WANTED: Angle of Attack Managers

This is one in a series of posts by special guest authors about SAFE’s new CFI-PROficiency Initiative™ (aka SAFE CFI-PRO™). The goal of the initiative is to make good aviation educators great!

Aviators, airmen, aviatrices—a few of the other words used to describe pilots. Yet none of these words reflect what we really do. Ultimately, pilots are angle of attack managers. Let’s have another look at AOA.

As David St. George notes in “Invisible Angle of Attack,” AOA is the difference between where the airplane is pointing and where it is going. Wolfgang Langewiesche describes the importance of AOA thus:

“If you had only 2 hours in which to explain the airplane to a student pilot, [AOA] is what you would have to explain. It is almost literally all there is to flight. It explains all about the climb, the glide, and level flight; much about the turn; practically all about the ordinary stall, the power stall, the spin. It takes the puzzlement out of such maneuvers as the nose-high power approach; it is the story of the landing.”

AOA implies two things: wind and an object around which the wind is flowing. Most everyone has played with AOA before. Remember sticking your hand out of the car window when you were a kid? What happened when you tilted your hand into the oncoming wind? “It went up!” is the common response. Reflect more deeply on the experience, however, and you’ll notice that your hand actually moved upward and backward. If we want to get technical about it, we could call the “up” part Lift and the “back” part Drag.

We’ve all seen examples of unusual things being forced to fly, too. For example, tornado-strength winds can cause even the most reluctant Holstein to go airborne.

A high velocity jet of air precisely aimed at a Snap-on screwdriver can cause it to hover (courtesy of SAFE member Shane Vande Voort—please don’t try this at home!).

And though we might describe a wing as having a “top” and a “bottom,” Lift- and Drag-producing AOAs are possible on either side.

AOA is discussed primarily in the context of the airplane’s main wing. But at the correlation level of learning, we see the entire airplane as an assembly of wings all of which are subject to the principles of AOA. The propeller, for instance, is a rotating wing. Main and jury struts are often symmetrical wings streamlined to minimize drag. “Aileron” is French for “little wing.” And our primary flight controls are AOA controls. The elevator controls the AOA of the main wing (aka pitch control).

Ailerons control local AOAs (typically the outboard part of the wings, aka roll control).
Rudder controls the AOA of the fuselage (aka yaw control).

Our job as instructors is to teach our trainees how to manage these AOAs to achieve desired performance outcomes. Although AOA itself may be invisible, changes in AOA can be sensed and its trend interpreted. In the visual flight environment, this means coupling aeronautical knowledge with sight, sound, and feel to manage our controllable AOAs.

Before we climb into the airplane, for example, we know that the combination of a high power setting and a slow airspeed during the takeoff phase will yaw the airplane. But we want coordinated flight during this particular takeoff. That will require a certain amount of rudder to manage the AOA of the fuselage to cancel the yaw. What does yawed flight look like during takeoff? What does it sound like? What does it feel like? What does it look and feel like if we try to use aileron to correct for the yaw instead of rudder? All of these questions can be explored in the practice area without staring at the slip/skid ball. The lessons learned can be applied during subsequent takeoffs.

Whether it’s pitch, roll, or yaw, changes in AOA manifest as changes in one or more of the following: attitude, G-load, control pressure, control displacement, and often sound. In the case of elevator inputs, add airspeed to the list of cues.

For fun, test your understanding of AOA with the following thought experiments. Imagine you are at an airshow watching a competent aerobatic pilot fly a capable aerobatic airplane.

1. The airplane makes a knife-edge pass from your right to your left at precisely 90 degrees angle of bank.
a. Where is the nose of the airplane pointing relative to its flightpath, and how is the pilot making that happen?
b. What is the pilot doing with the elevator to make the airplane fly down the runway?
c. What is the AOA of the main wing?
d. What is the pilot feeling?

2. The airplane climbs along a perfect vertical line.
a. In order to remain on the upline before pivoting in a Hammerhead, what is the pilot doing with the elevator?
b. Ultimately, what is the AOA of the main wing during the upline?

Want to learn more ways to push learning to the correlation level? Attend SAFE’s inaugural CFI-PRO™ workshop in Frederick, MD on October 2–3, 2019!

Join SAFE to support our safety mission of generating aviation excellence in teaching and flying. Our amazing member benefits pay back your contribution (1/3 off your ForeFlight subscription)! Our FREE SAFE Toolkit App puts required pilot endorsements and experience requirements right on your smartphone and facilitate CFI+DPE teamwork. Our CFI insurance was developed specifically for CFI professionals (and is the best value in the business).

