| The actual algorithms used for autopilots are really simple. A simple autopilot will do nothing more than hold the wings level so the pilot doesn't need to continually keep their hands on the controls. From there, more functionality is added as layers. Heading mode makes the autopilot always point towards a compass heading. Nav mode is a computer that changes requested compass heading every time it reaches a Nav point. A more advanced autopilot will add modes for speed-hold and altitude-hold that trade between altitude and speed. When combined with the auto-throttle, the autopilot can implement constant rate climbs and decent. The autoland mode simply updates to heading mode and constant rate decent to follow the glide slope. While it's true that a modern autopilot can takeoff, fly to a destination and land without the pilots touching the flight controls, the pilot is required to constantly switch between the various modes, feed nav points, and adjust the autopilots mode. At the same time, the pilots are doing a bunch of other tasks to keep the plane flying and safe. The simplicity is very intentional. Pilots are expected to know what the autopilot is doing at any point and understand why the autopilot is doing that. They are expected to spot when it's doing something weird very quickly and disconnect it. |