Aoa

[aviator79]

I do not think anyone has mentioned this but we all fly AOA.

In cruise we maintain altitude/level attitude by referencing the cowl to the horizon.

I do the same in climb, descent, and on approach. On final I regularly check airspeed and/or AOA meter if I have it.

What you describe here is flying by pitch attitude, not AOA. (Which I agree is how it should be done.) The way we teach and practice stalls really enforces the idea that a stall happens at a certain pitch attitude and creates this false equivalency between pitch and AOA. Without the indicator, there is no single reference, in the cockpit or outside, that gives you AOA information. We develop some sense of AOA, and the ability to synthesize AOA information from several indicators simultaneously only through experience and training. Unfortunately, when we look at accident data, we find that many of us aren't as good at it as we think we are.

[N981MS]

I should have been more clear.

With wings level, in relatively stable air, and in a relatively stabilized condition (ie not in a turn) the pitch information we get from referencing over the cowl is directly related to angle of attack. Therefore we are all using a secondary reference to angle of attack to fly even without an AOA gauge.

My point was that we all fly in reference to angle of attack even without an AOA gauge. I am not against AOA gauges and in fact think it is an excellent addition.

[Av8r3400]

Max, you are very much correct. But...

As your airspeed changes, that point on the cowl, attitude reference, is at a different angle of attack, relative wind to wing chord. You can hold that same point on the cowl to the horizon and as your air speed slows, the AOA will go from very shallow to full stall.

This is where the AOA instrument shows its value and what aviator79 was saying.

[n85ae]

In my airplane an AOA is really just a toy, which is mostly just fun to
play with, but I don't need it.

I have had two AOA systems on my airplane, one was similar to the old
fashioned Bacon Saver, and a more recent with a floating dot. My feelings
with my airplane, are that my control stick gives me as much information
as I ever need so I really don't use the AOA system.

A different airplane it probably makes sense, but my Kitfox really gets
very soft a long ways before it's even close to a stall when I'm landing.
For climb under power I watch airspeed only.

Jeff

[jiott]

For those of you who don't feel the value of an AOA indicator, how about the next low time pilot you sell your airplane to, or your brother-in-law who just got his ticket and wants to borrow your airplane. With most glass panels nowadays the AOA feature is already built-in and it is quite easy and inexpensive to add the sensor port on the wing to activate the feature.

[jiott]

Or maybe one of these days you might decide to get IFR rated. I think the AOA feature may be even more beneficial in IMC conditions.

[neville]

equating pitch attitude directly to AOA is a good way to perform the " loss of control maneuver". Go flying and at altitude simulate overshooting the turn to final. While doing so watch the AOA indicator. As the bank increases in your shallow descending turn you see the AOA increasing from 3 deg to 8 or 9 deg and the pitch angle has not changed. Your still in that shallow descending turn. Increase the bank a little more because your still overshooting and AOA jumps to 11 deg and pitch angle has not changed. The only thing that might save the day is that in your primary training you learned that those real sluggish controls are not an indication of normal flight. Nearly all of my flight time is spent looking outside of the aircraft and sensing what the machine is doing by sound and attitude in reference to the horizon (and to the RPM indication because I have this very nice Rotax 912iS which will be at overspeed in a heartbeat if not watched closely). But when doing any maneuvers AOA is scanned frequently and on approach to landing carries more weight than airspeed. Since having an aircraft with AOA I would really miss it if flying a plane without one.

[aviator79]

If you don't have an AOA indicator, and you think you know your AOA by other means, you're almost certainly wrong. Look in any flying handbook worth the paper it's printed on and you'll find something very similar to "An airfoil can stall at any airspeed and any attitude." Even "control mushiness" is not a reliable indicator. We only think it is because the airplane is usually slow with minimal airflow over the control surfaces when we practice stalls. By the time your AOA is causing your controls to be ineffective, airflow has separated and you are already stalled. I realize I'm beating a dead horse here, but as a CFI I feel obliged to point out that most of the surrogate indicators for AOA that have been suggested simply aren't. They are secondary indicators that depend upon a lot of other factors. It doesn't mean that maintaining a stall margin by referencing those indicators is unsafe, or color me guilty every time I fly our club plane. But we do need to be honest about how much information we really have in the cockpit, especially given the accident record.

I'm sure many of you are better pilots than I am, and yes, the Kitfox is pretty docile. But there have been LOC fatalities in Kitfoxes, and I'm sure those pilots would have told you that they knew their airplanes quite well.

[aviator79]

I guess the point I'm trying to state rather poorly is this:

If you don't install an indicator because you're comfortable flying safely without the information it provides, then go forth and enjoy.

If you don't install an indicator because you believe you already have the information it provides, you might want to think about it some more.

[av8rps]

Very well said.

Thanks for taking the time to educate all of us skeptics, or in my case, previous skeptic