Set a custom X-Plane 12 ATC tail number, tie it to a livery, and fix mismatches between the painted registration and ATC callsign.
To make X-Plane 12 ATC use a custom tail number, set the registration in the aircraft’s Customize panel before starting the flight. For a number tied to one livery, add a one-line tailnum.txt file to that livery’s root folder. Reload the aircraft, then file or re-file the ATC flight plan.
Set the X-Plane 12 ATC tail number
The quickest method is to change the aircraft’s tail-number metadata before opening an ATC session.
- Return to Flight Configuration. Do this before filing the flight plan so ATC does not retain the previous identity.
- Select the aircraft and livery. Choose the livery first because it may supply its own tail-number setting.
- Open Customize. Enter the registration in the Tail Number field if the aircraft exposes one, using a normal format such as
N123ABorG-ABCD. - Load or reload the aircraft. Merely closing the customisation panel may not refresh every aircraft or add-on system.
- File a new ATC flight plan. If one was already filed, cancel and re-file it. Our guide to filing and using X-Plane 12 ATC covers the clearance sequence.
ATC should then address the aircraft by the new registration unless an airline callsign and flight number have been configured instead.
How do I save a different tail number for each livery?
A tailnum.txt file is the most reliable choice when each repaint represents a different registered aircraft.
Create the file at:
X-Plane 12/Aircraft/[aircraft]/liveries/[livery name]/tailnum.txt
It belongs in the livery’s main folder, alongside its other top-level files—not inside objects. The file must contain only the registration on one line:
G-ABCD
Do not write Tail Number=G-ABCD or add comments. Check that the operating system has not silently named it tailnum.txt.txt; on case-sensitive systems, use the exact lower-case filename. If the folder arrangement is uncertain, see our explanation of the correct X-Plane livery folder structure.
| Method | Choose it when | Main caveat |
|---|---|---|
| Customize tail-number field | You need a quick change for the selected aircraft | A livery or add-on may replace the value |
tailnum.txt | The registration should follow a particular livery | The filename and folder location must be exact |
| Plane Maker aircraft setting | You want one default registration for every livery | Aircraft updates can overwrite the edited .acf file |
For an aircraft-wide default, open a backup copy of its .acf in the matching X-Plane 12 Plane Maker and change the tail-number field in the aircraft identification settings. We prefer the livery file for custom repaints because it avoids modifying the original aircraft, particularly with managed or plugin-driven add-ons.
Why does X-Plane 12 ATC still use the old callsign?
An old callsign usually means ATC loaded the identity before the change, or another setting is overriding the registration.
- The flight plan was already filed: reload the aircraft, cancel the old plan and file it again.
- The number exists only in the paint: ATC cannot read lettering baked into a texture; it uses aircraft metadata.
- An airline identity is configured: airline and flight-number fields can make ATC use a commercial callsign instead of the tail number. Clear them if registration calls are required.
- The add-on manages its own identity: some aircraft use a tablet, configuration panel or plugin to set the registration and may overwrite X-Plane’s value after loading.
- The wrong livery is active: confirm that the selected livery is the one containing
tailnum.txt. - You are using online or third-party ATC: these systems normally use the callsign entered in their own connection or flight-plan form, not X-Plane’s livery metadata.
A registration, an airline callsign and a flight-plan identity are related but not interchangeable. Our explanation of how to keep ATC callsigns and registrations consistent covers that distinction.
Will changing the ATC tail number repaint the aircraft?
Changing the ATC identity does not normally alter a registration painted directly into the livery textures.
Some aircraft render the registration dynamically and will display the metadata value, but others have fixed lettering baked into their image files. In the latter case, edit the repaint separately and keep its visible number identical to tailnum.txt; our aircraft repainting guidance explains the visual side without confusing it with ATC configuration.
How can I confirm the new number works?
The first ATC acknowledgement after filing a fresh plan is the practical check.
Select the livery, reload the aircraft and request clearance. X-Plane 12 should display or speak the expected registration, although its speech system may pronounce punctuation and letter groups according to its own rules. If the old identity remains, temporarily remove airline and flight-number details, verify the exact tailnum.txt path, and check whether the aircraft’s own configuration panel is restoring another value.