What it is
A 3-D model of light aircraft flying the visual circuit at a small airfield, shown as a top-down radar scope with a vertical profile strip underneath. Every pilot flies a realistic but imperfect circuit: wind and gusts push them around, and a personal skill level sets how sloppy their heading, height and speed are.
The experiment: by default there is no airborne collision avoidance at all. Only ground traffic gives way. The question is how long a busy circuit lasts before the first near miss or collision, and what changes when pilots can see or a tower controls the traffic.
Getting started
- Set a clock speed in the Simulation section. 1× is real time; 16×–64× fills the circuit in a few seconds of your time. Space pauses, +/− change speed, . single-steps.
- Launch an aircraft with the numbered Spawn buttons or keys 1–4: one circuit then land, continuous touch-and-goes, take off and depart, or an inbound join from 5–6 NM out. Ground spawns start on the apron and taxi to the hold.
- Turn on Auto-traffic to add a random mix every N seconds. Watch Conflict analytics for near misses, collisions and the time to first collision, and the Event log for what happened.
- Look around: drag to pan, wheel to zoom, click a target to select it. The Selected aircraft section shows its state and closest point of approach. f fits the circuit.
Interesting things to try
- See-and-avoid (Pilots & tower): pilots scan for traffic with high-wing and low-wing blind spots and take uncoordinated avoiding action. Select an aircraft to see its vision range and which traffic it has spotted.
- ATC tower: one frequency with realistic speech time, standard circuit calls, sequencing and a circuit capacity. Excess traffic is held on stand, at the hold or orbiting outside. Read along in the radio panel.
- Wind and runway (Environment): change the wind and the auto runway flips. Taxiing departures re-route and the circuit rebuilds. Try a right-hand circuit or a higher circuit altitude.
- Pilot skill: untick random and slide skill low for wandering circuits and go-arounds, or high for tidy ones.
- Join type: straight-in, 45° downwind and overhead joins each create different conflict geometry with circuit traffic.
- Near-miss thresholds (Display) define the box that counts an encounter. Copy stats JSON exports the counters and event log.
- Seed: the same seed with the same Auto-traffic settings replays an identical run, so you can compare options fairly.
- AI pilot: with an OpenRouter key you can spawn an aircraft flown by a language model that receives situation reports the way a pilot would see them. Best at 1×.
- Layout: every sidebar section collapses, and can be popped out into a floating window and dragged anywhere. Reset layout puts everything back.
Keyboard
space pause · + − clock speed · . step · 1–4 spawn · c circuit path · t trails · f fit circuit · Esc deselect · ? this help
Hover the ⓘ next to each section title for details of that section.