When your virtual airline flight flys from one airport to another airport using IFR (Instrument Flight Rules), they do so by flying along standard routes marked on published (printed) charts, often available to the general virtual airline pilot population on SimMiles. These virtual 'airways' are like roads in the sky and are drawn between points which are given names so that anyone planning to make a virtual airline flight can get from A to B in a controlled and structured manner instead of just flying online whichever way they please. The advantage of this is that once a virtual airline pilot has declared his intended route by filing a virtual airline flight plan simulated air traffic controllers do not have to give vectors and instructions all of the time - the virtual airline pilot has promised to fly a certain route and will stick to that route barring complications of weather or other virtual airline air traffic in the way. These routes effectively join every airport in the flight simulation world to each other via known pathways or the airways as they are referred to in flight simulator.
How to fly the SID or Standard Instrument Departure.
Some flight simulation routes are called 'Jet Airways' and generally are for virtual airline jet aircraft flying online at a high altitude. There are other flight simulation routes called 'Victor Airways' which are for lower flying aircraft such as turboprops. The routes usually run from point to point via virtual radio beacons (sometimes called VORs or NDBs) in flight simulator and points called intersections or fixes. These virtual radio beacons are actual radio transmitters dotted around the vitrual flight simulation globe. Intersections and fixes are imaginary points on the flight simulation globe which are marked on charts but do not exist as any physical item on the virtual ground. The fixes and intersection points are usually marked at the intersection of two virtual radials from a radio beacon in flight simulator or set at a certain distance from a known point. The airways, virtual fixes and virtual intersections are given real world names such as a fix name like 'LIFFY' or a route name like 'L975' (which can include multiple fixes) or a virtual VOR in flight simulator name such as 'STRUMBLE' so that virtual airline pilots and simulated controllers can mention them by name. Virtual Airline Pilots flying online in the same area over time get to know the names well after some experience flying the same virtual airline flights.
As mentioned above, an IFR (Instrument Flight Rules) aircraft will be following a set path from one airport to another airport. A SID (standard instrument departure) is a smaller initial virtual route which leads an aircraft from the runway in flight simulator they've just taken off from to the first point in his/her intended route. An airport usually has a lot of virtual airline aircraft departing from it's runways. To save confusion (and for safety), a busy airport will publish standard routes from it's runways to the various virtual airline routes away from that airport. This way a simulated controller can be sure that even if a steady stream of virtual aircraft using flight simulator is leaving the airport they will all be following in a nice neat line, one behind the other when flying online. There is a virtual point called LIFFY to the East of Dublin airport for instance which departing virtual airline aircraft travelling eastwards (perhaps to an airport in the Britain for instance) will usually fly to as the first point on their flight simulation journey. Dublin airport has a set online flying route to this point from each runway. These virtual routes are again given names so that simulated controllers and virtual airline pilots can communicate these procedures to each other online. For Dublin airport the standard virtual routes from runway 28 to the LIFFY intersection are called LIFFY2A, LIFFY2B. They are both different routes to the same point, 'LIFFY'. Depending on which runway the the virtual airline aircraft takes off from, a different standard route will be used. Along with the diagrammatical chart for the departure published by the Virtual Area Control Center airport, there is usually a written explanation of how to fly the procedure online in your flight simulator. This written explanation tells you how high to climb with your aircraft, when to make any turns needed and what VORs to fly towards or away from online.
