How to Fly an ILS Approach Step by Step
Learn how to fly an ILS approach, including localizer intercept, glideslope capture, decision altitude, visual references, and autopilot monitoring.
An ILS approach gives both lateral and vertical guidance to a runway. The localizer keeps you aligned with the runway centerline. The glideslope gives a descent path. Together, they make the ILS one of the most useful precision approaches in instrument flying.
The system is accurate, but it demands discipline. A pilot still has to brief the chart, tune and identify the correct frequency, intercept properly, monitor the needles, manage configuration, and make the land-or-go-missed decision at the correct point.
For the larger IFR setup, pair this with how to brief an instrument approach. The ILS is easier to fly when the chart review, nav setup, missed approach, and runway picture are handled before intercept.
What the ILS Shows You
The localizer provides left-right guidance. If the needle is left, you correct left. If it is right, you correct right. On an ILS, the localizer is more sensitive than a VOR course, so small corrections are better than large ones.
The glideslope provides vertical guidance. If the glideslope needle is above center, you are low. If it is below center, you are high. The goal is to keep both needles centered with small pitch, power, and heading adjustments.
Brief the Approach First
Before intercepting, brief the full procedure:
- ILS frequency and identifier.
- Final approach course.
- Glideslope intercept altitude.
- Decision altitude or decision height.
- Missed approach point and instructions.
- Required equipment and chart notes.
- Runway length, lighting, and touchdown zone information.
This briefing should make the approach predictable. If something later feels surprising, you either missed a chart detail or the airplane is not where it should be.
Intercept the Localizer
Tune the ILS frequency and identify it. Then set up the course display as appropriate for your aircraft.
Intercept the localizer with a controlled angle. Avoid aggressive intercepts close to the final approach course because the localizer is sensitive. Once the needle begins moving toward center, turn inbound and make small corrections to stay aligned.
Do not chase the needle. Make a correction, wait, and evaluate the trend.
Capture the Glideslope From Below
A good ILS is normally flown by intercepting the glideslope from below at the published altitude. This helps avoid false glideslope problems and gives you a stable setup.
Be configured early enough that glideslope intercept is not rushed. In a training airplane, that might mean slowing down, adding flaps as appropriate, completing landing checks, and setting power for a stable descent.
When the glideslope centers, start down. Use pitch and power together. The airplane should not feel like it is falling down the approach; it should feel managed.
Decision Altitude
At decision altitude or decision height, decide. If the required visual references are visible and the aircraft is in a position to land normally, continue visually. If not, execute the missed approach.
Do not descend below decision altitude just because you are close. Precision approaches work because the pilot respects the decision point.
Stay Ahead of Configuration
The ILS gets busy quickly if you wait too long to slow down. Before glideslope intercept, have a plan for power, flaps, gear if applicable, approach speed, and checklist completion.
In a training airplane, a stable approach might mean being configured before the glideslope centers, then using a known power setting to descend. In a faster airplane, the timing may differ, but the principle stays the same: do not let configuration changes distract from tracking the localizer and glideslope.
If you are unstable, go missed early. Salvaging a poor ILS close to minimums is not good instrument flying.
The contrast with non-precision procedures matters. A VOR approach can require more pilot-managed vertical planning, while an ILS provides published vertical guidance that still has to be monitored and flown precisely.
Autopilot Use
An autopilot can fly a coupled ILS approach in equipped aircraft, but it does not remove pilot responsibility. You must verify the correct frequency, correct mode, localizer capture, glideslope capture, altitude behavior, and missed approach readiness.
Mode awareness is everything. If the autopilot is doing something unexpected, disconnect and fly the airplane.
Common ILS Mistakes
Watch for:
- Intercepting the glideslope from above.
- Forgetting to identify the ILS.
- Overcontrolling the localizer.
- Getting configured too late.
- Looking outside too early.
- Failing to go missed when visual references are not adequate.
On a practice approach, debrief the needles. Were you correcting late? Was airspeed stable? Did power changes move the glideslope? Those small observations are how an ILS becomes repeatable instead of lucky.
An ILS approach is a precise tool, not a guarantee. Fly it with a clear brief, stable configuration, disciplined scan, and a firm missed approach plan.
Official References
Need help applying this to your training?
Use this guide as a starting point, then bring the confusing parts to a focused ground lesson. Diego works with Louisville-area and remote students on FAA knowledge, oral-prep, and practical training decisions.
Related guide collections
- Instrument Rating Guides - Plain-language instrument rating guides for IFR procedures, approach briefing, holding, currency, and instrument training decisions.
- IFR Procedures Guides - IFR procedure guides for approach charts, approach briefings, holding, IFR clearances, ILS, VOR, RNAV, minimums, and instrument currency.