Call 911 from the side of the road, and GPS satellites can tell dispatchers exactly where to send help. Airline passengers have access to detailed maps that show exactly where they are during their journey. Hop onto WiFi, and somehow Google knows whether you're logging on from Lima or London. For all these abilities, how is it that we have no idea where Malaysia Flight 370 has gone? The answers to some common questions offer a humbling look at the limitations of our current technology.
Q: What happened to radar?
A: Air traffic controllers use radar to monitor a flight's progress, and that's all very well over land. But radar also has a limited range, and you can't put a radar station in the middle of the ocean. So pilots have to stay in contact through other means, such as periodic radio check-ins. In between check-ins, the controller has only a general idea of where a plane is.
Flight 370 was tracked by military radar near its end — but whether a civilian air traffic controller knew where it was is less clear. We know that Flight 370's transponder signal was lost just as the plane was supposed to be entering Vietnamese air space — and because transponders are meant to work with radar, that suggests the plane was close enough to shore to be on somebody's screen.
Q: Could somebody have turned off the aircraft's transponder?
A: That's a tricky question. Pilots can send coded messages over the transponder in an emergency. But we're not really sure what happened to the transponder in this case. We don't know, for instance, if anybody tried to tamper with it. But why would they? Reports suggest that nobody on the plane made a distress call of any kind. That implies there wasn't time to cry for help in the midst of a technical breakdown or a violent struggle. If that's the case, it's not likely attackers — if there were any — would try messing with the transponder while they were still trying to gain control of the aircraft.
Q: What about passengers' cellphones? Could they be tracked?
A: The reason you can be tracked on land is because your phone is constantly talking to the cell towers that provide you service. No service? No location. While you're in the air, there's not much of an opportunity to use your cellular network — although that's changing in Europe and may soon begin to change in the United States, too. Technology now enables the use of cellular networks if a plane carries a special base station that sends communications to a commercial satellite, which then relays it to the ground. But adoption will be voluntary among airlines.
Q: Don't phones often carry GPS chips?
A: Yes, many cellphones do have GPS. But it's not the kind you'd find in a car. Cellphones typically rely on a kind of "assisted" GPS — one that requires a constant data connection. Without WiFi or a cell tower, you're not able to connect with the satellite.
Q: Did Flight 370 have WiFi?
A: WiFi would almost certainly have helped. Mobile devices on the plane would have been communicating with the Internet right up until its other communications systems went down. But Malaysia Airlines does not appear to offer in-flight WiFi.
Q: What other technologies might have helped maintain a fix?
A: The Federal Aviation Administration wants to transition to an air traffic control system that uses GPS satellites to keep tabs on planes. It's called Next Gen. Satellites have a distinct advantage over radar — a technology that dates back to World War II — in that they can monitor wide swaths of territory, including oceans. Unfortunately, this system is years away. Even if we had it now, the FAA is mainly concerned with domestic airspace. Malaysia Airlines would not have been covered. Someday, however, there might be a worldwide version of Next Gen.
Speaking of satellites, U.S. officials have examined spy satellite imagery from the region and have turned up no clues about Flight 370.