Flattening Airports In X-Plane 11: A Step-By-Step Guide

Flattening airports in X-Plane 11 is a relatively simple process, but it does require some technical know-how. The process involves adding a flatten tag to the apt.dat file, either manually or by using the WED tool. This process must be repeated for each airport that requires flattening. However, it's important to note that the current flattening engine has some limitations, such as flattening an area larger than the airport surface, which may result in crushed mountains nearby. Additionally, the mechanism is imprecise and may not work well for airports in hilly terrain.

Editing the apt.dat file

It's important to note that this process needs to be repeated for each airport you want to flatten. Additionally, the current flattening engine has some limitations. It flattens an area larger than the airport surface, which may crush surrounding mountains, and it only flattens vertices within the flattening area, not whole triangles. As a result, airports in hilly terrain may not be suitable for flattening.

Another option is to use the 130 code in a custom airport area to increase the airport boundaries and the amount of flattening. However, this method is imprecise and may not produce the desired results.

If you're using X-Plane 12, you can also apply a fix programmatically after each update to ensure your changes aren't overwritten. This can be done using a bash script and perl, as shown in the source material.

Using WED

To flatten an airport in X-Plane 11, you can use the World Editor (WED). This is a tool that allows you to create and edit airports and other scenery in the X-Plane simulator.

Alternatively, you can manually edit the apt.dat file outside of WED. To do this, open the file in a text editor and find the airport you want to flatten. Add the line "1302 flatten 1" below the line with the airport's name. This will need to be done for each airport you want to flatten.

It is worth noting that the default airports in X-Plane are already pre-flattened, so you may not need to make any changes. Additionally, using the 130 code in a custom airport area can increase the amount of flattening, but this may not be precise and can crush mountains around the airport.

Overall, using WED is a straightforward way to flatten airports in X-Plane 11. By either checking the 'always flatten' box or manually editing the apt.dat file, you can easily make the necessary changes to create a flat airport surface.

Manually editing the apt.dat file

To flatten an airport in X-Plane11, you need to add a flatten tag to the apt.dat file. This can be done in WED by selecting the airport and checking the box to "always flatten". Alternatively, you can manually edit the apt.dat file in a text editor.

To manually edit the apt.dat file, open the file in a text editor and find the offending airport. The airport header will look something like this:

1 149 0 0 PANC Ted Stevens Anchorage Intl 1302 city Anchorage 1302 country USA United States 1302 datum_lat 61.174155556 1302 datum_lon -149.998188889 1302 faa_code ANC 1302 gui_label 3D 1302 iata_code ANC 1302 icao_code PANC 1302 region_code PA 1302 state Alaska 1302 transition_alt 18000

To flatten the airport terrain, add the line "1302 flatten 1" after the airport header. The block should now look like this:

1 149 0 0 PANC Ted Stevens Anchorage Intl 1302 flatten 1 1302 city Anchorage 1302 country USA United States 1302 datum_lat 61.174155556 1302 datum_lon -149.998188889 1302 faa_code ANC 1302 gui_label 3D 1302 iata_code ANC 1302 icao_code PANC 1302 region_code PA 1302 state Alaska 1302 transition_alt 18000

Note that you will need to do this for each airport you want to flatten. Additionally, the current flattening engine has some limitations. It flattens an area larger than the airport surface area, which may crush mountains around the airport. It also only flattens vertices that are in the flattening area, not whole triangles, which can cause sloping.

Applying the fix programmatically

To flatten an airport in X-Plane 11, you need to add a "flatten" tag to the apt.dat file. This can be done in two ways: using WED or by manually editing the apt.dat file.

Using WED:

When selecting the airport in WED, there is a checkbox option to "always flatten". This automatically adds the "flatten" tag to the apt.dat file.

Manually editing apt.dat:

Open the apt.dat file in a text editor. Find the offending airport by searching for its ICAO code (e.g., PANC for Ted Stevens Anchorage Intl). Once you've located the airport's entry, add the line "1302 flatten 1" below the line with the airport's name. This will ensure that the airport terrain is flattened.

It's important to note that this process needs to be repeated for each airport you want to flatten. Additionally, when X-Plane is updated, the global airport apt.dat file gets overwritten. To address this, you can apply the fix programmatically after each update. Here's an example of a Bash script that can be used:

#!/bin/bash

APTDAT="/Users/$(whoami)/X-Plane 12/Global Scenery/Global Airports/Earth nav data/apt.dat"

Perl -pi -e '$_ .= qq(1302 flatten 1\n) if /PANC\sTed.+/' "$APTDAT"

This script assumes that the apt.dat file is located in the "Earth nav data" folder within the "Global Airports" directory of X-Plane 12. It uses Perl to search for the PANC airport entry and appends the "1302 flatten 1" line if found.

Another workaround is to create a custom airport directory for flattened airports. However, this approach may result in missing out on future updates and modifications to those airports released by Laminar Research.

Increasing the airport boundaries

To increase the airport boundaries, you can use the 130 code in a custom airport area. This will increase the amount of flattening around the airport. However, this method is imprecise and may crush mountains or other geographical features around the airport. It is therefore not suitable for airports in hilly or mountainous regions.

The 130 code works by flattening an area that is larger than the airport surface area. It also only flattens vertices that are in the flattening area, not whole triangles. This means that if a mesh triangle is partly inside and partly outside the flattening area, only one vertex will be moved, causing the triangle to slope.

To apply the 130 code, you can either use WED (WorldEditor) or manually edit the apt.dat file. In WED, there is a checkbox to "always flatten" when you select the airport. To manually edit the file, open it in a text editor and add the line "1302 flatten 1" below the line with the airport's name.

It is important to note that this method may not be future-proof. When X-Plane is updated, the global airport apt.dat file gets overwritten. One workaround is to apply the fix programmatically after each update. Another option is to create a custom airport directory for flattened airports, but this means losing out on any future modifications to those airports that Laminar Research publishes in its updates.

Frequently asked questions