Copyright SlashGear
TSA and its counterparts around the world, as well as a broad network of pilots, crew, and airport staff, are there to help ensure our traveling experience is as safe as possible. Their rules are intended for safety's sake, rather than the inconvenience or imposition that they can frequently be derided as by travelers. There are few better-known and more frequently questioned rules than the one governing airplane mode. It's essential to be familiar with TSA's electronics rules before setting off, and that includes understanding the guidance around cellphone use. Sometimes, this rule is considered a bit of a joke or a holdover from the past. The important thing is that just as rather old aircraft are still just as safe members of the fleet as they ever were in some cases, so we're still reminded about the importance of airplane mode for a reason. Anxious flyers may well switch airplane mode on before boarding the plane, wary of the fact that, as has been drummed into us for decades, cell signals can potentially interfere with the instruments on the aircraft. There are a myriad of sensors and systems on the average airliner, after all. In actuality, though, the potential impact of one phone is essentially negligible. Let's see what impact a cell phone that isn't in airplane mode can truly have on a plane's instruments, which ones can possibly be affected, and some potential factors that could increase this effect. An aircraft's cockpit is awash with sensitive controls and equipment, allowing the crew to control a plane's flight and constantly monitor its performance. Every day flying machines they may be, but they're also complex, so anything that could negatively impact a pilot's concentration needs to be taken seriously. Seemingly humble laser pointers, for instance, can be dangerous for an airplane, and the effects of not switching off airplane mode can also have a debilitating effect on pilots in some instances. In February 2025, Minnesota Pilots Association president Randle Corfman explained the impact that a phone without airplane mode enabled can potentially have on an aircraft to CBS News. Corfman said that there's a possibility of "interference if the cell phones are closer to the flight deck, but it's minimal, just a small buzzing sound apparently in the headsets of the pilots and the flight crew." It sounds minor, but in context, this could be a real threat. It's vital to remember that pilots and the rest of the crew are dependent on those headsets. Corfman goes on to note that a simple misheard instruction or warning could endanger a flight. An aircraft cockpit can be a busy environment, of course, and we all know how tricky it can be to concentrate perfectly on a given task when there are several things going on around you at once, or multiple other sounds making it difficult to pick out what was said in a conversation. The buzzing sound itself, though, isn't the only thing to potentially worry about. It's the action that the cell phone is performing to produce it. Travelers are used to activating the mode for fear of negatively affecting the equipment on board, but exactly how it may do so, and which pieces of equipment, tends to be unclear if you aren't in the aviation industry. There is one particular instrument that can be especially vulnerable to this. Professor Dan Bubb of the University of Nevada specified to Newsweek that it's the radio altimeter phones affect. This tool provides the flight crew with accurate information about the aircraft's altitude by transmitting radio waves to the ground and measuring the time it takes them to return to the plane. This becomes even more important the closer an aircraft is to the ground, and with landing being one of the most critical moments of a flight, such instruments need to operate at their best. This is also the time at which cell phones approach closer to the range of cell towers, thereby increasing their activity and the potential negative impact on the pilot and crew's vital work through that pesky buzzing, possibly exacerbated if multiple phones are doing the same. In 2023, the European Commission began a push to allow 5G services on applicable aircraft across the continent. Dai Whittingham of the U.K. Flight Safety Committee explained to the BBC that this works in Europe and the U.K. because they use "a different set of frequencies for 5G, and there are lower power settings than those that have been allowed in the U.S." There is little risk from not using airplane mode for that reason and it is broadly minimal in the U.S. and elsewhere too.
