AOA Indicators - User Reports? Updates?

[Dave Piehler]

Admittedly, using Tapatalk and a phone to search the forums is likely to miss threads, but it seems that the last time anyone posted about an AOA indicator (I specifically searched for the Garmin GI-260) was years ago. How many people have installed them? How are they working? Have they improved your flying? Are they worth the cost?

 

Dave

 

 

Sent from my iPhone using Tapatalk

[carusoam]

5 hours ago, Dave Piehler said:

 

Admittedly, using Tapatalk and a phone to search the forums is likely to miss threads, but it seems that the last time anyone posted about an AOA indicator (I specifically searched for the Garmin GI-260) was years ago. How many people have installed them? How are they working? Have they improved your flying? Are they worth the cost?

 

Dave

 

 

Sent from my iPhone using Tapatalk

 

There is one of every kind of AOAi around here installed in every type of Mooney around here…

Everything the lower cost CYA100 to fancy in your color display Aspen….

There must be a half dozen suppliers today…

They are good. They work…

They require a decent calibration to have them work…

If you want to land your Mooney like @201er it helps to have an AOAi like he uses…

If you like to hear…

1) Beeeeep  (stall warning)

2) Chirp  (tires accelerating)

In rapid succession, while landing on the centerline… do what 201er does….  

Best regards,

-a-

[carusoam]

There are tons of suppliers….

And one that doesn’t work at all….  (Sensorless AOA doesn’t work according to pireps around here)

https://mooneyspace.com/search/?q=AOA&quick=1

Some use LEDs to display…

Others have a display that flips up into view on the glare shield….

Many add the info where you can’t see it very well… on a glass panel somewhere…

Some glass panels expand the display for AOA when required…

Best regards,

-a-

[squeaky.stow]

On 6/16/2021 at 5:11 PM, Dave Piehler said:

Are they worth the cost?

I will probably get roasted by all of the Mooneyspacers that have AOA systems and love them, but here is my 2 cents anyway. 
I have flown several aircraft with really good AOA displays, from fighters to transport category aircraft. If you are operating close to the stall side of the performance envelope, it is a really good tool for helping you to know just how close you are to that edge regardless of your weight or the weather conditions. For a fighter, AOA is really important because it can lift almost its own weight in fuel and ordnance. That makes for a big range of potential approach speeds. My Mooney can only lift about one third of its empty weight, so the difference in stall speed between empty and gross weight is less than 10 kts.
That being said, I generally fly in and out of reasonably long runways and I try to operate my Mooney well away from the edges of the envelope so I don’t feel the need for an AOA indicator. If I were routinely flying into short fields where every extra knot meant increased risk of running off the end of the runway, I might feel differently. 
So unlike some of the cool toys we can buy for our airplanes, AOA can be quite useful under certain circumstances. I just don’t fly in those circumstances enough to justify the cost.

[carusoam]

On 6/16/2021 at 5:11 PM, Dave Piehler said:

 

Are they worth the cost?

 

Dave

 

 

Sent from my iPhone using Tapatalk

 

They don’t cost very much…. 

 

My favorite question…

 

1) They aren’t needed… if…

2) Real pilots have tremendous memory, and plenty of time to memorize POH pages… then never forget the detail.

3) Real pilots always know exactly how much weight they are carrying…

4) Real pilots never exceed their target bank angle while turning…

5) Real pilots always approach a landing with a stabilized approach…

6) Real pilots always know how fast they are going while looking out the windows…. Some kind of sixth sense…

7) Real pilots can have an AOAi aide them by displaying how far away from the stall they actually are…

8) If you follow all the rules, and have the charts memorized, and are familiar accelerated stalls…. The AOAi is there to back up your reasoning and your memory skills…

So… if you have added Ceis fuel level gauges where you already have a calibrated FF/totalizer… you will like the AOAi…. It’s that good…

If your budget is tight and you can’t swing another payment to include an AOAi….  You are kind of stuck doing it the old fashioned way…. Memorization and awareness….

Sure a fighter has huge weight variations and giant charts to memorize… and they are flown by the best pilots….

But Mooneys are flown really close to the edge of their envelope each time we get close to landing…

End result… if you use short runways, or your memory has aged, or stress messes with your thought process….   The AOAi is a great tool to use as a visual back-up to your flying skills, memory skills, and logic skills….

