Do you have an angle of attack indicator (poll)

[201er]

In response to lamont337's post on my stall topic, I wonder how many of you have been "promoted" by the faa to install an AOA? Do you have an angle of attack indicator in your Mooney? Do you plan to get one soon?

 

Mine already came with my Mooney and I will say that it is by far the most life-saving "gadget" you can have on board. Statistically those Ipads and such are a wash. On one hand they give you more situational awareness but on the other hand they're a distraction so from a recent course I took I got the impression that they don't necessarily reduce the accident rate. On the flipside, I have resolved near-stall situations multiple times thanks to having an AOA. With my experience I would suggest it as the very next upgrade you do over any other non airworthiness modification you can make.

 

[RocketAviator]

Here here!

Fly safe,

Rocket On

[aviatoreb]

In response to lamont337's post on my stall topic, I wonder how many of you have been "promoted" by the faa to install an AOA? Do you have an angle of attack indicator in your Mooney? Do you plan to get one soon?

 

Mine already came with my Mooney and I will say that it is by far the most life-saving "gadget" you can have on board. Statistically those Ipads and such are a wash. On one hand they give you more situational awareness but on the other hand they're a distraction so from a recent course I took I got the impression that they don't necessarily reduce the accident rate. On the flipside, I have resolved near-stall situations multiple times thanks to having an AOA. With my experience I would suggest it as the very next upgrade you do over any other non airworthiness modification you can make.

 

Hi 201er, I read your other post with great interest - I have had an AOA "next on my list" for like a year and actually 2 weeks ago I called a nearby avionics shop to begin the process of pricing the cost of install complete.  It looks like I will likely do it at the end of June while I am away. Well timed post for me.

[Oscar Avalle]

I have one installed, but I have not been able to calibrate it.

[Bill_Carter]

Haha, one more selection is necessary in the poll:

o No, I don't have a friggin' plane yet to have a AOA installed

[Piloto]

Although an AOA is a nice thing to have it will not help you in assessing how close you are to a stall condition. You could be doing 140kts IAS or 90kts IAS but the AOA will indicate the same for either one. With the air speed indicator you know you have that extra speed to overcome a stall condition before you turn to final. You can fly without an AOA but not without an ASI.

 

José  

[PTK]

An aoa indicator may be a nice gadget to have but I don't think it's an absolute necessity.

I prefer to be fully engaged and aware of my attitude and speeds at all times. Further I prefer to adjust my speeds according to my weight on my own.

As Jose said, can't ignore airspeed. I would add, can't ignore the need to adjust V speeds according to weight.

[Marauder]

Mike -- as always, you bring forth a good thought provoking topic. I am also willing to bet it has much more far reaching importance to the world than the potential metallic calamity caused by the failure to use CamGuard.

 

Seriously though, my exposure to AoA topics came in my Part 141 private pilot training. They had dedicated a full page of the curriculum to the topic which included not only ground school training on the topic but also flight maneuvers highlighting the varying configurations and flight situations that could lead to stalls.

 

What stood out to me was the base to final demonstration. We did the flight at higher attitudes and I was asked to pick a point on the ground that represented my landing spot. I then was asked to fly a base leg to that point and to fly past my normal turning from base to final. The instructor then had me tighten up the turn to try to get back to that point. What shocked me was that the stall horn starting coming on and I could feel the pre-stall shudder despite having ample airspeed over the stall speed. My natural instinct was to pull back on the yoke! This demonstration and a few unusual attitude departure stalls educated me to the corners of the flight envelope.

 

Any chance you can do a video of your AoA and show us how it works in flight? 

[RocketAviator]

Although an AOA is a nice thing to have it will not help you in assessing how close you are to a stall condition. You could be doing 140kts IAS or 90kts IAS but the AOA will indicate the same for either one. With the air speed indicator you know you have that extra speed to overcome a stall condition before you turn to final. You can fly without an AOA but not without an ASI.

 

José  

Not so on at least my version of an AOA it does and it very accurately tells you linearly how close you are and is accurate in various flight maneuvers such as turns!  While there are vane type which mine is not my AOA is also not an Air Speed Sensor it is a differential pressure sensor.  

