SIDs & STARs

SIDs and STARs are published flight procedures that aircraft follow during departure and arrival. They define a sequence of waypoints with altitude and speed restrictions at specific fixes. In radarcontrol.io, you manage these by telling aircraft to follow the procedure ("descend via") or by overriding individual constraints when traffic requires it.

What they are

A SID (Standard Instrument Departure) is a published route from a runway to the en-route airway structure. It tells departing aircraft which waypoints to fly and what altitudes to maintain at each fix.

A STAR (Standard Terminal Arrival Route) is a published route from the en-route structure to the airport area. It brings arriving aircraft from cruise altitude down to an approach-ready altitude through a series of waypoints with descent and speed constraints.

Both exist to keep traffic flowing predictably. Without them, every aircraft would need individual routing and altitude instructions.

Availability

SIDs and STARs are currently available for select US airports only, sourced from FAA CIFP data. International airports and smaller US airports without published RNAV procedures will not have procedure data. Aircraft at these airports get standard routing instead.

How they work in the sim

Aircraft spawn with a SID or STAR already assigned. You'll see the procedure name in the flight strip and radar panel. But the aircraft won't follow the procedure constraints automatically. You need to issue "descend via" or "climb via" first.

Once active, the aircraft:

• Descends (or climbs) to meet each constraint at the right fix
• Starts descent at the calculated top-of-descent point (300ft per nautical mile)
• Decelerates to meet speed restrictions within 20nm of the fix
• Reports "unable" if it can't physically make a constraint (too high, too close)

You can cancel at any time, override specific constraints, or just assign an altitude directly.

Commands

Command	What it does
dv	Descend via the STAR
cv	Climb via the SID
xp	Cancel all procedure restrictions
x GREKI 240	Cross GREKI at FL240
rdv	Resume descend via (after cancellation)
rcv	Resume climb via

These chain with other commands. AAL123 dv s250 activates descend via and sets speed 250.

When to use what

• dv when you want the aircraft to handle its own descent profile. Best when traffic is light.
• x FIX ALT when you need a specific altitude at a fix for spacing or sequencing. The rest of the procedure stays active.
• A direct altitude like c280 cancels descend via entirely. Use this when you need to stop the descent for traffic.
• rdv to re-engage the procedure after a manual altitude override.

Constraint types

Each fix on a SID/STAR can have an altitude constraint, a speed constraint, or both.

Type	Meaning	Example
At	Must cross at exactly this altitude (200ft tolerance)	Cross GREKI at FL240
At or above	Must be at or above this altitude	Maintain 3,000ft or above at CESID
At or below	Must be at or below this altitude	Cross CCC at or below FL240
Between	Must be within this altitude window	Cross HUULK between 8,000 and 10,000

Speed constraints work the same way - "at or below 250kt" means don't exceed that speed at the fix.

The 250kt restriction below 10,000ft is always enforced regardless of procedure status, unless explicitly waived.

Reading the radar

When you hover or pin an aircraft with a procedure, you'll see:

• Route overlay - constraint fixes show a ring around them with altitude/speed annotations below. Blue means upcoming, green means met, red means busted.
• Aircraft label - shows ▼PARCH4 (STAR) or ▲DEEZZ5 (SID) when descend/climb via is active.
• Route color - green for SIDs, blue for STARs (yellow when pinned, as usual).

The sidebar procedure panel shows the full constraint list with status indicators:

• ▶ next constraint to meet
• ✓ satisfied
• ✗ busted
• · pending

Scoring

Good procedure management earns points. Sloppy work costs them.

Event	Points
Constraint met	+40
Constraint busted	-60
All constraints met (perfect procedure)	+100 bonus
Continuous descent, no level-offs	+75 bonus

The efficient descent bonus rewards keeping aircraft on a smooth descent path without stopping them at intermediate altitudes for traffic. It's hard to earn in busy sessions.

Common workflow

A typical STAR arrival goes like this:

1. Aircraft enters sector at FL350 on the PARCH4 arrival
2. You issue AAL123 dv - aircraft begins following the STAR
3. Aircraft descends to meet FL240 at CCC, then 12,000 at ROBER
4. Traffic conflict - you issue AAL123 c280 to stop the descent (cancels via)
5. Conflict resolved - you issue AAL123 rdv to resume the STAR
6. Aircraft meets remaining constraints, you vector to the ILS

For SIDs, departing aircraft get cv after takeoff. They climb through altitude gates automatically.

"Unable" calls

If an aircraft is too high and too close to a constraint fix, the pilot calls "unable." This happens when the required descent rate exceeds 1,000 feet per nautical mile - steeper than any aircraft can physically descend.

When this happens, the descend via is automatically cancelled and the constraint is marked busted. You'll need to either:

• Issue a manual altitude and re-sequence the arrival
• Vector the aircraft for a longer path to the next fix

Plan descents early. If you keep aircraft at FL350 until 10nm from a fix that requires FL240, they can't make it.

Procedure data in scripts

Scripts can read procedure information and respond to constraint events:

onSpawn((aircraft) => {
  if (aircraft.procedureState?.procedureType === 'STAR') {
    aircraft.descendVia();
  }
});

onConstraintSatisfied((e) => {
  log(`${e.cs} met ${e.fix}`);
});

onConstraintBusted((e) => {
  log(`${e.cs} busted ${e.fix}: ${e.reason}`);
});

Load into sim

The procedures API lets you look up any SID or STAR:

onTick(({ procedures }) => {
  const star = procedures.getSTAR('PARCH4');
  // { id, airport, waypoints, altitudeConstraints, speedConstraints, runwayTransitions }
});

Load into sim

See the API reference for the full scripting API.

Quick reference

COMMANDS
  dv, rdv           Descend via STAR / resume
  cv, rcv           Climb via SID / resume
  xp                Cancel procedure restrictions
  x GREKI 240       Cross GREKI at FL240
  x GREKI 12000ft   Cross GREKI at 12,000 feet

BEHAVIOR
  Altitude cmd      Cancels descend/climb via
  Speed cmd         Does NOT cancel via
  Hold              Preserves via (resumes after exit)
  Unable            Auto-cancels via, busts constraint

SCORING
  Constraint met    +40
  Constraint busted -60
  Perfect procedure +100
  Efficient descent +75