Originally Posted by
pattern_is_full
Possibly repeating capngrog and b1lanc:
1) as mentioned, the A321neo apparently has a balance problem similar to what the 73M8 would have had with no MCAS - a tendency to overpitch-up in some rare scenarios.
2) the A321neo is tail-heavier than the A321, due to mass added behind the center of lift and the previous CG - larger sharklets, reinforced (heavier) main gear and wing, and in some configurations, additional (2-4) seat-rows/pax-weight extending further back (aft galley and toilets reduced in size/number), and some doors moved further aft (I make the assumption that doors with hinges and seals and frames and locking mx are more massive than standard fuselage frames).
3) Airbus did flight-testing and tweaked many things (including the control software) because of the changes - but apparently they have now discovered something overlooked. A patch is on the way, but until then, they are advising that steps be taken to avoid pushing the CG even further aft. And be careful with pitch-up control inputs.
4) Part of that is the "mystery phrase" which (to me) simply means - "Avoid a CG of 34% MAC or more when: calculating ZFW, or for TO and LDG." If the calculator spits out "CG >34% MAC" - move some weight forward.
Homesick Angel mode wasn't limited to the 737 Max. Didn't Thompson get one down to 20 or 30 KIAS on qa go around per the AAIB? The 737 and A321 are very different beasts. I dont think ELAC software hides any unpleasant aerodynamic characterisitcs. I'm sure all the Airbus drivers here have flown in direct law, and after 30 seconds to get your head around her, Fifi flys just fine, even on just the Blue Hydraulics....