An aircraft on the ground should take what action when receiving a flashing red signal?

When an aircraft on the ground receives a flashing red signal, the appropriate action is to taxi clear of the landing area or runway in use. A flashing red signal indicates to the pilot that they must vacate the area immediately to ensure safety, as there may be an imminent danger such as another aircraft preparing for takeoff or landing, or an operational situation that requires the runway to be clear.

This response is critical for maintaining safety and operational efficiency in busy air traffic environments. Such signals are part of standard ground control communications, designed to prevent accidents and ensure that aircraft adhere to safe taxiing procedures. The priority is always to keep the runway clear of any obstructions, including the aircraft that may be responding to the flashing signal.