Which statement is true about Angle of Incidence and Angle of Attack?

• A. Angle of incidence is mechanical; Angle of attack is aerodynamic.
• B. Angle of incidence is aerodynamic; Angle of attack is mechanical.
• C. Both are mechanical
• D. Both are aerodynamic

Answer: (A)

Angle of incidence is a fixed geometric relationship built into the aircraft’s structure—the angle between the wing’s reference line (chord line) and the aircraft’s longitudinal axis. It’s a mechanical property set during design and remains constant during flight unless the configuration is altered. Angle of attack, on the other hand, is the instantaneous aerodynamic angle between the wing’s chord line and the relative wind. It changes with pitch and flight path and directly governs lift. So the correct idea is that incidence is mechanical while angle of attack is aerodynamic. The other statements pair them incorrectly or claim both are the same type, which doesn’t fit their definitions.