Learn what SIDs and STARs are, how to select, brief and fly them, and how to handle ATC clearances, altitude limits and FMS mistakes.
SIDs (Standard Instrument Departures) take aircraft from a runway or airport into the en-route structure, while STARs (Standard Terminal Arrival Routes) bring them from en-route airspace towards an airport. Pilots fly the cleared procedure using its chart, navigation data and altitude/speed restrictions, while obeying any ATC amendments.
In real-world aviation, both are published IFR procedures designed to organise traffic and reduce repeated controller instructions. Flight simulators can reproduce them closely, but the line shown by a flight planner is not the procedure: the chart, clearance and aircraft navigation system determine what must actually be flown.
What is the difference between a SID and a STAR?
A SID organises the climb away from an airport, whereas a STAR organises the descent and arrival into the terminal area.
| Procedure | Connects | Usually contains | Does not replace |
|---|---|---|---|
| SID | Runway or airport to an en-route fix | Initial tracks, turns, climb gradients, altitude limits and speed limits | Take-off clearance or an assigned initial altitude |
| STAR | En-route fix to the destination terminal area | Arrival tracks, crossing altitudes, speeds and runway transitions | Descent clearance or an instrument approach |
Some procedures use conventional VOR or DME navigation; others require RNAV or a stated RNP capability. A STAR may lead to an approach fix, end at a holding point or finish where ATC normally supplies radar vectors. It should not be mistaken for the approach itself.
How do you choose the correct SID or STAR?
Choose the procedure that matches the cleared runway, planned route, appropriate transition and the aircraft's navigation and performance capabilities.
- For a SID, match the departure runway and the transition or final fix that leads towards the first part of the en-route flight plan.
- For a STAR, match the route's arrival fix to the STAR entry transition, then consider the expected runway and approach.
- Check required equipment, minimum climb gradients, altitude limits and any restrictions applying only to particular aircraft or times.
- Fly the procedure ATC clears, even if the flight plan originally contained a different one. Clarify any ambiguous transition or runway assignment before accepting it.
Arrival selection causes particular confusion because the closest-looking line may enter from the wrong direction. Our detailed method for matching a STAR to its entry fix, transition and runway covers that decision separately.
How do you fly a SID?
Fly a SID by loading and checking the exact cleared procedure, briefing its first segment and restrictions, then tracking it with the required navigation source while monitoring ATC amendments.
- Obtain the correct chart. Confirm the procedure revision, runway, transition, required equipment, minimum climb gradient and any textual notes. For real flight, use authorised and valid charts and navigation data.
- Read back the clearance precisely. Identify the SID name, transition, runway, initial or cleared altitude and any replacement instructions. A published top altitude does not automatically override an altitude assigned by ATC.
- Load and verify the route. Select the runway, SID and exit transition. Compare every fix and leg with the chart rather than accepting the FMS depiction blindly.
- Brief the opening segment. Know the initial heading or track, first turn point, first altitude restriction, climb requirement and the action required after take-off. This is where workload is highest.
- Configure the guidance. Set the correct navigation source, flight director modes and altitude selector. A conventional SID may require tuned radio aids and selected radials; an RNAV SID requires suitable area-navigation guidance.
- Fly and monitor. Confirm that the active mode follows the intended leg and that the aircraft will meet every applicable restriction. If ATC assigns a heading, direct-to fix or new altitude, follow the amendment and check what the change has removed or retained.
A mistake we see constantly in simulators is turning towards the moving-map line immediately after lift-off. Some departures require a runway heading, a specified track or no turn before a stated altitude. The chart's first instruction controls.
How do you fly a STAR and join the approach?
Fly a STAR by confirming the arrival before top of descent, loading its entry and runway transitions, checking the vertical profile and obtaining descent authority before leaving the assigned altitude.
- Confirm the expected arrival. Check the runway, approach, STAR and entry transition against the route and ATC clearance.
- Insert each component separately. The STAR, runway transition and instrument approach may be distinct selections. Check their junction for duplicated fixes, missing legs or an intentional discontinuity.
