What is the secondary purpose of adjusting pitch change rods?

• A. To reduce vertical and/or lateral vibration levels
• B. To increase blade pitch uniformly
• C. To change color of rotor blades
• D. To adjust airspeed

Answer: (A)

Pitch control linkages translate pilot input into blade pitch changes, but they also need to be set so every blade responds in near unison. The secondary purpose of adjusting the pitch change rods is to reduce vertical and lateral vibrations by ensuring the pitch changes are applied evenly and in proper phase across all blades. When these rods are misadjusted, blades can pitch differently or out of phase, leading to increased vibration, wear, and ride roughness. By dialing in the rod lengths and attachment points, you help minimize those vibrations and improve rotor system smoothness. The other options—changing blade color, altering airspeed, or simply increasing pitch uniformly—aren’t achieved through this adjustment and aren’t the intended secondary outcome.