Private Pilot License (PPL) Aerodynamics Practice Exam

What is the critical angle of attack?

1. The angle at which lift first occurs

2. The angle at which an airfoil stalls regardless of airspeed

3. The angle at which drag is minimized

4. The maximum angle of attack achievable

The correct answer is: The angle at which an airfoil stalls regardless of airspeed

The critical angle of attack refers to a specific angle at which an airfoil reaches its maximum lift coefficient before entering a stall condition. At this angle, the airflow becomes turbulent and begins to separate from the upper surface of the wing, drastically decreasing lift and increasing drag. This phenomenon can occur regardless of the aircraft's airspeed, meaning that the stall angle remains relatively constant for a given airfoil design. Understanding the critical angle of attack is crucial for pilots, as it is an essential parameter in stall awareness and recovery techniques. Knowing that it can vary by aircraft and conditions but is defined for each airfoil helps in leading to safe operational practices. Recognizing that it is not about the maximum angle of attack that can be physically achieved, but rather the specific angle at which the stall occurs, is vital for effective flight operation and safety management.