Traffic

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Traffic

get_traffic lists aircraft and helicopters nearby – AI traffic, live traffic and multiplayer, as far as enabled in the sim. Your own aircraft is excluded. The voice loop answers "Traffic check" the same way.

Parameters

Parameter	Default	Meaning
radiusNm	40	search radius, max. 108 NM (SimConnect's limit)
limit	10	at most this many targets, closest first (1–50)
airborneOnly	false	leave out aircraft on the ground

Per target

ident/callsign, atcId, type, distanceNm, clock, relativeBearingDeg, bearingTrueDeg, altitudeFt, altitudeDiffFt (+ = above), verticalTrend, groundSpeedKt with groundSpeedSource, headingTrueDeg/headingMagDeg, onGround. The closest target has closest: true and a callout:

Traffic, 2 o'clock, 5 miles, 1000 feet above, descending

How values are derived

Value	Notes
Callsign	airline + flight number if both are set (Lufthansa 123), otherwise the registration. Internal live-traffic numbers like 1432126 are not used as callsigns
Type	localization keys (ATCCOM.AC MODEL C441.0.tts) are cleaned up to C441
Clock	relative to your heading, 30° each
Distance	horizontal (great circle)
Altitude difference	like TCAS: against your pressure altitude (1013.25 hPa), because live traffic reports flight levels. "AltitudeReference": "True" switches to true altitude
Ground speed	computed from position changes (5–120 s apart), because the SimVar is useless for live traffic; until then the SimVar with groundSpeedSource: "simvar"
Trend	from vertical speed (±500 ft/min); if a target reports 0, derived from altitude changes

No other aircraft → status: "no_traffic" (AI traffic or multiplayer usually off in the sim). MSFS not answering → no_response.

Traffic warning TRAFFIC_PROXIMITY

While the aircraft is flying, Duopilo scans within 6 NM every 3 s. An airborne target closer than 3 NM and within ±1000 ft triggers a caution with callout; then 60 s quiet. It rests below 500 ft AGL, on the ground and while paused.

"Duopilo": { "Monitoring": { "Traffic": {
  "ProximityRangeNm": 3, "ProximityAltitudeFt": 1000, "ProximityCooldownSec": 60, "ScanIntervalSec": 3,
  "AltitudeReference": "Pressure", "MessageLog": true
} } }

Off: "DisabledRules": [ "TRAFFIC_PROXIMITY" ].

This is not TCAS: no resolution advisory, no prediction of the closest point of approach – just distance and altitude right now. Real TCAS RAs from the aircraft's FMA are called out separately (TCAS_RA).

Separate SimConnect connection

Traffic uses its own SimConnect connection directly via the native SimConnect.dll and only reads what each message actually contains (dwSize). This replaced the managed library for traffic after crashes in test flights. The background scan only queries numbers; callsign and type are known if get_traffic saw the target in the last 15 minutes.

Every response is logged to %LOCALAPPDATA%\Duopilo\logs\traffic-messages.csv (~250 KB per flight hour, rotated at 10 MB); get_traffic → messageCheck summarizes anomalies. Off: "MessageLog": false.

Traffic test (developer)

First step towards Duopilo's own traffic: traffic_test_start spawns one AI aircraft (DUO01) that flies a final approach by waypoints, lands and stops on the runway. Off by default – switch it on with "TrafficTest": { "Enabled": true } in appsettings.Local.json.

• A1: spawn 5 NM out with the gear down. A2: spawn 15 NM out, gear down at 10 NM.
• traffic_test_status shows the evaluation (touchdown, floating, speed, stop point), samples go to %LOCALAPPDATA%\Duopilo\traffic-tests\.
• traffic_test_stop removes the aircraft (also after 15 minutes and when Duopilo exits).

Background and plan: research on own traffic.