If you are afraid somebody will find out you use one… tell them it came with the plane… the PO had money to burn…. 

Or… just tell them you don’t trust your stall horn to work… the AOAi tells you where you are continuously… the stall horn only tells you, you are going too slow…

The stall horn never tells you that it is working… make sure to test it during pre-flight…

 

A summary… it is worth it.

It is fun data to have…

It has limitations…. But real pilots know what they are for their system…

Real Mooney pilots typically have to struggle with the exterior probe… it may slow you down 0.1 knots or so…

Super real pilots like to land with precision…   Beeeep, chirp, on the centerline….

The AOAi won’t help with the centerline….   

 

PP thoughts only, A fun way to mix technology with flying…

Best regards,

-a-

 

[GeeBee]

One thing for sure. When you roll out on final and hit Vref+5 you know PDQ if load control fed you BS numbers.

 

[slowflyin]

I've had a couple.  My current AC has the heads up display mounted above glare shield and I find it very useful.  My previous AC had the indicator on the panel and I flew AS and occasionally crosschecked the AOA.   Now, with the indicator in my field of view it's the opposite.  Pitch to the blue circle, crosscheck AS, and eyes back outside.  For me, moving the indicator above the glare shield removed the system from the "gimmick" category and placed it firmly into the "tool" space.  

[PT20J]

2 hours ago, slowflyin said:

I've had a couple.  My current AC has the heads up display mounted above glare shield and I find it very useful.  My previous AC had the indicator on the panel and I flew AS and occasionally crosschecked the AOA.   Now, with the indicator in my field of view it's the opposite.  Pitch to the blue circle, crosscheck AS, and eyes back outside.  For me, moving the indicator above the glare shield removed the system from the "gimmick" category and placed it firmly into the "tool" space.  

Thanks for this insight. I’m getting a quote to add AOA when I install the G3X. I haven’t decided yet whether I will add it. I have the Aspen AOA on my PFD now. Ignoring the fact that it’s not accurate despite multiple calibrations and verifying that the pitot doesn’t leak, I have found it less useful being down on the panel.

Skip

 

[KSMooniac]

Raptor, I've got the Alpha Eagle system in my J, with the display mounted on the glare shield as far forward as I could put it. I'm a firm believer that they only help if the display is where you can see it quickly and/or in your peripheral vision.

I find it very helpful and use it for primary reference for the most part. I would choose exactly this solution again, as well. I would not bother with one mounted on the panel or added to an EFIS display. FWIW, I did a supervised self-install and it was tedious, but not challenging. If we have some spare time in Madison, perhaps I can demo it for you.

Sent from my LM-V405 using Tapatalk

[Jim Peace]

I would not trust any of these systems unless there is an actual vane outside on the side of the airplane and a good heads up display for the indicator. All calibrated of course...then you got something...

absolutely insane that almost every corporate jet I have flown has one and not one airliner has one....

 

[GeeBee]

 

10 hours ago, Jim Peace said:

absolutely insane that almost every corporate jet I have flown has one and not one airliner has one....

 

That is not true. I was flying AOA on 737NG's in 1998, with a HUD.

[Jim Peace]

15 minutes ago, GeeBee said:

 

That is not true. I was flying AOA on 737NG's in 1998, with a HUD.

Thats impressive....was it a true AOA or PLI?

edited I just found this picture:

never seen this before..at least not at UAL or the other legacys....my company just outfitted all our 757/767s with new flight displays and we dont have any AOA.....just PLI

 

[GeeBee]

It is a true AOA. The data is there in every airplane, both Boeing and Airbus. You just have to choose to display it. And yes it is at a legacy carrier. DAL.

 

[slowflyin]

12 hours ago, KSMooniac said:

Raptor, I've got the Alpha Eagle system in my J, with the display mounted on the glare shield as far forward as I could put it. I'm a firm believer that they only help if the display is where you can see it quickly and/or in your peripheral vision.

I find it very helpful and use it for primary reference for the most part. I would choose exactly this solution again, as well. I would not bother with one mounted on the panel or added to an EFIS display. FWIW, I did a supervised self-install and it was tedious, but not challenging. If we have some spare time in Madison, perhaps I can demo it for you.

