What color light is used to indicate that certain switches are operational?

The blue light is specifically utilized to indicate that certain switches are operational on the A320 aircraft. This is important for pilots and crew members as it provides visual confirmation that a function or system is active. The blue indication helps ensure that crew members can quickly ascertain the status of various controls and systems, which is critical in both normal operations and during abnormal situations.

Other colors, such as red, yellow, and white, are reserved for different meanings in the aircraft's system, typically associated with warnings, cautions, and status indications that do not denote operational functionality. Understanding the significance of these color-coded lights helps in maintaining situational awareness and ensuring the safe operation of the aircraft.