Guide to Ramp Starts

Starting with X-Plane 10.50 and WED 1.5, ramp starts can be customized with a lot of data to help specify their use. Ramps starts should be designed based on their use in the real world and should never have aircraft scenery objects placed on them as this would interfere with the “Draw Parked Aircraft” and “AI Aircraft” functions in X-plane 10.50 and newer.

Ramp start definitions are also used when deciding what parking locations are suitable for the user aircraft.

Ramp start type

The majority of ramp starts should be either Gate or Tie-down spots. Static aircraft will show up only at these ramp types.

Misc and hangar type ramp starts should only be used for human player starts.  X-Plane will ignore Misc type and will not spawn static aircraft there. When Hangar is set, X-Plane assumes the aircraft is in a building (and therefore not visible) and won’t spend resources placing aircraft there. AI aircraft will use Hangar locations as a last resort if no tie down or gate spots are open, but will not use Misc.

Set only one type from the drop down here.

Equipment Type

This field determines what type of aircraft should use this parking spot. Set at least one type from the drop down here, but multiple types are supported on the same spot. The differentiation between “Heavy Jets” and “Jets” is based on their unladen mass and follows the ICAO standard. As a very rough guide, all aircraft size E or larger are usually classified as “Heavy” and those of size D and below as “Jets” although there are a few size D heavy aircraft. It is recommended to always include both “Heavy Jets” and “Jets” as equipment types for all ramp starts of size D and larger to avoid creating unintended restrictions.

Size

This field determines what size (wingspan) aircraft can be assigned to that spot, both for static and AI/user aircraft. For static aircraft, X-Plane will place aircraft that are marked in X-Plane’s scenery library as the specified size & one lower (i.e., size C will be used by size C & B aircraft).

The classification of these sizes follows ICAO Aircraft Size Standards and is as follows:

Ramp Operation Type

To further limit what type of aircraft can be shown as parked aircraft at that ramp, set an operation type. When set to “none,” no parked aircraft will be placed, but AI aircraft of a suitable size can still use this ramp start. Pick only one type from the drop down here.

Airlines

Case insensitive in WED, three letter ICAO codes as per the  Airline Codes Wiki Page separated by spaces. This field also affects both static and user/AI aircraft.

For static aircraft, if you have included more than one airline code in this spot, X-Plane will randomly pick one before the available liveries in the library are checked. If the airline code X-Plane selected is not found in the user’s library, a random result will be placed instead. So limit your definitions to airlines code most people actually have static aircraft installed for, otherwise most people will only see completely random liveries at those starts. X-Plane by default includes liveries for only a small number of major airlines, but these will always work. See the category lib/airport/aircraft/airliners/ for available liveries on ramp starts marked as Operation Type=’Airline’. Or the equivalent categories corresponding to the other operation types, if selected.

For moving aircraft, parking spots which are marked as suitable for the aircraft’s airline will be selected first when assigning parking.

Designing sceneries with Ramp Starts

All ramp starts of types “Tiedown” or “Gate” must be placed to allow aircraft taxing along ATC taxi routes to safely pass any aircraft parked there. To check for interference, switch to the “Taxi+Flow” view mode in WED and verify the yellow aircraft shapes are completely clear of the ATC taxi routes depicted in any color, with preferably 10-20 feet of clearance to spare.

User and AI Parking Allocation

When the ATC system needs to allocate a parking spot for the user or an AI aircraft, both when they are created and when they are about to land, it tries to narrow the choice to the best-matching set before choosing one from that reduced set semi-randomly. The information described above is all used in producing the initial reduced set.

All non-Misc parking spots are searched. Any that are blocked by an aircraft are first excluded, where the user’s aircraft, AI aircraft and static aircraft are all considered. A spot may be blocked by an aircraft parked nearby even if it is not itself allocated.

If nothing is available the search is repeated, dropping restrictions in a defined order, until at least one spot is seen as usable. This order is:

1. Airline
2. Operation Type
3. Equipment Type
4. Size Class (i.e. allow an aircraft which is too large for this parking spot)
5. Start Type (i.e. allow the inclusion of Hangar, but not Misc)

If the system is trying to allocate a spot for an aircraft which needs parking and more than one spot is usable at the end of each search, those which match the aircraft’s size class most closely are retained

When any criteria have been ignored, only those spots which form the least-bad match from the resulting set are included. In other words, if some spots match three criteria and some match four, only those which match four criteria will be considered.

Debugging Ramp Starts

If AI don’t seem to be using your airport or ramp starts, there are a couple art controls that you can turn on to help debug the situation. (Note you will need to set the art control then make sure the airport reloads by leaving entirely and coming back.):

• atc/debug/log_spawn=1   (Prints log info on AI aircraft arrival & departure logic. Use developer console to see this in-sim)
• airp/debug_ramp_starts=1 (Leaves on screen a bunch of visual debug markers telling you about the ramp starts, so if a static airplane is missing or wrong you can SEE the data.)

From X-Plane 12.1.3 on, you can check compatibility with particular aircraft using the new “Usable” toggle in the flight configuration page. Select the aircraft you wish to test and then enter the advanced location selection. If you zoom in a little the airport will show only those spots which are usable for this aircraft type. Bear in mind that this page will also show ‘misc’ starts, which will allow the user to start there but nobody, including the user, to be assigned parking there.

When testing, remember to check multiple aircraft types. Common problems include:

• GA parking spots which are not suitable for jets. Use the Cirrus Vision SF50, a class A small jet, to check this.
• Large spots (classes D, E and F) which are not marked as usable for Heavy aircraft.
• Airports where every spot has the same airline restriction. This happens with some in the US where people have marked every parking location as being usable only by SWA, for example. This effectively means that all SWA aircraft can park anywhere, and that for all other aircraft the airline restriction will have to be ignored, meaning that they can also park anywhere.