What happens when the Modular Avionics Unit (MAU) detects invalid fuel data?

When the Modular Avionics Unit (MAU) detects invalid fuel data, it displays an amber X on the cockpit instruments. This amber indication serves as a warning to the flight crew that there is an issue with the fuel data being received by the avionics system, which may affect flight operations and decisions. The display of an amber X prompts the crew to verify fuel quantities and assess the situation to ensure safety and performance are not compromised.

This response is designed to alert pilots to a potentially critical issue without causing alarm or initiating a shutdown, as the other options suggest events that would not typically occur in this situation. For instance, an aircraft shutdown, activation of emergency lighting, or an increase in engine power are not standard responses to invalid fuel data alerts, and they could create unnecessary complications or hazards.