Learn what approach to fly when an airport has no ILS, including RNAV, RNP, VOR, NDB and visual options, equipment needs, minima and diversion.
In real-world aviation and flight simulation, an airport without ILS may still offer a published RNAV (GNSS), RNP, VOR, NDB or localiser-only approach, or an ATC radar approach. In suitable weather, you may fly a visual approach. Charts, aircraft equipment, pilot approval and minima decide which option is usable; otherwise, divert.
No ILS therefore does not mean no instrument approach. It means using another published procedure that is available for the runway and that both pilot and aircraft are authorised and equipped to fly.
Which approach is best when no ILS is available?
For most suitably equipped aircraft, a published RNAV (GNSS) approach is the most practical substitute for an ILS. It requires no runway localiser or glideslope transmitter, although the aircraft must have the required navigation capability and a valid procedure in its navigation database.
An LPV line of minima can provide angular lateral and vertical guidance resembling an ILS display. LNAV/VNAV also provides an approved vertical path when the required systems and any temperature conditions are satisfied, while LNAV supplies lateral guidance only. Our comparison of ILS and RNAV guidance explains why these systems can look similar without being technically identical.
| Approach option | Guidance | Main requirement or limitation |
|---|---|---|
| RNAV (GNSS) | LNAV is lateral-only; LNAV/VNAV and LPV include approved vertical guidance when supported | Published procedure, approved GNSS equipment and the correct line of minima |
| RNP or RNP AR | Performance-based guidance, sometimes including curved radius-to-fix legs | Aircraft must meet the stated RNP value; any procedure marked AR requires specific authorisation |
| VOR or NDB | Course or bearing guidance, normally without an approved vertical path | Published procedure, working ground aid and suitable receiver |
| Localiser-only or LDA | Ground-based lateral guidance without an ILS glideslope | The relevant transmitter must be operational and localiser minima must be published |
| Radar approach | Controller-issued headings and descents; PAR may include vertical guidance | Available only where the ATC unit offers the service |
| Visual approach | Outside visual references | Suitable weather, required visual contact and any applicable ATC clearance |
RNP belongs to the wider RNAV family, and chart naming varies between aviation authorities. A plate may be titled RNAV (GPS), RNP or RNP APCH, so use the exact chart and minima rather than assuming the labels are interchangeable. Conventional procedures also remain useful; our simulator guide to VOR and NDB receiver use covers the underlying radio navigation.
How do you choose the right non-ILS approach?
Choose the procedure by checking availability, aircraft capability, weather and minima in that order.
- Check the current approach chart and operational notices. Confirm that the procedure serves the required runway and that its navigation aids, waypoints and restrictions are available. A procedure appearing in an onboard database does not prove that it is operational.
- Confirm aircraft and pilot eligibility. RNAV, SBAS, Baro-VNAV and RNP capabilities are not interchangeable. VOR, NDB and localiser procedures likewise need the corresponding working receiver and any required distance information.
- Compare weather with the correct minima. Use the minima for the exact approach capability being flown. An LPV, LNAV/VNAV and LNAV procedure to the same runway can have different decision altitudes or minimum descent altitudes.
- Identify the descent method. Do not treat an advisory VNAV path as an ILS glideslope. Lateral-only LNAV, VOR, NDB and localiser approaches normally use published step-down restrictions and an MDA, often flown with a continuous descent where permitted.
- Brief the missed approach before descending. If the weather, equipment or procedure becomes unsuitable, execute the published missed approach and use another runway, hold or divert while adequate fuel remains.
Common simulator failures
Most apparent RNAV failures are setup or capability mismatches rather than consequences of the missing ILS.
- No vertical path: the selected line may be LNAV only, or the simulated avionics may not support LPV or Baro-VNAV.
- Wrong navigation source: an RNAV approach normally needs the GPS or FMS source selected, while a VOR or localiser procedure uses the relevant radio source.
- Incorrect sequencing: using direct-to on the runway or final approach fix can remove required legs, altitude constraints or approach activation.
- Late or high intercept: some systems will not capture a vertical path when the aircraft reaches it from above or outside the permitted capture geometry.
- Chart and navdata mismatch: different database cycles can produce renamed fixes, missing transitions or an approach that does not match the chart being followed.
Aircraft-specific mode logic still matters: pressing APP is not universally the correct action for every RNAV procedure. For a practical example, see our Microsoft Flight Simulator RNAV setup walkthrough.
What if the ILS is temporarily out of service?
A failed glideslope may permit a published localiser-only approach, but only when the localiser remains serviceable and the chart provides localiser minima. Use those higher minima and the associated descent procedure rather than continuing to the ILS decision altitude.
If the localiser itself is unavailable, neither the ILS nor a localiser-only approach can be flown. An outage of required DME or another supporting facility may also make the procedure unavailable unless an approved substitute is explicitly permitted. Always distinguish a real outage from a simulator scenery or navigation-database mismatch.
What if there is no published instrument approach?
You may use a visual approach when the weather, visibility, visual references and applicable clearance requirements allow it. Our visual-approach technique for flight simulators explains how to plan the circuit, descent and runway alignment without electronic final-approach guidance.
Another possibility is an instrument approach to a different runway followed by a published circling manoeuvre, provided the chart, weather, aircraft category and operating rules permit it. This is not permission to improvise a low-level turn from an unrelated approach.
If there is no usable instrument procedure and conditions are unsuitable for a visual approach, the correct answer is to hold if practical or divert. A moving-map runway extension, direct GPS track or synthetic glidepath is not a substitute for a published approach. In real flying, base the decision on current charts, NOTAMs, ATIS information, aircraft documentation, operational approvals and ATC clearance.