- Review the descent. Note each mandatory altitude, altitude window and speed restriction. Make sure the aircraft can descend early enough without relying on an unrealistic last-minute VNAV path.
- Wait for descent authority. Clearance for the lateral STAR does not always authorise descent. Phraseology such as “descend via” has specific meanings, and those meanings vary between jurisdictions.
- Monitor the aircraft's modes. Check that lateral guidance is active and that vertical guidance will respect the cleared altitude and published constraints. The selected altitude can prevent VNAV from descending in many aircraft.
- Handle vectors and direct clearances deliberately. Select heading guidance when ATC vectors the aircraft, or activate the correct direct-to leg when cleared. Recheck any restrictions that the new route bypasses.
A route discontinuity before the approach is not automatically an error. It may represent radar vectors between the end of the STAR and the approach. Do not delete it merely to create an unbroken magenta line; first establish how the chart and clearance connect the two procedures.
Do you have to obey every altitude and speed restriction?
You must obey restrictions that form part of the clearance unless ATC explicitly amends or cancels them, but the effect of amended phraseology varies by country and operating rules.
- At means cross the fix at the stated altitude.
- At or above establishes a minimum crossing altitude.
- At or below establishes a maximum crossing altitude.
- An altitude window requires crossing between its upper and lower limits.
- A published speed restriction must be planned independently of altitude unless the chart or clearance couples them.
Chart symbols are not identical in every charting system, so use the chart legend and textual notes. An “expect” altitude is normally planning information rather than authority to climb or descend. If an ATC instruction appears to conflict with the procedure, ask for clarification rather than guessing which restriction survives.
Can the autopilot fly SIDs and STARs?
A suitably equipped autopilot can track much of a SID or STAR, but it cannot interpret the clearance or guarantee compliance without pilot monitoring.
On an RNAV procedure, lateral NAV guidance normally follows the stored legs, while VNAV may calculate the climbs or descents. Capability differs between aircraft: some systems provide advisory vertical guidance, some can command it, and others require manual vertical modes. Conventional procedures may need heading, VOR or localiser modes instead.
Always distinguish armed from active modes. A procedure can be entered perfectly while the aircraft remains in heading or altitude-hold mode. Direct-to commands, vectors, manually created waypoints and route discontinuities can also stop VNAV from honouring later restrictions.
Why does the FMS route not match the chart?
Most SID and STAR mismatches come from selecting the wrong transition, mixing navigation-data revisions or mishandling the boundary between the arrival and approach.
| Problem | Likely cause | Fix |
|---|---|---|
| The route doubles back | Wrong entry or exit transition | Reload the procedure with the transition that connects to the en-route plan |
| A fix or procedure is missing | Chart and navigation database use different revisions | Use matching data rather than manually guessing the changed procedure |
| The route stops before the approach | Vectors or a manual-sequencing leg | Leave it until the clearance supplies the next heading, fix or approach segment |
| A restriction disappears | A direct-to command bypassed its fix | Review the active leg and confirm the amended restriction with ATC |
| The aircraft ignores the descent path | Wrong vertical mode or altitude selector setting | Check the flight-mode annunciator, cleared altitude and VNAV status |
| The route changes after a runway update | Old runway transition remained loaded | Reload, compare with the chart and brief the changed legs |
In a simulator, the built-in avionics and flight planner may use different navigation data, so procedure names or legs can disagree. For one platform-specific example, we explain how to load departures, arrivals, transitions and approaches in X-Plane 12 and check them for discontinuities.
How should you practise SIDs and STARs in a simulator?
Practise one procedure at a time with the chart open, predictable weather and enough fuel and altitude margin to pause, review or repeat a troublesome segment.
Start by hand-flying or closely monitoring the lateral path, then add vertical restrictions and ATC changes. Use matching chart and navigation-data revisions where possible, and verify the route waypoint by waypoint. The useful skill is not making the map line continuous; it is understanding what the clearance requires and recognising when the aircraft is not doing it.