Sent from my LM-V405 using Tapatalk
 

Same

[carusoam]

Jumping between planes (GA) and trusting an AOAi without knowing how or if it was calibrated could be interesting… without going through slow flight and having eyes on the instrument…

 

there doesn’t seem to be a calibration like for the pitot/static system…

How do you know your Boeing/Airbus system is up and running properly?

They have all learned a ton about AOA vanes over the years…

Best regards,

-a-

[A64Pilot]

Some fly stick and rudder.

Some fly the fancy displays and occasionally look outside.

Nothing flies closer to stall at high angles of attack, with a load often exceeding aircraft empty weight than a crop duster, a crop duster is right at the edge of a stall in almost every turn as their stall speed when fully loaded is quite high. As the hopper load is quickly jettisonable they do not have to meet 61kt stall with a full hopper, pretty much every Ag pilot either bends the stall warning vane so it can’t go off, or pulls the CB marked stall warning, because they get tired of hearing it in every turn.

So you would think every one of them would have an AOA wouldn’t you? Well pretty much none do, I looked at installing them and came to the conclusion after some testing that the pilots being highly experienced were more accurate than the AOA sensor.

‘You’ll find the same thing with bush planes, sure a few have them, usually the guy who buys a new Husky and money is no object will have one, not the guy who flies for a living though.

Many very high performance aircraft such as the afore mentioned fighter have extremely wicked stalls that give essentially no warning and as the aircraft is being flown extremely aggressively an AOA sensor has merit, Transport category aircraft fly at exceedingly high angles of attack and have every lift device known to God on the wings, so an AOA has merit.

‘But if your flying a single engine GA airplane in flight profiles where an AOA is useful, then you may should look at how your flying the airplane and why your putting it at such high angles of attack, perhaps buy a good used Pitts to play with? 

[GeeBee]

Not many dusters have swept wings. Ever stall a swept wing aircraft without the warning systems?

 

[GeeBee]

5 hours ago, carusoam said:

How do you know your Boeing/Airbus system is up and running properly?

Because you have three systems with separate tubes, ports and ADC computers.

If AF447 had AOA read out, they would have known for sure their airplane was stalled.

[A64Pilot]

1 hour ago, GeeBee said:

Not many dusters have swept wings. Ever stall a swept wing aircraft without the warning systems?

 

You know I pointed that out by saying fighters etc have wicked stalls, but then your reference of AF 447, which did have swept wings stayed in a very stable stall for a very long time.

‘It wasn’t the lack of an AOA that doomed AF 447, it was the kids that flew the fancy displays that did.

Read the incident, the pilot at the controls had all kinds of warnings, two stall warnings and crazy low indicated airspeed, but as he was the type to fly the computer he couldn’t figure it out.

If the pilot had good stick and rudder skills, we would have never heard of AF 447. Would an AOA sensor have saved them? Maybe if it didn’t also ice up, but so would have looking at the attitude indicator 

https://en.wikipedia.org/wiki/Air_France_Flight_447

[GeeBee]

I am a type rated A330 pilot, was an LCA on them and friends with Bill Palmer, author of Understanding AF447. I have also been presented with the AF447 profile unannounced several times each time flying it successfully.

While I agree the pilots mucked it up, especially by not flying attitude, they also were confused by the airspeed indicators. If they had AOA it would have been a separate and absolute confirming source that the airplane was indeed stalled.

The training to focus on AOA is not a mistake. The Navy has taught it for years.

Here is something few people will tell you. Even if the flight crew had pushed the stick forward, to the stop and  no less, at anything less than FL270, the airplane still would have been lost. Do you know why? 

 

[A64Pilot]

Well in truth we are in a single engine piston forum, and anything the Airlines or Navy flies is significantly different.

‘But no, I have never flown anything like a large Airliner and never will, but you have me interested why  an Airbus needs more than 27,000 ft to recover from a stall.

Honestly I’m very surprised from what I have heard that a swept wing aircraft is as stable as that one was in a full stall, I assume it was not in a deep stall.

