At the Hack In The Box conference in Amsterdam, security consultant Hugo Teso demonstrated PlaneSploit, an app he developed that can take control of certain systems aboard an airplane and cause it to change direction or just crash itself into the ground.

Hugo’s no terrorist, mind you. He developed the app to point out the glaring, frightening, insane security holes in most planes’ onboard flight systems. His demonstration was done in a simulated environment, but the methods and effects, he says, are exactly the same as what could happen with a real plane.

“The complete attack will be accomplished remotely, without needing physical access to the target aircraft at any time,” wrote Teso in his presentation abstract for the conference. The hack exploits the plane’s autopilot, transferring control to the hacker, who (in theory) could command the plane from an app running on Android.