What causes a stall in an aircraft?

A stall in an aircraft is primarily caused by the separation of airflow from the wing's upper surface. This phenomenon occurs when the angle of attack—the angle between the wing's chord line and the oncoming airflow—exceeds a critical point. At this critical angle, the smooth airflow over the wing can no longer be maintained, leading to a significant decrease in lift. This loss of lift is what characterizes a stall.

When airflow separates from the upper surface of the wing, it creates turbulence and can lead to a rapid increase in drag. Pilots must be aware of this critical angle, as exceeding it can happen during various flight maneuvers, especially when attempting to climb or execute sharp turns. Understanding how to manage angle of attack is essential for maintaining safe flight, as stalls can lead to loss of control if not recognized and recovered from promptly.

The other options, while they can impact flight safety in different ways, do not directly lead to a stall in the same manner as the separation of airflow. For instance, excessive speed might lead to other issues like overshooting a runway, while too much weight can affect overall performance and handling but does not specifically trigger a stall. Low thrust during climb can contribute to overall performance challenges, but it is