It’s a safety measure we’ve all become accustomed to in recent years – switching our phones to ‘airplane mode’ before take off and leaving them offline until after landing.
But not everyone knows why airlines ask us to do it.
In a TikTok video, flight attendant Cierra Mistt broke down the flight mode rule and why it’s in place, saying: “The reason may actually shock you and make you think twice about trying to sneak and keep your phone on normal mode.”
Mistt explains: “From the moment the boarding door closes to the moment of landing the pilots are following specific instructions given to them from a group of people on the ground called Air Traffic Control, or ATC, whose job is to make sure that planes take off and land safely without running into each other.”
In the viral video, Mistt claims that mobile phone frequencies could potentially get in the way of conversations between the pilots and the ATC workers on the ground.
She explained: “In order for the pilots to be able to communicate with ATC, they use frequencies which is what we use on our phones.”
“Now picture how bad it would be for a pilot who is taking directions from ATC on the ground, all of a sudden loses signal and starts flying blindly all because of the frequency of a passenger’s phone which interjected it.”
However, not everyone agrees with this reasoning.
“It’s never been proven that a mobile phone signal has interfered with the navigation performance of the aircraft. But just because it’s never happened doesn’t mean it will never happen,” one pilot told Business Insider in 2017.
Commenting on Mistt’s TikTok video, one electrical engineer said that the real reason for flight mode was “unintended radio waves emitted by phones and other devices” or “intended radio waves being inadvertently picked up by the pilot’s equipment”.
Suggesting that “our devices don’t emit or accept unintended waves as much” the engineer questioned whether flight mode was still “absolutely necessary”, but added: “Out of caution, do it.”
In 2013, the US’s Federal Aviation Administration determined that it was safe for passengers to use electronic devices during takeoff and landing, as long as the aircraft is equipped with proper interference technology.
But the FAA stipulated that mobile phones must be set to airplane mode.
Flight staff have reported in the past that it is just as much a matter for passenger safety as flight technology, with the risk of phones flying through the cabin during extreme turbulence, and distracting passengers when safety instructions are being given or an evacuation is indicated.