The caution and warning panel (CWP), also known as "central warning panel" and "annunciator panel", is a group of lights arranged in rows and columns that provides information about the status of aircraft equipment and systems. While the selection of indications to be displayed and layout of the panel vary from aircraft to aircraft, the following colour coding is normally used:
Red lights indicate warnings, i.e. dangerous situations that require immediate attention (e.g. engine fire)
Yellow/amber lights indicate caution, i.e. abnormal situations that require attention, albeit not immediately (e.g. fuel imbalance)
In some panels other colours are used (such as green, white or blue) to indicate that a system is ready for use or already in use.
The panel usually has a test switch which illuminates all lights in order to confirm that they are operating normally.
Light activation is often accompanied by aural indication that can be a sound (e.g. beep), a voice message, or both.