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What are Annunciators?

8/23/2012 11:11:17 AM | by Anonymous


Annunciators can be used in industrial or aviation industries, with the bulk of the application of these devices in the latter. As their name would suggest, the job of these devices is to ‘announce’ or relay a message to the user. An annunciator panel is a group or array of warning lights that are used as an indicator of the status of the system or equipment under use in a building, industrial or aircraft installation. These panels are essential in relaying any emergency issues that might need immediate attention. Usually, annunciator panels include coloured lights with an audible signal to announce an emergency or the progress of the device. Once an annunciator is activated, it may be required to reset, whereas some may require for the fault to be corrected before the annunciator goes off, depending on the system the annunciator is being used in.



In aviation, annunciators play a huge role in determining the safety of an aircraft. These are a group of lights located within the cockpit of the aircraft, in the line of sight of the pilot and relay to the pilot the status of the aircraft’s subsystems. These systems usually have a test switch which the pilot would run before taking off, to ensure that all the lights are working in perfect condition. The test switch tests for any burned out lamps, which helps ensure the safety of the passengers and the crew onboard the aircraft. The light panels are grouped according to the operating system. For example, the lights associated with the engine systems are located at the same place which help the pilot indicate any fault on the working conditions of the engine systems. The lights are usually colour coded so that problems or issues can be identified more easily.


· White/ blue – annunciator lights with these colours indicate a system is in use; for example seat belt signs.

· Green – these annunciators indicate a system is ready for use; for example landing gear.

· Orange/ yellow – these lights do not relay immediate emergency but announce that the system would require attention but not urgently; for example in the case of fuel imbalance in the aircraft.

· Red – this relays that the aircraft system requires immediate attention; for example in the case of an engine fire.


The system of aircraft may not necessarily have to indicate emergency situations, but may also relay to the user that the systems are functioning properly with no faults. As for the red or orange annunciators, they relay to the pilot an emergency that would require attention, be it immediate or in the future. Annunciator signaling systems can help to save lives, as for example, if a fire was to break out in the engine, the annunciators would relay the message to the captain and action can be taken to avoid a crisis. These light usually have an audible alert fixed with them that aids in directing the pilot’s attention to the emergency situation, in case such a thing happens. In aircrafts, annunciator panels are usually located in areas that are easily visible to the pilot; usually near the lever, displaying warnings that have varying levels of severity.


Industrial application

In industrial applications, annunciators serve similar function as those used in aircrafts, informing the user of the systems operation. The annunciators in industrial applications feature multiple back-lit windows that have the name of the process alarm engraved on them for easier identification. Simila to the aircraft annunciator panels, these devices relay to the user any abnormal conditions such as high temperatures, low pressure etc. In event of such an instance, the light would start blinking with an alarm sounding to attract the user’s attention. The annunciator would require the user to reset the system, be automatically reset or reset once the problem has been solved.

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