The Real Reason You Have to Put Your Phone on Airplane Mode

Have you ever wondered why you have to put your phone on airplane mode? Finally, we have an answer.

Many airline passengers are frustrated and annoyed that well into the 21st century, we still can’t use our cellular service on planes. Despite incredible advances in aviation technology, passengers still can’t check their email or engage in retail therapy at 35,000 feet unless they pay for a wi-fi pass. To get to the bottom of this, we asked some aviation experts to explain why taking off your phone off airplane mode can be risky.

There Is a Small but Real Risk to Safety

Any personal electronic device, including mobile phones using cellular service, can interfere with an aircraft’s communication and navigation systems, explains Gudmunder Tomas Sigurdsson, vice president of flight operations for Icelandair.

Interference from cell phones could “potentially lead to missing critical information like traffic alerts, runway assignments, or changes to the route. Any misunderstanding of these transmissions could lead to dangerous situations very quickly,” adds Bobby Dutton, a commercial pilot, flight instructor, and engineer who runs the website Think Like a Pilot.

For example, if a plane is landing in thick fog, pilots may need to rely on precise guidance from air traffic controllers to land safely, says Anders Akerberg, safety manager at SAS.

Although most airplanes today are built to decrease the risk of interference with communications from any source, Sigurdsson says there is a small risk that it could occur. The risk is especially acute “during critical phases of flight such as takeoff and landing,” he cautions.

Although the risk posed by cellular service is low, Sigurdsson explains that “aviation safety is based on layers of protection, and restricting cellular signals in flight is one of them.”

Dutton adds that “aviation is all about making good choices before you get into trouble.” If there is any chance, no matter how small, that cellular service could cause a problem, airlines should be proactive in eliminating the threat. By banning cellular service while in the air, airlines are taking an important and proactive step to increase safety.

Sigurdsson explains that while “a single phone may not cause a major issue, multiple active devices transmitting signals inside the cabin” can create a bigger safety risk. If airlines allowed passengers to use cellular service on airplanes, most passengers would likely use their phones, increasing the risk.

The Crew Needs the Passengers’ Full Attention

Another reason passengers aren’t permitted to use cellular service on planes is that airlines want to minimize distractions during takeoff and landing, Sigurdsson says.

“The crew needs passengers’ full attention,” he adds. “Using personal devices can delay responses in case of an emergency.”

Although it’s tempting to tune out emergency instructions, “flight attendants and safety experts emphasize that passengers should remain focused on pre-flight safety instructions and emergency procedures,” Akerberg says. Prohibiting the use of cellular service while the cabin crew runs through these procedures is one way to reduce distractions and increase safety.

Cellular Service May Not Work Anyway

Even if using cellular service on airplanes were allowed, you probably wouldn’t be able to get service up in the air.

“Aircraft are designed to block external radio signals to maintain safe and controlled communications between the cockpit and air traffic control,” Sigurdsson says.

Moreover, “While your phone can technically detect cell towers from high altitudes, especially during takeoff and landing, the signal is generally too weak and unstable at cruising altitudes to maintain a reliable connection to ground-based towers,” Akerberg explains.

Plus, even if you could connect to a cellular tower, service wouldn’t be reliable because your phone would constantly need to switch towers and reconnect.

You Can Use Your Phone if You Purchase Wi-Fi, but Not for Voice Calls

Many airlines now offer wi-fi-based services, which allow messaging and, in some cases, internet calling. However, Sigurdsson notes that Icelandair and many other airlines do not allow voice calls over wi-fi “because they can be disruptive to other passengers.”

This is true even in an emergency. Sigurdsson advises that if a passenger ever needs assistance while in the air, they should inform the cabin crew.

The Cabin Crew Might Not Notice You Using Cellular Service, but You Shouldn’t Do It Anyway

Sigurdsson says that if you do get cellular service on a plane, the cabin crew may not notice. However, he cautions passengers not to try.

“The rule isn’t about noise. It’s about safety,” he says. Using cellular service while in the air could endanger the safety of everyone on board so no one should attempt to get away with getting around this rule.

“The risk of added stress or reduced communication for a pilot is serious. Critical information needs to pass between pilots and controllers quickly and clearly,” Dutton says.

Moreover, you might not get away with it. Although “there is no direct monitoring system to detect cellular activity, intermittent interference with radios or navigation systems could alert the crew,” Akerberg adds.

When Passengers Can Use Their Cell Phones Varies by Airline

Airline policies differ about when passengers can safely use their phones on board. On Icelandair, passengers can keep their phones on until the aircraft doors close, Sigurdsson says.

“At that point, they must switch their devices to airplane mode before pushback and takeoff. This ensures that no unintended signals interfere with the aircraft’s systems during these critical flight phases,” he explains.

Rules may also vary regarding when you can safely turn your cellular service on after landing.

“Passengers can typically disable airplane mode after landing, once the aircraft has cleared the runway and is taxiing to the gate,” Sigurdsson says. However, he cautions that some airlines may require waiting until the aircraft comes to a full stop at the gate. If you aren’t sure when you can turn your cell phone back on, Akerberg says to “wait for the official announcement before reconnecting.”

If the thought of even a few hours without your phone is upsetting, Dutton says to look at flights as a great way to take a break from being constantly connected. “Look out the window. Enjoy the miracle of flight,” he says. And for passengers who are still frustrated by not being able to use cellular service on airlines, Sigurdsson says not to take it out on your airline.

“This is not just an airline policy,” he cautions. “It is an international aviation safety regulation.”