What AoA Indicators Don't Do That They Should

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With the exception of tiny squiggles up and down, the general aviation fatal accident rate remains stubbornly at about 1.0/100,000 hours. That's down a little from a decade ago, when it was 1.28 and down a lot from the early to mid-1970s, when it was more than 2.0.

In GA, we tend to resist the notion of required training and recurrency—the 24-month flight review is a joke—in favor of gadgets that make safety automatic and painless.The latest seems to be the angle-of-attack indicator, of which there are at least now five systems to choose from. All of them perform as intended and in the aviation press, we've fallen all over ourselves reporting on how great these gadgets are and how they should reduce stall/spin accidents. As I've said before, I go a different way on this. I think it's nave to think these instruments will make a dent in stall accidents just as it was nave to think the CAPS system in a Cirrus would give the airplane an exceptionally low accident rate.

It took Cirrus the better part of 20 years to learn that you can't just slap a safety system on an airplane and expect it to magically keep pilots from crashing and dying. As the airlines have also learned, these systems need to be tightly integrated into initial and recurrent training; otherwise, they're just another blinking distraction the pilot has to deal with under duress. When Cirrus, along with a devoted owner community, got serious about CAPS integration training, the accident rate finally showed improvement—impressively so.

That's not to suggest that I think AoA indicators are a gimmick or not worth the investment. They're not especially expensive and they have the merit of reprogramming pilot understanding of stalls as an airspeed thing to an angle-of-attack thing, where it should have been all along. And that's why I think the marketing of these devices is off base. They're being sold as stall awareness devices when in fact, they're really performance-measuring instruments that happen to include stall warning and awareness capability. If you limit them to the latter, they're just a visual version of the stall warning horn or aural alert and that almost guarantees they won't be integrated into the pilot's understanding of what the airplane is doing.

About 15 years ago, the Navy invited me for an overnight tour of the U.S.S. Theodore Roosevelt, which was involved in carrier workups off the Virginia capes. Ahead of that, I spent some time at the LSO school at NAS Oceana flying an F-14 simulator to carrier landings. Like all naval aircraft, the Tomcat was equipped with an AoA indicator and an on-speed indexer that summarizes AoA and, through indicator lights on the nosegear, gives the LSO a continuous and instantaneous readout on the approaching airplane's energy state. It took my sim instructor about 30 seconds to explain the AoA workings and it took another 30 seconds to integrate its response to my manipulation of pitch in the simulator. Hey, I got this.

As you can see from the graphic I'm including, the indicator has an approach reference bar and a tape showing actual AoA. It uses arbitrary units rather than degrees, but that matters little in interpreting it. The indexer has colored chevrons and a circle to show slow, optimum or fast speed and corresponds to what the LSO sees on the nosegear speed indicator.

I flew four or five approaches using this system. I crashed every one of them. Hit the ramp twice, took out the island and, I think, flew through the hangar deck. But I was on speed for every one of these disasters because once trimmed up, the AoA makes it easy to stay on speed with minimal mental bandwidth. The rest can be devoted to staying on the ball vertically—not that easy—and adjusting lateral lineup; all but impossible for me. I could figure it out eventually, I think, but that isn't the point. What is the point is that the Navy considers the AoA a critical, everyday tool for pilots that, oh, by the way, has a little crosshatched area indicating that 29 units of AoA will stall the airplane.

With this doctrine in mind and for this video, we did a flight trial in a Bonanza equipped with Aspen's AoA system. The Aspen AoA is a clever piece of design in that it requires no additional hardware, just a software package that uses the system's internal MEMS gyros and an aerodynamic model to infer AoA. Conceptually, the display is not that different from the F-14 design and it's well damped and accurate, graphically projecting the shrinking stall margin as AoA increases. But I'm not interested in that. I'm interested in using it as an on-speed indexer.

So we set up some slow flight and an approach flying on the AoA indications. Aspen says that the AoA flags at the green/yellow intersection should correspond to the aircraft's published approach speed and indeed it does. And it should. When the system is calibrated, you plug in various values from the POH in order to populate the aerodynamic model with data points for the software to compute AoA.

I found that moving the needles well up into the yellow band still gives—at least for me—comfortable stall margin but also four to five knots slower speed, making the touchdown less floaty and a lot shorter. Approaches flown too fast—very often way too fast because so many pilots are terrified of stalls—are a common scenario leading to excursions and overruns. And even if they don't, they use more runway than necessary and chew up tires and brakes. Further, the AoA flags are nicely damped and thus don't jump around nervously like an airspeed digital display or even an analog needle tends to do. It's thus a little easier to fly. It could also be used to index best angle or best rate for best performance departures.

