Which of the following effects does an aerodynamic stall have on an aircraft?

An aerodynamic stall occurs when the airflow over the wings of an aircraft separates, leading to a loss of lift. One of the primary effects of a stall is a significant loss of control, as the aircraft may experience uncommanded pitch changes and a decrease in altitude. This loss of lift affects the aircraft's ability to maintain flight, and if not managed properly, it can lead to a more severe situation, such as a spin.

The nature of a stall is such that as the angle of attack exceeds a critical limit, the lift begins to diminish, making it difficult for the pilot to manage the aircraft. Recovery involves reducing the angle of attack, which allows airflow to reattach and regain lift. Therefore, the correct response highlights the critical safety concern pilots face when experiencing an aerodynamic stall: the potential for loss of control over the aircraft.