Why are there three hydraulic systems on the 787 often called Left, Center, and Right?

Why are there three hydraulic systems on the 787 often called Left, Center, and Right?

• A. For aesthetic labeling.
• B. To support dedicated landing gear hydraulics only.
• C. To provide redundancy and distributed hydraulic power for flight controls and systems.
• D. To allow independent fuel transfer.

Answer: (C)

The main idea is redundancy and distributed hydraulic power for aircraft control and systems. Having three independent hydraulic circuits—Left, Center, and Right—means each system has its own pumps, lines, and reservoirs, so a failure in one part of the hydraulics doesn’t leave the airplane without enough power to move critical controls. In normal operation, the left and right systems typically provide power to the primary flight-control actuators, while the center system supports other controls and essential systems. If one system is degraded or leaks, the remaining two can still move the flight controls and other important components, and isolation logic keeps the faulty system from affecting the others. This arrangement greatly improves safety by preserving controllability and the ability to land safely even with a hydraulic fault.

The main idea is redundancy and distributed hydraulic power for aircraft control and systems. Having three independent hydraulic circuits—Left, Center, and Right—means each system has its own pumps, lines, and reservoirs, so a failure in one part of the hydraulics doesn’t leave the airplane without enough power to move critical controls. In normal operation, the left and right systems typically provide power to the primary flight-control actuators, while the center system supports other controls and essential systems. If one system is degraded or leaks, the remaining two can still move the flight controls and other important components, and isolation logic keeps the faulty system from affecting the others. This arrangement greatly improves safety by preserving controllability and the ability to land safely even with a hydraulic fault.