I asked Aspen's developmental team about promoting the AoA system just this way, but they're uncomfortable with that, at least for now. It would require additional aircraft-specific testing rather than the affordable and certifiable one-size-fits-all software package they're offering now. It might also require external sensors, such as a dedicated pitot sensor or a vane. That adds cost and costs narrow the market. For its stated goal of stall awareness, the Aspen AoA and others like it are up to the task outlined for them and that's a broad-brush treatment for stall avoidance. Although I still think the integration training lags and these systems won't have the positive impact some people think they will, they're still a step in the right direction.

Ultimately, I'd like see AoA systems evolve in just the way I've described here—as speed indexers used on every approach to get the most out of aircraft performance and to wrap the sticker puller's head permanently around the concept of AoA. Otherwise, installing an AoA indicator is a little like having a live-in Cordon Bleu chef fix you spam sandwiches for lunch.

Comments (21)

All of my flying is civilian so I don't have the training that Naval aviators get. The Citation I fly has an AoA gauge but Cessna still uses different airspeeds for various weights for approach and adjustments to those airspeeds for residual ice on wing. It is my understanding that Airbus does not have an AoA gauge in their jets, don't know about Boeings. I do use the AoA gauge to back up the ref speeds in case the wrong ones are posted. I do know that military traffic patterns are sometimes flown with more than 1G while turning so an AoA gauge would defintely by beneficial to stay away from stall AoA. But I don't know of any situation in civilian flying where it is required to pull G's in the traffic pattern or at low altitudes. An AoA gauge is not much use if the wing is contaminated with ice since that wing will stall at a lower angle of attack than normal. Although I have an open mind on this issue, I find it hard to see any benefit in having an AoA gauge while flying normal catagory airplanes in normal private pilot/instrument maneuvers.

Posted by: matthew wagner | February 14, 2016 8:27 PM    Report this comment

While I see the value of an AOA measuring system in a fast and heavy military aircraft or any large airplane where being off speed a few knots makes giant differences in energy dissipation or runway requirements or cruise flight fuel usage, I fail to see why its necessary in most small and lightly loaded GA airplanes in most circumstances. As you say, it's the system du jour, I guess? I'd bet lawyers had something to do with it being so?

Beyond the issue of need, or not, I also question how taking one's eyes off the landing task is helpful, especially for something like the Aspen system shown in your video. The AOA warning bars on military airplanes are mounted on top of the glare shield for a reason. If newer ADS-B in and TAWS and TCAS systems can "talk" to us through the audio panel now, why shouldn't the AOA system, too? "AOA ... AOA." Putting in an audio warning ought to be a simple extension of what's already there. That said, by the time the AOA system figures out AOA is excessive, the GA pilot should have already recognized that and be fixing it or doing a go around.

Having to deal with still another visual sensory input at a critical phase of flight isn't something I'm interested in spending any $ on. You demonstrated and alternative method in your Cub. Then again, I think I already have a pretty nifty AOA warning system in my 172. It starts to chirp when I get into the yellow area, whistles when I'm seriously IN the yellow area and screams at me when I'm in the red zone ... while at the same time my butt warns me that my vertical descent rate is excessive and my stomach gives me that sick feeling that I'm gonna hit hard if I don't act. Well, maybe an AOA system would be a backup to all of that? :-)

Geez ... G3X systems now can shake the stick when we exceed preset values of pitch and roll or take over if we just push the blue button on the autopilot or don't respond within a preset time. Diamond tested a system that can automatically detect that the pilot conked out and then land the airplane. When is someone gonna wake up and figure out that reaching 100% safety is impossible as it's an asymptotic function? "Terrain." "Traffic." "Pull up, Pull up." Most pilots I know learn to filter all this stuff out. They'll do the same with a visual AOA warning after the newness wears off.

Posted by: Larry Stencel | February 14, 2016 11:50 PM    Report this comment

"That said, by the time the AOA system figures out AOA is excessive, the GA pilot should have already recognized that and be fixing it or doing a go around."

If that was truly the case, we wouldn't need AoA indicators because pilots would instinctively know what their AoA was. But obviously the accident record shows that isn't the case.

