How do SIDs and STARs work with ATC in a flight simulator?
Learn what SIDs and STARs mean, how ATC clears or changes them, and how to load, verify and fly the correct route in a flight simulator.
In Aviation & Real-World Flying, a SID carries an aircraft from the departure runway towards its en-route flight path, while a STAR brings it from the en-route phase towards an arrival. ATC clears, amends or cancels these procedures; the pilot must load the exact clearance, observe applicable restrictions and follow later instructions.
What do SID and STAR mean in aviation?
A SID is a Standard Instrument Departure: a published IFR route connecting a runway or airport departure path to the en-route structure. A STAR is a published IFR arrival route connecting the en-route structure to the terminal area, usually before the instrument approach begins.
STAR is expanded as Standard Terminal Arrival Route in FAA usage and as Standard Instrument Arrival in much ICAO-style material. The operational idea is the same. Both procedures can contain named fixes, runway branches, transitions, required tracks, altitude restrictions and speed constraints.
SIDs and STARs let ATC clear a defined route without reading every waypoint over the radio. They are not mandatory at every airport or on every IFR flight, and an aircraft must meet any stated navigation or performance requirements. For a fuller explanation of the route structure, see our guide to selecting, briefing and flying published departures and arrivals.
How does ATC use SIDs and STARs?
ATC may approve the procedure in the filed flight plan, assign a different one, or replace part of it with headings, direct-to clearances or another runway.
The filed route is a request, not authority to fly every entered leg. A departure clearance may contain a SID, transition, initial altitude and other restrictions. During arrival, ATC may clear or expect a STAR but issue descent clearance separately.
Exact phraseology and the effect of published restrictions vary by country. Phrases such as climb via and descend via have defined meanings where they are used, but they should not be treated as universal wording in every region or simulator.
| ATC instruction | What it usually means | What to do in the simulator |
|---|---|---|
Expect [SID or STAR] | Plan for the procedure, but it has not necessarily been cleared. | Review or preload it, then wait for the clearance before treating it as the active route. |
Cleared via [SID] | Fly the cleared departure and transition. This wording alone does not always authorise an unrestricted climb. | Load the lateral route and obey the cleared altitude, chart notes and applicable restrictions. |
Climb via [SID] | Where this phraseology applies, follow the SID's lateral path and applicable climb and speed restrictions to the authorised level. | Set the correct altitude, arm the appropriate modes and monitor each restriction. |
Cleared [STAR] | The arrival becomes part of the route, but descent may still need separate authorisation. | Load and brief the STAR without starting an unauthorised descent. |
Descend via [STAR] | Where used, descend on the arrival while complying with its applicable altitude and speed restrictions. | Set the cleared lower limit and monitor VNAV rather than assuming it will meet every constraint. |
Proceed direct [fix] | Intermediate lateral legs are bypassed. | Use Direct-To or activate the correct leg, then inspect the new turn and remaining restrictions before execution. |
Fly heading [number] | Leave the published lateral path and maintain the assigned heading. | Select heading mode. Do not force LNAV across an intentional vector segment. |
A later instruction changes the relevant part of the earlier clearance. It does not automatically answer what happens to every altitude or speed restriction, so ask the controller when the wording is unclear.
How do you load the correct SID or STAR for ATC?
The simulator flight plan, ATC route and cockpit FMS must represent the same clearance if you expect ATC and the aircraft to agree.
- Choose a valid candidate. Check the expected runway, route direction, entry or exit transition, aircraft capability and chart notes. The shortest route is not necessarily an authorised or practical one.
- File it in the system used by ATC. Built-in ATC commonly reads the simulator-level flight plan, while online or add-on ATC may read a separately filed or imported route.
- Copy the complete clearance. Record the runway, procedure name, revision, transition, initial altitude and any amendment. For an arrival, keep the STAR and instrument approach separate.
- Load the cleared procedure. Select it from the FMS, MCDU or GPS procedure database instead of manually entering every fix where possible. Our cockpit procedure-loading instructions cover Boeing-, Airbus- and Garmin-style systems.
- Compare the legs with the chart. Check the first and last fixes, runway branch, transition, turn direction, altitude limits and speed constraints. Use our guide to reading procedure charts and FMS legs if the chart and magenta line appear different.
