By now you've likely heard the denials about how a well-known hacker was able to break into an airliner’s flight control systems from within the passenger cabin, and about the resulting FBI investigation.
Chances are very good that those denials are wrong. But it's also true that the vast majority of those who say it's not possible have a point, since it really shouldn't be possible.
But let's suppose for a minute that security researcher Chris Roberts did exactly what he said he did, in exactly the way he described it. If that's the case, let's look at exactly what Roberts claims that he did. But let's also look at what he didn't say—and that's important.
First a little background. Most modern airliners contain a variety of digital systems. The entertainment system is just one of them. But modern airliners also include digital flight controls, navigation systems and flight management systems.
Flight controls handle rudder, elevators and ailerons and perhaps the engines. Navigation systems include the GPS as well as inertial navigation and some legacy navigation systems.
Flight management systems perform mainly flight engineering tasks, such as moving fuel between tanks to keep the plane balanced, tracking telemetry, performing automatic logging tasks, and taking care of other functions, including tracking maintenance requirements.
All of these flight systems are interconnected at some level. Normally you wouldn't think any of this would include the entertainment system, but remember those moving maps that show up on the screen in front of your seat.
Those maps use data provided by the airplane's navigation system. Likewise, the information such as the air temperature and airspeed are provided by other flight systems. So clearly, the entertainment system is in fact connected to the flight systems, despite the denials.
Looking into this further, it pays to read what the FBI is actually investigating and their information about what Roberts actually told them when he was interviewed by the FBI. It's worth noting that Roberts is a frequent consultant to the FBI, and that the agents conducting the interview characterized Roberts as being cooperative.
What Roberts said was that he managed to wiggle the cover of the entertainment system loose so that he could plug in an Ethernet cable. If you sit in the First Class section of many airplanes, there's an annoying black, plastic-covered box under the seat in front of you. This box is easy to spot because it prevents you from putting your briefcase under that seat in addition to preventing your feet from going there.
There are similar plastic-covered boxes in the Coach section of the airplane’s cabin, but they're smaller, presumably because the hoi polloi forced to fly in coach don't get deluxe entertainment service.
But the entertainment network isn't the only network running through the aircraft. And just because those annoying boxes are primarily used by the entertainment system doesn't mean that's all they're used for.