How do I update navdata in FSX?

FSX has no single navdata updater. The built-in GPS, Flight Planner and ATC read navigation records from scenery BGL files, while most add-on FMCs use a separate AIRAC database. Update the stock simulator with an FSX-compatible scenery/navdata package, and update each add-on aircraft with the dataset made specifically for it.

In Microsoft Flight Simulator X (FSX) and FSX: Steam Edition, “navdata” can therefore mean several different databases. Updating the wrong one is why a new waypoint may appear in an airliner's FMC but remain missing from the stock GPS and map.

Which FSX navdata are you trying to update?

The required method depends on which instrument or simulator feature contains the outdated information.

FSX service packs and Steam updates patch the simulator itself; they do not bring its navigation database up to a new AIRAC cycle.

How do I update the built-in FSX GPS and Flight Planner?

The stock database is updated by adding or replacing compatible BGL data, not by copying an AIRAC folder into FSX.

1. Check the update's coverage. Some packages change only VORs, NDBs and intersections. Others also include airways, airport approaches, runway identifiers or ILS records. Do not assume that “navdata update” means a complete worldwide AIRAC replacement.
2. Match the FSX edition. Confirm that the package supports boxed FSX, FSX: Steam Edition or both. An older installer may detect the boxed registry entry and write into the wrong directory; our explanation of checking FSX add-on and Steam Edition compatibility covers the common path and installer traps.
3. Back up anything being replaced. Avoid overwriting the default Scenery folders unless the package explicitly requires it. A separate scenery layer is easier to disable when something conflicts.
4. Install the files as directed. If the update is supplied as scenery, it will normally have a structure such as Addon Scenery\Navdata Update\scenery. Add that area through Settings > Scenery Library. Do not put an add-on FMC's AIRAC files here; the stock simulator cannot read them.
5. Set the scenery priority. Place the navigation update above the default world scenery. Detailed airport add-ons normally remain above a global update, unless the package documentation says otherwise.
6. Restart FSX. Let the simulator rebuild its scenery database before loading a flight.
7. Verify a documented change. Search for a revised waypoint or frequency in the map or default GPS. The stock GPS does not provide a dependable AIRAC-cycle display, so verification must use a specific change listed by the update package.

If the records appear correctly but FSX still creates an unexpected route, follow our guide to planning GPS, VOR and airway routes in FSX. Existing .PLN files may retain obsolete waypoint identifiers or coordinates, so rebuild an old route after changing the database.

How do I update an add-on aircraft's FMC AIRAC?

An add-on FMC must receive the database format written specifically for that aircraft or avionics package.

1. Identify the exact product and variant. Two aircraft using similar-looking FMCs may store completely different files.
2. Select its supported AIRAC target. A generic “FSX” dataset is not enough; the package must list the add-on itself.
3. Close FSX before installing. Point the updater at the actual aircraft or add-on directory inside the active boxed or Steam installation.
4. Replace rather than merge cycles. Let the supported updater perform the replacement, or follow the add-on's documented manual procedure. Mixing old and new files can leave duplicated or missing procedures.
5. Check the FMC status page. Most advanced units show the installed cycle on an IDENT or database page. If the old cycle remains, check the target path and whether Windows blocked writes to the FSX directory.

Updating one aircraft does not update another aircraft, the default GPS, FSX ATC or airport scenery. A data installer may support several products, but each requires its own target format and installation.

Why do the FMC, GPS and runways still disagree?

Disagreement usually means that only one of FSX's independent databases was updated, or that conflicting airport BGL files are active.

• New FMC, old scenery: the FMC may call a runway 09/27 while the airport still displays its former number. Install a compatible airport correction or use a cycle that matches the scenery.
• New frequency, old stock GPS: an aircraft AIRAC update does not alter FSX's BGL-based localiser record. Update the relevant scenery data as well.
• Duplicate airport files: two active BGLs can produce duplicate runways, displaced parking or conflicting ILS information. Disable the lower-priority outdated airport file rather than stacking more corrections over it.
• Wrong installation directory: Steam and boxed copies can coexist, and legacy installers often update whichever registry entry they find first. Confirm the modified files belong to the copy of FSX you actually launch.
• Partial update: a navaid package may not include terminal procedures, magnetic variation or airport geometry. For one incorrect airport or ILS, a focused scenery correction is usually safer than another global package.
• Unsupported legacy avionics: some add-ons use a fixed or proprietary database with no replacement format. A generic AIRAC package cannot be forced into such an aircraft.

For the fewest conflicts, keep the aircraft database, airport scenery and stock navigation update from roughly the same data period. Never stack multiple global navdata packages without checking which BGL records each one replaces.