I agree stall AoA varies with configuration, Mach # and others however, I don’t think that, given all other values constant, weight changes AoA. Ie, a wing stops being a wing at the stall AoA, regardless of how much lift is demanded..
Well, it's true that stall AOA doesn't change with weight - but the AOA *required* for a given airspeed absolutely changes with weight - more than any other variable other than flap setting. (I am a senior flight test and simulator test engineer and do this stuff regularly. I think I can speak definitively.)
The aero equation for lift is this: Lift = 1/2 * Coefficient of Lift * density * speed^2 * Wing Area.
- In level non-turning flight, lift must equal weight.
- In turning or accelerated flight, lift must equal weight * load factor.
- Coefficient of lift is (in most wing designs) a nearly linear function of AOA, up until stall.
- Moving flaps/slats changes the coefficient of lift curve, so different values of CL-AOA exist for different configurations.
Therefore, AOA changes approximately linear with weight for a given speed. You need a fairly complex set of tables to know the expected AOA for all possible configurations, but the exact relationship is extremely clear.
This is why I assert that the average pilot will never be able to say "that indicated AOA is exactly correct ." With some experience, he can certainly say "I'm used to seeing this approximate AOA for a configured approach at this fuel weight." He can also certainly say "Wow, that AOA value is off-the-chart wrong." I think you're just adding to the mental complexity of flying without benefiting the average pilot.
On the other hand, the FMC can compute the expected AOA value from internal charts; it already knows the gross weight (as entered by the aircrew during nav mission planning); it knows the flap configuration and gear configuration. It would need either load factor (g's) (which is probably doesn't have) or angle of bank (which it does have), assuming you're not flying an airshow and doing big pushovers/pullups. It should then be able to figure an approximate expected AOA, and compare the measured AOA, and pop up an alert if there is a big (and sustained) mismatch. (You don't want to flag brief mismatches, because turbulence would trigger it, and it will never be correct below flying speeds like taxi or rollout.) So there's plenty of ways to use the onboard computing power more wisely than it is being used now, without burdening the pilot with basically irrelevant information.
I also agree that simply introducing an AoA indication in the cockpit of an airliner will not benefit crews without some education. However, AoA is a fundamental parameter, if it is displayed and obviously in error (deduced by crew education) then it could assist in fault finding. One of the key parts of UPRT (being introduced as mandatory in Europe for all new CommerciL licence training from Dec 2019) is AoA & G awareness. I believe it would be of huge benefit if commercial aircraft had AoA displayed and pilots were educated in its interpretation from day 1 of flying training.
True enough - but if a third-world flight crew has trouble with other basic skills, would showing them raw AOA really benefit them?
I suppose a good compromise is don't show AOA unless there's a miscompare - then (along with a very obvious miscompare notification) show the left AND right values right next to each other, not cross-cockpit.