What control method varies the pitch of all main rotor blades equally and simultaneously?

The control method that varies the pitch of all main rotor blades equally and simultaneously is known as collective pitch control. In a helicopter, the collective pitch lever allows the pilot to increase or decrease the pitch angle of all rotor blades at the same time, which directly affects the lift produced by the rotor system. When the pitch is increased, the rotor blades create more lift, allowing the helicopter to ascend. Conversely, decreasing the pitch reduces lift and enables descent.

This uniform adjustment is crucial for managing the aircraft's altitude effectively without changing its horizontal position. Unlike other controls such as cyclic pitch control, which adjusts the pitch of the rotor blades individually to tilt the helicopter in a specific direction, collective pitch control focuses on overall vertical movement.

Understanding this distinction is vital for grasping the mechanics of helicopter flight and the different functions of pitch controls.