A pilot has revealed what really happens if you fail to put your phone in airplane mode after boarding a flight.

We all know how important it is to turn on airplane mode before the aircraft sets off – and if we did happen to forget, there are usually plenty of warnings from flight attendants.

What does airplane mode actually do?

Well, it basically stops your device connecting to a network, meaning you can’t make or receive phone calls or texts, or use the internet, either.

It’s an important safety feature because it stops the radio waves that are emitted from devices from affecting the aircraft’s navigation and radar equipment.

According to Allianz Travel Insurance, it can also interfere with pilots’ headsets.

In the US, it’s actually the law to turn your phone onto airplane mode while flying, with regulations explaining: “Cellular telephones installed in or carried aboard airplanes, balloons, or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground). When any aircraft leaves the ground, all cellular telephones on board that aircraft must be turned off.”

So how important is it?

One pilot and TikToker, @PerchPoint, has spoken about what happens if you forget to put your phone on airplane mode.

In a video, he said: “If you forget to put your phone on airplane mode, no, it’s not the end of the world, the plane will not fall out of the sky and it won’t even mess with the systems on board.”

That certainly doesn’t mean you shouldn’t turn it on, however, with the pilot adding: “If you have an aircraft with 70, 80, 150 people on board, and even three or four people’s phones start to try to make a connection to a radio tower for an incoming phone call, it sends out radio waves,” he added.

“There’s the potential that those radio waves can interfere with the radio waves of the headset that the pilots are using.”

The pilot went on to recall one particular experience in which he could barely hear the messages in his headset due to interference.

“It kinda sounded like a mosquito in my ear,” he explained.

“Like I said, it’s definitely not the end of the world but it’s pretty annoying when you’re trying to copy down instructions and it sounds like there’s a wasp or something flying around.

“So if you’re ever curious why you’ve got to put on airplane mode, that’s why.”