What powers the batteries that supply Emergency Lights?

What powers the batteries that supply Emergency Lights?

• A. Main aircraft battery
• B. DC power from the emergency buses
• C. APU generator
• D. External power unit

Answer: (B)

The batteries that power Emergency Lights are kept charged by DC power from the emergency buses. In normal operation, the emergency buses supply DC power to charge and monitor the emergency batteries. If normal power is lost, those batteries provide the lighting, ensuring the cabin stays lit for the required duration. The other sources (main aircraft battery, APU generator, external power unit) aren’t the intended charging path for the emergency-light batteries, so they don’t serve as the primary source for that specific backup lighting system.

The batteries that power Emergency Lights are kept charged by DC power from the emergency buses. In normal operation, the emergency buses supply DC power to charge and monitor the emergency batteries. If normal power is lost, those batteries provide the lighting, ensuring the cabin stays lit for the required duration. The other sources (main aircraft battery, APU generator, external power unit) aren’t the intended charging path for the emergency-light batteries, so they don’t serve as the primary source for that specific backup lighting system.