What does a fuel MODE SEL FAULT light indicate?

The indication that the fuel MODE SEL FAULT light activates when the center tank has more than 550 pounds of fuel while either the left or right wing tank has less than 11,000 pounds is a critical alert for maintaining proper fuel balance and management. This light serves to highlight a discrepancy in fuel levels that could potentially affect the aircraft's performance and safety.

The aircraft’s fuel system is designed to optimize fuel distribution from the center tank to the wing tanks as needed for balance and efficiency. When the center tank is overstocked while one of the wing tanks is underfilled, it signals a possible fault or issue in the fuel management system. This can lead to improper fuel flow dynamics and affect the aircraft's weight distribution, posing risks during flight operations.

The correct answer emphasizes the importance of maintaining specific fuel levels across the tanks to ensure safe flight conditions. Proper monitoring of fuel levels helps prevent potential issues during different phases of flight, including takeoff and landing, where weight distribution plays a crucial role in aircraft handling characteristics.