Flying all alone can be a tad boring, not to mention quite unrealistic. There are many ways to "add some company" to your flight sim experience and thankfully, XPlane has one of them built in. If you are accustomed to the ATC in XP9 you may understandably be let down with the offering in 10, but in some respects 10 is better and it certainly has the potential to do much, much more. It currently has the capability to get you from gate to gate with fairly accurate altitude control...and as long as you don't deviate too much from your planned route, you won't get nagged (much).

While the ATC system can seem daunting, we can only control what happens on the ground. If you are at an airport that doesn't have ground routes defined, XP will autogen them for you. Make no mistake, these are often atrocious (taxiing on vehicle service roads, going through buildings and other planes, etc.), so it is up to us to define the taxi routes to function the way they are supposed to.

As a scenery designer, I make a point of including accurate routes on every package I do. It's actually easier than it looks and uses the same principles like creating segments for scenery design, so let's jump right in. This how-to assumes you have a working knowledge of WED (the XP World Editor). There are three types of ATC segments you can create in WED.

• Active Zone - areas that require tower clearance to access. These will color code red
• LS Protected Zone - areas that aircraft hold short of so as to not block landing system equipment. These will color code yellow
• Taxiway - all other movement areas on the airport. These will color code green

ATC routes also make use of the WED default options bar and since I'm all about efficiency I try to gear the manner in which I work toward that which entails the fewest changes (to the defaults) as I go. Segments that involve active zones (the first two above) are most laborious to change because you have to click once to select or deselect EACH runway. For arrivals and departures that is four clicks to go from active to non-active segments or eight clicks for one runway to another. So...I do the active zone stuff first and just change the segment name field as I go (one click and type).

Start with one runway. Set the runway directional restrictions. Only use "Oneway" if it is actually required. This option can also be used with taxiways but bear in mind that you can create some hefty bottlenecks if you use it. Use caution even if the actual taxiway is one way. Next, select the runway from the "Runway" dropdown (you can only pick one at a time). Set the Departure and Arrival fields for the runway you are working on. ILS is only used for the ILS protection zone so skip it for now. Name is set to the runway identifier "17R/35L" etc. "Slop" is used to tell WED the separation distance for double node checking. Use 10 or 12.

Now that the options are set, click on one "end" of the runway then the opposite end. I put end in quotations, because we don't want to click on the actual end of the runway, rather at the point where aircraft have turned on to the runway and would be prepared to start the takeoff run. For runways with multiple entry points you do this near the one closest to the end of the runway. The next step is to do the sections from inside the runway hold lines to the runway segment you just created. Turn off the "Runway" option (as we are not creating a runway segment this time). The only other change you need is to set the "Name" field to whichever taxi segment you are working on. Since the arrival and departure options are set you are ready to roll.

Work in one direction from one segment to the next along the runway, only changing the taxi name as you move. If you are lucky, and the segment goes from a runway hold on one side of the runway to a runway hold on the other side just draw the lane to those (you don't have to do one to the runway line then another to the other side...WED will create the "split" on its own). Note that you should be clicking the hold short line (as it relates to the runway) to start/end your segment because this is where you want the ATC to have you or AI planes stop and wait for clearance to proceed.

Once you have done all the active zone segments (they will be red), look for any ILS zones. If you have to do these, remove the arrival and departure options and set the ILS option for the runway you are protecting. Like the previous segments, this will start with a click on the line where the zone begins (the ILS hold line) and end with a click near the runway hold line. If you clicked close enough (the slop area) the two segments should join automatically.

Remember that with any endeavor you should save OFTEN. Another practice to get in the habit of (especially when dealing with ATC) is checking for double nodes. These are end points that are close, but not within the "slop" area and will not be merged. If you did these inadvertently, WED can identify them (all of them) so you can easily fix it. If you do this often you won't end up at the end of your project with 500 sets of double nodes that would be very laborious to correct.

On the menu strip, click "Select", then "Select Double Nodes". If you are lucky there will only be one or two sets. If there are more than one set, you will need to find them on the map pane and drag select the pair. Once this is done, click "Edit" on the menu strip then "Merge". This will join the pair. Look at your display and make sure the path is what you intended it to be. Sometimes, if you join the wrong node into a pair, your route will get seriously messed up.

Repeat the merge process until all doubles have been removed (the empty selection from a Double Nodes check), then save your work. Once you have saved, WED will move your "focus" in the hierarchy pane to the top. If you are working in grouped items (and you really should be) you will need to click back inside your ATC routing group before moving to the next section.

Now it is time to start the basic taxiway segments. Although you can move on and do other runways and active zones first, I like to complete an area before moving on to another...especially if it is a complex airport. Taxiways have no affiliation with runways so make sure "Runway", "Arrival", "Departure" and "ILS" options are set to none. All we need are the segment names. If you can do long stretches of taxiway in a single click-pair, awesome...just make sure you don't run through hold lines or active zones of runways that intercept the taxiway.

There is a special case where you create a taxiway with a blank name option. These are segments where you still want to have control over planes/routing, but there aren't taxi identifiers (terminal areas, cargo/FBO spaces, etc. Create these the same way as a standard taxiway, just leave the name field empty. It will look weird in the hierarchy pane but ignore it.

Rinse and repeat for other runways, zones, ILS and taxiways until you have a complete network. the easiest way to check for missing segments (and one of the main reasons for grouping items in the hierarchy pane) is to turn off visibility of all other airport items and you get a picture like this:

If your network looks exactly like your airport does...perfect! If not, you should be able to see obvious omissions/errors.

In this shot I have zoomed in on the 18L & 18R area of DFW because it contains ALL of the elements of an ATC Taxi network. The keen eyed will notice that a taxiway is one directional. This is because the Y/Z and A/B taxi bridges at DFW are set for directional traffic regardless of landing flows, so I modeled it accordingly.

The last thing to do is set your "flows" so XP knows how to determine active runways according to conditions you set. There are two primary resources I use when working with flows: airnav.com and VATSIM ARTCC web sites. Airnav gives you the general operational characteristics of the airport and the ARTCC will often give you detailed traffic flow information. Obviously, you won't find data for the bulk of smaller fields on the ARTCC sites.

As with taxi routes, if there are no flows defined XP will autogen them based on the closest weather data. The downside is that you will only get one runway. You need creative flow conditions to activate and model realistic actions. In the case of DFW, I was able to put six of the seven runways of the airport in use but I had to fudge reality a bit (the seventh runway isn't normally used because of the approach pattern). A snippet from my South flow:

17R - Departures (all aircraft types)
17C - Arrivals (heavy jets, jets)
17L - Departures (turboprops)
13R - Arrivals (turboprops)

Flows are now very powerful tools that allow you to precisely control what traffic goes where and I highly recommend watching the flows video tutorial series by Chris Serio (creator of the ATC system on XP10. Thanks for tuning in and I hope you learned and are inspired to create. Remember, now that the Global Airports library is open for submissions, please contribute your work so that everyone may benefit!