What does the "Anti-Collision" light indicate in aircraft operations?

The "Anti-Collision" light on an aircraft serves as a visual warning system to alert others in the vicinity that the aircraft is active and operating. When the anti-collision light is illuminated, it indicates that the airplane is in flight. This light is typically a rotating beacon or strobe that is designed to enhance the visibility of the aircraft, especially in conditions where visibility may be compromised, such as at night or during bad weather.

When the anti-collision light is on, it signifies that the aircraft is in a state where it is either actively flying or preparing to fly, thus making it clear to other aircraft and ground personnel that the aircraft is not stationary and should be treated with caution. The other options do not accurately reflect the function of the anti-collision light in terms of indicating aircraft activity. For instance, it does not indicate an engine shutdown, being on the ground ready to taxi, or that the aircraft is not moving, as those scenarios would typically not require the anti-collision light to be activated.