Which of the following is NOT listed as an AC Bus?

• A. AC Bus 1
• B. AC Bus 2
• C. ADG Bus
• D. DC Bus

Answer: (D)

Power distribution on an aircraft is split into AC and DC networks. The primary AC buses supply alternating current to most systems, with AC Bus 1 and AC Bus 2 being the standard feeds. The ADG (Air Driven Generator) can power an essential AC path, often called the ADG Bus, to keep critical loads alive when main generators are unavailable; that makes it part of the AC bus system. The DC Bus, by contrast, carries direct current for DC-powered equipment and is not an AC bus. Therefore, the item that is not an AC Bus is the DC Bus.