Also, existing stall warning indicators work great, but only in unaccelerated, level attitudes. Perform even a 45-degree steep turn and let the airspeed get low enough, and you can stall the plane without the stall warning ever going off. And the airframe buffet often starts only a couple knots before the stall, not giving much warning time.

I have to agree with the blogger (the writing style reads like Paul) that AoA systems are more useful as continuous performance indicators. It's almost a bonus that they can also be used for stall awareness.

Posted by: Gary Baluha | February 15, 2016 7:58 AM    Report this comment

Warning, byline missing, pull up, pull up!

Posted by: A Richie | February 15, 2016 9:24 AM    Report this comment

I also agree it reads like Paul. Since he did the Aspen AOA video I think it was.

I've heard so many excuses for "I don't want to learn something new" that I was sorely tempted to not read the comments to this post but - woe is me - I did.

How does the fact that it is AOA that keeps flying machines in the sky keep getting lost on pilots.

The point of the post was that AOA might better serve the pilot population if it were used as a performance measuring tool rather than stall awareness indicator in lieu of airspeed. I could not agree more! The example of the short field landing at less than MGW is a great example of comparing non-precise IAS versus actual AOA.

Take a chance pilots, learning something new like AOA won't kill you. Indeed, it might just save your life.

Keep trying Paul.

Posted by: Chuck Cali | February 15, 2016 9:47 AM    Report this comment

Gary writes "Also, existing stall warning indicators work great, but only in unaccelerated, level attitudes."

Not the ones I'm familiar with. The stall indicator port on a 172 detects vacuum at that point on the leading edge, and the little vane on a Cherokee detects upward airflow - both AoA dependent phenomena. I still remember a training flight in a 172 on an especially bumpy day, where each updraft triggered a momentary stall warning. If the pilot doesn't see or hear the stall warning in an accelerated stall, it's because it happened too fast to notice.

Which leads to why AoA indicators are of limited direct use in preventing stall-spin accidents. As Larry says, the pilot is already plenty busy in the base to final turn and doesn't need another thing to watch. And of he does screw it up it will happen too fast to notice. The best hope is that AoA indicators will promote awareness of AoA and prevent mistakes in the first place.

- Andy

Posted by: Andy Goldstein | February 15, 2016 11:12 AM    Report this comment

I have one of each of those airplanes, Andy, and I basically agree. Now that you remind me, it's a heckuva lot more important to maintain coordinated flight than worrying about AOA in that turn. And no one has yet brought up the fact that there's a delay in commanded power output of a jet, unlike piston engines. Since pilots are afraid of stalls, they tend to land too fast; I don't know of many fatals involving running a landing GA airplane off the far end of a runway cuz of low AOA.

When doing kamikaze runs, I sometimes miss the Piper red light but it's tough to miss the Cessna whistle. I've considered paralleling a horn into my Piper for that reason. Hearing cues is important.

I went back and re-read Paul's article. Right at the beginning, the original premise seemed to be talking about how some folks thought AOA systems might reduce the GA fatal rate. Then Paul tells us about how he did carrier sim approaches and stayed 'on speed' yet crashed anyhow ... seemingly because he was fixated on AOA at the expense of other equally important issues during the landing (crash) phase. MY point, too.

So how's about this. There are two groups of GA pilots. Those who are experienced enough to instinctively recognize the cues of what an airplane looks, feels or sounds like when it's approaching high AOA and ultimate stall and those pilots who don't. The former can practice -- during their BFR or on their own -- if they fly just above a stall and do 90 deg turns without stalling and remember what that felt like. The latter can buy an AOA system and know they were on speed when they hit something too hard. My position is that GA pilots just need good training to understand the difference between airspeed and AOA and to occasionally practice same.

Maybe there's a third group? Airline pilots who fly airplanes where deck angle becomes an issue. Stewardii don't like pushing carts uphill so caring Captains figure out sly ways to make deck angle somehow coincide with good performance. There are vays. Then maybe an AOA indicator is a nice to have device, too.

Hmm ... do those fancy new M20V's have AOA systems installed? For $800K, they'd better? Since Paul's Cub likely has no electrical system, maybe he could tape some sort of vane onto a protractor on the wing strut. It'd be similar to the piece of yarn slip-skid indicator he uses or the simple 10 cent bomb sight that they rigged up on Col Doolittle's B-25's.

Posted by: Larry Stencel | February 15, 2016 12:18 PM    Report this comment

I, too, was surprised to see no byline on this article. I did see Paul B. right seat on the video.

