FYI: For small, private CAR3 or Part 23 aircraft a supplemental AoA indictor system install has been considered a minor alteration for about 12 years or so. While the SAIB points to commercial ops, the original FAA AoA has been updated over the years to make it easier for any category aircraft to have them installed.
Thank you. Good to know. Since they didn't reference that in the SAIB, would you happen to have a link to the guidance for that?
Policy Statement PS-AIR-21.8-1602 lays out the FAA policy on NORSEE - Non Required Safety Enhancing Equipment: https://www.gajsc.org/wordpress/wp-content/uploads/2016/08/PS-AIR-21.8-1602.pdf
These are the main ones, but there are several others.
That policy statement is similar to the AIR100 memo above which covers more design and production requirements. Usually there will be a separate PS memo covering installation like the one for installing electronic attitude indicators in place of vacuum ones.
Thats the company that pretty much brought an affordable AoA to the private Part 91 market so its a good reference. Also you'll see in the AIR 100 memo above most AoA systems are built to an ASTM standard. The data on their effectiveness is out in the public domain should you care to read up on it.
As someone who has calibrated, tested, flown with, and relied on more than a handful of AOA systems I think everything you said above could be equally applied to pneumatic airspeed indicators. They aren't FBM, and it's not that difficult if the system is implemented properly. Just like your pitot-static system.
IF what uAvionix describes in their manuals and brochures is the actual methodology used to "calculate" AOA it is garbage. Whenever we've discussed in the past here someone usually mentioned there is more to it and it's more in line with conventional air data/Kalman filter estimation that can be very good. I hope the written descriptions are just dumbed down for the less technically-minded.
It seens to me a lot of people get used to the plane's performance in light load conditions (pilot only, half tanks) and get surprised by the loss of performance once they add a couple heavy pax and fill the tanks. Also, base to final turns add the complication of not being level turns, but descending. This changes the AoA in the turn because you're not demanding the lift of a level turn.
There have been a number of studies/presentations done to mitigate loss of control accidents with the AoA being one method to do so. The links below give a general background with additional info available online from various sources like universities, etc..
No mandate. All optional and voluntary. Based on the background and mitigation to increase safety, the FAA developed a method to install AoA systems as a minor alteration and reduce cost similar to the methods replacing certain vacuum powered attitude indictors with electronic as a minor.