- Inspect the active leg before take-off or descent. Remove genuine duplicate fixes or route loops, but retain a discontinuity when the procedure expects radar vectors.
- Fly the latest clearance. If ATC changes the route, update the avionics and verify the new path before re-engaging LNAV, VNAV or approach mode.
The failure we see most often is one SID or STAR filed in the simulator planner and another loaded in the aircraft. In Microsoft Flight Simulator 2020 and 2024, built-in ATC may remain tied to the simulator-level plan even after a more detailed aircraft has been reprogrammed through its cockpit systems.
Why do ATC and the FMS disagree?
ATC and the FMS usually disagree because they are reading different route copies, procedure revisions or runway assignments.
- Separate flight plans: ATC follows the filed route while the aircraft follows later cockpit edits. Amend the ATC-facing plan where the system allows it.
- Different navigation data: the simulator, aircraft and ATC system may contain different revisions. A missing transition, renamed procedure or changed runway identifier is a strong clue.
- Wrong transition: selecting the correct SID or STAR name is not enough when it has several entry, exit or runway transitions.
- Runway changed in one place: changing only the approach can leave an obsolete STAR branch, duplicated fixes or a route back across the airport.
- Intentional vector leg: some procedures terminate in radar vectors. Closing that discontinuity may send the aircraft towards final before ATC has cleared it.
- Wrong duplicate waypoint: similarly named fixes can exist in different locations. Check the position and resulting track before executing Direct-To.
- Simulator ATC limitations: scripted ATC can issue late descents or unsuitable routing. Request an alternative where possible and go around if the approach cannot be stabilised safely.
What should you do after an ATC runway change?
After a runway change, reload the affected procedure and inspect the entire terminal route rather than changing only the runway field.
- Confirm the amendment, including the new runway, SID or STAR, transition and expected approach.
- Reload the procedure so the correct runway branch and associated constraints replace the old ones.
- Check every revised leg for loops, duplicated fixes, obsolete branches and unexpected discontinuities.
- Reassess the vertical profile, especially if the change arrives late in the descent.
- Verify the active leg and flight modes before selecting Direct-To, LNAV, VNAV or approach mode.
If there is not enough track distance to become stable, request delay vectors or another instruction. Do not salvage an unstable approach simply because the FMS has accepted the new runway.
Does ATC fly the SID or STAR for you?
No. ATC clears and modifies the route; the pilot flies it manually or uses the aircraft's automation.
LNAV normally follows lateral procedure legs. VNAV may calculate climbs and descents through published constraints, but its capability varies between simulated aircraft. Route edits, an incorrectly selected altitude or an unsuitable vertical mode can cause it to miss a restriction, so monitor the flight-mode annunciator, selected altitude and next constraint.
When ATC assigns a heading, use heading mode instead of allowing LNAV to continue along the procedure. After a direct-to or rejoin instruction, check the active waypoint and intercept geometry before returning to LNAV.
Is a STAR the same as an instrument approach?
No. A STAR delivers the aircraft into the terminal area, while an instrument approach defines the route towards a runway or missed-approach point.
The two may join at a common fix, or ATC may vector the aircraft from the STAR to final. Clearance for a STAR is not clearance for the approach and is never permission to land. Our guide to flying the approach after leaving a STAR explains approach clearance, interception and missed-approach handling.
What if ATC assigns a SID or STAR missing from the FMS?
If a cleared procedure is absent from the FMS, do not substitute a similarly named one without comparing its charted route.
Check the airport identifier, runway, exact procedure name, revision and transition. Also check whether the aircraft and simulator use the same navigation-data source. Airport scenery by itself does not normally add a missing procedure to the avionics database.
Some smaller airports genuinely have no SID or STAR. With live ATC, report that you cannot accept the procedure and request vectors or another clearance. With built-in ATC, the practical solution may be to use routing recognised by both the simulator planner and the aircraft.
Does DBYJAATHC mean a SID or an ATC instruction?
No standard SID, STAR or generic ATC instruction is represented by DBYJAATHC.
It may be concatenated route text, a corrupted database entry or a mistyped identifier. A shorter element such as DBY could be a context-specific fix, airport, operator or database code, but it has no single universal meaning. Compare the text with the filed route, procedure chart and FMS waypoint list instead of inventing an expansion for it.