Which bus charges the standby battery?

Which bus charges the standby battery?

• A. Main Bus
• B. APU Bus
• C. Left Mission Bus
• D. Right Mission Bus

Answer: (C)

The standby battery is kept ready by charging from the Left Mission Bus. In this aircraft’s electrical layout, the charging path for the standby battery is tied to the Left Mission Bus, so whenever that bus has power (from engine generators or the APU), it supplies current to the standby battery to keep it charged. This setup ensures a reliable source of power for essential standby systems if primary power is lost. The other buses don’t provide the standby-battery charging path in normal operation, so they aren’t responsible for charging it.

The standby battery is kept ready by charging from the Left Mission Bus. In this aircraft’s electrical layout, the charging path for the standby battery is tied to the Left Mission Bus, so whenever that bus has power (from engine generators or the APU), it supplies current to the standby battery to keep it charged. This setup ensures a reliable source of power for essential standby systems if primary power is lost. The other buses don’t provide the standby-battery charging path in normal operation, so they aren’t responsible for charging it.