Which device powers essential busses in an emergency?

Which device powers essential busses in an emergency?

• A. The Emergency Generator
• B. The APU
• C. The Main Battery
• D. The Ground Service Bus

Answer: (A)

In an electrical emergency, critical systems are kept alive by a dedicated power source that automatically feeds the essential buses. This Emergency Generator is designed to stay connected to the essential buses even if the main power sources fail, so important flight instruments, avionics, and controls remain powered. The APU or main battery can support power in other contexts, but the essential buses rely on that specific emergency generator to ensure reliability when the normal generators are unavailable. Ground service power is only for maintenance on the ground and does not cover the essential buses in flight.

In an electrical emergency, critical systems are kept alive by a dedicated power source that automatically feeds the essential buses. This Emergency Generator is designed to stay connected to the essential buses even if the main power sources fail, so important flight instruments, avionics, and controls remain powered. The APU or main battery can support power in other contexts, but the essential buses rely on that specific emergency generator to ensure reliability when the normal generators are unavailable. Ground service power is only for maintenance on the ground and does not cover the essential buses in flight.