Questions about AoA calibration and display

[vas4afs]

I have an RV-10 with 2xAF5600 (which I bought). The previous owner did the AoA calibration both for flaps up and (fully) down (donut is black vs. green). The flaps down calibration was done with the flaps fully down (3rd notch).

I am now working on my commercial certificate and am using the AoA display more to be able to fly the short field landing with minimal float so I have a few questions about AoA calibration and the display.

The documentation indicates that if the angle advisory was set to 1.15x Vso (or Vs1 depending on flaps down or up), the approach AoA (donut) would normally be set to 1.4x (by calculation) but it also looks it can be set to any speed during the calibration process. Is there any way to determine how the calibration was done? I have included a screenshot of the AoA config screen below.



Looking at video that I captured from a flight, it looks like the donut turns green as soon as I put down the first notch of flaps but I don

[Jonathon]

There is no way to tell how this was calibrated. It is, however, safe to assume that the approach coefficient was calculated rather than empirically derived. If the pilot followed the AOA checklist precisely, then only the zero lift and angle advisory coefficients would have been directly gathered, and all other coefficients would have been calculated. It is possible to manually gather all coefficients as desired by pressing the RECORD button in the calibration instead of the PAGE button to skip to the next coefficient.

So if you want to shift your approach AOA closer to 1.3Vs or wherever for your short field work, you could 1) redo the AOA in flight cal, press the PAGE button (even where the checklist says to hit RECORD) to skip past and not overwrite any saved coefficients you are happy with, then press the RECORD button on the 0AP/1AP pages to record new approach coefficients at your preferred airspeed.

Alternatively, you could just go into the AOA calibration menu and manually nudge the Approach CP (Cruise) and Approach CP (Landing) numbers closer to the Warning CP numbers, in a trial and error fashion, until you are satisfied with the results.

[vas4afs]

Thanks, Jonathon!

It looks like the second part of my post got chopped off so here it is:

Looking at the video that I captured from a flight, it looks like the donut turns green as soon as I put down the first notch of flaps but I do not see the AoA display change otherwise. Given that the critical AoA has changed once the flaps came down, my thinking is that the AoA bar would “slide up” - essentially, at the same airspeed, the donut should move towards the green. Am I thinking about it correctly? Or put differently, how does/should the AoA display change when the flaps are engaged?

Also, if the flaps down calibration was done with the flaps fully down, is it possible that the AoA representation at the first and second notches is not completely accurate?

Thanks,

Vas

[Jonathon]

Yes it will shift to the landing calibration when you put the flaps down, so in addition to the donut you would expect to see the aoa indexer shift, unless the flaps up and down calibrations were by coincidence very close at that airspeed.

Also, if the flaps down calibration was done with the flaps fully down, is it possible that the AoA representation at the first and second notches is not completely accurate?

This is correct. A stall will arrive slightly earlier than the indexer would suggest when you are landing with partial flaps.