Limitations

This page documents current functional and platform limitations of Flight Simulator First Officer (FSFO). These are not errors, but known constraints based on simulator, aircraft, or platform capabilities.

Use this page to understand what FSFO intentionally does not support or cannot control.

If something is listed here, it is expected behavior and not a bug.

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Autopilot Control

FSFO can set airspeed, heading, and altitude on supported aircraft.

Exception

• iFly 737 – Indicated Airspeed (IAS) cannot be set by the copilot.

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FMC / CDU / MCDU Programming

FSFO can automatically enter route and performance data for most aircraft, with the following limitations.

General limitations

• The copilot does not select SIDs, STARs, or runways.
• You must enter your SimBrief Pilot ID or username in the aircraft EFB/settings so the route can be imported.

Aircraft without MCDU programming support

These aircraft do not expose the required simulator variables.

• FBW A380
• iniBuilds A350

You can still import the flight plan using the aircraft’s EFB import function.

Aircraft without CDU programming support

• FSS ERJ

This aircraft provides its own internal copilot feature to populate performance data.

Aircraft that require EFB import first

For these aircraft, import the SimBrief flight plan via the EFB before starting FSFO programming.

• PMDG 737
• PMDG 777
• Aerosoft CRJ

FSFO will confirm the route has been imported before attempting CDU entries.

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Speech Recognition

FSFO voice control requires an English speech recognizer installed in Windows.

• Default engine: Microsoft SAPI using your default microphone.
• Optional offline engine: Vosk (experimental).

Currently included Vosk languages:

• English
• French
• German

Vosk is provided as an experimental alternative. Officially supported and recommended: Microsoft SAPI (English).

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VR Support

FSFO does not provide native VR rendering.

You can use FSFO in VR via the third-party tool OpenKneeboard. Because this is external software, compatibility and behavior may vary by system and are not guaranteed.

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FSUIPC7 Requirement

FSFO requires FSUIPC7 (including WASM and WAPI components).

Requirements:

• FSUIPC7 must be installed and running
• Status must show Connected with LVARs and Events available
• FSFO will display the detected FSUIPC7 version in the lower-left corner before flight

Important notes:

• FSFO v6 supports MSFS only
• FSUIPC6, FSX, and P3D are not supported
• Run FSFO and FSUIPC7 at the same permission level

 (both standard user or both administrator) to avoid connection errors

If the copilot is not moving switches or data is not updating, verify FSUIPC7 first. For connection problems, see Troubleshooting.

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Windows Version Support

• Recommended and fully tested: Windows 11
• Windows 10 reaches end of Microsoft support in October 2025

After that date:

• FSFO on Windows 10 is best-effort only
• OS-level compatibility fixes cannot be guaranteed

If remaining on Windows 10:

• Ensure English speech components are installed
• Keep audio and chipset drivers fully up to date

Upgrading to Windows 11 is strongly recommended for the most reliable experience. For general setup help, see Getting Started.

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MSFS and Aircraft Betas

FSFO supports only the latest public, stable releases.

Not supported:

• MSFS Insider builds
• Steam beta branches
• Aircraft developer or experimental builds

Beta versions often change internal simulator variables, which can break FSFO flows and profiles.

If you encounter an issue while on a beta: 1. Switch back to the stable release 2. Retest the issue 3. Then report it if the problem persists

Compatibility updates follow official public releases, not preview or test channels. Issues found only on beta versions will be closed as unsupported.