Originally Posted by murphy

They already have GPS and radar. They know exactly where the airplane is. To me, the big technical failure is that a plane can be in the wrong place without setting off alarm bells in both the cockpit and the tower.

It’s difficult to differentiate between a plane that is stopped and is going to wait for traffic to pass in front of it, and one that is stopped it isn’t going to wait. It’s easy to notice that an object with GPS and radar coverage isn’t where it’s supposed to be.