This question has probably come up before. I tried searching through the archives to no avail.
Why is it you can’t play a walkman or personal cd player during take-off or landing while flying? I can understand not being able to use a cell phone or beeper, something that receives a signal, but I honestly don’t understand why you can’t use anything that doesn’t rely on signals.
Does anyone know the reasoning behind this???
I suspect that the reason for this is that it it easier to enforce, from the arlines’ point of view. Some CD/tape players have radios and some do not. They don’t want to have to check each individual device, so they prohibit all of them.
I don’t know why they prohibit devices that only receive transmissions and do not send. It could be the same reasoning as above, i.e., when the crew walks down the aisle of the plane they only have to check for the presence of an electronic device, not whether is transmits or receives signals.
On a related note, I was flying home from Anchorage on Saturday and the guy in front of me in line was talking very loudly about how much fun it was to use his GPS during plane flights to determine his location and speed. :rolleyes: :smack:
Most electronic devices emit interference of some sort or another. These days just about everything has a little microcontroller inside of it. Digital signals are square waves, and square waves have harmonics that go out to infinite frequencies for a true square wave (although in practical circuits you don’t have that high of frequency harmonics and the waves aren’t quite square either). Even though your walkman isn’t designed as a transmitter, the tiny electrical circuits act as small antennas and the frequencies generated are high enough that they will be radiated out from the walkman. The danger is that this emitted energy will be picked up and misinterpreted by the plane’s control system, and all of a sudden it maybe does an uncommanded left rudder, and wheee doesn’t the excitement start then!
Takeoff and landing are the most critical times for an aircraft, which is why they are banned then. If you make the airplane burp at 35,000 feet, aside from making a few spilled cups of coffee and maybe some soiled underwear, it’s not quite as big of a deal. If you drop 1000 feet you’re still fine. If you drop 1000 feet while only 500 feet above the runway you’ve just buried the plane, which is generally thought to be not such a good thing.
Before you go into panic mode, keep in mind that aircraft electronics are specifically designed to be as immune as possible from outside electrical interference, and there has yet to be a documented case of something like a cell phone doing much more than making the plane lose radio contact with the tower (which is still a fairly bad thing). In some ways the airlines are playing a better safe than sorry game, but if they prevent that one in a million freaky thing caused by electronic interference that’s one less plane that ends up in a corn field.
None of the following is meant as an argument against prior posts, especially the one posted by engineer_comp_geek, but I’ve got an idea there are other reasons on top of those mentioned.
[ul][li]First any receiver could under the right/wrong circumstances pickup the transmissions of the pilots and this could cause problems.[/li]Concerning cell phones not being allowed even after laptops, etc are allowed, I’ve heard that the airlines want you to use those phones that are provided on the back of the seats. I personally wouldn’t mind if they barred cell from the airport, but then the pilots and flight attendants would not like that. :eek:[/ul]
I seem to remember a study published in an electronics magazine a while back (maybe 7-8 years) in which they measured the RF (radio frequency) interference from several types of devices. IIRC, cell phones were the worst, followed by laptops, then CD players and walkmans. I don’t think GPS’s were available at the time. Again, IIRC, the general conclusion was that the RFI from most of these devices was small enough not to interfere with a plane’s systems, but the airlines adopted a “better safe than sorry” policy anyway. In short, what e_c_g said.
Such as my aviation scanner? 
The Big Guy on radios and aircraft (written before widespread use of cellphones or the invention of the laptop).
From what I can remember (would that be FWICR?) the banning of cell phones at all stages of flight is more of an FCC issue than an FAA issue (in the U.S). This is because a cell phone at 35,000 feet will activate a whole ton of cell towers over a very large radius, causing interference and probably global chaos. 
Oh, and it is fun to use your GPS on an airplane!
I asked my sister this (former flight attendant, now a gate agent) question some time ago, and she told me that it is also a safety concern – if something happens midflight, there is some warning, so people will have time to get headphones off in order to hear instructions. But if something happens during takeoff or landing (the premiere times for incidents) it would be harder to ensure that everyone hears important safety announcements.
Not that it’d make much difference if you’re about to burst into a ball of flame, but hey, they gotta try!
As mentioned in a prior post, the “no cell phones” is an FCC issue and has to do with how many cell towers you’ll tie up when calling from 35,000 feet, which annoys the heck out of the cellphone companies. Those “cellphones” mounted in airplanes (and available for private sale for much money) do not have this effect. It’s not a safety issue of the cellphone screwing up the electronics in the plane (although that is a very remote possibility) and in a dire emergency they can and have been used.
