By Howard Deevers
As we all know, early into our aviation training, our instructor introduced us to stalls. So often I have been asked, “What happens when the engine stalls?” Of course, that opens up a discussion on what a “stall” really is.
Naturally, the new student, or just interested person, is equating the airplane with a car. Now we need to explain that an airplane is not a car, and the tern STALL has a totally different meaning.
When an auto engine stalls or just quits, you move to the side of the road and troubleshoot the problem, out of gas? (Or maybe amps in today’s cars?) Ignition problems? Call AAA?
When we apply the term STALL to an airplane it has nothing to do with the engine. We mean that the airplane is no longer generating lift, and will not fly, at least not the way we want it to. This subject is much more complicated than a one sentence definition.
This is when the stall lessons begin. By this time, we know that an airplane cannot fly without lift. And a short ground lesson on the physics and lift should be in order. Some students get lost in the details right about here. After all, I only want to learn to fly, not take a college level course in physics. Again, the instructor will review the principals of an aerodynamic stall, demonstrate them, and teach how to recover from a stall.
The Airman Certification Standards (ACS) has very precise requirements for stalls – power on – power off – and others, and how they must be demonstrated by the applicant. With the ACS more exacting demonstration of stalls were required for private pilot applicants. Risk elements were also added for each task in the ACS.
After the stalls are over with, a big sigh of relief comes from the student. Also, the thought that I won't have to do that again except for a flight review in two years. Here, the instructor thinks, “I hope he/she got it!” How do we know if they didn't get it? Reading accident reports will tell us a lot about pilots that didn't get it. The NTSB will call it pilot error. A classic example is a pilot departing an airport, developing engine problems, then trying to turn around an make it back to the airport, and ends up in a pile of unusable airplane parts. We hope the pilot survives, but all too often the results are not that good.
No discussion about stalls would be complete without the understanding of Angle of Attack. Another physics lesson to be sure, but so important. Understanding that any airplane that exceeds the critical angle of attack will stall at any altitude, any airspeed. The critical angle of attack is where the airflow separates from the wing causing lift to be degraded. This can happen even when the nose of the airplane is below the horizon, which is something most pilots have never seen.
Fortunately for us, technology is at work to help us out. An Angle of Attack indicator can be installed in just about any airplane and may come as standard equipment in some newer airplanes. These AOA indicators give the pilot a visual indication about how much lift is being generated in just about any attitude. A simple color bar from green to red is placed within view of the pilot. Many pilots who install one of these are surprised to find out just how close to a stall they come during a turn to final in a pattern. The AOA is a useful instrument and not very expensive. Have the AOA instruments saved any pilots from crashing? We don't know, but sure do hope so.
If technology alone could solve the stall problems, there would be fewer accidents for sure. But training is still the answer. Few of us like stalls. I remember NOT liking stalls as a student. But over time I understood them better and now address the stall in training as a necessary and useful way to understand flying even more than just the basics needed to pass a check ride.
During training, the instructor will tell you in advance that we are going to do stalls. We also have to demonstrate unusual attitude recovery. Both of these events are brief, and the student knows in advance that they must do these to pass a check ride. However, in real life flying, stalls and unusual attitudes are never anticipated, and may not be so brief either, catching the pilot by surprise. Only a well-trained pilot will be able to react quickly and correctly to get out of those situations.
There are aviation schools in Arizona that specialize in upset recovery and can help make you a safer pilot. Almost any good instructor should be able to explain “those pesty stalls” and help you to understand and recognize the situations and how to avoid them or get out of them if needed. On your next flight review, ask the instructor to give you a bit more training on pesty stalls. It could save your life.
Your ARIZONA PILOTS ASSOCIATION presents safety seminars all over the State for free. Check the website for a location near you, and earn another phase of the WINGS. And, don't forget to “Bring your wingman!'