What does a flashing red light indicate in flight?

A flashing red light indicates that the airport is unsafe and that pilots should not land. This signal is part of the system used to ensure the safety of operations within and around an airport. When pilots see a flashing red light, it's a clear warning that conditions at the airport may be hazardous, such as runway obstructions, emergencies on the runway, or other serious situations that make landing unsafe.

This is critical information that ensures pilots can make informed decisions regarding their approach and landing, ultimately enhancing safety for all aircraft in the vicinity. Recognizing and responding to such signals is an essential part of a pilot's responsibilities.