As for the rest of the electronic toys people carry these days… in aviation, if it isn’t proved to be safe it’s assumed to be unsafe and is therefore usually forbidden. There are devices (handheld aviation transceivers, scanners, GPS units…) that are intended for use in an airplane and are presumably safe, yet you many still be asked to put them away. This has to do with airlines having control over what happens in the passenger cabins, and because a blanket ban makes for an easier and quicker routine for the staff who do not have to inspect each and every item but simply tell you “put it away”.
I’m not sure about the person who thinks that passengers listening in on the pilots might cause a problem. The pilots aren’t doing anything secret up there - heck, they’re being recorded by the CVR and any communications with air traffic control are also recorded in the tower. A number of airlines have an audio feed that let’s you listen to the cockpit conversation through the same headphones you use for the movie.
As also mentioned, the safety issue is very important. Not only would a walkman interfere with your hearing of verbal instructions, but such an item could be a dangrous item of flying debris in the event of a crash. If something goes wrong on take off or landing it will probably go wrong very very very very quickly. You may not have time to take off the headset and go “Huh? Whudja say? Could you repeat that?”. Now, if you don’t mind the idea of crawling around a smoke-filled airplane with a chunk of walkman embedded in your skull, having missed the one-time-only announcement of which way to go to get out just keep rockin’ to the latest CD.
Actually, you might consider the rules in a commercial airliner liberal compared to the ones I impose on my passengers in small planes. In my airplane, not only will your walkman/other device be turned off and stowed, you will also be required to sit still and keep quiet though take off, and again from about five miles out through landing and until we are off the runway. En route while in cruise you may listen to music, tell jokes, or even chairdance - I don’t care, have a good time. It all comes down to safety - take off and landing are very demanding phases of flight. I have had to abort both take offs and landings and have done so safely becuase I pay attention to what’s happening outside the cockpit. That’s much easier with minimal distractions inside the airplane.
This does crank my handle - folks, a lot of the rules in aviation are there because someone was seriously hurt or died in the past and are intended to keep Bad Things at a minimum. Even if it seems silly or senseless to you, please follow the rules - they really aren’t there to torture you but usually for your own safety.
IIRC, GPS units are only receivers, so what’s the problem with this?
GPS receivers are receivers just like an FM radio is. There is a small danger of the harmonic frequency interfering with the NAV equipment (engineer_comp_geek can give us more info on that).
Even small aircraft usually have two communication radios, one or two navigation radios, and a transponder. They may also have LORAN and/or GPS. Some even have stereos. Whenever new equipment is installed, detailed records must be kept and installation procedures must be followed. For example, a new radio may require some sort of RF shielding (IANA A&P, so I don’t know; just being hypothetical) so that it doesn’t interfere with other equipment. The weight of the radio and its station must be recorded onto the weight and balance document. The compass may have to be swung to note any errors caused by the new radio (or whatever) and deviations noted on the card in front of it.
So randomly introducing radio receivers and/or other RF-generating devices into an aircraft may (or may not) affect the installed systems.
And just for the record, it’s the FCC that governs cell phone use; not the airline or the FAA.
Yeah, Im with the answer that they need you to be able to hear any annoucements, even though I
can’t, being deaf. One time on a plane they communicated to me on a napkin.
On the other hand, they made me turn off my GBA.
The phones on the back of the seats now have stickers that say the service was discontinued 3-31-02. At least on all the flights I have been on this year (about 10, various airlines, various domestic U.S. destinations).
[slight hijack]Actually, I was on a United Flight a few months ago (O’Hare to Toronto, if it matters) and one of the channels provided by the closed circuit audio system was the cocpit chatter. They madea big deal about telling us all it was available, so i checked it out. It was a cool mix of really facinating (in theory) and really boring (in actuality), i started listening to it as soon as i sat down, and it put me to sleep shortly after takeoff. Slept for the whole flight.
but it is kind of a cool idea, and it had its moments. I remember that it seemed- from what i was hearing- that taxiing and getting to ones asssigned gate amongst all the commotion and ground traffic was the by far most stressfull, confusing part of the whole flight.
[/slight hijack]
CJ
I should clarify the previous. it actually wan’t “cocpit chatter”, but rather Cocpit Radio Chatter.