What voltage does the Maintenance Battery supply to essential maintenance buses?

What voltage does the Maintenance Battery supply to essential maintenance buses?

• A. 28 VDC
• B. 12 VDC
• C. 28 VAC
• D. 115 VAC

Answer: (A)

The Maintenance Battery delivers 28 volts DC to the essential maintenance buses. Aircraft electrical systems are built around a 28 VDC distribution, so the maintenance battery must match that voltage to power the essential maintenance network and any test equipment when main generators or the APU aren’t supplying power. This keeps maintenance operations isolated from the aircraft’s primary AC systems and ensures compatibility with the onboard DC bus equipment. The other options are not used because they are AC voltages (28 VAC, 115 VAC) or a lower DC level (12 VDC) that doesn’t align with the aircraft’s 28 VDC distribution.

The Maintenance Battery delivers 28 volts DC to the essential maintenance buses. Aircraft electrical systems are built around a 28 VDC distribution, so the maintenance battery must match that voltage to power the essential maintenance network and any test equipment when main generators or the APU aren’t supplying power. This keeps maintenance operations isolated from the aircraft’s primary AC systems and ensures compatibility with the onboard DC bus equipment. The other options are not used because they are AC voltages (28 VAC, 115 VAC) or a lower DC level (12 VDC) that doesn’t align with the aircraft’s 28 VDC distribution.