On a recent, pivotal episode of Succession, the most jaw-dropping thing that happened was not the major plot twist—it was that nearly all of the passengers aboard the company jet were making calls from the airplane the entire time they were flying.
Granted, the inner circle of the Roy clan are not known for following the rules (and their private plane probably made its own rules), but still, shouldn’t they have been on airplane mode for the safety of everyone on board? And can you even make calls from the middle of the Atlantic? By this point, we’ve all been trained to think that keeping cellular service on during a flight is more dangerous than ordering that third Bloody Mary on an empty stomach. So what does airplane mode do? Here’s what air travelers need to know about airplane or flight mode and what happens if you don’t switch it on when the plane takes off.
What does airplane mode do?
Turning on airplane mode disables all wireless and cellular signals coming from the phone. Once the phone is in airplane mode (also called flight mode on some devices) though, users can manually toggle select signals back on, such as Bluetooth and Wi-Fi. Whether you should is another story.
Why are airplane passengers asked to put their phones in airplane mode?
Per the FAA website’s Safety Information page, “The FCC and FAA ban cell phones for airborne use because its signals could interfere with critical aircraft instruments. Devices must be used in airplane mode or with the cellular connection disabled. You may use the Wi-Fi connection on your device if the plane has an installed Wi-Fi system and the airline allows its use.”
What happens if you don’t switch to airplane mode in-flight?
The concern is that a phone’s radio transmissions could get in the way of the systems that planes use during the flight. According to the FAA website, “There are reports of suspected interference to communication and navigation systems in both the NASA Aviation Safety Reporting System and the FAA’s Service Difficulty Reporting system.”
What’s more, if the captain deems it necessary for safety, such as in a reduced-visibility landing, they have the prerogative to tell passengers to switch off their phones completely “to make absolutely sure they don’t interfere with on-board communications and navigation equipment.”
Can you even make calls from 36,000 feet?
Technically, yes. As explained by Sven Bilén, a professor of engineering design, electrical engineering, and aerospace engineering at Penn State University, in How Stuff Works: If the plane is low enough (generally below 10,000 feet), cellular calls might be able to connect, though they’d be pinging different cell towers as the plane moved, so the connection probably wouldn’t be great and could interfere with ground networks. Above that altitude, it’s unlikely you’d be able to make a cellular call unless the plane was outfitted with its own mobile service (like Virgin Atlantic planes had back in the 2010s, and like the Roy private jet most probably did). But none of that means cell phone calls are allowed. In the U.S., the Code of Federal Regulations states that the FCC prohibits use of cell phones when the plane is airborne. It says:
“Cellular telephones installed in or carried aboard airplanes, balloons or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground). When any aircraft leaves the ground, all cellular telephones on board that aircraft must be turned off.”
Are the rules different in the U.S. than in other countries?
Yes, and that’s due to the communications technology used in other countries, as well as how their airline safety is mandated.
For example, at the end of 2022, the European Commission ruled that airlines can use 5G during flight and that EU member states must make 5G technology available for planes by June 30, 2023. This isn’t necessarily a harbinger of things to come in the United States though: Boeing, Airbus America, and the trade association Airlines for America have argued that 5G could impede safety by interfering with a plane’s radio altimeter (the tool that measures how far a plane is above the ground), which is especially critical during bad weather.
But the 5G in the United Kingdom and EU is different. “There is much less prospect of interference,” Dai Whittingham, chief executive of the U.K. Flight Safety Committee, told the BBC. “We have a different set of frequencies for 5G, and there are lower power settings than those that have been allowed in the U.S.”
What happens if you don’t comply?
As travelers have no doubt heard on their flights, FAA regulations mandate that passengers follow all flight safety regulations, including those dealing with electronic devices.
And while it’s hard for flight attendants to notice whether you’ve toggled your phone to airplane mode, do you really want to be that passenger? What’s next—are you going to take off your shoes and go barefoot?
Besides, one of the best reasons to turn off your phone is that it’s important to pay attention to the preflight safety announcements, even if you’ve heard them a hundred times.
And for now at least, your cell signal is not going to work during the flight, so leaving your phone on full cellular mode is just going to eat up your battery—and prevent you from watching more episodes of Succession.