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Yoda2 11-13-2014 11:51 AM

Not understanding AoA indicators...
 
Not understanding why, lately, many seem to feel it is so important to have AOA indicators in light aircraft. This almost seems like a workaround or some type of attempt at a solution for lack of basic flying skills? If loss of control is an issue, couldn't that reflect more on training or just a dumb, unknowledgeable or risk taking pilot?

ZapBrannigan 11-13-2014 12:02 PM

I can't figure out why big airplanes don't have one! It was a valuable and informative instrument in the Learjet that gave you instant insight as to the amount of energy available in the wing regardless of airspeed or pitch attitude.

Cubdriver 11-13-2014 12:10 PM

Speaking off the top, AoA indicators are simply the best thing to have among attitude measuring instruments. They are better than stall horns in terms of telling the pilot where the aircraft is in it's range of flight attitudes. They make the pilot who knows how to use them more aware of the energy state of the aircraft as attack angles change. Military aircraft have had them for years as well as civilian jets, because those aircraft operate at specific AoAs for best economy and maneuverability, among other things and the pilot needs precise info on AoA to do that. AoA data is used for many advanced flight management computers and is more often available in jets than in piston aircraft. The trend lately has been towards light-jet style avionics in piston aircraft, such as the Garmin suites we have now running digital AHRS units with digital autopilots, TAWS, and complex flight computers. Those systems need AoA inputs to function properly. Another factor in the adoption of AoA for GA lately is simply the lower cost of off the shelf AoA units plus FAA willingness to approve them.

I think it's a good thing for GA because stall spin accidents as well as overall student awareness is tied to seeing how things work. AoA gauges really show what is going on when you approach a stall, do a spin, or change configuration on approach to name a few common uses.

BoilerUP 11-13-2014 12:11 PM

There is no reason to NOT have AoA data...

Yoda2 11-13-2014 12:19 PM

I agree with the responses, and thanks. It just seems for GA pilots it is being overly hyped as some big safety solution for the putt putt's.

Cubdriver 11-13-2014 12:21 PM


Originally Posted by BoilerUP (Post 1763101)
There is no reason to NOT have AoA data...

Not as technology marches on and costs go down for the gear to display AoA data now. But in the past they were seen as out of the range of basic piston aircraft because of the fairly expensive hardware required, and the lack of viable approval basis. Why add thousands to the cost of a Skyhawk or Seminole when nothing it does really requires accurate AoA data.


Originally Posted by Yoda2 (Post 1763107)
I agree with the responses, and thanks. It just seems for GA pilots it is being overly hyped as some big safety solution for the putt putt's.

Just a safety aid. I actually worry that light aircraft have become overly complex with glass cockpits, and the data seems to suggest that too much electronic stuff in front of them makes the average pilot less safe. I used to teach in glass panel planes and I could never solo anyone in less than about 25 hours which was almost all spent getting them to run the avionics to a basic level. I could solo someone in a steam gauge airplane in about ten hours, really even less if they were a good stick.

bedrock 11-13-2014 12:28 PM


Originally Posted by Cubdriver (Post 1763108)
Not as technology marches on and costs go down for the gear to display AoA data now. But in the past they were seen as out of the range of basic piston aircraft because of the fairly expensive hardware required, and the lack of viable approval basis.

It could be a bad thing for the GA pvt pilot. Too many already have their eyes inside looking at too many instruments while on final approach--thanks to the FAA and Jeppessen integrated method of teaching instruments at lesson 4 of the PPL! For navy pilots doing precision approaches to a postage stamp, it's critical. For a vfr 172, not so much.

Yoda2 11-13-2014 01:04 PM

Good points all. Maybe I'm just too old school in my approach to dealing with basic loss of control. My solution to training is to cover up the entire panel, at certain times, with a small blanket, T shirt, Etc. Then you can teach someone to fly.

USMCFLYR 11-13-2014 01:29 PM

I can't think of one good reason NOT to have AoA.
You can nearly do EVERYTHING with it!
Even if you still loss control as you propose - using AoA for the max benefit in recovery is a benefit.

rickair7777 11-13-2014 01:30 PM

Adding AoA indication to GA aircraft would be an unnecessary cost, and would further be pointless unless pilots are trained to use it.

By "trained" I don't mean somebody showing them how it works...I mean it's use would have to be extensively incorporated into primary training from the very outset. Otherwise it would be just another costly dust collector.

Unlike say a fighter, there are no normal phases of flight in which the AoA data would be interesting for GA aircraft...comply with the AFM speeds and attitudes and you'll never get near the AoA limit except maybe in the flare. Since it would not be interesting or useful, most pilots would tune it out...and it would be silly to expect them to suddenly revert to referencing the thing in a crisis.

It could be useful for aircraft certified for sustained FIKI. That's the only time I ever look at it.

USMCFLYR 11-13-2014 01:59 PM


Originally Posted by rickair7777 (Post 1763166)
Adding AoA indication to GA aircraft would be an unnecessary cost, and would further be pointless unless pilots are trained to use it.

By "trained" I don't mean somebody showing them how it works...I mean it's use would have to be extensively incorporated into primary training from the very outset. Otherwise it would be just another costly dust collector.

Unlike say a fighter, there are no normal phases of flight in which the AoA data would be interesting for GA aircraft...comply with the AFM speeds and attitudes and you'll never get near the AoA limit except maybe in the flare. Since it would not be interesting or useful, most pilots would tune it out...and it would be silly to expect them to suddenly revert to referencing the thing in a crisis.

It could be useful for aircraft certified for sustained FIKI. That's the only time I ever look at it.

That post if full of your OPINION...but doubtfully vey much experience.

