“If you can’t fly the airplane by feel, you have no business being in the cockpit.” So goes a theory espoused by pilots who seem to think that angle of attack (AoA) is a crutch that no one needs or should use. This is actually an ego-driven argument whereby they are trying to show how great they are as pilots, far above all those folks who use things like instrumentation to keep them safe. Well, “safe” doesn’t exist while flying (we can only reduce the risk) and tools are used to measure how far away we are from the edges of the envelope, which are not always where we think they are. Tools help us reduce the risk. While that doesn’t make flying “safe,” it moves it in the direction of goodness.
Confession time. I think I’m a good pilot. I learned to fly in a J-3 Cub over 50 years ago, I have flown hundreds of different types of (sometimes very wonky) airplanes and I fly lots of them “by feel” either because they don’t have AoA or, worse, if it’s installed it isn’t calibrated. Fair enough. I have no problem getting into these types of aircraft and flying them.
Mind the Margins
But I like to have AoA because it gives me a better idea of where I am relative to the margins before I have to go find the edges myself. And the real reason that I consider myself a good pilot is that I am willing to admit that I can make a mistake and screw up. Anything else is ego talking. Good pilots die in loss-of-control accidents all the time. The smart ones, the ones who are aware of the possibility of making a mistake, use tools that may prevent such a screwup. AoA systems are just one of those tools.
Here’s the problem with the “you whippersnappers are lesser because you want to have AoA” argument. First, lots of “old/bold” pilots have killed themselves in stall/spin accidents. Second, most of the airplanes that old/bold pilots learned to fly in had plenty of aerodynamic stall warning to tell them they were getting close to losing lift. No fancy instrumentation required. But even in airplanes with so-called forgiving airfoils, pilots die in stall/spin accidents.
What do we mean when we say “forgiving”? Older airplanes were generally using airfoils that gave plenty of warning—buffeting, burbling, shaking—of an impending stall. In theory, the airplane shaking like a wet dog was enough to get the pilot’s attention. Second, most people learn to fly in certified aircraft, and certification requirements require good aerodynamic stall warning plus aggressive annunciation. It’s true those certification requirements weren’t in effect when the venerable Cub wing was designed—see the first point about old airfoils naturally giving good stall warning. That “good stall warning” was designed into the regulations because it is what the folks generating the regulations thought was a good idea!
Modern Times
Now let’s look at modern airfoils (and wing design) used in lots of noncertified aircraft. Many of them give little warning of an impending stall. Many of them are flying, then they aren’t. It is hard to fly these “by feel” because there is no warning that you are getting close to the edge. When this happens at altitude? Not a problem. Close to the ground? You’re dead. As you know, Experimental aircraft go through no certification process. Although all good designers prioritize stall characteristics, it’s likely that if the wing can’t be “fixed” and still meet design requirements—speed, range, whatever—that’s how it goes out the door.
You’ll find that a lot of the proponents of AoA are former (or current) military pilots flying high-performance jet aircraft. Flying AoA is second nature because those things have horrible (or non-recoverable) stall characteristics because they are designed for optimal performance elsewhere in the flight envelope. Their pilots know that things can be very dangerous down at the bottom end of the speed range, and AoA is a way to keep them from falling off that cliff.
Does that mean they are poor pilots because they can’t fly their airplanes “by feel” in that regime? I‘d challenge you to walk into the O-Club bar in Fallon or Las Vegas and try that argument. And, yes, many of those folks fly GA airplanes as well and like to take the same “edge” with them. Your average GA airplane has far, far better aerodynamic stall warning than any of those Gen Five fighters—not a true statement about many E/A-B aircraft that we fly.
So, yes, if you learned to fly in a Cessna, Piper, Beech, T-Craft or whatever old or certified aircraft, you can easily fly them all “by feel” because they give you plenty of warning before the wing gives up on you. But get out there at the edge of the airplane envelope and you can expect no such warning. And you’ve got one chance if the fates align and you get slow (or high-G’d) at the wrong time and place, then you’re dead. No do-overs, no “oh let me try that again.” If we can give pilots an edge, some sort of warning to help them get through that moment, is it worth it? I think it is. And AoA is just that. You can call it a crutch, but if you do be prepared to admit your nosewheel is a crutch. Or your second magneto. Or, for that matter, the radio, ADS-B traffic and onboard weather. Who needs any of those to be a “real pilot”?
