Section 9, Lesson 1
In Progress

AOA

Angle of Attack (AOA)

Angle of Attack, also known as AOA or alpha, is the angle between the wing and oncoming airflow. As AOA increases, so does lift, until the angle is too great, and airflow separates from the top of the wing, causing a stall.


Lesson Notes

Intuitive understanding of angle of attack in flight is paramount to good “stick and rudder” skills.

Every airfoil is subject to angle of attack (AOA). AOA is the angle between where the airplane’s wings are pointed, and the actual flight path. If an airplane is pointed exactly in the direction it’s moving, the angle of attack is zero. However, as you’ll see, this is rarely the case.

Perhaps most importantly, airfoils stall when the angle of attack reaches a certain limit. This is called the critical AOA. The exact angle of the critical AOA varies between airplanes, but for a given airfoil is always the same angle. In many light training airplanes it is around 16 degrees. Whether an airfoil stalls is entirely dependent on whether it has reached, critical AOA, not on whether it is nose up or slow. 

A pilot at any level needs to understand how their actions change the angle of attack, and how to recognize when the angle of attack is nearing critical AOA.

Additional Resources

Flashcard Questions

What is AOA?

How does lift change as AOA increases?

What is a stall?

What is critical AOA and why is it important?

Does an airfoil’s critical AOA change depending on airspeed?

A propeller is an airfoil. How do we change the propeller AOA?

In a level turn your airplane is closer to critical AOA that it is in straight and level flight, assuming the same airspeed. Why is this?

How could an airplane be stalled at a high speed, in a nose down attitude?

Do all airfoils have an angle of attack or just the wings?

Some airplanes have horizontal stabilizers in front of the wings (normally called a canard). Often these designs have are designed so that the canard reaches critical AOA before the wings. What is an advantage of such a design?

You transition from a 80 knot climb to a 115 knot cruise. How has the AOA change as you level off?

During a turn from downwind to final, and airplane maintains the same descent rate, airspeed and airplane configuration. What happens to AOA through the turn?