Well there are A LOT of very smart people involved in this development and pilots that are using them right now (the FA just made getting them installed much easier because they have finally come around to see the usefulness in the systems) that would disagree with you on this point rickair.

I can send you a link to a informative thread should you like to pursue the posts before flat out saying that are near useless. You might even learn a thing or two ;).

USMCFLYR 11-13-2014 02:05 PM


Originally Posted by Yoda2 (Post 1763146)
Good points all. Maybe I'm just too old school in my approach to dealing with basic loss of control. My solution to training is to cover up the entire panel, at certain times, with a small blanket, T shirt, Etc. Then you can teach someone to fly.

Absolutely - but what if you could cover up all those instruments like you are suggesting and then look at ONE instrument that would give you (for instance) best range, best endurance, best climb, best descent, best landing (full or half or NO flaps) and if you did lose control - best recovery - under all conditions?

Well...as you can tell - I am bias on this subject - and it is my opinion.
I can tell you though that I wish I had an AoA gauge in every aircraft I fly - and if I owned (especially at today's costs) it would be one of the first things I'd have in my plane - - sort of like that tornado shelter I put in my house! :D

Adlerdriver 11-13-2014 03:33 PM


Originally Posted by USMCFLYR (Post 1763194)
Absolutely - but what if you could cover up all those instruments like you are suggesting and then look at ONE instrument that would give you (for instance) best range, best endurance, best climb, best descent, best landing (full or half or NO flaps) and if you did lose control - best recovery - under all conditions?



+1 to this.

Learning to fly high performance jets that spent a great deal of time in various stages of pre-stall buffet, AOA information was extremely helpful. Instructors would describe areas to avoid (like “heavy buffet”) as “elephants (or something else big) jumping on the wings”. An energy saving turn was a “light tickle”. Max acceleration to get knots was “light in the seat” or floating your feet off the rudder pedals.

The problem was, all those descriptions were subjective. One guy’s elephants weren’t the same as another’s. Having an AOA gauge to correlate what was really happening to what I was actually feeling made it so much easier to eventually, with some experience, fly the aircraft into those regimes accurately simply by feel.

Translating that to a new student in a light airplane – I think an AOA gauge would be extremely helpful. For starters, what a great independent backup in the event of a pitot-static problem. Also, they could learn more about how the aircraft performs closer to the edges of the envelope. Not that you want a student flying on the edge right away, but to make him fly in the middle all the time doesn’t allow him to gain full knowledge of the aircraft and its limits. There is still approach to stall and stall recovery training for a PPL, right? Most analog airplanes talk to you as you approach various AOA milestones. Being able to recognize those just by feel has always been an important thing to learn – an AOA gauge just makes that easier, IMO.

mojo6911 11-13-2014 04:16 PM

Landing the Metro was nearly impossible without the AOA gauge.

cardiomd 11-13-2014 06:27 PM


Originally Posted by BoilerUP (Post 1763101)
There is no reason to NOT have AoA data...

Cost, reliability, failure modes (e.g. if somebody begins to "depend" on the sensor, and it gets stuck, etc), decreased efficiency, tendency to break off or poke you on the walkaround, and many others that I can't think of right now are all good reasons.

That being said, I'm a fan and would like to have one but I'm not going to retrofit.


Originally Posted by Yoda2 (Post 1763107)
I agree with the responses, and thanks. It just seems for GA pilots it is being overly hyped as some big safety solution for the putt putt's.

I agree, if somebody is going to stall/spin then they probably should not be flying. It would just be one more gauge to ignore while yanking back on the yoke.


Originally Posted by Cubdriver (Post 1763108)
Just a safety aid. I actually worry that light aircraft have become overly complex with glass cockpits, and the data seems to suggest that too much electronic stuff in front of them makes the average pilot less safe. I used to teach in glass panel planes and I could never solo anyone in less than about 25 hours which was almost all spent getting them to run the avionics to a basic level. I could solo someone in a steam gauge airplane in about ten hours, really even less if they were a good stick.

You are far from the only person that has this opinion and I'm always somewhat surprised by it. I learned steam+G430 and upgraded to glass G1000 and it took all of an hour to become extremely comfortable.

I read the manual over a few more months, and on a BFR spent an extra 15 minutes instructing my instructor on some shortcuts with the computer, showing him how to insert waypoints rapidly in flightplans etc. It started out quizzing me to ensure I was competent but he was honestly interested.

Obviously I was an engineer and am comfortable with technical stuff, and did have some sim experience, but I can not conceive how it could take almost "all of 25 hours" to get somebody up to basics with those avionics!

Are you exaggerating or serious? Very confused.:confused:

Yoda2 11-13-2014 06:43 PM

Cardio, What is your definition of extremely comfortable? Would that also mean competent? After only an hour with the G1000, would you have launched into the clouds with it? And... You read the manual AFTER you were comfortable with the G1000? Also curious how much "some" Sim experience was?

cardiomd 11-13-2014 07:22 PM


Originally Posted by Yoda2 (Post 1763435)
Cardio, What is your definition of extremely comfortable? Would that also mean competent? After only an hour with the G1000, would you have launched into the clouds with it? And... You read the manual AFTER you were comfortable with the G1000? Also curious how much "some" Sim experience was?

Presumably somebody on a first solo after 25 hours is not launching into the clouds. I was definitely competent to fly VFR after an hour. IME easier to scan with glass, routinely do hard IFR and would feel good about both but all things considered I'd much rather launch with glass.

Tuning and identify, dialing in radials all much easier, enhanced SA, AHRS with less dip / lag / acceleration errors, no gyro precession, all advantages.

