How do I fly an ILS approach in FlightGear?

To fly an ILS approach in FlightGear, choose an ILS-equipped runway, tune its localiser frequency in NAV1, set the published inbound course, intercept the localiser from below the glideslope, then follow the lateral and vertical needles to decision altitude. Land only with the required runway references visible; otherwise, fly the missed approach.

The localiser provides lateral guidance and the glideslope provides vertical guidance. Our explanation of how ILS signals and cockpit indications work covers those fundamentals in more detail.

Where do I find the ILS frequency and course?

Use FlightGear’s airport information and map alongside an appropriate instrument approach chart to find the runway’s localiser frequency, identifier, inbound course and minimum altitude.

You can use FlightGear’s map to inspect the destination airport and runway layout before positioning for the approach. Record these items before flying:

• The ILS or localiser frequency and identifier.
• The published front course, rather than an estimate based on the runway number.
• The glideslope intercept altitude and any preceding altitude restrictions.
• The decision altitude and missed-approach instructions.
• Whether the procedure is a full ILS or a localiser-only approach.

FlightGear’s radio signal comes from its navigation database, while the visible runway comes from scenery data. If an external chart shows a different frequency from the simulator, check for mismatched or outdated navigation data. Do not assume the painted runway heading is an exact substitute for the published localiser course.

How do I fly the approach step by step?

1. Choose a suitable aircraft. Confirm that it has a working NAV receiver and a CDI, HSI or equivalent instrument capable of displaying localiser and glideslope guidance. Aircraft systems vary because FlightGear models define much of their own avionics behaviour. For basic panel and handling guidance, see our FlightGear Cessna 172 flying instructions.
2. Brief the approach. Note the front course, intercept altitude, expected intercept direction, decision altitude and missed approach. Set up early enough that radio tuning does not compete with aircraft control.
3. Tune NAV1. Enter the ILS frequency and transfer it from standby to active. Use NAV1 unless the aircraft’s documented system requires another receiver. Check the Morse identifier through the navigation audio panel where the model supports identification.
4. Select the correct guidance source. If the panel has a GPS/NAV or GPS/VLOC selector, choose the radio-navigation source. Set the OBS or course selector to the published front course; this provides the correct reference and may be required for coupled autopilot tracking.
5. Intercept from the front and below. Approach the localiser at the published altitude, normally using a modest intercept angle of about 20–30 degrees. Being established below the glideslope lets the vertical needle move down towards the centre. Trying to capture it from above commonly produces an unstable approach.
6. Capture the localiser first. As the lateral needle comes alive, turn towards the inbound course and make small heading corrections to keep it centred. Correct for crosswind rather than forcing the aircraft to hold the exact runway heading. Localiser sensitivity increases near the runway, so progressively reduce the size of each correction.
7. Follow the glideslope. When the vertical needle reaches the centre, lower the nose and adjust power to begin the descent while maintaining approach speed. On a typical three-degree path, groundspeed multiplied by five gives a useful initial descent rate: 90 knots is roughly 450 feet per minute. Follow the needle rather than treating that estimate as a fixed target.
8. Decide at minimums. At the published decision altitude, continue only if the required runway environment is visible and the aircraft is positioned to land normally. Otherwise, apply go-around power, establish a climb and fly the missed approach.

Can the FlightGear autopilot fly an ILS approach?

A FlightGear autopilot can follow an ILS only when the selected aircraft models coupled localiser and glideslope modes correctly.

• Use heading and altitude modes to establish a stable intercept from below the glideslope.
• Confirm that NAV1 is tuned and that the CDI or HSI source is NAV or VLOC rather than GPS.
• Arm the mode labelled APR, APP or its aircraft-specific equivalent before reaching the localiser.
• Watch the mode annunciations. Verify that localiser and glideslope modes change from armed to captured; an illuminated approach button alone does not prove capture.
• Monitor speed, configuration, trim and needle movement. Disconnect and go around if the aeroplane crosses the localiser, dives for the glideslope or behaves unexpectedly.

Some simpler autopilots track only the localiser, while more complete aircraft can couple both axes. The exact switches and capture logic come from the aircraft model, so procedures cannot be assumed to transfer unchanged between panels.

Why will the localiser or glideslope not capture?

ILS capture failures in FlightGear usually come from the wrong radio source, an incorrect frequency, poor intercept geometry or limitations in the chosen aircraft model.

Does an ILS approach mean FlightGear can autoland?

No. Capturing LOC and GS does not by itself provide an automatic landing.

Autoland requires an aircraft-specific implementation, suitable systems, correct configuration and appropriate runway facilities. Most FlightGear ILS practice should therefore be planned as a coupled or manually flown approach followed by a manual landing. ILS guidance may continue below decision altitude, but that is not a reason to descend without the required visual references.