So, back to the premise: Is flying by feel important? Absolutely we want pilots to get the feel of their airplane, to become one with the machine and know intuitively when they are getting the most out of it. This is a really good thing. But, frankly, it just doesn’t always work, as is evidenced by the numerous accident reports in files going back over a hundred years that include the names of very experienced pilots. Smart pilots use all the tools they have available to them, including their skill and talent, but also including technology when appropriate.
You see, it’s never a question of “need.” It’s a question of building margin by adding to your tool kit. AoA is a tool, as is stick position, pre-stall buffeting, awareness of G-loading or a slip/skid ball. Only a fool turns down a tool (when it’s available to them) that will make the job easier or lower the risk.
I’m an old pilot now, and I like to think that my boldness went out the window when I started flying more professionally, using all the tools in the box. Don’t be dissuaded by those who claim that using a tool makes you a lesser pilot. They’re full of it—or maybe just themselves—and are probably more likely to become a statistic than the pilots who embrace, understand and use every tool available to them.
Thank you for advocating the common sense approach of using modern instrumentation to reduce accident.
Thank you for this excellent article, and all of your advocacy on behalf of using AOA systems in our GA fleet.
Thanks, Paul, for writing this. I literally just read a post on AVWeb mentioning this article and fully 90% of the comments were against AoA. Many were against it due to price (one guy said it would cost $5000 to equip his airplane – must be made out of gold). Maybe you CAN spend that much, but you can easily equip for under $500 and these days you don’t even need an inspection. An A&P can install it and sign off without inspection authority
Others mentioned exactly what you’re dispelling here – that it’s not needed if you’re a good pilot. They said that airspeed is enough – but an airplane’s stall speed changes with several factors (weight, G-load, etc.), so airspeed isn’t always reliable. An airfoil stalls when its critical angle of attack is reached. Period. It has NOTHING to do with airspeed – you can stall a wing at cruise if you yank on the yoke hard enough – so a sensor that directly reports AoA is the only reliable way to measure a stall.
Some say we already have a stall horn – true, but they can sound when you’re already too far into a stall to fix the problem. With an AoA indicator, I can see exactly how close I am to a stall without waiting until I’m in trouble.
Several complained that it will require additional training. True, but which is harder to train – keep the AoA indicator out of the yellow or remember a value to target on an airspeed indicator – but also remember that the number changes under several scenarios? Just explaining those scenarios will take 20 times more training than simply looking at green, yellow, and red bars or a rotating gauge on an AoA indicator. It literally takes 10 seconds to explain.
The other common argument (the one that I think is worth discussion) was that an AoA is only good when it’s calibrated and that it has to be re-calibrated. True, but isn’t that the same for every other instrument in the cockpit? Pitot/static tests have to be performed every 24 months. Go out and stall your airplane every few flights to make sure your AoA indicator is doing what it’s supposed to – it’s good practice anyway.
Anyway, I’m confused why people are so hesitant adopt AoA for stall avoidance. There’s really no compelling argument against it that I’ve seen.
Proper training to fly with reference to AOA is critical to this equation. I saw a prolific online commentator essentially state AOA was useless, even dangerous, in a critical situation because that isn’t what pilots would be looking at. I disagree. My G3X AOA is my quick crosscheck item from base to final to final approach speed because I was trained that way. The bonus is AOA steers you right regardless of gross weight, something that gets overlooked in a lot of the discussions.
Yes, former Gen 3/4 military aviator.here.
what if you couldn’t start the engine with control locks still in? Or there were indicator lights on a simple switch to tell people their control locks were in? That could prevent more accidents.
Instrumentation certainly is a help. But a smart pilot will also learn to recognize the signals his airplane is sending to him. Engine noise, wind noise, control stick feel. I know a lot of Cub and Champ pilots who know EXACTLY when their airplane is going to stall even without an LRI or AOA. Just sayin’.
Excellent article Paul! Con/negative AOA views predominantly come from those who don’t fly with AOA. I suspect of those who do fly with AOA there are virtually none that say it’s not useful or beneficial. That tells you something!
One definition of Aviation: the human activity which should be totally full of strict cautious mentality, devices, practices and disciplines but where many in it push hard to make feel, ego, arrogance and pride the dominant culture.
I concur! Great info. My “bitching betty” AOA saved my butt one day when taking off on the wing of a dissimilar aircraft. The RV wing provides no warning buffet approaching the stall – it is smooth to the stall. During formation takeoff, I was concentrating on flying good position and didn’t realize the lead aircraft got slow at 50′ AGL. Bitching Betty said, “Angle, Angle, Push!” I dropped the flaps, loosened the formation, and insured I did not stall. It got my attention!
Experience doesn’t matter (23k hours in everything), an AOA can be a great tool!