What Is an Annunciator Panel? Definition, Meaning and Concept
The term annunciator panel most commonly refers to a group or set of warning or advisory indicators in the cockpit of an aircraft. These indicators "announce" to pilots any of a number of important issues regarding aircraft systems or flight progress. Most annunciator panel designs group warning indicators according to the systems they serve or, in the case of newer aircraft, by color-coded urgency ranges. Some annunciator indicators require a reset when activated; others simply illuminate for a short time, and some require a specific action to take place before automatically restarting.
The annunciator panel is also often unflatteringly known as an idiot light panel and serves to signal a variety of aircraft and flight system problems to the pilot. These issues will generally be grouped into warning, caution, and advisory categories, each with its own required course of action. Many types of aircraft have annunciator panels with most of these gauges grouped together, although others may have multiple groups arranged around the instrument panel. In general, however, the annunciator panel is located centrally in the cockpit and often features audible warnings to accompany the visual indicators.
Typical annunciator panel annunciators include system status indicators such as anti-icing, auxiliary power unit (APU) status, pitot, and fuel heating systems. These indicator lights simply give an instant visual indication of whether or not the relevant systems are active and generally do not require specific action to be taken. Caution annunciator indications typically include fuel, cabin pressurization, target altitude, engine, electrical and hydraulic alerts that give pilots early warning of potentially dangerous system developments that require intervention on their part.
These groups of annunciator panel lights will generally be color coded according to their advisory, caution, and warning status. Warnings are white, blue, or green, warnings are yellow or amber, and warnings are red. Most warnings and all warnings will also be accompanied by an audible tone. These groupings and their associated color codings have been retained in most modern aircraft equipped with Engine Indicating and Crew Alerting System (EICAS). In new systems, many of the traditional annunciator panel lights are being replaced by digital readouts on one or more multifunction display units (DUs).