First Air, a Canadian airline, flies across some of the most remote and sparsely populated areas on the continent, with routes going as far north as Resolute Bay, inside the Arctic Circle. Its planes are often beyond the reach of conventional radar. They are also nearly disappearance-proof.
That's because of a six-pound (2.7 kilogram) tracking system, about the size of a hotel room safe, installed in the planes' electronics bays. When flights proceed normally, the system never snaps into action. But if something goes wrong - a sudden loss of altitude; an unexpected bank; engine vibrations - the system begins transmitting data to the ground, via satellite, every second. That six-pound box spits out reams of performance data, as well as the basics necessary for a search-and-rescue: coordinates, speed and altitude.
The technology hardly sounds cutting edge, given today's access to cloud storage, satellite communication and real-time data tools. But First Air is an outlier. Most commercial airlines have no comparable safeguard. As seen in the case of AirAsia Flight 8501, they can crash into the sea without relaying information about their last minutes or seconds of flight.
Given the technology that's available, airplanes are surprisingly non-communicative. They have transponders that broadcast location, but those only work in tandem with radar. (So, good luck over the deep ocean.) About three-quarters of the world's airlines also use an additional data system, the Aircraft Communications Addressing and Reporting System (ACARS), that reports data back to the ground at predetermined intervals - say, every 10 minutes. But in the case of an ocean crash, that information can leave you a Texas-sized search field and plenty of guesswork.
Of all airplane technology, though, the black boxes are the most anachronistic. The boxes - commercial planes have two - contain key flight data, but they don't share it. They're like padlocked desktop computers without an Internet connection. Which is why, when a plane goes down, search teams might spend months or years scouring the ocean floor before they can figure out what went wrong.