Which statement about DC bus ties is true?

Which statement about DC bus ties is true?

• A. They are controlled automatically through DC Power Centers (DCPC)
• B. They are controlled manually by the pilots
• C. They are independent of the DCPC
• D. They are controlled by the APU

Answer: (A)

DC bus ties are there to share power between the two main DC busses so that essential systems stay powered if one source drops or a generator comes on or off. The DC Power Center (DCPC) oversees the DC bus voltages, generator status, battery, and APU power, and it automatically operates the bus ties to keep voltages stable and load distribution correct. This automatic coordination is why the buses don’t require pilot input in normal operations—the DCPC handles the switching logic. Manual control by the pilots isn’t how it’s managed in normal operations, and the bus ties aren’t independent of the DCPC or directly controlled by the APU. The APU can contribute power, but the DCPC governs when and how the bus ties close to balance power between buses.

DC bus ties are there to share power between the two main DC busses so that essential systems stay powered if one source drops or a generator comes on or off. The DC Power Center (DCPC) oversees the DC bus voltages, generator status, battery, and APU power, and it automatically operates the bus ties to keep voltages stable and load distribution correct. This automatic coordination is why the buses don’t require pilot input in normal operations—the DCPC handles the switching logic.

Manual control by the pilots isn’t how it’s managed in normal operations, and the bus ties aren’t independent of the DCPC or directly controlled by the APU. The APU can contribute power, but the DCPC governs when and how the bus ties close to balance power between buses.