System indicators are used for what primary purpose?

• A. To monitor outside environmental conditions
• B. To represent the status of the system
• C. To regulate oxygen flow to passengers
• D. To control cabin lighting levels

Answer: (B)

System indicators are used to convey the current status of a system to the operator. They provide at-a-glance information about whether a system is functioning normally, is powered, or has faults or warnings that require attention. This lets the crew quickly assess where to look or what action to take, improving situational awareness and decision making.

They aren’t designed to monitor outside environmental conditions (that’s what environmental sensors do), nor to regulate oxygen flow to passengers (that’s a life-support control function), nor to control cabin lighting levels (that’s a cabin management function). Indicators simply communicate status so the operator can respond appropriately.