Summary

  • Airplane mode prevents interference with aircraft communication devices and radio altimeters, ensuring clear communications for pilots.
  • The switch to 5G raises concerns about interference from ground antennas, but airlines are rolling out radio altimeters that are protected.
  • Forgetting to turn on airplane mode is unlikely to cause a crash, but it’s best to comply with flight regulations for safety.

Have you ever wondered why flight attendants instruct passengers to put their devices in airplane mode before departure? This is true for all smartphones, tablets, and laptops – but how would a small electronic device hinder aircraft systems?

In the early days of smartphones and smart devices, these had to be completely switched off during the entire flight time. It was much later that modern devices came with the option of the “airplane mode”, which airlines will ask passengers to turn on before takeoff.

phone on aircraft

Photo: Jaromir Chalabala | Shutterstock

There is definitely some confusion among travelers about why exactly phones must be switched to this mode, when so many disobey this request without any consequences. This article explains the reasons behind the aviation requirement to turn off or switch electronic devices to airplane mode and highlights the importance of doing so.

The effects of wireless communication

There have been several reports by flight crews of wireless devices causing disruptions to the aircraft autopilot and malfunctions to other critical systems. According to Live Science, in 1992, the Federal Aviation Administration (FAA) asked the Radio Technical Commission for Aeronautics (RTCA) to investigate the interference of mobile devices, but the latter found no tangible evidence. However, it still suggested restrictions on the use of phones during flights.

As such, the rules on device usage are more associated with interference with ground networks. Airplane mode prevents your phone from interfering with the plane’s electronic communication devices and radio altimeters. The aircraft’s communications and navigational systems utilize radio signals from the ground—these signals can be susceptible to mobile phone and tablet interference as they use the same frequencies.

An aircraft flying behind an Air traffic control tower.

Photo: Paparacy | Shutterstock

Because of this, a mobile phone can inadvertently pick up a signal, causing cross-talk or adjacent-channel interference. The same is evident when you are listening to the radio in your car and cannot hear the broadcast clearly because a signal from another radio station interferes with it. Because of safety, pilots need clear communications, and an errant telephone call on your mobile can compromise that.

Once in airplane mode, your phone will stop receiving radio signals, texts, calls, access to webpages, and email. Text messages or other data already downloaded and stored are still accessible. With the phone’s functionality reduced, you will also find your battery drains a lot slower.

Concerns around 5G

Setting your phone to flight mode is even more critical nowadays as service providers switch to 5G. With 5G, even though planes fly at over 30,000 feet, the signals generated by ground antennas could interfere with the aircraft’s radio altimeters. During the aircraft’s descent and landing, interference from a mobile device could lead to the pilots not knowing how far they are from the ground.

Pilots working in the cockpit.

Photo: DC Studio | Shutterstock

This has little to do with phone usage but more with cell towers. Recently, the Federal Communications Commission (FCC) gave service providers the green light to install 5G towers near US airports, raising concerns about flight disruptions. However, this is not an issue for aircraft whose radio altimeters are protected against 5G interference.

Related

5G Interference: The Risks And Systems Affected

A key piece of equipment – the Radio Altimeter – can be affected by 5G. Here’s what you need to know.

This may now have you wondering why it is possible to have inflight WiFi if the signals can interfere with communication devices and altimeters. The answer is simple – inflight WiFi is provided by satellites, not antennas on the ground.

What if I forget to turn on airplane mode?

Obviously, countless flights still take off and land safely every day with passengers having not turned on airplane mode. The truth is, it’s extremely rare for phones to cause significant interference with an aircraft’s systems, and there are no known cases of a mobile device leading to an accident. However, it’s still good practice to keep your device in airplane mode when asked for a few reasons, including:

  • Giving your full attention to the pre-flight briefing
  • Conserving your device’s battery
  • Preventing network overload on ground cellular towers

Related

Do You Really Need To Put Your Phone In Airplane Mode For A Flight?

A look at why airplane mode exists and how important it really is.

Android users may be able to benefit from an automated feature that switches to flight mode for you. According to the Android Authority, Google is looking to develop a ‘Connect Flight Mode’ feature allowing smartphones to automatically switch to airplane mode after boarding a flight.

An airplane passenger turning on airplane mode on their phone.

Photo: tete_escape | Shutterstock
 

In conclusion, the chances of you significantly interfering with the aircraft by failing to switch on airplane mode are remote. However, there are still good reasons to keep your device in flight mode—at the end of the day, flight regulations are meant to ensure the safety of passengers and crew, so it is always best to comply.

Do you always put your phone in airplane mode when flying? Please let us know in the comments.

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