Why you sometimes have to put your phone on airplane mode – and what happens if you don’t

Keep your phone in check

Those other rules are fairly straightforward when it comes to preparing for an emergency, but airplane mode can feel like a slightly pointless inconvenience when all you want to do is keep using your phone.

So why is it actually required, and what happens if you forget?

Airplane mode isn’t as pointless as you think

It mainly comes down to preventing possible interference. Phones, tablets, laptops and other wireless devices send out radio signals, which can potentially interfere with aircraft communications and navigation equipment.

There is also a separate issue that dates back to the early days of mobile phones. 

When a phone remains connected during a flight, it constantly searches for mobile towers, particularly during take-off and landing when it may try to connect to several towers at once. This can place additional strain on ground networks.

While the precise impact phones have on aircraft technology has not been extensively studied, pilots have reported hearing background noise and interference through their headsets, particularly as aircraft descend and phones begin reconnecting to mobile networks.

Better safe than sorry

Leaving your phone connected will also mean it continues hunting for a signal throughout the flight, which can use up your battery much faster. 

That does not mean forgetting airplane mode will send the plane plummeting out of the sky, but the rule is there as a precaution. 

By limiting potential radio interference, airlines can keep communication between the cockpit and ground control as clear and reliable as possible.