Airplane mode has been a feature on smartphones for more than two decades. Since 2003, as phones became an inseparable part of daily life, the setting has become something we reach for every time we board a plane.
In the past, passengers had to switch their phones off completely during a flight. With airplane mode, though, we can keep using the device to listen to music, watch movies, or play games, without the phone actively searching for a cellular network.
But can a phone actually bring down a plane? The answer to that myth is no. The real reason passengers are asked to enable flight mode has to do with possible interference with the aircraft’s communication systems.
For the pilot’s sake
Studies by the UK Civil Aviation Authority (UK CAA) have shown that emissions from mobile devices can interfere with pilots’ headsets, making it harder for them to communicate clearly with air traffic control.
Specifically, mobile phones emit radio waves and, when not in airplane mode, are constantly searching for an available cellular signal.
On a plane flying at around 30,000 feet or higher, that search becomes harder. Cell towers are designed mainly to cover ground-level areas, not aircraft moving at high speed at high altitude.
When a phone struggles to find a signal, it can boost its transmission power in an attempt to connect to an available tower. At the same time, it keeps sending and receiving short radio bursts as it searches for and tries to maintain a connection.
This constant effort to connect can, under certain conditions, create interference.
How the sound reaches the cockpit
Radio waves from a mobile device can affect wiring and electronic systems, especially when the phone is near the cockpit or the aircraft’s cabling.
Pilot headset cables, sound amplification systems, and wiring can act as “receivers” for this kind of interference.
In some cases, the cockpit’s audio equipment can turn that interference into an annoying sound, described as a hum, a screech, or a distinctive “beep.”
The result is that it becomes harder for the crew to communicate clearly with air traffic control. This matters even more during critical phases of flight, like takeoff and landing, when communication needs to be as clear as possible.
What airplane mode actually does
That’s why airplane mode was created: it turns off the phone’s wireless transmissions, reducing the chance of interference and making things easier for both pilots and air traffic controllers.
