Definition
A signal source used in aviation to mark a location, provide identification, or aid navigation. Beacons can be visual (such as a rotating airport beacon that flashes alternating colors at night) or electronic (such as a non-directional radio beacon that aircraft can home in on using ADF equipment).
Plain English
A light or radio signal placed at a known location so pilots can see it, find it, or fly toward it.
Context Anchor
You may see BCN in airport information, maintenance notes, or notices about lights that are working, not working, or limited in use.
Derivation
From the Old English 'beacen,' meaning a sign or signal. Originally referred to a fire lit on a hill to warn of danger or guide travelers. The modern aviation use keeps that same idea: a fixed, recognizable signal that helps people locate something important.
Why Pilots Care
Beacons help pilots identify airports at night, locate hazards, and navigate using older but still-valid radio aids. A NOTAM reporting a beacon out of service can affect both visual recognition of an airfield after dark and the usability of certain instrument approaches.
Intuition Check
A beacon is not just any light. In aviation, it is a signal meant to mark or identify something important to pilots.
Example Sentence 1
The pilot spotted the rotating airport beacon flashing green and white, confirming the field was just ahead.
Example Sentence 2
A NOTAM reported the BCN out of service, requiring extra care during the night arrival.