Yes sir - read the manual after I was comfortable. Did 10 minute ground intro then maybe 1 hr flight. Enough to get basics, then read the manual for the rest. Perhaps people take 25 flight hours because they don't do a tiny bit of ground work. :confused:

USMCFLYR 11-13-2014 07:45 PM


Originally Posted by cardiomd (Post 1763420)
Cost, reliability, failure modes (e.g. if somebody begins to "depend" on the sensor, and it gets stuck, etc), decreased efficiency, tendency to break off or poke you on the walkaround, and many others that I can't think of right now are all good reasons.

That argument doesn't hold any more water than saying that any instrument isn't worth the cost then. Failure modes? That is why you cross check - just like with many other instruments. Do you have data to show that many of the simple AoA systems now available on the marker are NOT reliable?


I agree, if somebody is going to stall/spin then they probably should not be flying. It would just be one more gauge to ignore while yanking back on the yoke.
DANG! I've stalled and even gone out of control a few times at least and you've decided that I shouldn't be flying. Harsh.
Guess what helped me recover during some of those OCF moments.
Sounds like that person needs more training. At least with a AoA gauge that person might just pull enough instead of too much. ;)


Care to tell us how much experience you have flying with reference to an AoA instrument? If you are trained to it - it doesn't take much experience to learn how to incorporate it effectively. I mean you're good enough on the G1000 after 1 hr - I can't imagine a single gauge would be too overwhelming.

rickair7777 11-13-2014 09:04 PM


Originally Posted by USMCFLYR (Post 1763188)
That post if full of your OPINION...but doubtfully vey much experience.

I have several thousand hours in a turbine airliner with an AoA indicator. It never comes into play if you fly the profiles, and they didn't really train us on it's use in abnormal situations. But like I said it's reassuring in icing conditions.


Originally Posted by USMCFLYR (Post 1763188)
Well there are A LOT of very smart people involved in this development and pilots that are using them right now (the FA just made getting them installed much easier because they have finally come around to see the usefulness in the systems) that would disagree with you on this point rickair.

Smart, I wouldn't doubt. In tune with reality maybe not so much.


Originally Posted by USMCFLYR (Post 1763188)
I can send you a link to a informative thread should you like to pursue the posts before flat out saying that are near useless. You might even learn a thing or two ;).

Please send it, I'm always open to new ideas. But for most of the GA community AoA is a bridge too far, UNLESS the FAA wants to revamp the training syllabi.

BTW, my post was at the same time as yours, I hadn't seen your post and was not replying to it.

Adlerdriver 11-13-2014 09:25 PM


Originally Posted by rickair7777 (Post 1763537)
I have several thousand hours in a turbine airliner with an AoA indicator. It never comes into play if you fly the profiles,

Which, IMO, would be the situation that would provide the fewest opportunities to use and realize the value of such a tool. You even admit that you don't use it on a regular basis. So, if flying an airliner with an AOA gauge is the sum total of the experience you're using the make these judgments, I'm not surprised about your attitude.

The OP's question was directed at the use of AOA in a GA training environment - not 121 ops.


Originally Posted by rickair7777 (Post 1763537)
... and they didn't really train us on it's use in abnormal situations.

Not surprising. We've had it for years at FedEx and it's just recently began to be incorporated into the very few scenarios that might require (or at least benefit) from using AOA.

USMCFLYR 11-14-2014 05:00 AM


Please send it, I'm always open to new ideas. But for most of the GA community AoA is a bridge too far, UNLESS the FAA wants to revamp the training syllabi.
Actually AoA come into play on your airliner with most things that you are doing I would guess - it is just behind the scenes and since you fly how much of every flight in the heart of the envelope I'm not surprised that you don't value what the instrument can provide in the area of safety of flight.

Here is a short thread on it. But for explanation, the first post is really what you are looking for.

BeechTalk - Login

You could search for Fred Scott's posts on the subject though and read a lot more on the subject.
BeechTalk - Information

Continue reading through the various posts if you want to get a good idea of what GA pilots are feeling about the opportunity to install AoAs and the usefulness of such instruments. And fear not! You'll find some of your opinion in there too. Can't please everyone ;)

E2CMaster on this forum can give you some more information as well.

Cubdriver 11-14-2014 12:23 PM

I am with USMC on this one. AoA is good. Perhaps his background in military aviation is why he sees the value in AOA information in the cockpit. The two of us usually clash on everything, but he finally he sees something totally right. ;) It makes perfect sense to me being (modestly) experienced in airline flying, that in contrast, watching AoA indications is not even close to an important part of RickAir's daily flying life. USMC nailed the reason- all the AoA stuff is engineered into the airplane and the procedures used there. What the pilot finally sees and does is what the background designers want them to see. But AoA really is the essence of flying, it is one of the key things a pilot can manage, and also one which must always be within limits for optimum safety.

Great point about icing Rick, the whole icing alternate v-speed regime is simply to keep AoA within safe limits as lift and drag goes to hell in icing. As an engineer the alternate v-speeds used in icing could all be replaced by one to four accurate AoA gauges and a simple set of marking bands in each one.

AoA has numerous pilot uses aside from icing and stall recovery, it is useful in maximizing economy and all the things USMC mentioned earlier as well as intentionally getting out of limits sometimes in aerobatic flight, spin training, and certain types of landing. As a former aircraft engineer and flight instructor I could talk about AoA a long time because it has so many didactic and engineering purposes. Most are safety related but engineering uses AoA to optimize wing design and there have to be a thousand other uses for it. In teaching one of the big areas of course spins and stalls, which are very much AoA discussions.

When I made the comment that a con to having yet another cockpit instrument is a student distraction, or something along those lines, I was really talking about glass cockpits not the basic 6 packs with a few extra dials inside. I actually think that a g-meter and AoA gauge should be in every trainer as standard instruments. Am I nuts? Well maybe, but at times I have found both of those instruments very useful and while I do think they appeal more to advanced pilots than primary flight students, a 172 should have them somewhere.

