Which component transmits the pilot's flight control inputs to the hydraulic actuators?

• A. Flexball cable
• B. Control rods
• C. Hydraulic lines
• D. Pitot tube

Answer: (A)

The moving of the pilot’s controls into the hydraulic system is done by a flexible push-pull linkage called the flexball cable. When you move the control column, the flexball cable translates that motion into linear movement that drives the hydraulic control valves inside the actuators. The hydraulic system then uses fluid pressure to operate the actuators and move the control surfaces.

Control rods are rigid linkages that can transmit some motion, but in this setup they don’t directly convey the pilot’s inputs to the hydraulic actuators the way a flexball cable does. Hydraulic lines carry the fluid, not the input signal, and a pitot tube has no role in transmitting control inputs.