Add support for real-world scheduled traffic by planevan · Pull Request #933 · mmp/vice

planevan · 2026-07-21T14:06:14Z

This pull request adds support for generating traffic from real-world airline schedules.

Instead of relying entirely on randomly generated departures and arrivals, Vice can now load scheduled departures and arrivals from CSV files and generate traffic that closely follows real-world airline operations.

The initial implementation includes a built-in MSP weekday schedule as a proof-of-concept implementation in the M98 Scenario.

Features

Adds a Real World Schedules traffic source.
Loads schedules from CSV files.
Supports built-in schedule catalogs.
Matches scheduled flights to available airlines and aircraft types.
Preserves existing random traffic generation for airports without schedules.
Adds realistic departure gate/taxi timing and queuing for scheduled departures.
Preserves existing random traffic generation when real-world schedules are not used.

Testing

Tested using the included MSP weekday schedule.

Verified:

Schedule loading
Arrival generation
Departure generation
Realistic departure timing
Multiple traffic sessions without crashes

The feature compiles successfully, existing tests pass, and simulator testing showed significantly more realistic traffic flow compared to immediate scheduled departures.

This is intended as a foundation for additional airports and schedules. Eventual additions will include the ability for users to create their own schedules by simply creating an airport file in the schedules folder and dropping their CSV in there. Currently, a schedule.json needs to be used.

Future improvements may include automatic schedule discovery, additional built-in schedules, further refinement of departure sequencing, and arrivals spawning inside TRACON to simulate taking over from another controller.

mmp

This is a great addition and I think will be a huge step forward for the realism of vice. Lots of comments below, some small things, some bigger changes, but overall I think the general form of this is quite good.

mmp · 2026-07-24T23:06:37Z

@@ -0,0 +1,13 @@
+{
+  "airport": "KMSP",


"airport": "KMSP" is somewhat redundant since the airport name is in the folder name. What about a) renaming this file to schedules.json and then b) having the contents be like:

[ { "id": "summer_weekday", "name": "MSP Summer Weekday", "file": "summer_weekday.csv", "description": "Full-day real-world MSP schedule.", "timezone": "America/Chicago" } ]

Good point. I'll refactor it to use a schedules.json catalog within each airport directory.

mmp · 2026-07-24T23:08:28Z

Rather than documenting it here, could you add a short section to website/facility-engineering.html? Maybe a new section after "Arrivals and Overflights" and before"VFR Aircraft" under "Scenario Groups"?

It would also be nice to mention there that routes are taken from existing routes in the scenario file if the departure/destination airports match up.

I moved the schedule documentation into facility-engineering.html, added a new "Real World Schedules" section (including the route reuse behavior), added it to the navigation sidebar, and reduced the README to a pointer to the engineering documentation.

mmp · 2026-07-24T23:12:15Z

+
+	departures            []scheduledDeparture
+	nextDeparture         int
+	departuresInitialized bool


I believe this is unused and could be deleted.

oops This was left over from an earlier version of the traffic provider and wasn't being used anymore. Removed.

mmp · 2026-07-24T23:12:40Z

 	depState := s.DepartureState[ac.FlightPlan.DepartureAirport][runway]
 	if ac.FlightPlan.Rules == av.FlightRulesIFR {
 		if manualLaunch {
-			// Keep them moving and for HFR, request the release immediately.


Please restore this comment.

mmp · 2026-07-24T23:35:37Z

 				validDuration := apMETAR[idx+1].Time.Sub(sampledMETAR.Time)
 				startTime = startTime.Add(rand.Make().DurationRange(0, validDuration))
 			}
 			c.StartTime = startTime


Currently the local time in the UI is shown as "00:00" (unless it's manually edited). I think that if we have if TrafficSoruce == RealWorldSchedule and then do something like

loc, err := time.LoadLocation(schedule.Timezone) local := c.StartTime.In(loc) lc.ScheduleStartMinute = local.Hour()*60 + local.Minute() c.scheduleStartTimeText = formatScheduleStartTime(lc.ScheduleStartMinute)

it will stay in sync.

mmp · 2026-07-24T23:37:55Z

+
+}
+
+// initializeDepartures generates one taxi-out duration for each scheduled


stale comment?

mmp · 2026-07-24T23:44:58Z

+
+const scheduleCatalogFilename = "schedule.json"
+
+// BuiltInSchedule describes one schedule distributed in Vice's resources.


