Definition
High-intensity flashing or rotating lights fitted to an aircraft to make it conspicuous to other aircraft. The system typically includes a red rotating beacon and white strobe lights, and is required to be operated whenever the aircraft engine is running, except when the pilot determines that operating the lights would be inimical to safety.
Plain English
Bright flashing lights on the aircraft that help other pilots see it and avoid hitting it. They are usually a red flashing beacon plus white strobes, and they are normally turned on whenever the engine is running.
Context Anchor
Seen during preflight, engine start, taxi, takeoff, flight at night, and discussions about protecting night vision.
Derivation
"Anti-collision" simply means "against collisions." The name describes the purpose directly: lights designed to prevent mid-air or ground collisions by making the aircraft visible.
Why Pilots Care
These lights are required for night operations and help prevent mid-air collisions by ensuring the aircraft remains conspicuous to others.
Grounding Statement
At night, a blinking aircraft light can catch your eye from far away, but staring at it can make it harder to see dimmer things afterward.
Intuition Check
Anti-collision lights do not prevent a collision by themselves. They help make the aircraft more visible so pilots can see and avoid each other.
Example Sentence 1
Before starting the engine, the pilot turned on the anti-collision lights to alert anyone nearby on the ramp.
Example Sentence 2
The flashing aircraft anti-collision lights allowed the traffic in the pattern to spot the training aircraft from a safe distance.