Fly safe,

Rocket On! 

[PTK]

In my opinion, an aoa indicator will show you what you already know if you're not distracted but are monitoring and engaged into keeping the airplane within its envelope. Normally, with few risky exceptions, you're within the aoa limits if you're operating inside the envelope. Also an aoa indicator will not act to correct for you. iow, with an aoa readout or not the airplane still can be lost way before corrective action can even be applied.
Take the infamous base to final turn. The airplane is at the margin of its envelope, low, slow, dirty and banking. An aoa ind. only confirms this. The fully engaged pilot knows to unload the nose and keep turn coordinated way before the airplane departs its envelope. If this is not done, it's over no matter what!
Would aoa info be helpful? Sure! Will it save the day when pilot is distracted and allows the airplane to stray? Probably not! Would I go out of my way to get one? No!
This is why, imo, I prefer to actively keep the airplane inside the envelope on my own.

[Alan Fox]

They all have an aoa... The stall horn...

[M016576]

They all have an aoa... The stall horn...

That's like saying all cars already have a speedometer- the gas pedal.

[M016576]

An aoa indicator may be a nice gadget to have but I don't think it's an absolute necessity.

I prefer to be fully engaged and aware of my attitude and speeds at all times. Further I prefer to adjust my speeds according to my weight on my own.

As Jose said, can't ignore airspeed. I would add, can't ignore the need to adjust V speeds according to weight.

All airfoils stall at a single angle of attack regardless of weight.

I think you might be considering the utility of an AoA indicator backwards. The Vspeeds are derived from Known angles of attack by company test pilots using a test aircraft with an AoA indicator installed. They then copy these Vspeeds into the PFM. You use these estimated speeds, estimate your aircraft's gross weight, interpolate an airspeed based on these numbers that were estimated from a test aircraft (not YOUR production plane), and then you have what you think is your accurate approach speed.

If you install an AoA indicator, you have difinitive information on the stall and approach speeds for YOUR aircraft. At any and all weights. You skip the estimations and interpolations, and that AoA also takes into account any sort of bends, tweaks, camber, hail issues, etc that your particular aircraft may have.

Can you fly with airspeed alone? Yes... But it's like cutting butter with a chainsaw... Effective but not precise. And towards the edges of the envelope (approach turns at high gross weights... Low altitude landings on short runways with low gross weights), an AoA indicator really is the only precise way to know how your aircraft is flying.

[M016576]

In my opinion, an aoa indicator will show you what you already know if you're not distracted but are monitoring and engaged into keeping the airplane within its envelope. Normally, with few risky exceptions, you're within the aoa limits if you're operating inside the envelope. Also an aoa indicator will not act to correct for you. iow, with an aoa readout or not the airplane still can be lost way before corrective action can even be applied.

Take the infamous base to final turn. The airplane is at the margin of its envelope, low, slow, dirty and banking. An aoa ind. only confirms this. The fully engaged pilot knows to unload the nose and keep turn coordinated way before the airplane departs its envelope. If this is not done, it's over no matter what!

Would aoa info be helpful? Sure! Will it save the day when pilot is distracted and allows the airplane to stray? Probably not! Would I go out of my way to get one? No!

This is why, imo, I prefer to actively keep the airplane inside the envelope on my own.

The problem here becomes more that without an AoA indicator, you might not even know that you are approaching stall, as most pilots typically don't calculate a 30, 45, 60 degree stall speed at gross weights.... And that doesn't account for an accelerated stall (a wrapped up turn). An AoA indicator will show you all of these things.

Check one out one time, you'd be surprised at how liberating it is, and how consistantly precise your approaches and landings will become.

[bnicolette]

Come on guys.  Nothing but nothing is going to save somebody from poor piloting technique and lack of understanding.  You can throw all kinds of gadgets in the airplane with all kinds of bells and whistles blaring in your ear but in the heat of the moment it's just not going to save that bad/distracted pilot.  Fly the airspeeds prescribed in the POH, keep your banks to 30 degrees or less and put your horse back in the barn in one piece.  We're not flying transport category aircraft here with huge speed/weight envelopes.

