What does a DC bus off advisory indicate?

What does a DC bus off advisory indicate?

• A. Normal startup condition.
• B. A loss of DC bus power requiring an electrical abnormal procedure.
• C. Overvoltage on DC bus.
• D. Battery charging.

Answer: (B)

The DC bus off advisory means the airplane’s DC electrical bus has lost power. DC buses are the backbone for supplying essential avionics and systems, so when a bus goes off, power to those loads is interrupted and you must follow the electrical abnormal procedures to restore power or reconfigure the system. This isn’t a normal startup condition, and it isn’t signaling an overvoltage or a battery charging situation—the advisory specifically indicates a loss of DC power on the bus and the need for corrective action.

The DC bus off advisory means the airplane’s DC electrical bus has lost power. DC buses are the backbone for supplying essential avionics and systems, so when a bus goes off, power to those loads is interrupted and you must follow the electrical abnormal procedures to restore power or reconfigure the system. This isn’t a normal startup condition, and it isn’t signaling an overvoltage or a battery charging situation—the advisory specifically indicates a loss of DC power on the bus and the need for corrective action.