Learn how to fly a SID in a flight simulator: load the correct runway and transition, verify FMS legs, obey constraints and fix LNAV/VNAV errors.
To fly a SID in a flight simulator, select the departure runway, load the exact SID and transition cleared or planned, verify every waypoint against the chart, then follow its lateral, vertical and speed restrictions after take-off. Use the assigned initial altitude, not the SID's highest published altitude, and monitor automation throughout.
In flight simulators—and in real-world aviation—a Standard Instrument Departure connects the runway area to the en-route structure. Some SIDs are flown entirely by the pilot or FMS; others begin with a heading and require radar vectors. The chart and clearance determine which applies, not the shape of the magenta line.
What does a SID clearance actually mean?
Being cleared for a SID does not automatically clear you to every altitude printed on it. Set the altitude selector to the level assigned by ATC and comply with published altitude and speed restrictions unless the controller explicitly changes them.
Departure phraseology varies by country. A clearance such as climb via SID normally keeps the published restrictions in force up to the authorised altitude, while other regions issue the climb separately. If the clearance and chart appear to conflict, clarify before departure rather than borrowing phraseology rules from another region.
Without live or simulated ATC, choose a sensible initial altitude during planning and treat it as your clearance limit. The SID's published top altitude, where one is shown, is not permission to climb beyond that limit.
How do I load and verify the SID?
Load the SID only after choosing the expected runway, departure procedure and en-route transition. A correctly named SID can still contain the wrong runway branch or exit transition.
- Brief the chart. Identify the procedure name and revision, runway applicability, first heading or fix, minimum climb gradient, altitude and speed restrictions, navigation requirements and final transition. Our guide to decoding SID and STAR chart symbols explains the notation in more detail.
- Check database compatibility. The chart and avionics should represent the same navigation-data cycle. If waypoint names, tracks or restrictions differ, do not assume the FMS is correct merely because it drew a continuous route.
- Select the full procedure. Choose the departure runway, runway transition, SID and en-route transition that join your filed route. In Microsoft Flight Simulator, this may begin by loading the departure through the World Map planner; X-Plane users can follow the equivalent process for building and activating a departure in the FMS.
- Inspect every leg. Compare waypoint order, tracks, distances and constraints with the chart. Look closely for
DISCONTINUITY,VECTORor manual-sequencing legs. A vector discontinuity is intentional and should not be closed unless ATC has cleared you towards the next fix. - Brief the first minute. Confirm the runway, initial heading, first turn condition, first restriction, cleared altitude, navigation source and intended flight-director mode. Set local pressure before take-off and change to standard pressure only at the applicable transition altitude.
How do I fly the SID after take-off?
After lift-off, fly the chart's initial instruction first and engage automation only when the aircraft permits it. The SID may require runway heading, a specific heading, a track to a fix or no turn before reaching an altitude or distance.
- Confirm the runway. Before applying take-off power, compare the displayed runway and first leg with the runway beneath the aircraft. A late runway change requires the SID to be reloaded and briefed again.
- Fly the initial leg exactly. A heading is flown as a heading; an FMS track accounts for wind. Do not turn towards the first visible waypoint if the chart requires maintaining runway heading to an altitude or DME distance.
- Engage the correct lateral mode. Many airliners allow LNAV to be armed before take-off, while other aircraft require NAV mode after becoming airborne. Confirm that the annunciated mode is active rather than merely armed.
- Manage the climb. Use a vertical mode that will honour the restrictions. VNAV may do this automatically, but selected-altitude capture, flight-level change or open-climb modes can bypass an intermediate limit if they are not monitored.
- Cross-check the aircraft. Watch active-leg sequencing, cross-track error, distance to the next fix, altitude trend and speed. The autopilot is following commands, not independently verifying that the loaded procedure is correct.
- Respond to amendments. If ATC assigns a heading, direct-to fix, new altitude or new speed, follow that amendment and update the avionics without erasing the remaining route unnecessarily.
Which lateral guidance does a SID use?
Use FMS guidance for an RNAV departure, radio-navigation guidance for a conventional departure and heading mode for a vector segment.
| SID type | How it is flown | Common trap |
|---|---|---|
| RNAV or RNP | GPS/FMS position and LNAV guidance, with the required navigation capability | Wrong runway transition, inactive flight plan or unsuitable navigation data |
| Conventional | Published headings, VOR radials, DME distances and fixes; an FMS overlay may assist | Wrong CDI source, frequency or inbound/outbound course |
| Radar vector | Published heading followed by headings or a direct clearance from ATC | Turning directly to the next FMS fix without clearance |
If flying offline without ATC, a vector SID cannot be reproduced exactly beyond the vector point. Use the simulator's ATC, choose a fully pilot-navigated departure, or plan a specific vector and recognise that it is a simulation substitute rather than the published procedure.
How do altitude, speed and climb constraints work?
Treat each restriction according to its exact meaning: cross at the stated altitude, at or above, at or below, or within a published altitude window. A speed restriction normally remains effective until its stated fix unless ATC amends it.
Obstacle-driven climb gradients deserve a separate calculation. Convert a published gradient to approximate vertical speed with required VS ≈ groundspeed × gradient ÷ 60. At 120 knots groundspeed, for example, 300 feet per nautical mile requires about 600 feet per minute. Recalculate as groundspeed changes and allow margin rather than aiming at the exact minimum.
Before departure, confirm that the aircraft can meet the gradient at its weight and expected conditions. More thrust does not solve every problem: accelerating early raises groundspeed and therefore increases the vertical speed required to maintain the same feet-per-mile gradient.
Why is LNAV or VNAV not following the SID?
Most SID failures come from an incorrect active leg, wrong navigation source, mode confusion or a mismatch between the chart and navigation database.
| Problem | Likely cause | Fix |
|---|---|---|
| Aircraft turns the wrong way | Wrong runway branch or first leg activated | Fly a safe heading, verify the chart and activate the correct leg only after checking its intercept |
| LNAV stays armed | Aircraft is outside capture limits, flight plan is inactive or the CDI source is wrong | Use heading mode to establish a sensible intercept, select the proper source and confirm the active leg |
| VNAV ignores a restriction | VNAV is not active, the selected altitude blocks it or the loaded constraint is missing | Enter the correct restriction and use pitch, vertical-speed or another suitable mode to meet it manually |
| Route stops at a discontinuity | Expected vector/manual leg or an incomplete procedure | Compare it with the chart; retain an intentional vector leg and close only an accidental gap |
| SID is missing or different | Old or mismatched navigation data | Use a chart matching the installed data, update compatible data, or request and fly another departure |
| Route doubles back after a runway change | Old runway transition remains in the flight plan | Reload the departure, remove obsolete legs and recheck the complete sequence |
When is the SID complete?
The SID ends at its final fix or transition, or when ATC vectors or clears the aircraft away from it. Confirm that the next en-route leg is active, retain the assigned altitude and continue following any amended clearance rather than assuming the aircraft may climb freely.
If joining the airway and managing the rest of the flight is the next problem, our explanation of the complete IFR workflow from clearance to approach shows where the SID fits into the larger flight.