 Originally the side-stick controller was non-moving, but this proved uncomfortable and difficult for pilots to adjust to, sometimes resulting in a tendency to "over-rotate" during takeoffs, so the control stick was given a small amount of "play".Since introduction on the F-16, HOTAS controls have become a standard feature on modern fighters.The F-16 has a head-up display (HUD), which projects visual flight and combat information in front of the pilot without obstructing the view; being able to keep their head "out of the cockpit" improves a pilot's situation awareness.