Which power source is required to operate the Maitenance Bus Switch?

Which power source is required to operate the Maitenance Bus Switch?

• A. Battery
• B. APU
• C. External Power
• D. Engine Generators

Answer: (C)

The maintenance bus is a dedicated power path used for ground maintenance and servicing, so it’s designed to be energized by a ground power source rather than the aircraft’s in-flight power sources. External power provides a stable, sufficient supply specifically for maintenance operations without drawing from the aircraft’s essential systems or draining the on-board battery. The engine generators and APU feed the main and essential buses during normal or emergency operations, not the maintenance bus in this context, and the battery is intended for starting and emergency loads rather than powering the maintenance bus for routine ground work. So, external power is the proper source to energize the Maintenance Bus Switch.

The maintenance bus is a dedicated power path used for ground maintenance and servicing, so it’s designed to be energized by a ground power source rather than the aircraft’s in-flight power sources. External power provides a stable, sufficient supply specifically for maintenance operations without drawing from the aircraft’s essential systems or draining the on-board battery. The engine generators and APU feed the main and essential buses during normal or emergency operations, not the maintenance bus in this context, and the battery is intended for starting and emergency loads rather than powering the maintenance bus for routine ground work. So, external power is the proper source to energize the Maintenance Bus Switch.