Edited June 20, 2021 by A64Pilot

[GeeBee]

The reason why is fly by wire aircraft except for the Gulfstream and some newer yet to be certified models have zero feedback controls. There is no control feel. (This is the reason why people have so much problem flying GA simulators) For this reason, the stabilizer automatically trims to zero with the elevator. In the case of AF 447 the constant back pressure held resulting in constant stab nose up trim. As the airplane began the in stall decent, the stab trim was full nose up. At that point, stalled with full nose up stab trim, the elevator was insufficient, even nose full nose down on the stick to have the elevator overcome the pitch authority of the stab. Sure, the stab would start trimming full nose down, but not in time to recover the aircraft.

Now you would say, that's poor design. But if you have ever been out on functional check flights doing full stalls on a Boeing, where you disable the stick shaker and stick nudger, you would pay attention to the Boeing instructions which have maximum stab trim up settings to prevent you from getting into the same situation. 

Zero control feel is all the more reason why AOA is important, because you fly the airplane by numbers, not control feel.

As for swept back wings, in most designs, the wing is swept back as well as tapered. The is results in wings which stall tip first, even worse, the center of lift moves forward resulting in pitch up tendencies and finally little warning of stall. Couple that with strong span wise flow effect and you have an airplane that gives little warning of stall, when it does it pitches up when it breaks, and becomes highly unstable laterally. Which is why you have things like artificial stick shakers, and indeed nudger to prevent stalls. Worse, as most transports are constructed, the underslung engines powerfully pitch the airplane nose up when power is applied, and the elevator lacks authority due to low speed.

Now back to the value of AOA. If as every text tells you, the airplane can be stalled at any attitude and any airspeed, there is only one instrument that will tell you directly and without interpretation how close you are to stall and that is AOA. Everything else  is a secondary and interpretive indication. 

There is also a lesson for those of us who fly Mooneys. In particular long bodies. When you trim nose up against the elevator, or enter a maneuver with a lot of nose up stab, be aware, if you stall, your elevator effectiveness is reduced, because the elevator will have to fight the stab trim. So only use what you need and no more for maximum pitch response.

 

[Blue on Top]

Agreeing with @GeeBee.  In addition, one doesn't need an AOA indicator to have AOA.  It is built into other systems ... and that needs to be taught to pilots.

AOA and airspeed are totally different and independent systems (that knowledge would have saved AF447).  The CAAs messed it up, too, saying stall warning can't go off during takeoff.  In the case of AF447 and at an airspeed below 60 knots, the AOA system is disabled.  As the airplane was held in the stall (not deep stall, which is an aerodynamic flow problem), the INDICATED airspeed went above and below 60 knots ... turning the stall warning (stick shaker) ON and OFF.

Stick shakers (stall warning, >7 knots or 7% before aerodynamic stall) and stick pushers (stall barrier ... 2 to 5 knots before aerodynamic stall) are driven solely by AOA.  Single input for shaker, and dual input for pusher.  Those pretty colors on the side of the vertical airspeed tapes on PFDs of Part 25 airplanes and high end Part 23 airplanes are also driven solely by AOA (it is just put on the airspeed scale so pilots don't have to think as much or read another instrument.  For example, if the pitot tube(s) got blocked at 100 knots, the red arc for stall, the yellow arc or cross-hatched red arc for stall warning (if in that system), and the green or blue carat for Vref (1.3Vs) will still move up and down properly.    In that case, the proper way to fly an approach is with the Vref carat in the middle of the "T" speed (current airspeed).  In the example above, the real indicated airspeed would be 130 (not the 100 that is stuck in the window).   

As for swept wing airplanes stalling poorly, quit repeating data from the '30s and '40s.  The best stalling airplane in Textron Aviation's Cessna fleet is the Citation X.  It stalls inboard out and better than a C172 or C182.  We tailored it that way.

[Raymond J1]

https://www.bea.aero/docspa/2009/f-cp090601/pdf/f-cp090601.pdf

[Blue on Top]

2 hours ago, Raymond J said:

https://www.bea.aero/docspa/2009/f-cp090601/pdf/f-cp090601.pdf

Thanks!  I am not fluent in French.  I think that I have read this report, but I also think that there was a lot lost in the interpretation of the cockpit voice recorder (CVR) and in the translation from French to English.

Bottom line for me is that this accident was a long chain of events: very abnormal event, poor training, too much correct information to the pilot and too much incorrect/misleading information to the pilot.  Hopefully we'll learn from this tragic event.