Fast, On-Speed, Slow: A Common Language for Aircraft Control

[David Paule]

I flew with a single-position AOA system for over 50 years - Cessnas have an audible stall warning sensor. You can buy and install a similar device from Van's. It worked, was reliable and helpful. It said quite clearly, "Okay, far enough now, be wary." And then I flew OnSpeed's tone-based AOA system once, in an RV-10. The owner gave emergency a short description and with the volume adjusted properly for me, I found it easy house and gave me rather more information than the Cessna single-point system. I prefer the OnSpeed system, which was actually useful.

For people complaining about always needing to listen to the tune, no, just turn the volume down in cruise. Add adjusting the volume to the pre-take-off and pre-landing checklists.

It does require an AOA pickup, though, which might not be easy for your specific airplane. It would now be very difficult to retrofit to my RV-3B project for several reasons (that plane has the stall warning vane) and the SLSA I have on deposit would need to be put into ELSA status and then some careful designing done for it. But worth it.

On the basis of a single flight, I encourage any builder to install that AOA pressure pickup during construction.

Dave

 

[YellowJacket RV9]

I think this is a disingenuous response.
They have a chart with five studies that show different things.
The conclusion clearly states the following: "In general, the findings were not conclusive."
This is what I regard as data rather than information.

There is not a single randomized control trial that shows parachutes save lives either. The vast majority of pilots involved in a loss of control stall-spin are not around to provide conclusive evidence as to weather AOA may have changed the outcome. It seems very reasonable to assume that it may have in some cases. I use it and practice with it not because I fly near any limits, but because by being comfortable with it, I hope that should I ever find myself in a dangerous situation I will have the muscle memory to react appropriately before things get worse.

Ive been around to know that “just not making a mistake” is not the best plan. I plan for when I make a mistake, not if.

As to being overly complicated, “fast, on-speed, and slow” seems much simpler than calculating the appropriate air speed based on my weight, bank angle, and g-loading.

 

[dmattmul]

I've been flying with the Tones on for about a year now. I still don't like them and find them distracting. When its constantly making a tone - its easy to tune out. Like the boy crying wolf analogy. I like the tones for getting near the edge of a bad place to be like too slow (stall) or too fast (Vne). But I don't like the constant tone for "on speed". I absolutely tune it out.

"Having said that - I absolute HATE HATE HATE the colored bars and green donuts on most or all GA AOA gauges. I find it busy and totally unusable."

Maybe I'm missing something, but you don't like the tones, and you HATE HATE HATE the colored bars for AOA.

So how do you want to be informed you are about to stall the airframe?

For me audible works !!!!!!!! (If it's constantly making a tone suggest you review AOA calibration procedures, you don't have to have a tone for "on speed", I don't)

 

[rsultzbach]

“Its a single point failure if you have only one AoA”….. well of course it is. But you also only have a single engine, a single elevator pushrod, a single Airspeed Indicator, single Pitot tube….. so you can argue just to argue, or recognize that flying is all about keeping your head up and cross-checking. {Or do like I do - I have at least two AoA systems in each of our airplanes (and in some places, three….), but that’s just because I test them - not because I feel the need for multiple systems.} AoA is a tool - like any other - not a crutch.

“Oh, but big airplanes have vane sensors.” Yes, they absolutely do. They also have jet engines, so the prop slipstream is not a factor. Yes, you can put a vane sensor out near the wingtip of your RV - but they are delicate and I bet it won’t last. I’ve used several GA systems with the vane transducer, and have found that inexpensive ones tend to stick or bind. The pressure sensor AoA (either in teh pitot or “top/bottom? Holes) has been proven to keep you out of the weeds pretty reliably (there are always exceptions of course), and unless you are trying to do a test program where AoA needs to be measured to sub-degree accuracy, they are good for pilot use.

Tom paul - I really liek the quality and pasion behind the Alpha Systems unit! The one I have is probably eight years old, and it doesn’t have “progressive” tones - just a tone when you are getting flap sped, and a tone near the stall. I have talked with them about a progressive (and they were receptive) , but don’t know if they implemented it (yet) - will be interested in how it works for you. But you’ll have progressive tones in the Garmin, so I bet you’ll use that more than the Alpha systems display.

In the Navy, it was standard practice to crosscheck the functioning of the AOA gauge and indexer when entering your first downwind of the flight. Then, once the AOA has been checked for normal functioning the AOA was your primary speed sensor and the airspeed was secondary.
AOA was so great that once a pilot was versed in its usage if it wasn't working on an approach to the carrier it was reported to the LSO's inop AOA. That was infrequent but very infrequently the AOA did fail just like all aircraft systems.
As a suggestion, in addition to a tone I intend to have a stick shaker with a small eccentric motor strapped to my stick. Some AOA systems have a pin that goes to ground when approaching unsafe AOA. I plan on completing a ground activated relay to power the eccentic motor as a stall warning. I taught in the Navy and found tactile stimulation is answered by overwhelmed pilots who have tuned out aural warnings. Many of my flight students exhibited tuning out sounds when overloaded. I believe a small stick shaker would really get most peoples' attention.

