How do I fly an RNP approach in a flight simulator?

To fly an RNP approach in a flight simulator, load the published procedure in the FMS or GPS, verify its fixes and constraints against the chart, track it in LNAV or GPS/NAV, and use vertical guidance only when both the selected minima and the simulated avionics support it. Otherwise, fly the charted step-down altitudes.

This answer applies to flight simulators generally, including Microsoft Flight Simulator, X-Plane, FSX and Prepar3D. The button labels and depth of system modelling vary, but the chart-reading, mode-management and minima principles remain the same.

What counts as an RNP approach in a sim?

In a sim, an RNP approach is a database-coded area-navigation procedure flown through the aircraft's FMS or GPS, ideally with onboard navigation-performance monitoring.

Sim pilots often use RNP and RNAV interchangeably, but they are not identical. RNAV describes area navigation generally; RNP adds a requirement for the aircraft to monitor its navigation performance and alert the crew when that performance is inadequate. Many default aircraft reproduce the route and guidance without fully modelling that monitoring.

Chart naming also varies by region. The procedure may be titled RNAV (GPS), RNAV (GNSS) or RNP, while the available minima are listed separately.

A vertical magenta path does not by itself grant LNAV/VNAV or LPV capability. Some units calculate an advisory path, often shown as +V, while the valid minima remain LNAV.

How is an RNP approach different from an ILS?

An RNP or RNAV approach derives its path from the aircraft's navigation system, whereas an ILS follows ground-based localiser and glideslope signals.

An ILS normally captures LOC and GS. An RNAV approach may use LNAV and VNAV, or GPS/NAV with a GP glidepath. It may also have no approved vertical guidance. Do not switch from GPS to VLOC merely because the runway has an ILS frequency unless the procedure or aircraft-specific technique calls for it.

What must match before you start the approach?

The chart, navigation database, loaded procedure and aircraft capability must agree before final approach.

• Runway and transition: confirm the exact procedure, runway and initial approach fix. Selecting vectors-to-final can remove intermediate fixes and leave the FMS unable to establish the intended sequence.
• Database and chart: compare every fix, course and altitude constraint. A newer chart paired with old simulator navdata can produce missing transitions, renamed fixes or a different missed approach.
• Active leg: remove genuine discontinuities only after understanding why they are present. Check for duplicated waypoints, manual legs, holds and a direct-to command that has bypassed part of the approach.
• Minima line: select LNAV, LNAV/VNAV or LPV according to what the chart publishes and what the simulated avionics can actually fly. The lowest printed minima are not automatically available to every aircraft.
• Altimeter and temperature: set the correct QNH. Barometric VNAV depends on accurate pressure information, and any charted temperature limits still matter even when the simulator does not model their effects properly.
• Navigation performance: if the aircraft displays required and actual navigation performance, actual performance must remain within the required value. Treat an UNABLE RNP or navigation-accuracy warning as a reason not to continue using that guidance.
• Missed approach: brief the missed approach point, initial track, altitude and first fix before reaching final.

If approach preparation, clearances and missed-approach timing are still unfamiliar, our complete simulator IFR workflow explains the surrounding procedure without duplicating the RNP-specific steps here.

How do I fly an RNP approach step by step?

Fly the approach by establishing the correct database sequence first, capturing lateral guidance, and then accepting only the vertical mode supported by the chosen minima.

