ILS Y and Z are separate procedures, not accuracy grades. See what differs, which one to load in MSFS 2024, and how to fix missing FMS entries.
An ILS Y approach and an ILS Z approach are separately published ILS procedures for the same runway. The suffixes only distinguish the procedures; they do not indicate ILS category, quality or accuracy. Routing, equipment requirements, altitude constraints, minima and missed-approach instructions may differ, so use the exact cleared procedure.
What do the ILS Y and Z suffixes mean?
In real-world charting and Microsoft Flight Simulator 2024, the letter is part of the complete approach name: for example, ILS Y RWY 27 and ILS Z RWY 27. It identifies the whole procedure, not the transmitter or runway.
Where naming conventions use lettered variants, assignment commonly begins at Z and runs backwards. Z is not newer, easier or better than Y; on the radio, the suffixes are spoken as “Yankee” and “Zulu”. They are unrelated to the L, C or R identifying left, centre or right runways.
| Procedure element | What may differ between Y and Z |
|---|---|
| Routing | Initial fixes, transitions, feeder routes and intermediate segments |
| Requirements | RNAV, DME, radar or other aircraft and operational requirements |
| Constraints and minima | Altitude, speed, decision altitude, visibility and circling minima |
| Final guidance | Often the same ILS transmitters, although the published frequency, identifier and course must be checked |
| Missed approach | Climb instructions, track, altitude, holding fix and required navigation capability |
One version may use RNAV feeder segments before joining a conventional ILS final. That does not turn it into an RNAV approach; our explanation of how ILS and RNAV guidance differ covers that distinction.
Can ILS Y and ILS Z use the same frequency?
Yes. ILS Y and Z may use the same localiser and glideslope transmitters, so their cockpit indications can look identical after the aircraft joins final. The variants can still have different arrival routing, restrictions, minima and missed approaches; see which guidance comes from the localiser and glideslope.
Tuning the right frequency does not prove that the correct procedure is loaded. Cross-check the charted frequency, identifier and inbound course using our guide to matching the ILS data to the exact runway procedure.
Which ILS Y or Z should I load in MSFS 2024?
Load the suffix assigned by ATC or, without a clearance, the published variant whose routing, transition, requirements and minima suit the planned flight.
- Read the complete approach name: distinguish ILS Yankee from ILS Zulu. Seek clarification if a real-world clearance is ambiguous.
- Match the chart and FMS: confirm the runway, suffix, transition and waypoint sequence against the same effective procedure.
- Choose the transition carefully: connect it sensibly to the arrival or last en-route fix. A vectors transition expects heading guidance and may not create a continuous route.
- Check the notes: verify navigation equipment, altitude and speed restrictions, weather minima and aircraft-category limits.
- Inspect the loaded legs: look for duplicate fixes, implausible turns and course reversals. Do not automatically remove a discontinuity associated with vectors.
- Verify final and missed-approach data: check the localiser, course, intercept altitude, minima, climb instructions and holding fix before commencing the approach.
A mistake we see frequently in simulators is briefing one suffix while loading the other because both show the same frequency. The localiser and glideslope may capture normally while the FMS sequences the wrong constraints or missed approach. Our practical guide explains how to verify and fly the selected ILS procedure.
Does ILS Z mean CAT III or autoland?
No. Y and Z say nothing about CAT I, CAT II, CAT III or autoland capability. The applicable category and minima are published separately and depend on the ground installation, procedure, aircraft equipment, operating conditions and crew or operator approval. An autopilot capturing the localiser and glideslope does not by itself make the approach approved for autoland.
Why is an ILS Y or Z approach missing from the FMS?
A missing variant usually indicates different navigation data, a revised procedure, outdated airport scenery or avionics that do not expose every available transition.
- Look for abbreviated names such as
I27-ZorILS27Z, or for the suffix in a separate field. - Check the runway number. Runway renumbering can leave older scenery and newer navigation data out of step.
- Compare the EFB or flight-planner sequence with the aircraft FMS; stock and add-on avionics may present different entries.
- Determine whether the entire approach is absent or only one transition. The procedure may remain available through another initial fix or vectors entry.
Do not substitute Y for Z solely because both serve the same runway, and never combine the transition from one with the final or missed approach from the other. In the simulator, a raw-data vectors-to-final ILS may still be practised when the receiver can be tuned, but that does not load or sequence the complete published procedure.