What is the primary purpose of pitch control in an aircraft?

The primary purpose of pitch control in an aircraft is to control the angle of the aircraft's nose for climb or descent. When the pilot adjusts the pitch, they effectively change the aircraft's angle of attack, which directly influences lift and drag. By increasing the pitch, the aircraft can climb as the angle of attack is optimized for greater lift. Conversely, lowering the pitch angle causes the aircraft to descend as lift decreases. This control is essential for managing altitude and ensuring safe ascent and descent during flight.

The other options, while relevant to various aspects of aircraft operation, do not accurately represent the primary function of pitch control. Maintaining a constant speed relates more to throttle management and engine power rather than pitch. Stabilizing flight during turbulence involves various stability and control surfaces, but pitch control focuses specifically on climb and descent angles. Similarly, navigation is primarily concerned with directional control and does not directly pertain to pitch adjustments.