Paul, several points come to mind.
1. You reviewed a complex system and found fault with it. I prefer the KISS reserve lift indicator based on a differential pressure indicator and two pitot tubes that use relative differences to indicate angle of attack. This could be upgraded with a sound indicator instead of a sight device.
2. Combining airspeed with AOA in one instrument is redundant. Pilots are taught to scan instruments.
3. Pilots that are scared of stalls and stalling should find something else to do.
4. Pilots that consistently fly with too fast approach speeds should learn how to control their aircraft.
The one thing I agree with is the comment relating to a chef making a sandwich.
Alan Laudani, Shady Cove, OR

Posted by: Alan Laudani | February 15, 2016 1:03 PM    Report this comment

"seemingly because he was fixated on AOA at the expense of other equally important issues during the landing (crash) phase. MY point, too."

That's not what I said at all. You may be making an assumption based on a bias against the value of AoA indicators in this context. As I explained, I crashed the sim because setting the AoA is only one variable in a complex approach problem. Two others are setting power to maintain the glideslope and adjusting it to correct above and below. That happens independent of AoA once you've trimmed the airplane correctly. And by independent, I mean it's mentally independent, not aerodynamically independent. (Change power; adjust pitch...maintain AoA.)

The second is lateral alignment and avoiding PIO in an airplane with the roll inertia of an F-14. All my approaches were at night in clear weather, what the Navy calls Case III operations. The carrier appeared visually in the distance as a point of light in a completely black field; no horizon. So on long finaI, I flew the carrier landing system indications--basically like an ILS--until the ball was in sight. Because of the roll issue, I could sort of get the ILS part okay, but tended to overcorrect. Once the ball was in sight, deft corrections are necessary and that just takes experience to master. I didn't have it, thus the tendency to over and under correct.

Claiming that an AoA is just too complex to add to the scan strikes me as illogical. I had no trouble with it on the sim with no training. The scan wasn't the problem; control was. In the context of a GA airplane, consider the base turn to final. You're going to want a speed hack there of some kind, so you steal a glance at the ASI. We've never said that was too complicated to learn. In an AoA-equipped airplane, scan the the indexer instead. That ain't rocket science. A properly designed indicator is as easy to interpret as an ASI and probably easier than a glass panel tape ASI.

But...this needs to be integrated into training, which was the overall point I'm trying to make. AoA is no magic bullet, it's just a scalpel in place of a butter knife. We had one in our Mooney 201--the original Huntington LRI--and it worked very well for a max performance short landing. Best L/D was maybe 5 knots under the recommended approach speed. If you don't think that shortens landings, you need to get out of the house more.

I think it's both a mistake to oversell the benefits of AoA and to dismiss them entirely as just another gimmick.



Posted by: Paul Bertorelli | February 15, 2016 1:27 PM    Report this comment

Overall, we're hummin' the same tune in a different key, Paul.

I definitely agree that slowing 5 kts will shorten landings AND -- as is the case with my 172 but NOT my PA28 -- excess speed can, at times, be bad. It causes the airplane to start climbing out of ground effect and then run out of smash if I'm not 'on speed" during landings when light. If magically I HAD an AOA indicator, I'd use it to steal your 'glance' vs an ASI but ... I won't spend any money or time installing one. My MO is to tell where I'm at by the way the airplane handles and the amount of power required to produce a reasonable descent rate/angle. Has worked for me in this A/C for 30 years.

I flew this airplane for years at Mojave and I can assure you flying 'on speed' woulda resulted in disaster in the very gusty often crosswind desert conditions out there.

In my older PA28 with the shorter 30 ft wing span and 10 ft tail plane and shorter fuselage, it's a different story. It tends to act like a rock with wings by comparison. It is nose heavy (or lacks sufficient pitch authority when slow) and demands closer attention to speeds so that I can raise the nose in the flare. It's tough to keep the nose elevated with no one in the back seat. It tends to go nose down no matter what I try but a bit of extra airspeed (inertia) helps. That's why newer low end PA28's have 32 ft wings and 12 ft tail planes, or greater.

My first sentence in the my comment and your last sentence above IS the way I/we view AOA systems, I guess. I suppose that's the punch line some thought was missing? In fact, the old adage, "Fly the airplane first" fits. Old guys don't need no steenkin' AOA's while -- I'm convinced -- young guys would try to fly a GA airplane with their iPhone IF they could ... can you spell Airbussus? :-)

Now then, it's close to 5 o'clock ... As ordered, I gotta get 'out' to get some beverages of choice. :-)

Posted by: Larry Stencel | February 15, 2016 3:05 PM    Report this comment

Freedommmm!!!! Atta boy Larry!

