What is meant by the term 'deflection' in relation to control surfaces?

Deflection refers to the angle of movement from the neutral position of a control surface, such as the ailerons, elevators, or rudders on an aircraft. When a pilot moves a control surface, it alters the flow of air around the aircraft and thus modifies its flight characteristics, allowing for changes in direction, lift, and stability during flight.

Understanding deflection is crucial because it directly affects how the aircraft responds to pilot inputs, influencing its control and overall maneuverability. For example, if an elevator is deflected upward, the aircraft's nose will pitch up, leading to an increase in altitude. Conversely, if the elevator is deflected downward, the aircraft will pitch down.

In other contexts, the other options focus on different aspects of flight and control without capturing the specific meaning of 'deflection' in relation to control surfaces. The rate of speed change pertains to acceleration or deceleration rather than the positioning of control surfaces. The distance traveled by the aircraft describes its movement over the ground or through the air, not the action of the control surfaces themselves. Lastly, the responsiveness of the control yoke relates to feedback and handling qualities rather than the actual angle or extent of the deflection of control surfaces.