The Secret of Pattern Safety!

We all know a majority of accidents occur in the traffic pattern; especially during descent and runway line-up. But the burning question is “why?” Basically, we fear the wrong things. Most pilots don’t understand the basic flight dynamics of descending turns and the real consequences and risks of unstabilized flying. With a little knowledge, practice and a committment to artful flying excellence, we all can do better and fly safer.

But instead pilots try to achieve safety by never banking over 20 degrees, flying huge patterns and becoming increasingly timid.  Others advocate oval patterns to eliminate the steeper corners of the pattern (but fly a constant turn). Why not just “learn to turn” correctly and safely in the first place? I watch in amazement as pilots horse their planes around to final with varying bank angles and wildly changing airspeeds (hold on partner!) exhibiting a lack of stability, ground track control and overall discipline. The physical problems with patterns are obvious but they are driven by a lack of understanding risk and knowledge of the forces at work.  This lack of stability and control continues directly into professional piloting where unstable approaches and overrun accidents are the #1 cause of accidents in corporate jets. As aviation educators (and pilots) we need to do better. Understanding some basic flight dynamics is critical to success.

Safety and a passion for pattern precision starts with an understanding of the invisible angle of attack (AOA) where the real risk hides. Simply presenting and thoroughly explaining  a set of pictures like the ones above  can jump start the conversation and clear up some very common misunderstandings. When asked which aircraft depicted above has the greatest angle of attack (AOA) almost every pilot (and many CFIs) pick the nose-high Cessna. The “a-ha” learning opportunity is that the AOA is the same on both of these aircraft. And that means the airplane in the glide is just as close to a stall as the nose-high plane on the left (now risk becomes clear). If we never demonstrate a stall with the nose *below* the horizon a new pilot in training will never understand AOA and how accidents occur. There is a “natural” (but erroneous) assumption that with the nose low, we are “safe” and “all stalls occur with a nose-high flight attitude” – wrong and reason #1 for pattern accidents! Even if this error is not stated verbally, practicing and demonstrating only nose-high stalls builds this myth and masks the true danger of descending turns.

In our initial flight instruction teaching the basic level turn, we emphasize that when a plane is banked, the lift vector is redirected to the horizontal (to create the turn) and no longer entirely opposes gravity. Consequently, some back-pressure is necessary to maintain altitude in a level turn. And during initial flight training, we build up this rote, muscle memory “bank and add pressure” response through repetition. But when we move on to the descending turns, is essential to emphasize this previously memorized script is incorrect.

A descending turn is completely different and requires “bank and release” because the added load of the bank will add drag and cause a decrease in airspeed (and greater AOA) unless back pressure is relaxed (and trim is a wonderful and underused tool here). Pilots descending tend to lose airpseed on every turn; they are banking and inappropriately adding back pressure (or failing to appropriately release). This is reason #2 of the “why” that explains many pattern accidents. This failure to understand the basic flight dynamics of the turn and AOA (also probably add some initial “ground fear” of being low) causes pilots in training bank to mishandle AOA. And once bad habits are extablished in training, they never go away.

How “eyeball friendly” is your trainer?

Outside visual reference and proper trimming are also vastly undervalued in modern flight training. If the airplane is trimmed properly and the pilot in training knows the proper, predictible flight attitude for a descent in various configurations, the stabilized control of the aircraft is much easier. Unfortunately, many pilots in training are inappropriately focused inside on the panel chasing the airpseed indicator instead of setting a flight attitude with outside references. Personally, unless my pilot in training can fly the whole pattern visually, with eyes outside (and the instrument panel covered) I hesitate to even consider a solo. Fly safely out there (and often).


And of course, more on this and other key educator tools at our Oct. 2/3 SAFE CFI-PRO™ workshop at AOPA in Fredrick, MD. The registration form will be live in a week. This will have Hilton and Marriott rooms at a discount and a networking dinner at the National Aviation Community Center!

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Join SAFE to support our safety mission of generating aviation excellence in teaching and flying. Our amazing member benefits pay back your contribution (like 1/3 off your annual ForeFlight subscription)! Our FREE SAFE Toolkit App puts required pilot endorsements and experience requirements right on your smartphone and facilitates CFI+DPE teamwork. Our CFI insurance was developed specifically for CFI professionals (and is the best value in the business).