When the emergency light switch is set to ON, what is displayed?

When the emergency light switch is activated to the ON position, the proper indication is that an amber "EMER LIGHTS ON" message appears on the Crew Alerting System (CAS). This alert signifies that the emergency lighting system is operational and ready to provide illumination in the event of an emergency, ensuring that both crew and passengers can navigate the cabin safely under low-light conditions.

The choice of amber color is particularly significant because amber alerts typically indicate caution or the need for attention without implying an immediate danger, allowing the crew to assess the status of their emergency lighting system. This helps maintain situational awareness during critical phases of flight.

In a real-world context, understanding this indication enhances crew readiness and ensures that necessary actions can be taken quickly should an emergency situation arise, reinforcing the importance of monitoring CAS messages during operation.