CardioMD, you are obviously a quick learner being as doctor and engineer and I am not surprised that simply reading the Garmin manual was most of what you needed to get the glass cockpit process. That is one factor in your progress, another is (if I understand correctly) that you brought steam gauge instrument skills with you to the first glass panel aircraft you flew. I had a lot of trouble getting people to start from day one in a glass cockpit and no, that 25 hours was just to bring them to a safe enough level to solo not to master the system. People who really master the G1000 often have many more hours than that. In fact, I occasionally see people who are unable to operate a G430 or 530 well at 2,000 hours, hell even 5,000 hours in one case. Some are inclined and some are not, but the average was always adding 15 hours of flying around the patch in a G1000 Skyhawk with a new student if they did not have any prior flight time or were not practicing with a desktop trainer. I think the AoA and g-meter data could be optionally configured by the pilot on an individual basis in the G1000, and those who cannot use it can hide it from view. But not having it at all is in my opinion a serious weakness in any aircraft, including an airliner.

cardiomd 11-15-2014 03:04 AM


Originally Posted by USMCFLYR (Post 1763491)
That argument doesn't hold any more water than saying that any instrument isn't worth the cost then. Failure modes? That is why you cross check - just like with many other instruments. Do you have data to show that many of the simple AoA systems now available on the marker are NOT reliable?

The ones I've seen are still the mini-weathervane sticking out of the side of the plane that rotates with the relative wind. Vulnerable to freezing, so may need heater. Heater goes - gauge may stick. It could also be broken off or damaged. It is hard to ignore a noncovered invalid instrument and if that failure is subtle it may contribute to a chain of events instead of preventing it.

Nowdays everything is microcontrollers and digital instead of old systems, so I'd bet the electronics are very reliable.


Originally Posted by USMCFLYR (Post 1763491)
DANG! I've stalled and even gone out of control a few times at least and you've decided that I shouldn't be flying. Harsh.
Guess what helped me recover during some of those OCF moments.
Sounds like that person needs more training. At least with a AoA gauge that person might just pull enough instead of too much. ;)

Oh come on... If you did it unintentionally on a routine base to final turn then yes, you shouldn't be flying. I suspect it was not though, and more of an intentional maneuver or practice, and you know and appreciate the difference. ;)


Originally Posted by USMCFLYR (Post 1763491)
Care to tell us how much experience you have flying with reference to an AoA instrument? If you are trained to it - it doesn't take much experience to learn how to incorporate it effectively. I mean you're good enough on the G1000 after 1 hr - I can't imagine a single gauge would be too overwhelming.

I don't think you understand my position at all. I have zero experience with AOA gauge, and wouldn't retrofit my plane if it were zero cost. I'm a fan of it though with new planes and I personally would use it, but do not feel it is remotely needed for most GA pilot who doesn't go into the flight levels or pull high g maneuvers into near accelerated stalls at the edge of the performance envelope. The average pilot, who finds the G1000 exceedingly complex, would simply ignore it.

cardiomd 11-15-2014 03:19 AM


Originally Posted by Cubdriver (Post 1763935)
CardioMD, you are obviously a quick learner being as doctor and engineer and I am not surprised that simply reading the Garmin manual was most of what you needed to get the glass cockpit process. That is one factor in your progress, another is (if I understand correctly) that you brought steam gauge instrument skills with you to the first glass panel aircraft you flew. I had a lot of trouble getting people to start from day one in a glass cockpit and no, that 25 hours was just to bring them to a safe enough level to solo not to master the system. People who really master the G1000 often have many more hours than that. In fact, I occasionally see people who are unable to operate a G430 or 530 well at 2,000 hours, hell even 5,000 hours in one case. Some are inclined and some are not, but the average was always adding 15 hours of flying around the patch in a G1000 Skyhawk with a new student if they did not have any prior flight time or were not practicing with a desktop trainer. I think the AoA and g-meter data could be optionally configured by the pilot on an individual basis in the G1000, and those who cannot use it can hide it from view. But not having it at all is in my opinion a serious weakness in any aircraft, especially an airliner.

Well said. I did have a bit of additional time in the G430 before G1000 that obviously helped, and yes have a technical background. GA pilots range from actual rocket scientists, engineers, to C-student joe six-pack and the soccer mom who wants to fly. Some of my best friends flying mooneys to untalented hacks driving DC8s. Obviously a large range.

It is not that intuitive for a non-computer user, but I would expect any technical guy to pick it up very quickly.

USMCFLYR 11-15-2014 07:40 AM


Originally Posted by cardiomd (Post 1764238)
The ones I've seen are still the mini-weathervane sticking out of the side of the plane that rotates with the relative wind. Vulnerable to freezing, so may need heater. Heater goes - gauge may stick. It could also be broken off or damaged. It is hard to ignore a noncovered invalid instrument and if that failure is subtle it may contribute to a chain of events instead of preventing it.

Nowdays everything is microcontrollers and digital instead of old systems, so I'd bet the electronics are very reliable.

That is exactly the type that I am aware of. Yes - they would be heated - just like a pitot tube. Can they be damaged - yes - just like a pitot tube. Can they fail and give inaccurate information? Yes - just like a pitot tube. Can you fly with them? Yes - just like a pitot tube. Are they useful pieces of equipment and make flying easier? Yes - just like a pitot tube.

I've had them break off. I've had them fail. I've had them bent and twisted. At least my former community finally went away from the 'wing' style vanes to the conical vanes which were a little less prone to being ripped off.