 

However, if you've got money and want another gadget to play with and want to shave that 4 knots off your approach speed to be flying at precisely 1.3 or less to get into that 1200' runway, then have at it.  It surely CAN'T hurt.

[PTK]

...you might not even know that you are approaching stall, as most pilots typically don't calculate a 30, 45, 60 degree stall speed at gross weights....

No need to calculate. It's all in the Performance section of the POH. "Stall Speed vs. Angle of Bank" for various weight/gear/flap configurations.

Often the problem is that people who fly light most of the time get used to certain performance parameters. Then on that one flight when they're heavy get an unwanted surprise if they don't adjust.

These performance figures need to be in our head. It's an essential part of pre-flight preparations.

imho, I don't see how a pilot can pretend to know the airplane without this level of understanding. They really don't. And with this lack of understanding they're taking a huge question mark into the air. That can't be good.

[Alan Fox]

That's like saying all cars already have a speedometer- the gas pedal.

No its not... The stall vane activates at a certain AOA regardless of airspeed.....it is an angle of attack indicator...... 

[M016576]

No need to calculate. It's all in the Performance section of the POH. "Stall Speed vs. Angle of Bank" for various weight/gear/flap configurations.

The problem is that people who fly light most of the time get an unwanted surprise when on one flight they're heavy and don't adjust.

These performance figures need to be in our head. It's an essential part of pre-flight preparations.

imho, I don't see how a pilot can pretend to know the airplane without this level of understanding. They really don't. And with this lack of understanding they're taking a huge question mark into the air. That can't be good.

Again, all those charts are based off of test data generated through AoA, then transcripts into airspeeds. The further down those charts you go , the greater your chances of inaccurate data. An AoA indicator will tell you how your aircraft is actually performing, not an estimate of your performance based off of a test aircraft and interpolated.

So.... What's better: actually knowing your true position in the envelope, or thinking you know based on estimated/interpolated data?

You make a good point above- most pilots shoot for the middle of the performance envelope, thus never find the edge. If you want to accept estimates for approach speeds, etc, then the ASI gets you there. But the problem comes when a pilot thinks he knows where the edge is and ends up "surprised" because the chart isn't accurate for your condition of flight and actual airframe.

Think about how "accurate" those engine performance charts are (at least in my early '80's 20J book)... What makes you think the stall speed charts are any better? Again, they get you in the ballpark, but all those charts should be considered estimates, not hard and fast truth data for YOUR aircraft....

All just my humble opinion....

[M016576]

No its not... The stall vane activates at a certain AOA regardless of airspeed.....it is an angle of attack indicator......

It's not an indicator, it's an on off switch (or warning, if you will). You can't fly off of it like you can an indicator.

My analogy was a little weak; I'll explain. An AoA indicator shows how close to stall you airfoil is in a graduated "unit" that is pilot controllable. A stall warning trips at a single AoA, this it has two conditions- on and off. A speedometer in a car shows a range of speeds that you can control while driving. The gas pedal (without the speedometer) just tells you one of two things: stop or go. In time you can learn to estimate your speed looking outside while driving, but to actually "know" you need to look at the speedometer. An Aircraft is the same way, but it's the AoA indicator that tells you how close to stall you are, not your airspeed indicator. You can estimate with the airspeed indicator, but to know, you need an AoA gauge.

[M016576]

Boy, you guys sure know how to push my buttons! I don't understand why every time this issue comes up that guys refuse to acknowledge the aerodynamic principles of AoA.

I'm not saying that there is anything wrong with using airspeeds, I'm just saying its not as accurate of a way to fly (and its more complicated). But most GA aircraft out there don't have AoA. And it seems that most GA pilots don't learn and/or understand what it means. My guess, as I've stated before, is because GA pilots, and people learning to fly, are more comfortable with an "airspeed indicator" than something that sounds ominous and is not immediately obvious like an angle of attack indicator. So some guys have huge heartburn even accepting the idea of it. But think about how much easier life is/could be if you have an AoA indicator, not to mention safer. Of course, all assumes you are trained to use it, and know what you're looking at. Just like Glass cockpits- if you don't understand how to use it, it won't do you any good! But if you do..... Life can be less complex, easier and safer. Again, just my opinion.

