Which hydraulic systems are independent of each other on the 737-800?

The hydraulic systems on the 737-800 are designed to ensure redundancy and reliability in the aircraft’s operations. The Aircraft features three hydraulic systems: Systems A, B, and Standby. While all these systems work together to provide necessary hydraulic power, Systems A and B are independent of each other, each serving different functions and systems on the aircraft.

System A typically operates primary flight control surfaces and other critical components, while System B supports different hydraulic functions, including landing gear operation. This independence means that if one system experiences a failure, the other can continue to operate and enable safe flight operations, allowing the pilots to maintain control and maneuverability of the aircraft.

The Standby system, on the other hand, is designed to provide backup power for critical systems if both A and B fail. However, it does not operate independently in the same sense as A and B but rather acts as a supplemental system. Thus, while it provides important redundancy, it does not qualify as an independent system alongside A and B.

Therefore, the selection of Systems A and B as independent from each other accurately reflects the design and operational philosophy of the 737-800's hydraulic systems.