By Lluis del Cerro
The goal of this lesson is to learn when is it desirable to fly a direct path instead of using the airways in IFR flights.
All IFR flights should fly using airways and following a route previously planned and approved by the official administration in charge of flight planning. In our virtual world, and to make it as realistic as possible, it is recommendable to get the routes from a flight planning site such asVRoute∞) and file the flight plan using the button found there to send it to the VATSIM flight plan office∞. By doing this, among many other advantages, we will ensure that it will available to all ATCs, will be recovered after a disconnection from the network without resending it, and will be publicly visible as a prefiled flight up to two hours before logging in. See the VATSIM Charts and Flight Planning page∞ for a complete list of recommended flight planning tools and services.
Thus, a normal flight will always follow an IFR route made by waypoints and airways, starting with the SID fix and ending with the STAR one. To learn how to properly fly using airways, please read Airways lesson∞ in "VATSIM 300 - Basic IFR" section.
In IFR flights there are few occasions when to fly direct instead of using airways. These situations can be: 1) when the distance is too short as to join an airway or 2) when the SID and STAR fix is the same or 3) when offered as a shortcut by ATC while enroute. The first case can be exemplified by routes between islands, where a direct flight between two navaids is enough to reach the destination. The second case is self-explanatory but, to show a real case, a route between LEBL and LEZG would only have LOBAR in the route box as this is the SID fix for LEBL and STAR fix for LEZG. This route could be flown at even flight levels (exceptionally following the semi-circular rule) although the airway (UN725) we join at LOBAR is for odd flight levels in that direction (westward).
When flying direct, we will not join an airway and we will follow a flight level according to the semi-circular rule (basically, odd levels flying eastwards and even levels flying westwards).
Also, it is a good practice for those willing to do things the more realistic as possible, at least in Europe, to regularly check the Route Availability Document (RAD)∞ of Eurocontrol and comply with any restrictions in the route of flight.
I am indebted to Pepe Morales and Francisco Urqu?a, real ATCs in Seville Control Centre and the Canary islands, respectively, for their suggestions and revision of this article.