Does anyone know of any evidence that mobile phones actually present a significant problem to aeroplane communications systems? Or is it just a ploy to force people to spend $10 a minute on the phones in your seat? What is the difference between those phones and mobile phones anyway?
My brother has left his mobile and pager on by accident during a flight, to no ill effect. Incidentally he’s a pilot, and this was in the cockpit of a 737…
But he told me not to try it. Once I did leave my phone on by accident getting onto a plane, and it went off (people were still getting on, it hadn’t even started taxiing to the runway). Didn’t seem to do anything bad, but we weren’t in flight.
This has been a subject of frequent and sometimes very heated debate here. You can likely find more than enough info by Searching; unfortunately, the Board is not responding to me well at the moment so I cannot Search for you.
Rather than rehashing it, I will ask you all one question with respect to the “interferes with navigation” aspect of their bannings only, from which you can apply Occam’s Razor.
Given the incredibly heightened security and procedures in place after 9/11, if there was even a 1 in a billion chance of an aircraft’s avionics being disturbed by a cell phone or pager signal, do you think the FAA would allow them to be onboard? And why wouldn’t terrorists start carrying “dirty” cell phones designed to send out wide-band interference signals to cause planes to crash?
Simple - because there is no proven danger. At all. If there was, and the FAA still allowed them on board, you’d be seeing some 60 Minutes reports on it…
Quite simply, they are banned for other reasons. For the reason that they interfere with the cell phone system itself because they hop from cell to cell too fast, and (mainly, IMO) because the airlines want you to pay between $4 to $6 a minute to use the airphones.
I’ve heard basically the same as ** Anthracite** - no danger - just to insure the airphone will stay in business.
Here is a discussion on this topic that took place on our temporary board, Cell Phones on Airplanes.
But it has to be more than that. For one thing, you can use your cell phone up until they close the doors of the airplane.
For another, they don’t let you use electronics during climb-out and descent. It’s less plausible that a notebook computer would interfere with the plane’s systems than a cell phone, because the cell phone is intentionally transmitting much higher power levels. Why don’t they let you use electronics? It’s not like they have a competing for-pay system they want you to use.
No, they’re just being overly cautious.
Another thing I’ve heard is that the airphones are set on a specific frequency that will not interfere with the electronics.
Actually, I’m not certain cell phone usage is prohibited by the FAA. It is prohibited by the FCC. Here’s a cite:
The FCC regulates cell phone usage in aircraft because when you’re at altitude, your little cell phone can potentially be connecting/interfering with the hundreds of basestations. Also, because of the nature a basestation antenna’s 3-D coverage, you’d be constantly switched among those many basestations. A bad thing, both from the telecom’s point of view and your connection quality.
Can anyone find a cite for an FAA regulation?
This is my idea of the reason for banning the use of electronics. In the first place, not allowing any use on take-offs and landings is the same as placing your seat in an up-right position and trays up. They don’t want anything out that could go flying thru the air.
Once they are up and cruising, what items do the prohibit? Cell phones, radios and TV’s. Now there is no reason to ban radios and TV’s as far as the operation of the plane is concerned, because both are passive receivers. All they do is catch signals; so does the cell phone, but it also sends out a signal. I believe that is the problem. Not being an expert I can’t explain it, but when you are near the source of a transmission, there is a good chance of spill over onto another frequency. Airlines do not want you hearing what the pilot is saying to the tower, etc. so just as a precaution they ban devices that receive signals. The cell phones on the plane may be on a frequency that is unlikely to receive what the pilot says. They can’t check the frequencies of all the devices carried on the plane.
Uhh, I guess that all those airplanes that have a channel on the built-in headset that let you listen to the pilot’s radio communications must be a sham? Not too many people (other than me) would want to listen to “Delta 78 heavy, descend to four thousand, proceed to outer marker,” but some airplanes do have it available for us.
Sorry, simply not true.
Both are recievers, but the only truly passive ones I can think of are crystal recievers which do not have local oscillators.Perhaps the techies here might include t.r.f recievers but I digress.
Radios recieve a wide band of signals and the tuning is method of selecting exactly which part of that signal band will be allowed to pass to the decoding and amplification stages.
The key part of the selection process is to mix the incoming signal band with a signal derived from within the radio itself.
This mixture is then extracted by the use of various filters and further mixing with other signals from within the radio.(the Inermediate Frequency or I.F stages)
The result is that radios can and do produce significant retransmissions
TV’s in particular retransmit a lot of noise, and even the screen display itself(as distinct as the I.F stages and local oscillators) can be picked up and its signal content can be used to form the display signal for another monitor.
This is a serious consideration for banks, commodities traders and anyone who may display sensitive information on c.r.t displays.
In the UK we have a government department which is responsible for detecting the use of T.V sets where a licence to recieve is not registered at the address. The equipment can not only determine that a TV is being used, but it can display and record the retransissions from the errant owners TV set.
Computors can be extremely noisy because they operate digitally and this gives rise to a great many harmonics, some are better behaved than others.
Try this, get your AM radio and tune in to any station, then hold it next to your computor whilst it is running.
Now would you want that operating near to sensitive electronic equipment ? Especially when it might be intimately connected with your well being.
In many hospitals there are restricted areas on the use of moblie phones and laptops since certain measurements made on patients involve detecting very small electrical changes, try making a moblie phone call when you stand next to a CAT scaner whilst it’s in use ? I think you will be asked to leave.
These noisy retransmissions may have unpredictable power, and frequency and may resemble other signals in ways not foreseen.
I would expect critical systems to have a good built in immunity to stray transmissions but there have been a number of ghosting navigation beacons where no obvious explanation has come up, so it would seem that there is a great deal of the unknown to deal with, it would make sense to try to keep possible interferance to a minimum.
Aren’t those devices sometimes called Van Eyck (sp?) devices?
Of course from a practical real world standpoint, any attempt to ban or enforce a ban on cell phones on airplanes would be completely buried by the simple playing of some of the calls placed from the various 9/11 planes. I don’t recall where I read it, but shortly after the attacks I saw an article suggesting that cellular companies were probably going to start marketing their services from a safety perspective rather than the fun/convenience angle hey’ve been using. I’m kind of glad they haven’t yet, though…gnawing on the bones of the dead to cell airtime is pretty gross.