Name the four mechanical mixes provided by the MMU.

• A. Collective to Pitch; Pitch to Roll; Collective to Yaw; Yaw to Pitch
• B. Pitch to Roll; Roll to Yaw; Yaw to Pitch; Collective to Pitch
• C. Collective to Pitch; Collective to Roll; Collective to Yaw; Yaw to Pitch
• D. Yaw to Pitch; Collective to Pitch; Collective to Roll; Collective to Yaw

Answer: (A)

The MMU in the UH-60S uses four cross-coupled mechanical mixes to translate pilot inputs into coordinated rotor and tail-rotor actions, keeping the aircraft stable and predictable across axes. The mixes are: collective to pitch, which tie collective input to the pitch attitude so changes in lift don’t yank the nose up or down unexpectedly; pitch to roll, which links longitudinal cyclic (pitch) input to roll behavior to help the aircraft bank and turn smoothly; collective to yaw, which connects changes in collective to tail-rotor authority for heading control during lift changes; and yaw to pitch, which allows pedal (yaw) input to influence the nose pitch to maintain stable attitude during yaw motions. These four specific mixes are what the MMU provides to ensure proper cross-coupling between axes during different flight conditions. Other option configurations would either introduce mixes that aren’t implemented or omit a required mix, leading to improper handling and instability.