The MMU mechanically combines, sums, and couples cyclic, collective, and yaw inputs and provides proportional outputs to the main rotor and tail rotor systems.

• A. Cyclic, Collective, and Yaw inputs; Main Rotor and Tail Rotor systems.
• B. Throttle, Pitch, and Yaw inputs; Main Rotor and Nose Rotor systems.
• C. Cyclic, Collective, and Throttle inputs; Tail Rotor and Stabilizer systems.
• D. Yaw, Pitch, and Roll inputs; Main Rotor system only.

Answer: (A)

The main idea is how the helicopter’s flight controls are blended to drive the rotor systems. The UH-60 uses a mechanical mixing unit that takes three pilot inputs—cyclic, which tilts the main rotor disk to steer; collective, which changes the overall lift by moving the swashplate up or down; and yaw pedals, which command anti-torque via the tail rotor. The MMU combines these inputs and translates them into proportional commands for both rotors, so maneuvers come out smoothly as a coordinated effort between changing lift, tilting the rotor disk, and producing tail rotor thrust.

So this option is correct because it identifies the exact inputs being mixed—cyclic, collective, and yaw—and the two rotor systems they control—the main rotor and the tail rotor. The other choices introduce elements that aren’t part of the MMU’s mixing function (like throttle or a hypothetical nose rotor), or they omit the tail rotor control, or they imply control of only one rotor, which doesn’t reflect how the UH-60’s mixing unit operates.