Which fuel tanks have a magnetic site gauge that can be used for a mechanical indication of fuel tank level?

• A. Auxiliary fuel tanks
• B. Main fuel tanks
• C. Wing tip tanks
• D. Centerline tanks

Answer: (A)

Magnetic site gauges give a direct mechanical readout of fuel level by using a float inside the tank that drives a magnet-driven indicator along a calibrated path. This setup is especially practical for auxiliary tanks because they are removable and can carry a self-contained sight gauge that reads without needing the aircraft’s electrical systems. In contrast, main, wing tip, and centerline tanks typically use cockpit-connected electrical or capacitance gauges tied to sensors in the tank, so they don’t rely on a magnetic site gauge for a mechanical indication. So auxiliary fuel tanks are the ones that have a magnetic site gauge for a mechanical indication of fuel level.