can someone please explain to me the concept behind waypoints. I dont see how you can program the plane to turn in midflight, cause planes just dont do that. can someone explain this briefly to me. thanks
Actually, planes do do that.
Waypoints have been used in air navigation for a very long time. Prior to the advent of GPS and LORAN, waypoints were usually a defined electronic intersection but they could be something as simple as a terrain feature if you were in VFR conditions. Now, any point can be programmed into the GPS as a waypoint.
There are a variety of reasons for using waypoints. Sometimes, ATC does not have the capacity to allow a direct routing from point A to point B. To get to point B, ATC may require you to fly to points C. D, etc enroute. In other cases, a direct routing may take you over a prohibited area or through restricted airspace. There may also be capability problems that require waypoints - you probably do not want to route yourself across a 14,000 foot mountain in a C-172. In all of these cases, one or more waypoints, each requiring a course change would be required.
I also have personal minimums that require waypoints on some flights. In a single engine aircraft, I will not fly across water if it will take me further away from land than I could glide back from the altitude I am at. In multi-engine (twins only-I don't fly heavy iron), I will not get further from land than I could get back in 30 minutes in the event of an engine failure. These are not legal requirments but they require me to use waypoints in many coastal flights. We also have a high concentration of military restricted areas in the western US that often prevents the use of direct routing.
There is a way cool nav system called INS that you can dowload. It uses -like the real one that this is modelled after- geographic coordinates to navigate. And if you do not reprogram it at the right time,,, the aircraft WILL turn around in mid flight as you say.
I use a world atlas to get the geo coord. from. Works great!!!!!!!