The Mobile Dead Zone on Airplanes
Read: Why airplane food is so bad
Jon Brittingham, a technical pilot in the Airbus A319/320/321 program, explained the causes to me in greater detail. Older aircraft, such as the McDonnel Douglas MD-90, don’t have the same electronic-systems shielding to protect cabin equipment from third-party signals that more modern airliners, such as the current Airbuses, have. In fact, this shielding is most dense around the cabin—thus confirming my pilot friends’ agreement about poor reception within the cockpit. (This same fact can also cause cell reception in first-class seats to be the worst in the plane, when parked by the gate.)
Airports are giant swaths of empty space where large vehicles exit and enter the sky. That makes them poor candidates for cellular-antenna towers. Towers might grace the airport’s edges, but the expanse of airfields, and the distance to the terminals, makes coverage a stretch. To compensate, airports use distributed antenna systems (DAS): small, targeted cellular-access points (some barely bigger than smoke detectors) that work particularly well in indoor, controlled spaces. A DAS provider explained the particular challenge of airports: “These spaces are often challenging topologies that have high ceilings, wide-open areas or are located in harsh environments that present a challenge to designing and deploying reliable wireless service.” Harsh environments—what a nice euphemism for the sound and fury of terminals.
It works, indoors at least. The Denver International Airport, for instance, has been lauded for its use of DAS networks to provide superior service to passengers in the terminal and throughout the concourses—even better than customers are used to at home in the suburbs. But once you’re sitting on the plane, the signal problems begin. As Wired reported several years ago, that may have to do with conflicting signals caused by the plethora of small cellular antennae inside the terminal and the cell towers beyond the air field. (There’s also onboard Wi-Fi, further complicating things. That’s another issue, but one more reason, as a Delta ad put it, we’ve come to “expect the internet” when flying.)
Basically, on the plane your phone can’t decide which antenna to connect to, and this confusion contributes to the slow service. It doesn’t help that on any given plane, anywhere from 50 to 300 passengers might be clambering for a signal as soon as they are seated or as soon as the plane touches down. Pair this with certain aircraft models, such as the Boeing 787, whose structural materials may impede cell signals, and you get a perfect storm of poor service.
A coverage rift erupts most noticeably between the terminal’s interiors and the surrounding cellular landscape. On the airplane, you’re neither inside the airport nor clearly outside it—you’re in a bizarre netherworld, where cell signals are muddled.