Plain English Meaning
A warning or status light on the instrument panel that turns on to tell the pilot something — for example, that a system is running, has failed, or needs attention.
Full Definition
A small indicator light on the cockpit panel that illuminates to alert the pilot to the status of a specific system or condition, such as a system being active, a fault being present, or a limit being approached. Annunciator lights are typically color-coded — red for warnings requiring immediate action, amber for cautions, and green or white for advisory or status information.
Context Anchor
Seen on the instrument panel or system control panel, including panels for anti-ice and deice equipment.
Derivation
From the verb 'announce,' meaning to make something known. An 'annunciator' is something that announces — in this case, the light announces the state of a system to the pilot.
Why Pilots Care
Allows immediate awareness of whether anti-ice systems are active or faulty, supporting safe decisions in icing conditions.
Analogy
It is similar to a car dashboard warning light, but in an aircraft it may also show normal system status, not just a problem.
Intuition Check
Do not read this as just a light that makes the panel brighter. An annunciator light is a message light: it tells the pilot a specific system condition.
Example Sentence 1
After switching on the wing anti-ice system, the pilot confirmed it was working by checking that the corresponding annunciator light was illuminated.
Example Sentence 2
An illuminated annunciator light warned of a failure in the wing anti-ice system during the approach.