Realistic AI aircraft traffic at airports requires specifying multiple parameters in the WED scenery file.
Thoughhout all version of X-Plane 11, minimum requirements for successful AI traffic operation at an airport are:
- The airport is of type “airport”, i.e. not a “seaport” or “heliport.”
- Have at least one ATC frequency of type “Tower” defined.
- Note this refers to the “Type” property, not the name given to the frequency entry, which has no relevance for AI operation.
- At least one (very preferably multiple) ramp starts of sufficient size is specified:
- The size of the largest ramp start (of any type) must be larger or equal to the actual AI aircraft attempting to spawn/land.
- X-Plane will not check if that ramp start is actually vacant or the right type – it rather gives ATC authority to make “emergency” decisions like parking a 747 on a Size A “Props” “Misc” ramp start, if none of the size F starts at that airport are available for some reason.
- See the “Guide to Ramp Starts” for details on ramp start fields.
- The airport should have at least one ramp start of type “gate/tiedown” and all starts near the runway should be of type ”misc” only. This prevents ATC accidentally spawning AI inside a runway hotzone – which creates a fatal deadlock.
- At least one paved runway (surface = “Asphalt” or “Concrete” only) of sufficient width and length is active.
- Active means either
- there is valid flow specification that meets the current weather condition and it includes a “Runway use” rule for that runway
- or no flows are specified. In this case, X-plane will auto-generate suitable flows that activate all runways under any weather condition.
- Sufficient width & length depends on the AI aircraft category as in the table below:
- Active means either
|Aircraft category||Min. Rwy Width||Min. Rwy Length|
|Heavy||125 feet||10,000 feet|
|Fighters||125 feet||7,500 feet|
|Jets||100 feet||7,500 feet|
|Turboprops||75 feet||2,500 feet|
|Props||50 feet||2,500 feet|
|Anything else||25 feet||1,000 feet|
These are all conditions to make AI spawn or attempt to land at the airport.
Note: In older documents – the “has ATC” property was noted as required for AI use. Since X-Plane 10 it is actually officially ignored – so it’s not required. Some airports may even have AI and ATC functionally without an ATC tower frequency defined in WED/apt.dat – if there is a (very rarely) used option to define ATC tower frequencies in an atc.dat file to accompany the scenery.
It also implies the actual ramp start types and ATC taxi network details do not prevent AI operation, but only help to make it look more “plausible” once AI are present at the airport. A working ATC Taxi network, either auto-generated by X-plane or specified in the scenery is required to have those AI successfully leave the runway and taxi to/from the ramp starts.
To debug problems with AI operations it is recommended to start with hiding all user specified flows and ATC taxi networks in the WED scenery pack. X-Plane will then auto-generate these items, which will result in functional flows & networks, although they will also appear less polished.
By default, the X-Plane log.txt also includes information about AI spawning, flow selection and AI Taxi instructions. The art control atc/debug/log_spawn=1 prints log info on AI aircraft arrival & departure logic. Use the developer console to see this in-sim or view it in the log.txt