[carusoam]

My fear of the AoA is the calibration of it. One day instrumentation works the next day, it drifts. On a third day it doesn't work at all.

Are these devices FAA approved for the important process they will be controlling? Approved by somebody?

My stall warning device stopped working one day. If I used it for judging my level of safety above the stall, that would have been bad.

It took several weeks for me to finally know it wasn't working. Thought I was not approaching the stall better...

It would be nice to have the stall warning as a back-up to the AOA. Fly the AoA, but if the stall warning blares, you know something is out of agreement...

Make sure both are working before depending on it.

Otherwise, maintain nose low attitude and bank angle less than 30 degrees for minimal degradation of stall speed.

As a test for yourself... Right down what you remember the stall speeds for your airplane are both level and 60deg bank with flaps and gear down. Throw in a couple of weights, mgtow and one other.

Mine are near 65 and 95 kias.... Pretty wide range...

Let me know how you do?

Best regards,

-a-

[bnicolette]

Boy, you guys sure know how to push my buttons! 

 

LOL!!  Take it easy there M?????

 

I have to ask.  Since you've got this precision instrument in your airplane and you fly on the ragged edge with very little cushion for mom and the kids flying your approach at 1.05, just enough extra airspeed to flare............have you checked to see how the speeds in the POH fare against what your AOA says?

 

Forgive the sarcasm above.  But I am really interested to know what the difference are from the POH.

 

 

By the way, I am surely not against having the AOA and it would be a cool gadget to have I just think it is unnecessary and of little benefit for normal operations.  However, I just fly my lil ole airplane from point A to point B and some fun flights in between.  

[M016576]

LOL!! Take it easy there M?????

I have to ask. Since you've got this precision instrument in your airplane and you fly on the ragged edge with very little cushion for mom and the kids flying your approach at 1.05, just enough extra airspeed to flare............have you checked to see how the speeds in the POH fare against what your AOA says?

Forgive the sarcasm above. But I am really interested to know what the difference are from the POH.

By the way, I am surely not against having the AOA and it would be a cool gadget to have I just think it is unnecessary and of little benefit for normal operations. However, I just fly my lil ole airplane from point A to point B and some fun flights in between.

That's valid- like I said before- you can get the job done with an ASI- we've all been trained to do it that way, and it's completely legit. But it's a different level of accuracy than from the AoA approach.

As for differences from the POH- each individual airframe will be different. Some airframes will be close. I bet some are as far off as 3-5kts in certain areas of the envelope. Probably +\- 2 kts in a level power off stall. That would be consistent with errors I've seen in the past on other airframes (I haven't run the numbers on my personal mooney yet). Just like the varying top speeds each airframe has, the stall speeds vs AoA vary from book as well.

Here's my personal technique for using AoA for an approach:

Slow to gear speed.

Drop gear.

Stabilize at a known airspeed / AoA cross check (90kts seems like a good spot for a mooney).

Check to make sure AoA is at correct value for indicated airspeed in known configuration check.

Yes? Fly "onspeed AoA" all the way through the flare.

No? figure out which gauge is in error, and fly the good one! (Remember, they are on seperate systems).

The beauty of the AoA gauge is twofold IMO- first, it gives you the perfect "speed" for every approach (regardless of weight, or anything else) and you have a living reference of where the stall exists compared to where you are flying.

A) comes in handy when your kids sneak that extra piece of cake onboard... Or your wife sneaks on the kitchen sink!

[201er]

In my opinion, an aoa indicator will show you what you already know if you're not distracted but are monitoring and engaged into keeping the airplane within its envelope. Normally, with few risky exceptions, you're within the aoa limits if you're operating inside the envelope. Also an aoa indicator will not act to correct for you. iow, with an aoa readout or not the airplane still can be lost way before corrective action can even be applied.

Take the infamous base to final turn. The airplane is at the margin of its envelope, low, slow, dirty and banking. An aoa ind. only confirms this. The fully engaged pilot knows to unload the nose and keep turn coordinated way before the airplane departs its envelope. If this is not done, it's over no matter what!