Oh come on... If you did it unintentionally on a routine base to final turn then yes, you shouldn't be flying. I suspect it was not though, and more of an intentional maneuver or practice, and you know and appreciate the difference. ;)
Well now you didn't specify the base to final turn now did you? ;)
Nope - not always intentionally, but when you regularly fly near the edges of the envelope and are asking for the airplane to give you everything its' got (and usually add in a little hamfisting for good measure), you sometimes found yourself in a bad situation. Until the early 2000s - OCF was the number one cause of loss in my community. Finally a new software fix to the flight control program helped fix the major contributor to mishaps. Not they just have to figure out how to stop CFIT and midairs and it will almost be as safe as airline flying :D


I don't think you understand my position at all.
No...I don't understand your position except that you don't think you need it because you have no experience with it.
Just like those old hands sitting around the hangars on Saturday who still give you the sideways glance when you start talking about this GPS thingy-ma-gibber. But even the *old hands* in my organization were quick coverts to our new ProLine21 cockpits though there had been a long standing rumor that those same *old hands* were going to retire rather than learn a *new* way of flying.
Maybe you should look at those links I provided to the other forum where many GA pilots are sharing their positive experiences with AoA installations.

I get it cardiomd - you don't understand the benefits of an AoA. That is OK. I'm sure you will complete a lifetime of flying without needing one, but that still doesn't mean it is NOT a useful tool in any type of flying activity - airline, GA, or military.

cardiomd 11-15-2014 08:58 AM


Originally Posted by USMCFLYR (Post 1764325)
No...I don't understand your position except that you don't think you need it because you have no experience with it.

...

I get it cardiomd - you don't understand the benefits of an AoA. That is OK. I'm sure you will complete a lifetime of flying without needing one, but that still doesn't mean it is NOT a useful tool in any type of flying activity - airline, GA, or military.

Again, that is not my position. I don't need it because I'm perfectly capable of flying in a safe fashion without it. Not because I "don't understand" the benefits or am an "old codger" or because I have no experience with it.

I do NOT DOUBT it is an extremely useful tool, and as I told you, I'd appreciate it in any plane that I get, but most people will ignore it.

The plane I learned in did not have any GPS. I didn't need it for what I used that plane for - pilotage and radionav did all right. I still recognize GPS as a great tool. However, anybody that has an agenda saying "everybody needs GPS" is just false for a lot of people, even though they may very well realize the possible benefits it gives.

I've spent a lot of time flying a plane without an attitude indicator (almost all older aerobatic planes). Does that mean I don't understand and appreciate the instrument? Of course not.

Similar for AOA. It is a great tool, and has its place. Does everybody "need" it? No. Should it be in airliners? Yes. Should it be in all new GA planes? Probably, if cost and reliability allow.

Yoda2 11-15-2014 09:51 AM

Thanks all, again for the great input. I think now, it is fine to go forward with this in GA. My concern began as my thoughts were more along the lines that this was being implemented as a sort of Band Aid for folks not having a firm grasp on basic/fundamental skills...

JamesNoBrakes 11-15-2014 02:05 PM

I've investigated several accidents where the pilots just didn't realize the AOA they were at. I think there are many accidents where this is the case. I don't think many pilots realize the radical difference in AOA between making a descending power (mostly) off turn descending to base and final vs. doing the same thing at the same airspeed and maintaining level flight. More than one accident I've investigated involved "some flight" but running into trees at the end of the runway. Here is a classic one: LiveLeak.com - (Must Watch!!) Plane crash video from inside cockpit

I think the perception is that due to the forward movement, the AOA must be "ok", but if you were to look at it, it'd be "screaming" the whole time.

Yes, cockpit clutter is an issue, not to mention really using the outside horizon as a pitch reference (rather than just saying "look outside, which can be equally useless as looking inside), but GA accident rates are in the spotlight these days. There's resistance to do anything at any level, whether it's increasing training hours, increasing standards, etc., but this will hopefully have a positive effect, and based many accidents that I've seen, it's likely.

Yoda2 11-15-2014 02:49 PM

Interesting JNB; though there might be some causal factors. It appeared a cap was over the compass and the ashtray was closed. Maybe he didn't know which direction he was going and needed a smoke... Glad you guys are OK!

Adlerdriver 11-15-2014 02:57 PM


Originally Posted by JamesNoBrakes (Post 1764491)
I don't think many pilots realize the radical difference in AOA between making a descending power (mostly) off turn descending to base and final vs. doing the same thing at the same airspeed and maintaining level flight. More than one accident I've investigated involved "some flight" but running into trees at the end of the runway. Here is a classic one:

James, can you clarify the comparison you're making here? It's probably me - I'm having a hard time putting everything together - the AOA discussion in a descending turn vs level flight, ending up in trees at the end of the runway (approach end/departure end?) and the video.

Yoda2 11-15-2014 03:17 PM

Yes James, could you elaborate. In the meantime... I think lots of pilots confuse AOA with deck angle. They don't realize how small the AOA range is in comparison. Further, many students don't understand high speed stalls, or are never exposed to them.

JamesNoBrakes 11-15-2014 04:31 PM


Originally Posted by Adlerdriver (Post 1764512)
James, can you clarify the comparison you're making here? It's probably me - I'm having a hard time putting everything together - the AOA discussion in a descending turn vs level flight, ending up in trees at the end of the runway (approach end/departure end?) and the video.

A descending turn, which is usually done at low power (that's a good indicator right there), is usually at a fairly low AOA if done a any kind of normal speed.

A level turn, which requires higher power, may be done when a pilot is already fairly low on the downwind and base, so he's "saving" for final, but they often start to slow up, put in flaps, etc. This can create an excessively high AOA situation coupled with a turn. The stall warning may help, but this usually comes on pretty fast and some advance notice would be nice.

