VectorHeavy · Air Traffic Control Simulator
Two free browser ATC simulators, compared honestly. Where each one leads, and which you should play.
If you have worked a browser radar scope before VectorHeavy, there is a good chance it was openScope. It is the open-source project that showed a generation of us that a real approach-control simulation could live in a browser tab: no install, no license, just a scope and a problem to solve. Its airport library spans the globe, its procedures run deep, and its code is open for anyone to read, fork, and improve.
We have enormous respect for it. VectorHeavy stands on the shoulders of the browser ATC games that came before it, atc-sim and openScope especially, and it would not exist in the shape it does without the trail they cut first. This page is an honest comparison for anyone deciding between the two. We are not going to pretend openScope is behind us, because in several ways it is ahead, and we will say exactly where.
Side by side
| Area | openScope | VectorHeavy |
|---|---|---|
| Airports | Dozens of real fields worldwide, many contributed by its community. | Seven real US airports, built from published FAA data, with more on the way. |
| Source code | Open source (MIT). Anyone can read it, fork it, and add an airport. | Closed source. In its place we publish a Fidelity Ledger: an adversarial audit of our rules against the FAA orders. |
| Procedures | A deep, mature library of SIDs and STARs across many facilities, years in the making. | Published RNAV STARs with descend-via are live; SIDs and a two-step ILS clearance are in development. |
| Radio | Text readbacks on the strip and command log. | Voiced radio: every instruction gets a spoken pilot readback, and the frequency chatters, right in your browser. |
| VFR and general aviation | Focused on the IFR airline picture. | VFR pattern traffic and light GA are modeled alongside the airline flow, with a see-and-avoid separation regime of their own. |
| Wake turbulence | In-trail wake separation between aircraft. | In-trail wake separation plus modeled same-runway wake departure intervals, non-waivable, off the heavy's rotation. |
| When you slip | Reset and try again. | A session-ending loss triggers an after-action review, with a one-minute rewind to replay the moment and learn from it (unrated). |
| Development | A mature, steady, community-maintained project. | Under active development, shipping new facilities and procedure eras. |
The short version: openScope has more airports, a longer procedure history, and open source on its side. VectorHeavy adds a voiced radio, VFR and GA traffic, wake departure intervals, and an after-action review with rewind, and it is moving fast.
Which should you play
You want the widest choice of real airports worldwide, you love a deep, mature SID and STAR library, or you want to read the code and contribute, right down to adding your home field. It is a genuinely great, generous open-source project, and for airport breadth and hackability it is still the one to beat.
You want to hear the frequency, with spoken pilot readbacks and radio chatter, work VFR pattern traffic and GA next to the airline flow, learn from a session that ends in an after-action review you can rewind, and follow a sim that is shipping new facilities and procedure eras. Start on a small tower and work up to Atlanta or Denver.
Curious exactly where our rules match the FAA orders and where we simplify? Read the Fidelity Ledger, our public, adversarial audit of the model.