked for gave us a mobile that we could use to contact them with using the CDMA network, in outback NSW. As for the other comments about passenger discipline in the event of an emergency, I'd suggest that you'd have everyone's complete attention if there was a fair dinkum emergency, so I don't agree. On that QANTAS landing, the cabin crew demanded no-one take their luggage with them - the reason - because they were worried that someone might trip while walking down the stairs with their bag. The stairs that they were forced to wait for before deplaning because they decided it would be safer than using the emergency slides, and so it goes. Instead of enlisting the help of the passengers, they treat them like fools who can't walk down a set of stairs safely. Any wonder why they have introduced Loyalty Programs? Treat pax badly, then throw a few worthless frequent flyer points at them to shut them up. Cabin crew have forgotten their primary purpose is service, not safety. I've never heard of an airline passenger dying because someone left their tray table down.
BTW, I've also heard that the mobile phone companies can't bill you if you are transmitting via numerous stations.

Peter Callil, Brisbane Australia
May 12, 2014 3:54am

I don't think that a properly funktioning cellphone can meaningfully interfere with systems of an aircraft.
But there is a problem.

1. cellphones (in standby) periodically check the connection quality to the tower
2. if it gets low and there is a stronger tower it will switch to that

now imagine 500 cellphones switching from tower to tower every few seconds

i can see how this might "clog" the cell network
I don't know how stong these effects are but I think they would need significantly more cell-towers around airports if cellphones were allowed

although i see no problems with devices in "airplane mode"

Clemens Richter, Germany
August 29, 2014 2:00pm

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