What is meant by the "angle of incidence"?

The angle of incidence refers specifically to the angle formed between the aircraft's longitudinal axis and the chord line of the wing. This angle is crucial as it helps determine how the airfoil interacts with the airflow above and below the wing. A wing designed with a specific angle of incidence will have a predetermined lift curve and stall characteristics, significantly affecting the aircraft's performance.

This angle influences how a wing generates lift at various airspeeds and attitudes. A higher angle of incidence can increase lift, but it can also lead to abrupt stall characteristics if it exceeds critical limits. Understanding the angle of incidence is essential for pilots when assessing their aircraft's performance and handling characteristics in different flight conditions.

Other choices refer to different concepts in aviation and do not accurately define the angle of incidence. For instance, the angle between the ground and the aircraft's wings is more about the aircraft's orientation to the horizon rather than the technical relationship defining incidence. The angle of the pilot's line of sight to the horizon is related to visibility and situational awareness, while the angle at which the wing cuts through the air pertains more to dynamic aerodynamics rather than the static incidence that defines the aircraft's wing design.