Then there was the issue of takeoff, when the airplane isn't climbing, but it is in the air and covering ground, there may not be a great appreciation as to where the AOA really is. The pilot may think they have some protection because they are moving fairly fast over the ground, but the AOA is so high and the induced drag so high that it's not going to end well. Maybe with this indication earlier one would fly it to a safe-spot earlier, avoiding trees later.

I think what I'm getting at is that we tend to not appreciate where the AOA is. Plenty of these attitudes are "normal" for flight, I've seen plenty of airplanes in almost level flight "attitude", yet their AOA is nearly off the scale (in terms of right about to stall). That's probably one of the bigger issues with that takeoff video, the plane "appeared" to be in a normal attitude, so the guy probably thought the AOA was "normal". It wasn't.

Yoda2 11-15-2014 04:53 PM

JNB, I get what you're saying for the most part; though if they are in the realms you speak of or are not flying the typical/standard profiles, they better know how to fly an airplane if venturing into those zones. Generally speaking, I don't think, a measurable portion... of newer pilots are satisfactorily familiar with those areas or really knowing their envelope, Etc. I could be wrong but it seemed the FAA started emphasizing LOC not long after the proliferation of TAA... If an instructor has roughly X amount of time to train a primary student and the TAA takes somewhat longer than a traditional 6 Pack, something has got to give. I think where it is giving is in the basic flying skills department. I think the FAA should increase the Min for Private Pilot by 10 Hrs. I know guys that have ferried jet airliners on some real raw data, less than a typical ferry kit. They got where they were going, because someone took the time to teach them to fly... If you want, probably, the best and most accurate summation of the state of basic flying skills; talk to the folks who specialize in tail wheel or seaplane ratings...

JetJocF14 11-15-2014 07:23 PM

[QUOTE=rickair7777;1763166]Adding AoA indication to GA aircraft would be an unnecessary cost, and would further be pointless unless pilots are trained to use

Unlike say a fighter, there are no normal phases of flight in which the AoA data would be interesting for GA aircraft...comply with the AFM speeds and attitudes and you'll never get near the AoA limit except maybe in the flare.

Those are two of the stupidest sentences I've ever read. You really have no idea how AOA works or what it is trying to tell you. To you it's just a gauge with some pretty colors attached to it. Like USMC says, " I'd take a AOA gauge in every airplane that I've ever flown. In fact I plan on installing one in my personal Comanche at my next annual.

cardiomd 11-15-2014 08:59 PM


Originally Posted by JamesNoBrakes (Post 1764491)
I've investigated several accidents where the pilots just didn't realize the AOA they were at. I think there are many accidents where this is the case. I don't think many pilots realize the radical difference in AOA between making a descending power (mostly) off turn descending to base and final vs. doing the same thing at the same airspeed and maintaining level flight. More than one accident I've investigated involved "some flight" but running into trees at the end of the runway. Here is a classic one: LiveLeak.com - (Must Watch!!) Plane crash video from inside cockpit

I think the perception is that due to the forward movement, the AOA must be "ok", but if you were to look at it, it'd be "screaming" the whole time.

Yes, cockpit clutter is an issue, not to mention really using the outside horizon as a pitch reference (rather than just saying "look outside, which can be equally useless as looking inside), but GA accident rates are in the spotlight these days. There's resistance to do anything at any level, whether it's increasing training hours, increasing standards, etc., but this will hopefully have a positive effect, and based many accidents that I've seen, it's likely.

If grandpa can't even figure out how to lean an engine for altitude takeoff, taking off a full 3,000 feet DA above performance limit at max gross weight, and not aborting after the multiple opportunities he had, he's sure as hell not going to learn how to interpret an AOA gauge.

Adlerdriver 11-15-2014 09:45 PM

I disagree with you're assessment that a level turn poses a higher potential threat than a descending turn. I think an AOA gauge would help a pilot in both scenarios, but IMO, more so to the descending turn pilot, especially if he accidentally strays into the high AOA regime.

Originally Posted by JamesNoBrakes (Post 1764538)
A descending turn, which is usually done at low power (that's a good indicator right there), is usually at a fairly low AOA if done a any kind of normal speed.

What is the low power a good indicator of?

From my perspective, the final turn (i.e. a descending turn with power back) is notoriously dangerous because pilots fail to appreciate the lack of energy available in their aircraft. I’ll go out on the limb and suggest that more pilots have lost control of their aircraft in the final turn than on a level turn from downwind to base. Ask that pilot in the descending turn to level off or tighten his turn to prevent an overshoot and the AOA gauge will water his eyes. His relatively low AOA 3 seconds ago is going to shoot into the danger area far quicker without proper power and flying technique than his buddy in the level turn back up at pattern altitude.


Originally Posted by JamesNoBrakes (Post 1764538)
A level turn, which requires higher power, may be done when a pilot is already fairly low on the downwind and base, so he's "saving" for final, but they often start to slow up, put in flaps, etc. This can create an excessively high AOA situation coupled with a turn. The stall warning may help, but this usually comes on pretty fast and some advance notice would be nice.

I don’t get the “saving for final” term. Also, is he lower than he would be in the turn to final? Certainly, excessive AOA and a turn are not a good combination. However, adding a descent to those two is worse, IMO. Personally, if I had to choose between encountering a stall in a level turn versus a descending turn, I’ll take level every time. If you’re turning level at high AOA and you stall at pattern altitude, you have altitude to recover. If your AOA spikes in a descending turn, you don’t, plus you already have a significant sink rate you have to counter as well.



Originally Posted by JamesNoBrakes (Post 1764538)
Then there was the issue of takeoff, when the airplane isn't climbing, but it is in the air and covering ground, there may not be a great appreciation as to where the AOA really is. The pilot may think they have some protection because they are moving fairly fast over the ground, but the AOA is so high and the induced drag so high that it's not going to end well. Maybe with this indication earlier one would fly it to a safe-spot earlier, avoiding trees later.

