Therefore the typical light aircraft setup with an ASI for those who look at the instruments and an acoustic stall warner (or stick shaker in lager planes) for those who don’t is the safest approach. Adding another instrument to the panel in the form of an AoA indicator will do nothing to improve safety.
I bow to your greater experience and expertise, but still find it difficult to accept such categoric (and unproven) statements.
Sorry, but if they didn’t notice 30 degrees of pitch then they certainly won’t have noticed an unusual AoA value either.
How do you know for sure? Might there have been a different outcome?
How do you know for sure? Might there have been a different outcome?
You can never know for sure what would happen in different circumstances, but in the AF447 case, the PF was obviously not functioning so I, too, doubt that another instrument would have helped. (Someone wrote that AF447 had a PNF and an NPF.) From the CVR recording, you hear that when the captain entered the flight deck, he instantly realised what was happening without the benefit of an AoA indicator but by then it was too late.
… but still find it difficult to accept such categoric (and unproven) statements.
The problem is that there is no way to prove or disprove them. As almost no light aircraft is fitted with an AoA indicator (the only piston aircraft I ever flew that had an AoA fitted was a Cessna 421 which had it as an option but with an almost unreadable indicator that was not even illuminated in the dark) there is no meaningful statistics of incidents and accidents that occurred with and without AoA. Also I did not yet come across a credible report of a pilot who was saved from crashing by an AoA indicator (as already written: In civilian aviation only. I know nothing about military aircraft.)
We’ve had that discussion several times already and I clearly see the benefits of AoA indication on some high-performance aircraft and prototypes or otherwise modified aircraft that don’t come with a calibrated airspeed indicator or that were not test flown to all corners of the envelope. But apart from that (to me!) it looks just like a money-making scheme of an industry that is confronted with a constantly falling number of sales. Obviously that scheme did not work becuase the AoA threads ran dry about a year ago.
The correct way to see an AoA meter is as a lift reserve. Not only that, it will be able to tell you if you’re flying inefficiently with a lot of forward CG etc. It could in its most precise iteration act as a fuel saving tool and act as a load factor meter. I would even go as far as to say it could potentially eliminate the need for the Va (maneuvering speed limitation) speeds and just have them as a function of AoA. It’s a tremendously useful tool.
I have to question the value of this device at the smaller end of aviation. The margin at the low speeds under discussion seems minimal to warrant yet another distraction in the cockpit.
I also feel that as an after market add on it has limited credibility without specific test data on exact airframe AOA combinations.
That low to the ground I respectfully decline the role of test pilot.
I have been operating out of a very short grass strip this last year under varying weights and runway conditions, sufficient to respect the data in the POH and also set my own personal limits on the runway conditions. I have found the IAS and stall warner more than sufficient for some very precise landings.
In practise after establishing a stable approach and speed my eyes are 99% out of cockpit during the last 200 feet of descent to touch down, with only an occasional glance at speed. Eventually experience will give you an excellent sight view of how the approach looks and feels.
Cheers. E
The correct way to see an AoA meter is as a lift reserve.
Not really. AoA is only one of several parameters that contribute to the generation of lift. The most important is airflow/speed. AoA is linearly proportional to lift while speed has a square influence. Little variations is speed affect lift much more than little variations in AoA.
(Equation and graphics taken from Wikipedia)
If you look at the coefficient of lift over AoA curve, you can observe that especially at the top of the curve, where the Cl is highest (i.e. the low speed regime most important for take-off and landing), changes in AoA produce almost no variation in Cl. In this regime, lift is governed by speed. The example curve shows no variation at all of Cl between 13 and 18 degrees AoA. Airfoils of civilian aircraft are specifically designed to have such a flat curve around max Cl to make them safe. (Totally different for military aircraft, if you look at the wing of something like a F104 this curve is more sawtooth-like, rising linearly to the maximum and then dropping abruptly, this is why these guys really need an AoA indicator.)
Not only that, it will be able to tell you if you’re flying inefficiently with a lot of forward CG etc
Yes. But only if the test flying programme of the aircraft would include reading and tabulating of the AoA values encountered. I have not yet come across an airplane operating manual that includes tables for optimum AoA values for various phases of flight. On the contrary: The aircraft I fly at work is fitted with AoA indicators, one analog instrument, an indication on the airspeed tape on the PFD and a traffic-light-style indexer on the glareshield and yet all the manual says about it is: “The AoA indication system may be used as a reference but does not replace the airspeed display in the PFD as primary flight instrument”. Which means that the manufacturer (who has a lot to lose when accidents occur) wants his aircraft to be flown by speeds, not by angles.
In general, I’m with what next here – can’t really see the value of an AoA indicator in a light a/c other than possibly experimentals and mil.
That said, it might perhaps have helped the guys piloting QZ8501 (AirAsia) to fly pitch and power and get out of whatever – probably wx related – event they found themselves in. Don’t think I would spend money on it.
@what next Thank you for taking the time to comment in such detail – interesting! 
other than possibly experimentals
And that would be US homebuilts too.
What concerns me a bit is that these devices need calibration. You can’t just screw them on and get the AoA reading. (You will get an AoA reading but the indication of the safe range will not be calibrated). And you don’t want to be doing the calibration at low level e.g. 1000ft 
And you don’t want to be doing it on any aircraft which might have non-recoverable stall/spin behaviour, unless you have the proper gear (a tail parachute for example, to arrest a spin).
You may be able to find another owner of the same type and install an identical AoA indicator, at the same position and same orientation, but then you are relying on him having done the tests properly. Which, with some aircraft types, his being still alive may be evidence that he didn’t do them properly
Which, with some aircraft types, his being still alive may be evidence that he didn’t do them properly
Or he has set up is device with such a broad safety margin that it will be mostly useless. But this calibration problem only applies to pneumatic AoA probes. The mechanical vanes only require geometric alignment relative to the chord line of the wing which can be done on the ground. But they are a lot more expensive, especially heated ones.
