What is the function of a rotorcraft collective pitch control?

The function of the rotorcraft collective pitch control is to change the pitch of each rotor blade uniformly to alter lift. When the collective is raised, all rotor blades increase their pitch angle simultaneously, resulting in an increase in lift produced by the rotor system. This allows the helicopter to ascend or maintain altitude. Conversely, lowering the collective decreases the pitch angle, which reduces lift and can cause the helicopter to descend.

By uniformly changing the pitch of all rotor blades, the collective ensures that the lift generated is balanced, allowing for stable flight while minimizing the adverse effects that would occur if only individual blades were affected. This unified control is essential for managing altitude efficiently and precisely, making it a critical component in rotorcraft operation.