External power is distributed on which bus?

The distribution of external power is primarily associated with the Battery Bus. This bus is designed to handle the power supplied to various systems in the aircraft when external power is not available, allowing it to utilize battery reserves effectively. In many aircraft systems, the Battery Bus connects to other buses, providing power to essential components during operations when external power, such as ground support equipment, isn't in use.

In contrast, other buses like the Control Bus are responsible for communication and control signals among components and do not handle power itself. The Power Bus serves a similar function but is usually tied to specific power-related activities and not typically where external power is first managed. The Avionics Bus connects to electronic systems for navigation and communication but again, does not distribute external power as its primary function. Therefore, identifying the Battery Bus as the correct bus for distributing external power recognizes its role in managing electrical energy needs in an aircraft environment.