1. Load the database procedure early. Select the correct runway and transition through the FMS or GPS rather than manually entering its fixes. Microsoft Flight Simulator users can follow our practical GPS and RNAV procedure setup for the platform-specific loading and activation sequence.
2. Compare the route with the chart. Verify the initial and final approach fixes, inbound course, altitude constraints, missed approach point and missed sequence. Do not assume the magenta route is correct merely because it connected successfully.
3. Brief the minima and vertical method. Decide before final whether you will use LPV, LNAV/VNAV or LNAV-only minima. Note whether the published value is a DA or MDA and identify the visual reference required to continue.
4. Select the correct navigation source. A GPS-equipped light aircraft normally needs GPS as the CDI source, while an airliner normally tracks the FMS through LNAV or managed NAV. Confirm that the expected leg is active before engaging the autopilot.
5. Complete the descent and configuration early. Reach the approach at a sensible speed and altitude, with the aircraft stabilising before the final approach fix. For jet operations, our 737 descent and approach preparation method covers FMC constraints, energy management and avoiding a rushed final.
6. Intercept final from a suitable position. Join the inbound track with a moderate intercept angle. For vertical capture, remain at the published altitude and beneath the descending path; trying to capture from above is one of the most common reasons a glidepath is ignored.
7. Arm the appropriate vertical mode. Use APR or APP when that aircraft uses it to capture an RNAV glidepath. Use VNAV or the aircraft's FMS approach mode when that is the documented method. For an LNAV-only procedure, manage the descent without pretending advisory guidance changes the minima.
8. Read the flight-mode annunciations. Confirm the intended lateral and vertical modes are armed and then captured. A diamond moving down the display means little if the annunciator still shows altitude hold, vertical speed or pitch mode.
9. Cross-check every restriction. Make sure the aircraft crosses each fix at or above the charted altitude. If VNAV disagrees with the chart, level off or intervene early rather than following a suspect path below a restriction.
10. Make the decision at minima. At an LPV or LNAV/VNAV DA, continue only with the required visual reference and a stabilised aircraft. On an LNAV approach, do not descend below the MDA without that reference; if remaining level, continue only as far as the missed approach point.
11. Supervise the missed approach. Apply power, establish the required climb and follow the published track. Set the missed altitude at the point appropriate to the aircraft, and watch for GPS units that enter suspend mode or require confirmation before sequencing beyond the missed approach point.

Do I use APP mode on an RNP approach?

Use APP or APR only when that aircraft's avionics use it to capture RNAV approach guidance.

• Integrated general-aviation GPS: GPS/NAV usually provides lateral tracking, with APR armed for a supported LPV or other glidepath.
• Boeing-style FMS: many simulated aircraft use LNAV and VNAV rather than the ILS APP button, but implementation differs between add-ons.
• Airbus-style systems: a managed approach mode such as FINAL APP may provide guidance where modelled; the ordinary LOC/ILS workflow is not interchangeable with it.
• LNAV-only minima: remain in lateral navigation and manage the vertical profile using published altitudes and an appropriate descent mode.

The flight-mode annunciator is the final authority. If the expected GP, VNAV PATH or aircraft-specific approach mode has not captured, the autopilot is not flying the intended vertical path.

How do I fly an LNAV-only RNP or RNAV approach?

An LNAV-only approach is a lateral non-precision approach, even if the GPS draws an advisory descent path.

Track the centreline using LNAV or GPS/NAV, then descend only after passing each applicable fix and never below its published altitude. You may use a planned continuous descent profile for a stabilised approach, but that does not convert the MDA into an LPV-style DA or remove the missed approach point.

At the MDA, maintain altitude unless the required visual reference permits descent. If the runway environment is not acquired by the missed approach point, or the aircraft is unstable, execute the published missed approach.

Why does the sim turn away, level off or ignore the glidepath?

Unexpected RNP behaviour usually comes from the wrong active leg, an unsuitable intercept, incorrect mode selection or incomplete avionics modelling.

If simulator ATC vectors you high and close to final, do not force a steep descent or attempt to capture from above. Reposition, request more track miles where the simulation permits it, or go around and fly the approach again.

Can every sim aircraft fly an RNP AR approach?

No; RNP AR procedures require leg types, turn anticipation, navigation accuracy and guidance that many default simulator aircraft do not reproduce faithfully.

RF legs and tightly constrained curved paths are the usual failure points. A route that looks correct on the map can still be flown badly if the FMS converts a radius-to-fix leg into a direct track or the autopilot cannot hold the turn.

For realistic practice, use RNP AR only when the aircraft documentation and displays show that the procedure is supported, then monitor the coded path throughout. Flying the curve manually or with heading mode may salvage a casual sim flight, but it is no longer a faithful simulation of the published RNP AR operation.