What causes a stall in flight?

A stall in flight occurs when the aircraft exceeds its critical angle of attack, which is the angle between the chord line of the wing and the oncoming airflow. This critical angle typically ranges from 12 to 20 degrees, depending on the wing design. When the angle of attack surpasses this critical threshold, the airflow begins to separate from the top surface of the wing, leading to a significant loss of lift. This condition is not primarily caused by airspeed; in fact, a stall can occur regardless of airspeed if the angle of attack is too high.

The relationship between angle of attack and lift is vital to understand. As the angle increases, lift increases up to a point (the critical angle). Beyond that point, lift drops off sharply, resulting in a stall. Therefore, recognizing and managing the angle of attack is crucial for flight safety, making it the primary factor that leads to a stall.