Questioins about navigation...

[Guest]

Hi,I've been using FSNav for flight planning and this program has been an invaluable tool. I'm just curious:1. How does the program calculate flight routes? I guess my real question is how does one formulate flight route in reality? How do those airline pilots do it?2. With the advent of GPS, why can't we all simply fly straight to our destinations? In reality and in FSNav, the route is often not straigt especially in those long hauls.3. Quite often I will let the FSNav fly the plan for me, is it realistic? Do modern airlines have computers that can automatically follow preset flight plan?You can probably tell I know very little about aviation. But I'm truly fascinated by this new hobby.Any reply would be much appreciated.Jonathan Kong

[Guest]

>Hi, >>I've been using FSNav for flight planning and this program >has been an invaluable tool. I'm just curious: >>1. How does the program calculate flight routes? I guess my >real question is how does one formulate flight route in >reality? How do those airline pilots do it? >>2. With the advent of GPS, why can't we all simply fly >straight to our destinations? In reality and in FSNav, the >route is often not straigt especially in those long hauls. >>3. Quite often I will let the FSNav fly the plan for me, is >it realistic? Do modern airlines have computers that can >automatically follow preset flight plan? >>You can probably tell I know very little about aviation. But >I'm truly fascinated by this new hobby. >>Any reply would be much appreciated. >>Jonathan Kong The pilots conform to what are known as high or Low altitude airways. Set up by the FAA. They are just like the highways that you drive on the ground. Its the only way to keep a very crowded sky under control.Planes are designed to fly towards devices that emit a frequency. You, as the pilot have a list of all the frequences associated with any emmiter along the route and its location. In addition to that there are many a military base that you may not be aloud to fly over.Unfortunatly FSNAV isn't samrt enough to set up the plan to avoid closd airspace. It also does not take mountain ranges into account. So you'll find yourself crashing into a mountain side.While I am not a pilot, to my knowledge the big Jets do have such an autopilot. Hell, I've seen the Captian and the co-pilot step out of the cockpit at the same time. all be it breifly. Some real jets even have an autoland feature.Pete

[Vulcan 14]

1) Don't know how the program does it 'cos I didn't write it :-)Commercial pilots don't usually create their own routes it is done by the airlines and the route handed to the pilots when they sign in.To construct your own route the easiest way is to let FSNav generate a route automatically and then check that it follows the airways shown in FSNav.Most European Countires have 'preferred' routes, that is specified airways from a departure point to a destination.The only way I know of to have a real world route is to get one from a serving pilot or look on avsim for real world flights plans that often get uploaded.2) A route will never be straight even with GPS. All basic long haul routes use a 'Great Circle' route to obtain the shortest distance between two points. Because the earth is round such a route will show as a curve in FSNav but, as explained by the other poster, these routes are modified to use the airways.The use of airways is to regulate traffic so that ATC knows where aircraft are and can flow the aircraft into airports, impossible with a 'free for all' system.About the only time you can fly where you want is when flying VFR outside controlled airspace.3) Modern airliners do have on-board computers to fly the route similar to, but far more sophisticated than FSNav.To find out what these are like purchase PIC767 or Dreamfleet's 737 or the PSS Airbus, all these have such on-board computers. To learn more try the AER link at the top of the page here at avsim.This hobby will suck you in for life if you are not careful :-)