Posted by: William Granch | February 15, 2016 4:50 PM    Report this comment

There was this guy who lived to be pretty old. His name was Wolfgang and if he were asked, he'd likely point out that there'd be a lot more old guys around today, had they been using AOA during pilot training before, during and WWII.

He tried, back then, even wrote a book.

It's not rocket science and frankly, it is hard to argue with the old guys who like their ASI, but were taught look out the window, fly the wing and that thing in their right hand is not the same as the gas pedal in their car.

It is obvious I'm an advocate of AOA yet, when put upon to posit the nature of seemingly avoidable stall/spin accidents, I don't go to AOA but seriously ponder the possibility that the modern flight instructor is not teaching the new pilot how to fly the wing or - to a large extent - how it works at all. Worse, I'm concerned that they not teaching it because they don' t know.

Not that Paul needs my words, but I never read his blog to be anything but an exploration of possibilities. A suggestion that maybe there is a more useful way to use AOA indicators. Since they're now essentially available by the push of a button, why not?

Larry, I'm going to follow your lead. It's only 1500 here in NorCal but it's 5 o'clock somewhere.

Posted by: Chuck Cali | February 15, 2016 5:16 PM    Report this comment

The thing that strikes me the most and nobody else seems to have noticed is the colour sequence on the AoA is all wrong. Too SLOW should be RED(danger), Too FAST should be ORANGE(caution), Optimum should be GREEN(OK) this seems more natural and intuitive. Plus, audio is essential (RED danger stick forward) (ORANGE caution stick back) (GREEN Ok hold angle) the colour should be stated in the audio. Just as a suggestion this would even cover you if you are colour blind. In general AoA indicators should be helpful if used properly, I agree with Paul it wont save you unless you understand its an energy gauge you still have to fly the aircraft and adjust for conditions like wind shear and different aircraft characteristics. Lots of people have driven their aircraft into the ground while listening to a stall warning horn in the background. Fly the aircraft.

Posted by: James Crocker | February 15, 2016 10:49 PM    Report this comment

Just get a BRS and all will be well. Here, have a cookie.

Posted by: Thomas Cooke | February 16, 2016 5:27 AM    Report this comment

An AoA absolutely is NOT "an energy gauge." This is perhaps the most compelling reason to combine AoA and airspeed information in one presentation.

Posted by: Tom Yarsley | February 16, 2016 6:13 AM    Report this comment

Paul,
I would be interested if during your appoach using the AoA in the Bonanza, did you get to the buffet that would give plenty of warning of a stall in most Beechcraft. The various Beechcraft models I have flown give you plenty of warning through airframe buffeting that you are getting too high of AoA. A light aircraft that I have a lot of time in that could really use an AoA gauge is the Aerostar. Aerostars do not have a stall warning system and what little airframe buffet it does have prior to stall happens real fast. I think the accident record of this airplane shows that. I think the FAA would be better putting more emphasis on stall training and awareness especially with CFI candidates. It amazes me how many pilots out there are afraid of practicing stall recoveries in light aircraft. One of the reasons I still occasionally fly jumpers in light aircraft even though I am employed flying a business jet.

Posted by: matthew wagner | February 16, 2016 12:51 PM    Report this comment

Yars ... great point. I almost killed myself back in the 80's in a T-34A for that exact reason.

I'd been flying 'rides' at a USAF Aero Club in CA all day when a pilot buddy got in and asked me to 'show him some stuff.' Being a card carrying registered kamikaze pilot, I roared down the 5,000' runway and pulled back a bit too hard. I got the airplane pointed up probably about 40+ deg whereupon I RE-learned about accelerated stalls at 500'AGL. The only thing that saved me as the airplane was mushing toward the ground with flight controls that weren't working was keeping the nose from turning, full power and pumping the elevator at about 5 pumps/sec (learned from getting gliders to stand up straight). Had I had an AOA, I woulda known I had exceeded max AOA in the 2-3 seconds after I did that despite the high indicated airspeed, huh.

Hard to believe that during WWII they didn't understand the concept of accelerated stalls. In a way, that's what this discussion is all about, isn't it. Wolfgang WAS right but there's always at least two ways to do most things ... starting with understanding the mechanics of how wings work.

