Angle of incidence is defined as the angle between the wing's chord line and the aircraft's longitudinal axis. Does it affect lift?

• A. The angle between the wing's chord line and the aircraft's longitudinal axis; it is fixed on most aircraft and determines lift characteristics.
• B. The angle between the wing leading edge and the ground.
• C. The difference between pitch and roll.
• D. The angle between tailplane and fuselage.

Answer: (A)

Incidence is the fixed angle between the wing’s chord line and the aircraft’s longitudinal axis. This geometric setup sets how the wing experiences angle of attack as the airplane pitches. Lift depends on angle of attack, so the incidence acts as a baseline offset: with a given fuselage pitch, a higher incidence increases the wing’s angle of attack and thus lift (up to a limit / stall), while a lower incidence lowers the angle of attack and lift. Because incidence is fixed on most aircraft, pilots change lift by changing pitch (which alters the actual angle of attack), not by changing the incidence itself. The wing’s incidence isn’t the angle to the ground, nor the difference between pitch and roll, nor the tailplane angle, so those terms don’t describe what incidence is.