What happens when a single generator fails?

• A. The generator bus goes offline and Cabin and Nonessential buses are turned off; the bus-tie relay closes allowing the operating generator to power the remaining buses.
• B. The remaining generator automatically powers all buses without shedding.
• C. The electrical system automatically switches to battery power for critical systems only.
• D. The engine automatically shuts down the airplane.

Answer: (A)

When one generator fails, the electrical system isolates the failed unit and sheds nonessential loads so the remaining source isn’t overloaded. The bus-tie relay closes, connecting the live generator’s bus to the other buses, allowing the operating generator to power the essential and remaining buses. This keeps the airplane powered without overtaxing the single generator, while the engine itself continues running.