What does a "RED" fuel filter warning indicate?

The "RED" fuel filter warning specifically indicates that the fuel filter is clogged, and this situation requires immediate action. This warning is critical because a clogged fuel filter can severely hinder the fuel flow to the engine, leading to potentially dangerous performance issues. The engine may experience loss of power, rough running, or could even stall if not addressed promptly. Therefore, immediate attention to this warning is crucial to ensure the aircraft operates safely and efficiently.

The other options do not align with the function of the "RED" warning. While low fuel levels, low fuel system pressure, or high fuel temperature can certainly pose problems, they would not trigger a "RED" warning specific to the fuel filter condition. Each of those issues might have its own indicators or alerts in the aircraft's systems, but in this case, a "RED" warning directly highlights a clogged filter as the primary concern.