How about renaming this to FlightSchedule (and similarly for BuiltInScheduleCatalog and BuiltInScheduleSummary)? The rationale being that "built-in" is sort of implied and "flight" more accurately describes what it's holding.

mmp · 2026-07-25T00:45:49Z

+	}
+
 	lg.Infof("LoadScenarioGroups total: %s", time.Since(start))
 	return scenarioGroups, catalogs, mapSpecs, briefs, extraScenarioErrors


Let's also return scheduleCatalog here, so that we don't end up re-loading the schedules in newScheduleTrafficProvider. In that way, we load and validate schedules just once, which matches how the scenario loading flow works currently for other things. (Generally, we do all the error checking for scenarios at initial loading time and then the rest of the code can assume that things are reasonable, since we error out and exit if there are scenario errors.)

Roughly, if we then store the full schedule catalog in SimManager, then pass the selected schedule (if any) to NewSim in sim.NewSimConfiguration, then we can store it directly in the Sim. Then Sim.activeTrafficProvider() can be simplified to just pass the schedule to newScheduleTrafficProvider without needing to load it.

mmp · 2026-07-25T00:47:24Z

+	}
+}
+
+func normalizeScheduledAircraftType(value string) string {


Just thinking out loud, should these rewrites be encoded in a JSON file in resources so that people doing facility engineering can add them? Should we just require that the schedule CSV files have these rewrites already done? This partially connects to the question of where the data comes from and how we want to be importing it.

planevan

Restored comments.

planevan · 2026-07-27T17:05:52Z

 	nasFp.AssignedAltitude = util.Select(!isTRACON, ac.FlightPlan.Altitude, 0)
 	nasFp.RNAV = s.State.FacilityAdaptation.Datablocks.DisplayRNAVSymbol && exitRoute.IsRNAV

-	ac.HoldForRelease = (ap.HoldForRelease || exitRoute.HoldForRelease) && ac.FlightPlan.Rules == av.FlightRulesIFR // VFRs aren't held


planevan · 2026-07-27T17:07:29Z

 		return nil, err
 	}

-	// Departures aren't immediately associated, but the STARSComputer will


planevan added 19 commits July 12, 2026 15:21

Refactor automatic IFR traffic behind a provider

86fc026

Add real-world schedule CSV model and loader

8fb45d5

Add built-in real-world schedule catalog

431f7f1

Expose built-in schedules through scenario catalogs

3d0843a

Add real-world schedule launch settings

0914229

Add scheduled IFR departure creation

2c9af19

Schedule IFR departures by published time

4902569

Add bundled MSP development schedule

8644a95

Add real-world schedule launch controls

915692c

Add scheduled IFR arrival creation

fb2e91e

Schedule IFR traffic by selected local time

224d58c

Add independent scheduled arrival and departure controls

744f2e8

Add built-in schedule validation

81e088e

Restore clean schedule provider baseline

ebbd090

Remove real-world schedule gate bypass

636180d

Centralize departure gate delay

ea41ab1

Add taxi delay for scheduled departures

72caaa9

Rename MSP real-world schedule resources

336b8d4

Simplify scheduled departure routing

741cafb

mmp reviewed Jul 25, 2026

View reviewed changes

Address PR review feedback

d79f646

planevan commented Jul 27, 2026

View reviewed changes


		}

		// initializeDepartures generates one taxi-out duration for each scheduled


		const scheduleCatalogFilename = "schedule.json"

		// BuiltInSchedule describes one schedule distributed in Vice's resources.

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planevan commented Jul 21, 2026

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