How do I change an aircraft's ATC callsign in FSX?

In FSX and FSX: Steam Edition, change the callsign temporarily through the selected aircraft’s Details panel, or edit that variation’s aircraft.cfg entry for a permanent default. Set atc_airline to a recognised spoken callsign and atc_flight_number to the number; use atc_id for the registration.

How do I change the callsign for one FSX flight?

1. Open Free Flight and select the option to change the current aircraft.
2. Highlight the aircraft and open its Details panel.
3. Enter a tail number, select an available airline callsign, and enter the flight number.
4. Enable the Heavy option only when appropriate, then accept the changes and load the flight.

This is the safest method because the airline list contains callsigns the installed FSX voice pack can pronounce. The selection applies to that flight; a saved flight may retain it, but it does not reliably redefine the installed aircraft variation.

How do I make the FSX callsign permanent?

Edit the relevant [fltsim.x] section in the aircraft’s aircraft.cfg file. Our explanation of the standard boxed and Steam aircraft-folder paths shows where the aircraft directories and configuration files are normally stored.

1. Close FSX so it cannot retain or overwrite the loaded aircraft configuration.
2. Back up aircraft.cfg before making any changes.
3. Find the correct variation by matching its title, ui_variation and texture entries. Each livery can have a different callsign.
4. Edit the ATC fields in that variation’s [fltsim.x] section. For example:

• atc_id=N123AB
• atc_airline=World Travel
• atc_flight_number=452
• atc_heavy=0

1. Save the file as aircraft.cfg, not aircraft.cfg.txt, then restart FSX and reload the aircraft.

Use the airline’s spoken telephony callsign rather than assuming its company name is valid. For example, an airline may be identified on air by a callsign completely different from its trading name. This worked aircraft.cfg callsign example demonstrates the same type of edit.

What do the FSX ATC callsign fields control?

The separate atc_type and atc_model entries identify the aircraft type and model; they do not replace the airline callsign and flight number. If the Heavy suffix is unclear, our explanation of when ATC uses “Heavy” covers the distinction.

Why does FSX ATC ignore or mispronounce the new callsign?

Typing text into atc_airline does not create new speech. If that phrase is absent from the FSX voice pack, ATC may omit it, fall back to the registration or pronounce something unexpected.

• Unknown airline: choose a callsign offered in Aircraft Details, copy the exact value from a working aircraft, or install a compatible voice-pack addition such as this FSX callsign expansion for EditVoicePack.
• Wrong livery edited: check the active variation’s title and ui_variation; changing another [fltsim.x] block has no effect.
• File did not save: Windows may block edits under a protected Program Files directory. Copy the file somewhere writable, edit it, then copy it back with administrator permission.
• Old value remains: reload the aircraft or restart FSX. A previously saved flight can also contain its own aircraft details.
• Add-on utility overwrites the edit: use the aircraft developer’s configuration utility when one is supplied, because it may regenerate aircraft.cfg.

Does aircraft.cfg change my online-network callsign?

No. These entries control FSX’s built-in ATC and aircraft details. Multiplayer networks and their pilot clients normally use the callsign entered when connecting, so change it in that client rather than relying on aircraft.cfg.