I think what I'm getting at is that we tend to not appreciate where the AOA is. Plenty of these attitudes are "normal" for flight, I've seen plenty of airplanes in almost level flight "attitude", yet their AOA is nearly off the scale (in terms of right about to stall). That's probably one of the bigger issues with that takeoff video, the plane "appeared" to be in a normal attitude, so the guy probably thought the AOA was "normal". It wasn't.

Are you saying there are scenarios in a GA aircraft that could result in an “almost level flight attitude” with AOA “nearly off the scales” and the pilot would be unaware were it not for an AOA gauge? I don’t have a huge amount of experience with those aircraft, so perhaps you can give me some of the scenarios you are referring to.

That takeoff was a classic density altitude accident. I think his problem was more of energy deficiency than simply high AOA (at least at first). I could be off base here, so correct me if I’m wrong. I assume he attained the normal takeoff/climb IAS when he got airborne. Because of the density altitude, his TAS was higher to produce the same IAS. With little to no excess thrust for his climb, in order to maintain that IAS and the usual AOA at such an extreme density altitude, he had to hold a lower pitch attitude and he was unable to climb. So, when they were muddling along in semi-level flight after takeoff, wouldn’t the AOA gauge (if he had one) have been indicating something close to normal? Assuming he was holding the IAS he wanted (even if that required a descent), wouldn’t he see the roughly the same AOA he saw every other flight at that IAS?

I think, what would have shown him he was in trouble would have been ANY attempt to turn, climb or just increase back pressure on the yoke when his airspeed began to decrease. Now he would have seen that AOA gauge spike into the danger zone faster and further than with those same inputs at lower density altitude – giving him a true understanding of how low on energy he really was. So, to your point, there were definitely times during that flight an AOA gauge would have clued him about how close to the edge he really was. I’m just not sure he would have had an AOA indication that was “not normal” for the entire flight.

cardiomd 11-16-2014 04:37 AM

Uh, wow.

JNB was simply saying you trade a good deal of potential to kinetic energy when descending. I'm sure you remember doing power-off approaches in the pattern and being surprised how much altitude you have to trade during the turn.

This is why the "impossible turn" is difficult for people to judge and people tend to attempt it when not advised.

Agree that high DA crash sequence started way before power was applied. An AOA gauge won't fix stupid.

BoilerUP 11-16-2014 05:03 AM

While I certainly understand considering the value proposition of retrofitting older aircraft....AoA can and should be as much of a "game changa" in GA as avionics-driven safety advances like synthetic vision, or even terrain & traffic awareness devices.

Do you "need" any of them in a piston-driven aircraft? Nope.

Do they provide tangible operational benefits in a variety of situations? Yes.

Do you need training in order to fully take advantage of them? Absolutely!

Timbo 11-16-2014 05:52 AM

Here's one for you guys with light airplanes:

Advanced Flight Systems

About the only place I found the AOA useful was in the final turn in the T38, and in a Scout I was flying for the Sheriff's Dept. where I had to do a lot of low speed steep turns, so the Sheriff in back could take pictures of the grow houses we were circling over.

The airplane had one of those little vanes on the strut called a "Bacon Saver" which was nothing more than a 2" wedge on a card with some red paint in the 'no go' zone.

Because it was mounted on the left strut, it was right in line with my sight as I turned final. I found I looked at that more than the airspeed indicator in the pattern, and certainly while doing the steep turns taking pictures.

But like someone said above, you can't fix stupid. Putting an AOA vane on all airplanes won't stop idiots from killing themselves in airplanes, especially light airplanes, if they try hard enough, they will always find a way!

I tried to find a link for the Bacon Saver, but can't, maybe they are out of business? It was a really low tech, cheap AOA with no electronics required, just bolt it on the strut, but it wouldn't have a place to mount on a low wing airplane, you need the wing strut to mount it on.

JamesNoBrakes 11-16-2014 09:55 AM


Originally Posted by Adlerdriver (Post 1764649)
I disagree with you're assessment that a level turn poses a higher potential threat than a descending turn. I think an AOA gauge would help a pilot in both scenarios, but IMO, more so to the descending turn pilot, especially if he accidentally strays into the high AOA regime.


Here's what happens a lot around here:

People often scout out a landing spot just a few hundred feet above the ground, often with terrain considerations besides trees and brush. Then they start turning to "line up", but because they are already at such a low altitude, they don't descend, but they do start slowing up. This has resulted in more than one landing accident around here, but I think it's equally applicable to guys flying SR22s that get slow making these same turns, often not realizing they have to either get the nose down to speed back up or get rid of the excessive bank and coordination issues, but again, many of those have "spiraled" right in. In the 1st scenario, it's somewhat of a conscious decision to "stay high" and stray into the higher AOA region, but I wonder if those pilots really understand where their AOA is and how much higher it is than a normal descent. In the 2nd scenario, probably not quite as concious, as they get distracted by something like looking for traffic, configuration changes, etc, and don't notice the other warning signs, keeping the nose high while possibly staying fixated on the runway (ever see how a runway is like a magnet for a pilot's head on base? I've witnessed plenty of attitude deviations just due to this)

The other scenario is climbing out, letting the nose get too high, not noticing the decay in airspeed, and a similar result.


