Why do we shut off electronics during takeoff?

Every holiday season, as air travel picks up, people start wondering why, exactly, they need to switch off their electronic devices during takeoff and landing. And, weirdly enough, no one ever seems to have an entirely satisfying answer.

Over at Scientific American, Larry Greenmeir tries to sift through the most plausible theories and boils it down to this:Some electronic devices could theoretically interfere with aircraft equipment; it’s not always clear which gadgets are likely to offend; and it’s easier to diagnose any possible interference when the plane is at cruising altitude rather than during takeoff and landing. So it’s simpler to just ask passengers to turn all devices off, even those, like the Kindle, that barely draw a charge while in use. That’s the conventional explanation, at least. But not everyone’s buying it.

The Atlantic’s James Fallows has been running an entertaining series of posts on this topic all month, eliciting feedback from pilots and people inside the industry (here’s a good starter post). The various theories are often surprising. Many of his correspondents doubt that modern aircraft equipment is so fragile. Some emphasize the fear that handheld electronic devices could turn into dangerous projectiles during takeoff. Others think the rules are mainly about making sure passengers are attentive during key flight phases (of course, that concern doesn’t seem to extend to people reading old-fashioned books and magazines). Still others suspect cellphone use is banned from planes less for technical reasons and more to prevent loud talkers from driving other passengers into a frothing rage.

And some commentators suspect that the rules are all a petty form of social control. Here’stech columnist Kevin Kelly grumbling about the time he had to turn off his (likely harmless) camera: “I immediately asked a United pilot what I can do if a flight attendant makes an unreasonable request? His answer was that it was in my best interest to obey, no matter what. That means that the usage policy is dictated by the most unreasonable party. I take this absurd request as another example of a policy that has gotten out of hand because it is not based on evidence.”

So there you have it. An explanation. Sort of.