What action is signified by a flashing red light signal when on the ground?

A flashing red light signal when on the ground indicates that an aircraft must clear the active runway immediately. This signal is crucial in ensuring safety on the airfield by alerting pilots to the need to vacate the runway for other operational requirements, such as the landing or takeoff of other aircraft. It serves as a critical communication tool to prevent potential collisions and ensure that the flow of air traffic is maintained efficiently.

Understanding the context of this signal is vital for flight safety and ground operations. While other signals may convey different messages, a flashing red specifically emphasizes an urgent need to clear the runway.