From my T-34A SCARE, I learned to NEVER yank on the elevator ... especially in a high energy state. Be smooth. Elevators have far more pitch authority than a wing can produce lift for. You don't have to pull 5 G's to have fun. Just keep the AOA in the green. I do that by feel and remembering the sick feeling I had that day in the Mentor. :-)

Jim C ... I did notice the color issue. Good point on the audio call outs. Wouldn't be hard to do. Some of the different ways vendors are displaying it on those little indicators is pretty confusing, too.

Posted by: Larry Stencel | February 16, 2016 1:46 PM    Report this comment

"Some of the different ways vendors are displaying it on those little indicators is pretty confusing, too."

I agree.

The winner: www.flyingmag.com/avionics-gear/instrumentaccessories/video-icon-reveals-a5s-pilot-friendly-aoa-system

Posted by: William Granch | February 16, 2016 5:03 PM    Report this comment

To those calling for different color displays on AoA indicators, I agree, they are all over the map. I build and sell the CYA-100 angle of attack system, which is FAA approved. However, the FAA provided nada guidance on display orientation or colors in the SAE spec I had to comply with to get approval, so I built the device to display what I would like to see.

Even the US Military does not standardize AoA displays between the different service branches.

The CYA-100 display was designed to act like a glideslope needle (lights up/ pull up, lights down/, push down) with the colors RED=danger, YELLOW=caution, GREEN=OK (can't stall) to be consistent with the interpretation of the same colors on any other instrument.

Most users quickly learn to use the AoA indicator as a quick method to determine TODAY"S best approach SPEED. As an an example, a Mooney will have drastically different "book" approach speeds dependant upon gross weight. The AoA indicator does away with all of the calculation, and lets you SEE the proper approach speed for today's conditions. The difference can be in excess of 10 knots. I've been told by many Mooney pilots that they used to fly the highest appropriate approach speed, with maybe a few knots more for gust "fudge factor". With the CYA-100, they consistently settle on the approach speed that's correct TODAY. Almost always a much slower approach speed, with less float and tendency to porpoise at touchdown, critical in the very low-wing Mooney.

I think Paul's intent here is very valid. The AoA is NOT a stall warning device. It's a pre-stall, accurate approach SPEED computer, one that displays the one critical parameter about your wing that you need to know during critical flight manuevers. That critical parameter is the critical angle of attack (stall angle of attack), and that parameter never changes, regardless of bank angle, gross weight, density altitude, or g loading.

Folks that install an AoA indicator are left to themselves to determine how best to use the information it provides. There will have to be an appropriate change in the training curriculum as these devices become more common. Still, I'd strongly urge everyone to install an AoA indicator, even if it's not one of mine. I firmly believe these things can save lives.

Posted by: Ripley Quinby | February 16, 2016 5:34 PM    Report this comment

To Tom Yarsley perhaps I should have been more specific it's a lift energy gauge telling you how much lift energy you have left before the inevitable. The important part of my post is the colour coding, if as Paul said better training is required then a standard colour code would make that training a lot easier. and that code should match with current instruments the most common of which is IN THE GREEN is ok. RED for danger and Orange for caution. Or if you want a linear approach Green, Orange, Red from high lift to no lift. The FAA or the aviation industry needs to set a standard.

Posted by: James Crocker | February 16, 2016 7:32 PM    Report this comment

I found adding the AOA module to my Dynon D10A in my Glasair 1 RG was extremely helpful, but not for the reasons discussed.

The Glasair has fairly high wing loading, about 50% higher than most Cessnas and similar GA aircraft, and small control surfaces. At slow speeds in a dirty configuration, the sink rate picks up and the directional control becomes mushy. Flying the calibration stalls for the AOA showed me that the actual stall speeds for the plane are more than 10 knots lower than the speeds at which landings start to get overly interesting due to the sink rate and mushy controls.

So I don't look at the AOA much as I near a landing - learning about the gap between comfortable sink and control speeds and the actual stall speed relieved the worry about stalling at low approach. I fly the slowest airspeed that keeps me in a comfort zone with adequate directional control and an acceptable sink rate. But before the AOA, I didn't realize that there was a fairly sizable cushion before I had to worry about stalling on approach.

Where the AOA is really helpful in this plane is in taking off, when I can convert airspeed to altitude pretty rapidly without worrying about an unexpected stall - because I'm checking the AOA.

Posted by: Richard Persons | February 17, 2016 12:58 PM    Report this comment

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