Fix an add-on airport floating or sunk in the ground by checking duplicate scenery, mesh elevation, load order, compatibility and terrain cache.
An add-on airport floats above or sinks into the ground when its runway, flatten or object elevations do not match the active terrain. Across Microsoft Flight Simulator, FSX, Prepar3D and X-Plane, the usual causes are duplicate airports, incompatible mesh, wrong scenery priority, an outdated package or stale cached terrain.
The shape of the error provides an early clue. A plateau or cliff around the whole airport usually indicates a flatten or terraforming mismatch; a runway cutting through otherwise correct terrain often points to a duplicate airport definition. Floating buildings over correctly placed pavement are more likely an object-placement or dependency problem.
What causes airport elevation errors?
Most airport elevation errors occur because two scenery components disagree about the airport's reference altitude or surrounding ground.
- Duplicate airport packages: Two add-ons may define the same ICAO code, or a third-party airport may overlap a separately installed handcrafted airport.
- Conflicting terrain: Regional mesh, photogrammetry, orthophoto scenery or another airport's terraforming can override the intended ground profile.
- Incorrect scenery priority: The airport, flatten, overlay and mesh load in an unsuitable order.
- Simulator-version mismatch: Terrain and exclusion systems can change between simulator generations. If the package was made for an earlier Microsoft simulator, check its compatibility between MSFS 2020 and MSFS 2024 rather than assuming it will work unchanged.
- Missing companion files: Some airports require a supplied terrain package, object library or elevation correction. Installing only the main airport can leave its objects and ground at different heights.
- An authoring error: If the airport fails with every other add-on disabled, its elevation, flatten or object placement may simply be wrong.
How do I fix a floating or sunken add-on airport?
The reliable fix is to establish a clean baseline and add scenery back until the conflicting package reveals itself.
- Confirm the package matches the simulator. Check the supported simulator, airport ICAO and any required update. Do not use an elevation fix made for a different release of the airport.
- Read the installation requirements. Verify that every supplied terrain, library and dependency package is present, but remove optional legacy fixes unless the documentation specifically requires them.
- Build a clean baseline. Exit the simulator, then disable all unrelated third-party scenery. On a PC installation of MSFS, temporarily move unrelated packages out of
Community; on console editions, use the simulator's content-management controls. Our MSFS 2024 installation and package-isolation guidance explains the process without deleting add-ons. - Test the airport by itself. If the default airport is correct but the add-on alone is wrong, the airport is incompatible, incomplete or defective. If the add-on works alone, another package is conflicting. If the default airport is also distorted, investigate base terrain, streamed data or cache.
- Restore likely conflicts in small groups. Start with regional mesh, terrain enhancements, orthophoto packages and other scenery covering the same area. Restart the simulator between meaningful changes because scenery may remain loaded during a session.
- Remove duplicate airport definitions. Keep one third-party version of the airport. In MSFS, do not delete core simulator files: an ordinary stock airport is normally left in place because the replacement should exclude it, while a separately installed handcrafted version may need disabling. See our explanation of when an MSFS 2024 default airport should be disabled.
- Correct the scenery order. Put airport scenery above broad-area overlays and mesh where the simulator uses an explicit priority list. Package order alone cannot reconcile two add-ons that define incompatible elevations.
- Refresh terrain data only after removing conflicts. In MSFS, recreate the rolling cache if the problem involves streamed terrain. Let FSX or Prepar3D rebuild its scenery indexes after library changes. In X-Plane, review
scenery_packs.inirather than deleting it blindly, because automatic regeneration can produce an unsuitable order. - Update or reinstall the airport. If it remains broken in a clean setup, install a complete package from a known-good archive. Preserve the old installation outside the simulator until the replacement has been tested.
What scenery order should I use?
The correct order depends on the simulator, but detailed airport data generally needs priority over broad regional scenery while base mesh remains lower.
| Simulator | Recommended check | Important caveat |
|---|---|---|
| MSFS 2020/2024 | Disable duplicate airports, mesh and terraforming packages covering the same location. | Folder names do not provide a dependable manual priority system; exclusions and package relationships matter more. |
| FSX/Prepar3D | Place the airport and its supplied flatten above broad regional scenery. | The terrain engine may still select higher-resolution mesh, and a separate elevation-correction BGL can override the expected result. |
| X-Plane | Keep custom airports above Global Airports, overlays below airports, and mesh or orthophoto tiles near the bottom. | An airport package cannot always correct an incompatible underlying mesh merely by being moved higher. |
Why is only part of the airport floating?
A partial elevation problem usually involves a specific scenery component rather than the entire terrain package.
- Runway or apron only: Look for a duplicate airport definition, old flatten or mismatched reference altitude.
- Buildings, jetways or lights only: Check for a missing object library, companion package or objects authored at an absolute altitude.
- Static or AI aircraft only: The model's contact points or placement may be wrong. If the pavement and other objects are correct, terrain is unlikely to be the cause.
- Spikes, trenches or abrupt walls: Suspect competing mesh, terraforming polygons or damaged terrain data.
- The defect appears only after approaching the airport: Test without streamed scenery and refresh the terrain cache after confirming that no package conflict remains.
Should I install an airport elevation correction file?
Use an elevation correction only when it was made for the exact airport, simulator and scenery combination you have installed. Generic or obsolete corrections frequently create the floating airport they were intended to cure.
FSX and Prepar3D airports sometimes install a small companion BGL in a global folder such as Scenery\World\scenery. That file can survive after the main airport is removed and continue forcing the old elevation. Disable only a file positively identified as third-party; deleting an unknown base-simulator BGL can damage other airports.
For MSFS, an updated airport or compatible terrain package is preferable to stacking another generic flatten on top. In X-Plane, a conflicting mesh tile may require a compatible or patched tile rather than another airport overlay. If the airport still fails with only its documented dependencies enabled, the useful evidence is the ICAO, simulator version, package version, affected coordinates and screenshots showing whether the runway, terrain or objects are displaced.