What is the function of the Mechanical Mixing Unit (MMU) in relation to tail rotor control?

What is the function of the Mechanical Mixing Unit (MMU) in relation to tail rotor control?

• A. It remains intact enabling limited tail rotor control
• B. It provides full tail rotor control
• C. It disables tail rotor control
• D. It drives the yaw boost servo only

Answer: (A)

The Mechanical Mixing Unit is the part of the tail rotor control path that physically translates the pilot’s pedal input into the tail rotor pitch commands, blending those inputs with other signals so the tail rotor can produce yaw control. If the MMU remains intact, the tail rotor can still respond to pedal commands, giving some usable yaw control even in degraded conditions. Full tail rotor authority, however, usually requires the rest of the tail rotor control system to be functioning as well, so the MMU by itself provides limited control rather than full control. It does not disable tail rotor control, nor does it solely drive the yaw boost servo.

The Mechanical Mixing Unit is the part of the tail rotor control path that physically translates the pilot’s pedal input into the tail rotor pitch commands, blending those inputs with other signals so the tail rotor can produce yaw control. If the MMU remains intact, the tail rotor can still respond to pedal commands, giving some usable yaw control even in degraded conditions. Full tail rotor authority, however, usually requires the rest of the tail rotor control system to be functioning as well, so the MMU by itself provides limited control rather than full control. It does not disable tail rotor control, nor does it solely drive the yaw boost servo.