General Updated Sun, 13 Sep 2026 19:42:26 GMT 9 min read 172 views

What do NAV and APP autopilot modes do in flight simulators?

By Ian StephensEditor-in-Chief

In short

NAV mode tracks lateral guidance; APP adds approach capture. Learn when to arm each, choose GPS or VLOC, confirm capture and fix common failures.

In a flight simulator, NAV mode makes the autopilot track lateral guidance from the selected GPS/FMS or radio-navigation source. APP/APR mode is for final approach: it captures approach lateral guidance and, when the procedure and avionics provide it, vertical glideslope or glidepath guidance. Neither mode controls speed or guarantees an automatic landing.

This is general flight-simulator guidance rather than a procedure for one aircraft. Labels, capture limits and mode logic vary between avionics packages, so the flight-mode annunciator must always take precedence over the wording on a button.

What is the difference between NAV and APP autopilot mode?

NAV normally controls lateral tracking only, while APP adds the approach-specific vertical mode when suitable guidance is available.

Mode	Guidance followed	Typical use	What it does not do
NAV	An active GPS/FMS leg, VOR course or, on compatible systems, a localiser	Following the en-route flight plan or positioning laterally	Capture an ILS glideslope or control speed and altitude
APP, APR or APPR	Approach lateral guidance plus an ILS glideslope or compatible RNAV glidepath	Flying the final approach segment	Create vertical guidance where none exists or guarantee an automatic landing

The navigation source and autopilot mode are separate choices. Selecting GPS, FMS, VLOC, NAV1 or NAV2 determines which signal drives the course-deviation indicator; selecting NAV or APP tells the flight director and autopilot what to do with that signal. Our explanation of how the GPS/NAV source selector changes the CDI and autopilot input covers this distinction in detail.

NAV does not mean NAV1. NAV1 is a radio receiver, while NAV is an autopilot lateral mode. A mistake we see constantly is a valid route displayed on the moving map while VLOC remains selected, or a correctly tuned ILS while GPS is still driving the CDI.

Mode names also differ. A Garmin-style panel may have one NAV button but announce GPS, VOR or LOC after capture. Airliners commonly use separate LNAV, LOC and APP modes.

What is NAV mode on an autopilot?

NAV mode steers left and right to reduce deviation from the active course supplied by the selected navigation source.

With GPS or FMS selected: it follows the active flight-plan leg, not every line merely visible on the map.
With a VOR receiver selected: it follows the course chosen with the course or OBS selector.
With an ILS localiser selected: some systems can track the localiser in NAV mode, but they will not capture its glideslope until APP is armed.

NAV normally needs a valid course and reasonable intercept geometry. If the aircraft is far from the active leg, approaching it at a steep angle or tracking towards a waypoint behind the aircraft, NAV may remain armed or command an unexpected turn. Heading mode is usually the better way to establish a controlled intercept before NAV captures.

NAV is not a vertical mode. Altitude hold, vertical speed, flight-level change and VNAV are separate functions, even when NAV is following a GPS route.

Can a Garmin aera 760 provide NAV mode guidance?

The Garmin aera 760 is a portable GPS navigator, not an autopilot or a NAV mode by itself.

In a compatible real installation, an aera 760 can provide navigation data to supported external equipment through the appropriate connections. Its presence alone does not make an installation approved for coupled instrument approaches.

In a simulator, a virtual aera 760 will drive NAV mode only if the aircraft or add-on developer has connected its navigation output to the CDI and autopilot. Select GPS as the source and check whether the CDI and flight-mode annunciator respond to its active leg. If the route appears only on the aera display while the panel CDI does not move, the autopilot has no course to follow.

How do I use NAV mode, and when should I arm APP?

Use NAV to follow the route or position for the approach, then arm APP once the correct approach guidance is configured and the aircraft is established on a sensible intercept.

Activate the required course. Make sure the GPS/FMS has an active leg, or tune the required VOR or ILS. Resolve any flight-plan discontinuity, suspended sequencing or inactive approach leg that would leave the GPS without usable guidance.
Select the correct source. Choose GPS/FMS for a GPS route or compatible RNAV approach. For a conventional ILS, final guidance normally comes from VLOC or a NAV receiver, although some integrated systems switch automatically. See our guidance on which source to use for an ILS in a simulator.
Set up an intercept. Use heading mode or hand-fly towards the course at a moderate angle. For an ILS, use the published intercept altitude and plan to meet the glideslope from below.
Select NAV for route tracking. Arm NAV before reaching the course, then watch for the armed indication to become active. Selecting NAV while only the flight director is on provides command bars but does not make the aircraft fly them.
Prepare the approach. Confirm the runway and approach type, tune the ILS where required, verify its identifier where modelled, set the published front course if the avionics use it, and configure the correct CDI source.
Arm APP before final capture. Do this before crossing the localiser or final approach course, while the aircraft is stable and within a reasonable capture area. APP may wait in an armed state until valid lateral and vertical guidance reaches the capture point.
Confirm each capture. Look for LOC, GPS or another lateral mode to become active, followed by GS for an ILS glideslope or GP for a compatible RNAV glidepath.
Keep managing the aircraft. NAV and APP do not normally set power, speed, flaps, landing gear or minima.

