What contributes to a decrease in lift at excessive angles of attack?

A decrease in lift at excessive angles of attack is primarily due to the increase in angle of attack beyond the critical angle of attack, referred to as CLmaxAOA. At this critical point, the airflow begins to separate from the surface of the wing, leading to flow disruption and a significant reduction in lift production.

When the wing is at angles of attack greater than CLmaxAOA, the airflow cannot smoothly follow the contour of the wing, resulting in a stall condition where the lift is no longer effectively generated. This stall phenomenon occurs because the lift curve starts to flatten and eventually declines as the angle of attack increases beyond this critical threshold.

The other aspects related to lift generation, such as thrust or total lift increase, do not maintain their effectiveness in producing lift when the angle of attack is excessive. Additionally, airflow separation is detrimental in this context rather than being decreased, as it actually becomes more pronounced as the angle increases beyond CLmaxAOA. Thus, the key factor here is understanding how exceeding the critical angle of attack leads to diminished lift capabilities due to airflow separation and the onset of stall.