In the event that generators are offline, which component serves as a power reservoir?

• A. The GPU
• B. The avionics power supply
• C. The aircraft battery
• D. The magneto

Answer: (C)

The aircraft battery is the power reservoir when generators are offline. It stores chemical energy and can supply the essential DC power to the electrical buses, keeping critical avionics, flight instruments, and basic systems powered for a limited time while you address the outage. This allows you to maintain control and complete a safe procedure until generators are back or external power is available. The magneto is an ignition source for starting and running the engine, not a power source for the avionics. The avionics power supply conditions power for avionics but draws from the battery or generators rather than serving as the energy reservoir itself. Ground Power Units can provide external power on the ground, but they’re not the onboard energy reservoir during flight.