What is the critical angle of attack?

The critical angle of attack is the specific angle at which a wing reaches its maximum lift capabilities before exceeding its lift-generating capacity, resulting in a stall. At this angle, airflow over the wing becomes turbulent, causing a significant loss of lift. Understanding the critical angle of attack is crucial for pilots, as flying beyond this angle can lead to a stall condition, during which the aircraft can lose altitude rapidly and become difficult to control.

The other options do not relate to the definition of the critical angle of attack. For instance, the maximum speed an airplane can reach pertains to the aircraft's performance limits rather than aerodynamic stall characteristics. Similarly, the minimum altitude for flight refers to safety regulations and operational limits, and the angle required for takeoff focuses on the angle necessary for achieving sufficient lift off the ground—none of which accurately describe the angle at which a stall occurs.