There is no universal requirement to press NAV before APP. Heading mode can take the aircraft to an ILS intercept and APP can capture directly. If NAV is already tracking the localiser, selecting APP commonly retains lateral tracking and arms the glideslope. The exact sequence is covered in our guide to the practical timing for arming APP on an ILS.

Do not assume APP is used for every RNAV approach. Garmin-style general-aviation systems often use APR to capture a modelled glidepath, while some airliners use LNAV/VNAV or another aircraft-specific approach mode. An LNAV-only procedure has no vertical path for APP to capture, and advisory vertical guidance may not be coupled.

How can I tell whether NAV or APP has captured?

The flight-mode annunciator is the authoritative indication of whether a mode is armed, active or not selected.

HDG active with NAV armed means the aircraft is still following the heading while waiting to capture the navigation course.
NAV, GPS, LNAV, VOR or LOC active indicates lateral capture, depending on the avionics.
ALT active with GS or GP armed normally means altitude is being held while the aircraft waits for vertical guidance.
GS active means an ILS glideslope has captured; GP active usually means an RNAV glidepath has captured.

Many displays use one colour for armed modes and another for active modes, but the colours are not universal. A lit NAV or APP button shows that the mode was selected; it does not prove capture. A centred needle is not proof either.

The flight director and autopilot also need to be distinguished. The mode annunciator may show valid steering commands while the autopilot servos are disconnected, leaving the pilot to follow the command bars manually. Check for a separate autopilot-engaged indication.

Why will NAV or APP mode not capture?

NAV or APP usually fails because the selected source, active course, approach setup or intercept geometry is wrong.

Wrong CDI source: Select GPS/FMS for the active route or RNAV guidance, and VLOC/NAV for a radio-based ILS unless the avionics perform a documented automatic change.
No active GPS leg: Activate the intended leg and check for a discontinuity, OBS mode, suspended sequencing or a waypoint behind the aircraft.
Poor intercept geometry: Use heading mode to establish a shallower intercept rather than expecting NAV to recover from a steep crossing or an overshoot close to the course.
Incorrect ILS setup: Recheck the runway, frequency, receiver, inbound front course and identifier. Add-on airport scenery and the avionics navigation database can sometimes disagree, so verify the values shown within the simulator's installed avionics.
Aircraft above the glideslope: Many autopilots will not capture correctly from above. Reposition for the published intercept from below instead of forcing a steep descent.
No compatible vertical guidance: VOR, localiser-only and LNAV-only approaches cannot provide an ILS glideslope or coupled RNAV glidepath.
Mode is only armed: APP may be waiting normally because the aircraft has not yet entered the capture area. Read the annunciator rather than repeatedly pressing the button.
Autopilot is not engaged: The flight director can display NAV or APP commands without the servos controlling the aircraft.
Another command cancels the mode: Selecting heading, vertical speed or another incompatible mode can replace an armed mode. Duplicate joystick, throttle or keyboard bindings may also cancel it immediately after selection.
Aircraft-specific logic: Some airliners use LOC first and APP later, while other systems require particular FMS approach states. Use the mode sequence modelled for that aircraft rather than assuming every APP button behaves alike.

Why does the localiser capture but the glideslope does not?

A localiser without glideslope capture usually means the aircraft is still below and waiting for the signal, is already above it, has no GS mode armed, or is flying an approach without usable vertical guidance.

Check that GS is visibly armed and that the glideslope indicator is alive above the centre mark and moving down towards it. Hold the published intercept altitude until capture. If the indicator is already below the centre mark, the aircraft is above the glideslope; reposition rather than diving after it.

Does APP mode land the aircraft automatically?

APP mode does not normally land the aircraft; it tracks final approach guidance until the pilot disconnects the autopilot, initiates a missed approach or an aircraft-specific landing system takes over.

Autoland requires a suitably equipped and correctly modelled aircraft, an appropriate ILS, the required autopilot configuration and explicit autoland status indications. APP alone does not operate the landing gear, select flaps, observe minima, flare, manage the throttle unless a separate autothrottle system does so, or fly the missed approach. Unless the aircraft clearly indicates a valid autoland configuration, plan to disconnect and land manually.