What items are on the DC utility bus?

What items are on the DC utility bus?

• A. Passenger Service Units (PSU) reading lights
• B. Emergency exit signs
• C. Oxygen masks
• D. Flight data recorders

Answer: (A)

The DC utility bus powers nonessential cabin equipment used for passenger comfort and convenience. Passenger Service Units’ reading lights are fed from this bus, providing individual illumination for passengers without tying into systems that must remain active for safety. Emergency exit signs, oxygen masks, and flight data recorders belong to other power provisions: exit signs and emergency lighting are tied to emergency or essential power circuits to ensure visibility during power loss, oxygen masks operate from the onboard oxygen system rather than electrical power, and flight data recorders use a dedicated or separate power source. So the reading lights in the Passenger Service Units are the items that sit on the DC utility bus.

The DC utility bus powers nonessential cabin equipment used for passenger comfort and convenience. Passenger Service Units’ reading lights are fed from this bus, providing individual illumination for passengers without tying into systems that must remain active for safety. Emergency exit signs, oxygen masks, and flight data recorders belong to other power provisions: exit signs and emergency lighting are tied to emergency or essential power circuits to ensure visibility during power loss, oxygen masks operate from the onboard oxygen system rather than electrical power, and flight data recorders use a dedicated or separate power source. So the reading lights in the Passenger Service Units are the items that sit on the DC utility bus.