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.
Plain English
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.
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.