Limitations
This page lists the current functional limitations, system requirements, and unsupported configurations for Flight Simulator First Officer (FSFO).
Before reporting a problem: Review this page to determine whether the behavior is a known limitation or platform requirement.
A limitation listed on this page is expected behavior and is not considered a bug. If FSFO behaves differently from what is described here, see Troubleshooting.
Please review these limitations before purchasing. Refunds are not issued because of limitations clearly documented on this page, except where required by law.
Quick Reference
| Area | Current Limitation or Requirement | What You Should Do |
|---|---|---|
| FMC/CDU/MCDU programming | FSFO does not select SIDs, STARs, or runways. Programming support also varies by aircraft. | Import the SimBrief flight plan through the aircraft’s EFB when required, then complete any unsupported entries manually. |
| Speech recognition | Microsoft SAPI with an English Windows speech recognizer is the officially supported option. Vosk is experimental. | Install an English Windows speech recognizer and use Microsoft SAPI for the most reliable results. |
| Virtual reality | FSFO does not render its panels natively inside VR. | Use OpenKneeboard to display FSFO in VR. |
| FSUIPC7 | FSUIPC7, including its WASM and WAPI components, is required. | Confirm that FSUIPC7 is running, connected, and reporting LVARs and Events. |
| Operating system | Windows 11 is the recommended and fully tested operating system. Windows 10 support is best effort only. | Upgrade to Windows 11 for the most reliable experience. |
| Beta software | MSFS beta builds and experimental aircraft versions are not supported. | Return to the latest public stable version before reporting an issue. |
Flight Management System Programming
FSFO can enter route and performance information in many supported aircraft. The exact level of automation depends on the data and controls that each aircraft exposes to external applications.
Limitations That Apply to All Aircraft
- The copilot does not select a SID, STAR, approach, or runway.
- You must enter your SimBrief Pilot ID or username in the aircraft’s EFB or settings before FSFO can access the flight plan.
- Any route or performance entries that FSFO cannot complete must be entered manually.
Aircraft-Specific Programming Limitations
| Aircraft | Current Limitation | Required Action |
|---|---|---|
| FBW A380 iniBuilds A350 |
FSFO cannot program the MCDU because these aircraft do not expose the required simulator variables. | Import the SimBrief flight plan using the aircraft’s EFB, then complete any remaining entries manually. |
| FSS ERJ FlightFX Cessna Citation X |
FSFO cannot program the CDU. | Use the aircraft’s own copilot, route-import, or performance-entry feature where available. Enter any remaining information manually. |
| PMDG 737 PMDG 777 Aerosoft CRJ |
The SimBrief route must already be loaded before FSFO begins CDU programming. | Import the flight plan through the aircraft’s EFB first. FSFO will confirm that the route is present before attempting its CDU entries. |
Speech Recognition
FSFO offers two speech-recognition options.
Microsoft SAPI — Officially Supported
Microsoft SAPI is the recommended and officially supported speech engine.
Requirements:
- An English Windows speech recognizer must be installed.
- Windows must have the correct microphone selected as its default input device.
- The selected microphone must be available before FSFO starts listening.
For the most reliable voice-control experience, use Microsoft SAPI with an English Windows speech recognizer.
Vosk — Experimental
Vosk is an optional offline speech-recognition engine. It is currently provided as an experimental alternative to Microsoft SAPI.
Included Vosk languages:
- English
- French
- German
Vosk behavior and recognition accuracy may vary. Microsoft SAPI in English remains the officially supported configuration.
Virtual Reality Support
FSFO does not provide native VR rendering. Its windows and panels do not automatically appear inside the VR environment.
You can display and interact with FSFO in VR using the third-party application OpenKneeboard.
OpenKneeboard is external software. Compatibility, performance, and behavior may vary by system and cannot be guaranteed by FSFO.
FSUIPC7 Requirement
FSFO requires FSUIPC7, including its WASM and WAPI components, to communicate with Microsoft Flight Simulator and supported aircraft.
Before Starting a Flight
Verify the following:
- FSUIPC7 is installed and running.
- Its status shows Connected.
- LVARs and Events are available.
- FSFO displays the detected FSUIPC7 version in the lower-left corner before the flight begins.
Application Permissions
FSFO and FSUIPC7 must run at the same Windows permission level:
- Run both applications as a standard user; or
- Run both applications as an administrator.
Do not run one application as an administrator while running the other as a standard user.
FSUIPC7 is required. FSUIPC6 is not compatible with FSFO v6 and cannot be used as a substitute.
If the copilot is not moving switches, aircraft data is not updating, or FSFO is not detecting cockpit events, verify the FSUIPC7 connection before troubleshooting the aircraft profile.
For connection assistance, see Troubleshooting.
Supported Simulator and Operating System
Simulator Support
FSFO v6 supports Microsoft Flight Simulator only.
The following simulators are not supported:
- Microsoft Flight Simulator X
- Prepar3D
- Any simulator that requires FSUIPC6
Windows 11
Windows 11 is the recommended and fully tested operating system for FSFO.
Windows 10
Microsoft support for Windows 10 ended in October 2025. FSFO may continue to operate on Windows 10, but support is provided on a best-effort basis only.
This means:
- Windows 10-specific compatibility fixes cannot be guaranteed.
- Future Windows components or third-party software may no longer support the operating system.
- Problems caused by outdated Windows components, drivers, or speech services may not be correctable through an FSFO update.
If you continue using Windows 10:
- Make sure the required English speech components are installed.
- Keep your audio, chipset, and device drivers up to date.
- Install all available Windows updates.
Upgrading to Windows 11 is strongly recommended for the most reliable experience.
For general installation and configuration assistance, see Getting Started.
Beta and Experimental Builds
FSFO supports only the latest public, stable releases of Microsoft Flight Simulator and supported aircraft.
Unsupported Versions
The following are not supported:
- MSFS Insider builds
- Steam beta branches
- Aircraft developer builds
- Aircraft beta or experimental versions
Beta and experimental versions may change internal simulator variables, events, or aircraft logic without notice. These changes can prevent FSFO flows, checklists, and aircraft profiles from operating correctly.
Before Reporting an Issue
If you encounter a problem while using a beta or experimental version:
- Return MSFS or the aircraft to the latest public stable release.
- Reproduce the same flight or procedure.
- Report the issue only if it continues on the stable release.
Issues that occur only on beta, Insider, developer, or experimental builds will be closed as unsupported.