 

[lr172]

During routine GA operations in the airport environment, say for flying a standard pattern or an instrument approach, under what conditions does one have a stall or loss of aircraft control when flying per the POH or standard patterns of flight that an AOA adds anything to?

I say it is just a tool, a useful one if one wants to fly at the aerodynamic edge, but of limited additional benefit above the normal tools one escapes with from PPL training (maybe even student solo level) .

Clearly you should do more research before you start saying aoa has no value outside the edge of the envelope. Quick test: what is your airplanes stall speed? Next, without research or a calculator, what is your airplanes stall speed in a 30* bank? What about a 45* bank? What if you have to pull a bit hard on the stick due to a sink near the fence and pull 1.3 Gs? What is your new stall speed? What if you accidentally pull 1.4 in a 30* bank? If you think aoa is a waste, i sure hope yoy have this memorized. This is one of the reasons why the base turn causes so many problems.

 

[Ironflight]

In the Navy, it was standard practice to crosscheck the functioning of the AOA gauge and indexer when entering your first downwind of the flight. Then, once the AOA has been checked for normal functioning the AOA was your primary speed sensor and the airspeed was secondary.
AOA was so great that once a pilot was versed in its usage if it wasn't working on an approach to the carrier it was reported to the LSO's inop AOA. That was infrequent but very infrequently the AOA did fail just like all aircraft systems.
As a suggestion, in addition to a tone I intend to have a stick shaker with a small eccentric motor strapped to my stick. Some AOA systems have a pin that goes to ground when approaching unsafe AOA. I plan on completing a ground activated relay to power the eccentic motor as a stall warning. I taught in the Navy and found tactile stimulation is answered by overwhelmed pilots who have tuned out aural warnings. Many of my flight students exhibited tuning out sounds when overloaded. I believe a small stick shaker would really get most peoples' attention.

I’ve actually been testign a stick-shaker grip for AoA, and the results are …. Itneresting so far. I agree that in a jet, the stick shaler gets your attention, In a vibrating prop plane…its a little differnt. It is also (so far) good as a discrete “warning” (which is how I think you’re planning on using it), but I am not yet comfortable saying that it can give you gradients to tell you where you are on the AoA curve.

Stay tuned!

 

[Notso]

I think this is a disingenuous response.
They have a chart with five studies that show different things.
The conclusion clearly states the following: "In general, the findings were not conclusive."
This is what I regard as data rather than information.

That was also written in 2019. LOTS has changed in GA in the last 7 years.

 

[Notso]

"Having said that - I absolute HATE HATE HATE the colored bars and green donuts on most or all GA AOA gauges. I find it busy and totally unusable."

Maybe I'm missing something, but you don't like the tones, and you HATE HATE HATE the colored bars for AOA.

So how do you want to be informed you are about to stall the airframe?

For me audible works !!!!!!!! (If it's constantly making a tone suggest you review AOA calibration procedures, you don't have to have a tone for "on speed", I don't)

Did you not read the rest of the post you quoted?? https://vansairforce.net/threads/fa...age-for-aircraft-control.244802/#post-1946374

lol. It explains my perfect system pretty well, I thought. Hint, combo of digital # display and tones only for when approaching a stall or other "about to get yourself into trouble limit".

 

[RNB]

That was also written in 2019. LOTS has changed in GA in the last 7 years.

Ok, but what research has been done on this subject and why would it be any different?

 

[RNB]

These discussions seem to be absolutely ignoring the potential unintended consequences.

I can think of several things that could have impact:
1. Improper installation, which seems to run rampant in experimental aviation (recent sure fly magneto/hot start example).
2. Improper calibration. This seems to have several data points that get entered into the system, each of which can introduce error and might be subjective anyway.
3. Improper or ignored maintenance.
4. If GA pilots push the flying because AOA says they can, might there not be more accidents as a result?

Examples. Over the course of my working career numerous new drugs were brought fully onto the market, they had passed every FDA drug study and had full approval. Some of these were later withdrawn from the market due to side effects. One of the ones I best remember is Propulsid, which did something funny to the electrical conductivity of the heart (it prolonged the QT interval) and led to death. There have been at least 10 drugs removed from the market due this exact same problem.

Colonoscopies...brought forth to save society from the scourge of colorectal cancer. Norton Hadler in his book worried sick argues that these screenings provide limited marginal benefits and harm four people for every live they save. I worked somewhere where an elderly woman died as a consequence of just such an exam.

Safe non toxic non flammable CFCs that worked holes in the atmosphere.

In a car, hasn't your GPS ever taken you down a dirt path or similar that ends nowhere?

Want more? Think back over aviation history and if you can't think of anything ask your AI for a "list of negative unintended consequences for aviation".

 

[RNB]

Clearly you should do more research before you start saying aoa has no value outside the edge of the envelope. Quick test: what is your airplanes stall speed? Next, without research or a calculator, what is your airplanes stall speed in a 30* bank? What about a 45* bank? What if you have to pull a bit hard on the stick due to a sink near the fence and pull 1.3 Gs? What is your new stall speed? What if you accidentally pull 1.4 in a 30* bank? If you think aoa is a waste, i sure hope yoy have this memorized. This is one of the reasons why the base turn causes so many problems.

I did not say that.