What is the role of the Electrical Power Management System on the 787?

• A. To monitor, distribute, and protect electrical power across buses and loads.
• B. To manage hydraulic fluid temperatures.
• C. To control flight software for autopilot.
• D. To provide purely mechanical redundancy.

Answer: (A)

The Electrical Power Management System is responsible for monitoring, distributing, and protecting electrical power across all buses and loads. It continuously checks electrical parameters—like voltage, current, and fault conditions—and automatically reconfigures the distribution by operating relays and breakers to keep power flowing where it’s most needed. It prioritizes essential systems (such as avionics and flight controls) and can shed nonessential loads to preserve power for critical equipment during limits or faults. It also coordinates with multiple power sources, including engine generators, the APU, and onboard energy storage, to ensure a reliable and safe power supply. When a fault or generator issue occurs, the EPMS isolates the affected area to prevent damage and maintain as much critical operation as possible.

Other options don’t fit because hydraulic temperature management, autopilot control software, and purely mechanical redundancy are handled by different systems: hydraulic thermal management, flight control computers, and mechanical redundancy provisions, respectively.