How are approach minimums set and used in a simulator?

Approach landing minimums are published limits derived from obstacle clearance, procedure type, navigation performance, runway aids and operational rules. In a flight simulator, select the charted minima matching the approach, aircraft category and equipment; set the correct barometric or radio value, then land only with the required visual references; otherwise fly the missed approach.

What determines approach landing minimums?

In Aviation & Real-World Flying, approach minimums have two distinct parts: the lowest permitted altitude or height and the required visibility or runway visual range. They are designed together, but they do not mean the same thing.

Procedure designers calculate obstacle clearance through the arrival, final approach and missed-approach segments. This produces an obstacle clearance altitude or height, often identified as OCA/H. The published operating minima may then include additional margins, rounding and restrictions imposed by the aviation authority or operator.

• Terrain and obstacles: Buildings, masts and rising ground affect the protected approach and missed-approach areas.
• Approach type: An ILS, LPV, LNAV/VNAV, LNAV or VOR approach provides different guidance and containment.
• Navigation performance: The required accuracy, monitoring and integrity affect how tightly the protected area can be drawn.
• Runway facilities: Approach lighting, runway lighting, ILS equipment and declared runway distances influence the available minima, particularly visibility.
• Aircraft category: Faster approach categories generally need larger protected manoeuvring areas and may have higher minima.
• Operational approval: CAT II, CAT III and certain RNP minima require suitable aircraft equipment, procedures and authorisation.

The chart brings these factors together. Our guide to reading aviation charts and minima rows explains how to identify the controlling altitude, visibility and chart notes.

Weather does not normally recalculate the published altitude. It determines whether the approach may be used and whether visual references are available, although cold-temperature corrections or an operational additive can raise the altitude you must observe.

Which minimum do I use: DA, DH or MDA?

Use the value attached to the exact approach capability you are flying, not simply the lowest number printed on the plate.

For example, if a chart shows 620 (200) for DA(H), 620 is the barometric altitude and 200 is the associated height. With BARO minimums selected, enter 620—not 200. A radio-altimeter setting of 200 is appropriate only when the chart and procedure specifically use a radio decision height.

DA is typical of ILS, LPV and LNAV/VNAV minima, while MDA is typical of LOC, VOR and LNAV minima. There are exceptions and regional differences, so use the plate rather than assuming from the approach name. Our comparison of approach types and their minimums covers these distinctions in more detail.

Which minima line should I choose?

Match the line to the procedure, avionics capability, aircraft category and any charted restrictions. A generated vertical path does not automatically entitle you to use vertical-guidance minima.

• Use the ILS line only when receiving and monitoring the required ILS guidance.
• Use LPV or LNAV/VNAV only when the procedure and simulated avionics support that mode.
• Use LNAV minima when that is the available or applicable RNAV capability, even if the avionics draw an advisory glidepath.
• Use the correct aircraft category. It is based on the aircraft's certified approach-speed basis, not whichever category gives the lowest number. Depending on the governing rules, flying above a category speed boundary can require higher-category minima.
• Do not use specialised minima when required equipment, navigation performance or authorisation is absent.

How do you set and use minimums in a flight simulator?

The reliable simulator workflow is to brief the chart first, set the aircraft second and verify the indication before starting the final approach.

1. Confirm the exact procedure. Match the airport, runway, approach name and any suffix. The chart and installed navigation data should describe the same procedure; otherwise waypoints, altitude constraints or the missed approach may differ.
2. Select the applicable minima row. Match the approach capability, aircraft category and equipment. Read all notes that raise or prohibit particular minima.
3. Read both altitude and visibility. Record the DA, DH or MDA together with the required RVR or visibility. Do not confuse the parenthesised height with the barometric altitude.
4. Set the local pressure. Enter the correct QNH or local altimeter setting and cross-check the primary and standby instruments. Leaving standard pressure set below the transition level can move the apparent decision point by hundreds of feet.
5. Apply required corrections. Cold-temperature corrections, equipment penalties or operator additions can raise the working value. See our method for checking published approach altitudes and corrections when the charted figure is not the final value to fly.
6. Set the minimums control. Choose BARO for a barometric DA or MDA and RADIO only for an authorised radio decision height. If the simulated aircraft lacks a minimums selector, note the value and make the call manually.
7. Brief the missed approach. Know its initial track, altitude and first fix before reaching final approach. Confirm the go-around controls and expected flight-guidance modes.
8. Make the decision at the correct point. At DA, continue only with the required visual references and a normal landing path; otherwise go around. At MDA, remain at or above it until those conditions are met and do not continue beyond the missed-approach point.

The minimums selector is normally an alerting aid, not an autopilot command. Setting 620 feet does not make the autopilot level off, disconnect or initiate a missed approach. Aircraft and add-on implementations differ, so the pilot must monitor altitude and act.

What counts as visual reference at minimums?

A vague glimpse of the airport is not enough. Real operating rules prescribe acceptable references such as runway or threshold lights, markings and touchdown-zone cues, with the exact list varying by authority and approach.

For realistic simulator practice, make the decision from the cockpit view without using an external camera, moving map or airport labels to find the runway. The aircraft must also be positioned to make a normal descent and landing; diving from MDA after spotting the runway late is not an acceptable substitute.

On an MDA approach, either level at or above MDA or fly a properly planned continuous descent. A continuous-descent technique may require a derived decision altitude or additive so that initiating the missed approach does not carry the aircraft below MDA. The full simulator instrument-approach workflow covers briefing, stabilisation and the missed approach.

Why does the minimums callout occur at the wrong height?

An apparently incorrect callout is usually caused by the wrong reference, pressure setting or chart value rather than the approach itself.

• Height entered as altitude: Entering 200 with BARO selected when the chart shows 620 (200) produces a callout near 200 feet above mean sea level, not 200 feet above the runway.
• Wrong minimums source: Radio altitude follows the ground beneath the aircraft. Before the threshold it may not equal height above the touchdown zone, especially over sloping terrain.
• Incorrect pressure: Standard pressure, stale QNH or mismatched captain and standby settings shift the indicated crossing point.
• Chart and navigation-data mismatch: Different procedure revisions can contain changed thresholds, constraints or minima.
• Scenery elevation mismatch: An add-on airport may not agree perfectly with the navigation database or charted runway elevation.
• Units or corrections: Feet, metres, temperature corrections and rounded MDA values can all create an apparent discrepancy.
• Aircraft implementation: Some simulated aircraft provide only a basic callout, while others distinguish between “approaching minimums” and “minimums”.

Diagnose the discrepancy by comparing indicated altitude, radio altitude, runway elevation, pressure setting and the exact chart entry. Do not fix it by arbitrarily changing the minimums until the callout sounds where expected; that can conceal the real reference error.