Would aoa info be helpful? Sure! Will it save the day when pilot is distracted and allows the airplane to stray? Probably not! Would I go out of my way to get one? No!

This is why, imo, I prefer to actively keep the airplane inside the envelope on my own.

But your opinion is just plain wrong. You DON'T know. The POH only gives you a one size fits all stall speed (not custom calculated for your aircraft and your airspeed instrument) for 0, 20, 40, and 60 degrees and only at gross weight. You're gonna tell me that you know exactly what 1.3Vso in a 27 degree bank is?

 

The AOA doesn't just confirm that "the airplane is at the margin of its envelope, low, slow, dirty and banking." It is an analog instrument that moves as this condition is being created. If it is part of your instrument scan (which it should be if you have one and intend to use it) then you will see it go from good to bad to worse as you are increasing bank angle. You won't let yourself get "low, slow, dirty, and banking" because you will be aware when you have reached or begun to dip below 1.3Vso. On the other hand, without it, you have only to guess if you are at the right speed when you tighten up a base to final turn at 2689lbs, flaps wherever they are, and an increasing bank angle.

 

You suggest that the inattentive pilot can get too slow and that further awareness would be useless. Well this can hold true for anything. However, if a pilot can keep track of airspeed in a turn, he can especially keep track of AOA. I don't even other looking at the airspeed during those critical phases. I alternate between looking outside (or my instrument scan in IMC) and looking at my AOA. As far as I'm concerned, at that moment airspeed doesn't matter. I only occasionally cross reference the airspeed when I'm less busy for reference. But on the flipside, I think the attentive pilot is at far greater risk of a base to final turn without AOA information than the pilot who has it. If I begin turning too slow and to steep, I will see the AOA indicator begin to creep toward where I don't want it to be and can correct my turn by dropping the nose further or reducing bank angle. The airspeed flying pilot is simply unaware of the exact 1.3Vso point he should be targeting during an arbitrary bank turn at an arbitrary weight.

 

By not flying the correct angle of attack, you are not only putting yourself at greater risk of stall on departure or arrival, but you are also inhibiting the maximum performance capability of your aircraft which is dangerous as well. Your misunderstanding of angle of attack is not only foolish but also dangerous. Not because you don't want a device but because you don't understand why understanding angle of attack is so imperative.

 

An aoa indicator may be a nice gadget to have but I don't think it's an absolute necessity.

I prefer to be fully engaged and aware of my attitude and speeds at all times. Further I prefer to adjust my speeds according to my weight on my own.

As Jose said, can't ignore airspeed. I would add, can't ignore the need to adjust V speeds according to weight.

A stall can happen at any speed or attitude but only one angle of attack. With an AOA indicator, you don't have to adjust speeds for weight. You just fly the gauge in the most critical moment. It's when you're climbing hot and heavy out of a short field that you need to squeeze all the performance you can get (not cause you wouldn't make it otherwise but to give yourself more margin if something else goes wrong). But when you're in the process of flying that low airspeed, not only are you at high risk of stall, you are also at risk of reducing your climb rate by straying from it. The AOA not only shows you your margin above stall but also ensures you are climbing in the optimal configuration to get the most climb performance regardless of weight, attitude, or bank angle.

 

You don't even know what your exact weight is. You don't know what your exact bank angle is. You don't know what the 1.3Vso speed at that arbitrary bank angle and weight is. You don't know how much your plane differs from the test model on which the speeds are based. Your airspeed indicator can easily be a few knots off (and on a performance climb even a few knots matters). With an angle of attack indicator none of these things matter because you simply fly the proper angle of attack every time. I'm shocked how difficult it is to understand how brilliantly simple the concept is.

 

As far as I'm concerned, an angle of attack indicator + gps groundspeed is all you need to fly an airplane and ultimately better than airspeed indicator by itself. The AOA is probably less likely to become inop than the ASI as well. It's by far the greatest instrument on my airplane after the six pack. Heck, for strictly VFR only flying, if I could have only a single instrument on board, I'd choose an AOA.

[201er]

An aoa indicator may be a nice gadget to have but I don't think it's an absolute necessity.

It would help keep you alive a lot more than a shiny new paint job.