From my perspective, the final turn (i.e. a descending turn with power back) is notoriously dangerous because pilots fail to appreciate the lack of energy available in their aircraft. I’ll go out on the limb and suggest that more pilots have lost control of their aircraft in the final turn than on a level turn from downwind to base. Ask that pilot in the descending turn to level off or tighten his turn to prevent an overshoot and the AOA gauge will water his eyes. His relatively low AOA 3 seconds ago is going to shoot into the danger area far quicker without proper power and flying technique than his buddy in the level turn back up at pattern altitude.
Well, in years of watching pilots, the ones pulling back to tighten turns and not realizing they are pulling the nose up while their eyes are fixated on "the numbers" are the ones that scare me. If they are throwing in the bank while descending, because they are actually looking at where they are going, vs. where they want to go, I'm far less concerned.


I don’t get the “saving for final” term. Also, is he lower than he would be in the turn to final?
See above, also, plenty of situations in the pattern where you don't descend on base, either due to distraction, being extended, other traffic, etc.


Certainly, excessive AOA and a turn are not a good combination. However, adding a descent to those two is worse, IMO.
Going to have to disagree here, pushing the nose down when you reduce the thing that is propelling you forward (power) is usually a good thing. Don't do this, and you'll stray into an ever-increasing AOA situation. Lots of people get "ground scared" and want to save their approach, so the closer they get to the ground, the more they pull up, but I'd rather scream a few hundred feet off the ground at high speed than at 40kts straight down in a spin.


Personally, if I had to choose between encountering a stall in a level turn versus a descending turn, I’ll take level every time. If you’re turning level at high AOA and you stall at pattern altitude, you have altitude to recover. If your AOA spikes in a descending turn, you don’t, plus you already have a significant sink rate you have to counter as well.
Won't matter if it's coordinated, but the idea is to use the AOA indicator to alert you to where your AOA is going, like pilot that starts slowing up and making a turn to base without descending, oops, getting into the yellow, let me push the nose down. Again, having watched pilots fly GA approaches over and over, I have often seen them fixated on the runway numbers and not aware of where the nose really is, sounds easy to fix, but more widespread and ingrained than you'd think, it's one of those places we let our guard down too because we are so concerned about "the runway", but I digress. If your AOA spikes during a descending turn, you are way WAY out of the norm, like 70 degrees of bank and uncoordinated, while that happens, I'd put money on distraction and not descending/pitching up while the aircraft is supposed to be descending.

Are you saying there are scenarios in a GA aircraft that could result in an “almost level flight attitude” with AOA “nearly off the scales” and the pilot would be unaware were it not for an AOA gauge? I don’t have a huge amount of experience with those aircraft, so perhaps you can give me some of the scenarios you are referring to.
Overloaded aircraft flying in ground effect. It might seem like you are at a normal climb attitude where the aircraft should be climbing, even if you lower the nose to an almost level attitude, but the combination of going slow, plus the weight, etc, the AOA is way out there, even though most everything "seems" normal and the aircraft would "usually" pass through this 2nd phase climb just fine. Also simply when you get slow when confined by terrain, more than one guy up here has landed on a mountain or in trees miles from where they took off because they "ran out of energy", or more accurately, the terrain required more than they had. Again, when they get slow, they can get into a regime where they are not at an excessive pitch attitude, so not stalled or stalling, but where they are sinking and the AOA is way high due to the combination of slow speed, induced drag, etc. One way to think about this is that stalls are often taught power on and power off, in both situations you are usually starting from a fairly excess amount of energy, so you can often get the nose pretty high up there before it stalls. Now think about getting much slower, maybe you'll notice your pitch attitude being higher, but if you've been flying for a few minutes like that, possibly not, and you have mountains and terrain obscuring the horizon, so you really have no good indication when the mountains are towering above. Now you get slow, now you want to turn around and the terrain is rising, do you not lower the nose because you'll hit the trees? How do you know if you have any reserve AOA to do this or whether you MUST lower the nose to have any chance? AOA gauge could come in pretty handy here.

That takeoff was a classic density altitude accident. I think his problem was more of energy deficiency than simply high AOA (at least at first). I could be off base here, so correct me if I’m wrong. I assume he attained the normal takeoff/climb IAS when he got airborne. Because of the density altitude, his TAS was higher to produce the same IAS. With little to no excess thrust for his climb, in order to maintain that IAS and the usual AOA at such an extreme density altitude, he had to hold a lower pitch attitude and he was unable to climb. So, when they were muddling along in semi-level flight after takeoff, wouldn’t the AOA gauge (if he had one) have been indicating something close to normal? Assuming he was holding the IAS he wanted (even if that required a descent), wouldn’t he see the roughly the same AOA he saw every other flight at that IAS?[/FONT]
His AOA would never have gotten out of the red in that situation. The AOA gauge is not going to care about TAS, it's going to care about air pressure against it, you'll have to go faster at high density altitude to get the same "pressure" on the wing, but the AOA gauge won't care, it will already be compensated for.

Yes, lots of things went wrong there, is it easier for us to re-evaluate every pilot that's gotten a license? Or require FADEC on every airplane? Or require a manifest and weight and balance be transmitted for every GA flight? No, those things are not practical, so the regulators try to see where a practical improvement can be made in safety.


I think, what would have shown him he was in trouble would have been ANY attempt to turn, climb or just increase back pressure on the yoke when his airspeed began to decrease.
That airplane was never really "flying". It never really got out of the 2nd segment climb. The AOA would have been spiking the entire time, at the least between yellow and red. If the pilot had been unfortunately enough to yank back on the controls earlier, he would have stalled much earlier. Based on my flying and that aircraft's attitude and speed, it should have been apparent early on that the aircraft was way out of the normal AOA and not transitioning into normal flight (from essentially slow flight). That's nice to say in retrospect, but perhaps an AOA would have helped and alerted him as he was flying around in the red. I know, that's a big assumption, it totally may not have made any difference in this case, but these are closer to the "typical" cases that I am discussing.


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