What instrument provides primary flight instrumentation in case the integrated avionics system fails?

• A. Navigation MFD
• B. Alternate attitude indicator
• C. Tactical situation display
• D. Backup flight instrument (BFI)

Answer: (D)

When the integrated avionics system fails, pilots rely on a separate, independent set of instruments designed to provide the essential flight data needed to keep the aircraft safely under control. This backup flight instrument gives you the key indicators—attitude (horizon), altitude, and airspeed—so you can maintain level flight, assess climb or descent, and manage basic navigation enough to reach a safe landing. The other options are dependent on the main avionics: the navigation MFD and tactical situation display are display functions tied to the primary system, and the alternate attitude indicator alone only provides attitude information without the full set of flight data. So the backup flight instrument is the instrument that ensures you have primary flight data when the main system is down.