You talk, it listens
Hold push‑to‑talk (a key or a yoke button) and speak. faster‑whisper transcribes locally and is primed with this flight's callsign, stations, runways and taxiways, so it hears "hold short runway one three", not "whole short".
Microsoft Flight Simulator 2024 · Windows
Air traffic control that never leaves your computer.
LocalTC gives you a full IFR flight on the radio — clearance delivery to taxi‑in — with your voice, real phraseology and readbacks that are actually checked. Speech recognition, the voices and the language model all run on your own machine.
No cloud. No account. No API keys. No monthly fee. Ever.
- $0 forever
- Offline after setup
- Open source
LocalTC
COM1 118.300
COM2 121.700
XPDR 4512
Flying
ATCQuick Settings
Live MapAirport Lookup
DestCYYC
Squawk4512
AltFL350
Rwy08R
Right Ctrl held — talking
What it does
Everything below runs on your PC while you fly. Nothing here is a demo or a mock-up — it is what LocalTC does today.
Every controller has a voice
ATC answers through Piper with a proper radio effect — band-pass, compression, carrier fade, a squelch burst at the end. Each station draws its own speaker from a pool of 40, and keeps it: Phoenix Tower never sounds like Phoenix Approach.
A real IFR flight, in order
Clearance delivery → ground → tower → departure → centre → approach → tower → ground. Taxi routes are computed from the sim's own taxiway graph. Phraseology comes from FAA templates, so routine calls are word-for-word correct every time.
Readbacks that count
Get it right and you get "readback correct". Get it wrong and you get "negative, squawk 4512". Miss something and you get "read back hold short runway 13". Nearly right — "12.1" for 120.1 — gets "confirm". Self-corrections count.
A small language model, kept on a leash
A 1B–4B model via Ollama reads what you said and fills in a small form. It never talks to you and never decides anything: every value it reports must actually appear in your words, or the whole answer is thrown away and the grammar wins.
Go off script
"Request direct BLAKO." "Request vectors for the ILS." "Could we get runway 16R?" "We'd like the visual." "Moderate chop at seven thousand." "Going around." You get a real answer — or a real "unable", with the reason.
Radar vectors and sequencing
Headings and altitudes mid-flight, speed control on the arrival, a turn to intercept the final. Tower sequences you against the sim's real traffic — "number two, follow the 737 on a four mile final" — and sends you around if the runway is still occupied.
ATIS and weather it builds itself
MSFS won't hand out its ATIS, so LocalTC makes one: wind and gusts, visibility, temperature, altimeter, approach and runway in use, and cautions. Tune it and hear it on a loop. The letter advances when the weather really changes, and ATC tells you when it does.
ATC starts things too
Traffic advisories on the sim's real AI traffic. "Check altitude, maintain five thousand" when you drift. "How do you read?" when you go quiet. A nudge when you sit on the old frequency after a handoff. And a full emergency tree when you declare one.
An optional copilot
Assist reads back every instruction and tunes COM1 for you. Full works the whole radio — clearance, taxi, ready for departure, check-ins, final — while you just fly. Turn it on or off mid-flight with a switch.
The app
Radios and transponder up top, the airport's frequencies to click, your clearance at a glance, and the radio log underneath. Plus a live map with your track and AI traffic, an airport lookup with runways and taxiways, and one-click SimBrief import.
Private by construction
Your microphone audio is transcribed on your CPU or GPU. The model runs on your machine. There is no server to talk to, no account to make, no telemetry. Pull the network cable and the whole thing still flies.
Why pay monthly for this?
The good paid ATC add-ons are genuinely good. They also bill you every month, need a live internet connection, and send your voice to somebody else's server. LocalTC trades that for a one-time install.
| LocalTC | A typical ATC subscription | |
|---|---|---|
| Price | $0, forever | Usually $10–$20 a month |
| Works without internet | Yes — that's the point | No, it's a cloud service |
| Where your voice goes | Your CPU or GPU | Uploaded and processed remotely |
| Account, login, DRM | None | Required |
| If the company folds | Still on your disk, still flies | It stops working |
| Change the phraseology | Edit a text file | File a feature request |
| Read the code | All of it, on GitHub | Closed |
| Usage limits | None — it's your hardware | Often tiered by hours |
What a subscription costs you while you fly
Subscription
$540
LocalTC
$0
If LocalTC saves you that, and you want to say thanks, a coffee is plenty.
Honest caveat: a subscription buys you a team, a support desk and a roadmap. LocalTC is one person and an open repo. If a bug annoys you, you can file it — or fix it.
Install
Windows, with MSFS 2024. One installer does the lot: Python, LocalTC, Whisper, Piper, Ollama, CUDA if you have an NVIDIA card, and the models sized for your machine.
1
Get the files
Download or clone the repository from GitHub.
git clone https://github.com/duckiest428/LocalTC.git
2
Run the installer
Double-click Install LocalTC.cmd, or from PowerShell:
powershell -ExecutionPolicy Bypass -File install\install.ps1It picks the light, balanced or quality model set from your RAM and graphics card. After this, flights work offline.
3
Fly
Open LocalTC from the desktop shortcut. Import your SimBrief plan or type one in, press Start, and call for your clearance. Mute the sim's own ATC first: Sound → Character voices → 0.
No NVIDIA card?
It runs on the CPU. Whisper's base.en transcribes a transmission in
about 0.4 s on a laptop CPU, and ATC's voice takes about 0.3 s to synthesise. Pass
-Cpu to the installer, or -NoOllama to run on
the grammar alone.
Where it is
Working today
- The full IFR flow, clearance delivery to taxi-in
- Voice in and voice out, with push-to-talk
- ATIS, weather and the runway in use
- Radar vectors, speed control, approach clearances
- Traffic sequencing and go-arounds against the sim's AI
- Emergencies, and off-script requests
- The copilot, in assist or full
- The app: map, airport lookup, SimBrief, settings
Not yet
- SIDs, STARs and published arrivals — ATC clears "as filed" and vectors you instead
- AI aircraft talking on the frequency alongside you
- VFR and ICAO phraseology (it speaks FAA)
- macOS and Linux at the controls — they're for development against recordings
Nothing here is hidden behind a paywall or a "pro" tier. When it's built, it ships.
Free, and staying free
LocalTC is built in spare time and given away. There's no tip jar in the app, no nag screen and no locked feature. If it made a flight better, that's the whole reward — and if you'd like to buy the coffee that wrote the next feature, the door's open.