Airplane pilots always have to give that little speech about turning off electronic devices, and I want to know exactly why. My guess is that they might interfere with communications between the airport and airplane. How much distortion can these devices realistically cause though? I can see a cell phone maybe being a problem because it actually receives and transmits information, but what about iPods or laptops? And, assuming cell phones operate on an entirely different frequency band than airplane radios, do they pose any real problem?
A guess only:
I feel that the majority of people in this country are not smart enough to realize that certain devices can cause communication interference, whereas others (your iPod presumably) really wouldn’t. IMHO, if we need to tell everyone to turn off ALL portable electronic devices to avoid having to list the really interfering ones (and therfore cause the usual confusion ‘but you didn’t say ‘Blackberries’!’), and it makes air travel safer, then by all means.
Then again, I’m known as ‘Last of the White Knucklers’.
I seen to remember that the rule came into effect shortly after a crash was blamed in part on a laptop being turned on during either takeoff or landing. We all know that electronic devices interfere with other electronic devices in the vicinity (at least we do if we ever tried to watch TV while our mom vacuumed). I wouldn’t be surprised if in extreme circumstances, even small devices can cause enough interference to just the wrong sensor at just the wrong time.
–Cliffy
I have a friend who is a pilot for American Airlines and when I asked him he said it was because someone using a cell phone, or an IPOD, or watching a portable DVD might not be paying attention if something goes wrong during takeoff or landing.
That’s the most likely time for something bad to happen so the crew wants the passengers to be paying attention to them in an emergency… and not a Beavis and Butthead movie they might be watching instead…
BTW, a cell phone at the back of the plane isn’t going to interfere with the cockpit’s instruments.
Cite?
pretty much what BlueLine said; an all-or-nothing policy is less confusing and easier to implement than one that actually addresses just the potentially troublesome devices - The crew can’t be expected to know the properties of every device on the market; an ipod might be OK, a PDA might be OK, but what about a PDA with WiFi?, AND If you let someone use one device, there will be someone who wants to use another and so on, until you’ve got people who aren’t really paying attention thinking it’s just fine if they only turn their cellphone on for thirty seconds to check their text messages… etc…
Easier just to say no and be done with it.
Mebbe. On the other hand, the instruments in the cockpit are connected to sensors scattered everywhere throughout the craft.
RF/EMI is a tricky thing. If’n ya don’t believe me, take a gander at MIL-STD-461. It’s a cast iron bitch to shield some devices; those designed to broadcast, or having an antenna, being the worst.
Here’s a “brief” description of what MIL-STD-461 tries to accomplish as it applies to consumer goods.
http://www.amrel.com/ASL_whitepaper.html
Enjoy!
Here’s a small item from the FAA about portable electronic devices and the possible problems they may cause.
I used to drive to work along Qantas Drive, which runs along the perimeter fence at Sydney airport, and the aircraft were so low it felt like their wheels were going to hit the roof of the car, and at night I’d take General Holmes Drive which actually goes under the other end of the same runway (and a taxiway) in a tunnel. Now between us, my fellow motorists, their passengers, and I would have all manner of cellphones, laptops, DVD players, taxi radios, police radios, scanners, iPods, and CD players. And we are probably not much further away from the cockpit than the guy in seat 56B. There are no road signs telling us to refrain from using electronics.
Realistically, an iPod is exceedingly unlikely to cause any disruption to a plane. Since it’s got an electrical circuit, it does leak some signals that could theoretically interfere with something, but it’s pretty minor.
Even cell phones or other wireless devices are unlikely to be an issue. Of course they test the planes with laptops and cell phones in them, because someone’s not going to pay attention.
I’m convinced that the real reason they tell you to turn off and put away electrical devices is that, in the event of some unrelated problem on takeoff or landing, they really don’t want dozens of small, hard, dense objects becoming projectiles. By that reasoning, they should also tell people to put books away, but there’s a tradeoff to be made in favor of having calmly distracted passengers.
As other’s have said, it’s a blanket policy to avoid saying “this one is ok, that one is not, etc.” Here’s is the applicable reg, 14 CFR §125.204
That’s where they get that announcement from. As to why… the FAA goes with the “it’s better safe than sorry” policy. However, they are beginning to change their view of cell phones. The FAA is in the process of certifying onboard cell stations that would allow passengers to use their phones enroute. The following quote is from this article.
I forgot to add… I have used cell phones inflight on numerous occasions (in small airplanes). Each time I was sitting at the controls, so I don’t know how much closer I could have been to the instruments. I was flying by visual reference, so it was legal, but I didn’t notice anything happen with the nav or comm radios or any other instruments.
On a transatlantic flight I was on a couple of months ago I asked a flight attendant if I could use my portable dvd player and was told “of course.”
The Powers That Be can’t be too worried about cell interference on airplanes as there are plans afoot to add cell sites to aircraft so that phones can be used during the entire flight.
They let people use MP3 players, laptops, and such during flight. It’s just during takeoff and landing that they ask you to switch everything off. Cell phones have to stay off all the time, though.
At least that’s what the announcements are when I fly USAirways, which I’ve done maybe 10 times in the past year.
I read an article about this in IEEE Spectrum about ten years ago. It described some incidents in which portable consumer electronics did affect airliner avionics. The article was called “Do Portable Electronics Endanger Flight? The Evidence Mounts,” and it was in the September 1996 issue. Unfortunately I no longer subscribe, so I can’t read it now, but you might look it up if you’re interested in the subject.