飞机上到底能不能使用电子设备？

Love it or hate it, flying is necessary if we want to get to a faraway destination. For those of us who love to read e-books or listen to music on our phone to pass the time, however, taking a flight in China can be a boring experience.

不论你喜欢与否，想要到一个遥远的地方去，搭乘飞机就成了必要的选择。然而，对于我们之中喜欢在手机上看电子书或者听音乐的人而言，在中国坐飞机是场很无聊的体验。

This is because Chinese airlines didn’t allow smartphones to be powered on during flights, even in flight mode. However, since Oct 1, airlines are now allowed to lift the ban if they wish.

这是因为中国的航空公司不允许乘客在飞行期间打开手机，甚至连飞行模式也不行。但从今年10月1日开始，航空公司可以自行选择取消这项禁令。

The reason behind the ban is something called electromagnetic interference. This is when electrical signals mess with other electronic equipment, causing them to react in unusual ways.

这项禁令背后的原因在于一种名为电磁干扰的现象。当电子信号遇上其他电子设备时，会产生一些不寻常的反应。

And according to a study by plane manufacturer Boeing in 2014 published by CNN, electromagnetic interference can sometimes cause flight equipment to react, too.

根据CNN2014年发布的一份飞机制造商波音公司的研究显示，电磁干扰有时也会对飞行设备产生影响。

During the study, Kenny Kirchoff, a Boeing engineer, measured the radio signals sent out by a laptop’s Wi-Fi radio.

在研究中，波音公司工程师肯尼·基尔霍夫测量了一台笔记本电脑的无线上网功能所发出的无线电信号。

“You can see that some of the signals from the laptop actually jump over the limit,”Kirchoff told CNN at the time.

“你可以发现，笔记本电脑的一些信号事实上已经超出了界限，”基尔霍夫当时在接受CNN采访时表示。

“So that means there’s a potential that this piece of equipment could interfere with [plane instruments].”

“所以这意味着，这台设备很有可能会干扰(飞机上的仪器)。”

This issue is worse with mobile phones, which constantly send and receive strong signals while they search for a connection to the network. Even in flight mode, many phones still do this.

这个问题在手机上表现得更为严重：当手机在搜索网络连接时，会不断发出并接收强信号。就算使用了飞行模式，不少手机也是如此。

Despite this, there were just 29 cases of electromagnetic interference caused by mobile phones reported worldwide between 2003 and 2009, according to CNN.

据CNN报道，尽管如此，在2003-2009年间，全球范围内记录的由手机引起的电磁干扰现象只有29例。

Besides, the instruments in modern planes are protected from electromagnetic interference by metal “shields”.

此外，现代飞机上的仪器都被“金钟罩”保护着，不受电磁干扰。

You’ve probably already seen this technology if you’ve ever seen the inside of a TV cable.

如果你曾看过电视电缆的内部结构的话，大概就已经见识过这一技术了。

Covering the main wire in the center are often two or three layers of metal that protect the TV signal from outside interference caused by other devices.

中间的主接线之外通常还包裹着两三层金属，保护电视信号不受其他设备的外来干扰。

Similarly, the metal box design of microwave ovens keeps the interference they create from escaping.

同理，微波炉金属盒子的外形设计也锁住了其自身产生的电磁干扰。

Many Chinese airlines are now expected to allow passengers to use their smartphones freely, meaning that we can finally catch up on our favorite books and songs while at 30,000 feet in the air.

国内的许多航空公司如今都希望能够允许乘客随意使用智能手机，这意味着，我们终于能在30000英尺的高空中看书和听歌了。