Is that behaviour known and clear to an average AB Crew?
I would certainly expect so, it's part of knowing one's airplane. But it is one of those transient characteristics that is somewhat "invisible" because normally we're on the way to something else in terms of a selection. On the engine-out on takeoff, we would level off the A320 by selecting "0" on the V/S but when initially rotating the knob it would synch with the current VS, from which an adjustment would be made.
The UAS memorized items require that the AP/AT/FDs are all turned off.
Automatically, (meaning the system does it, not the pilot), turning the FDs off with an abnormality such as an
NAV ADR Fault may or may not be a good thing. Solving one specific issue always has a "dozen" other perhaps-unanticipated outcomes so it would have to be studied, just like the THS continued trimming after a stall warning, and the loss of the stall warning (NCD - no computed data) below 60kts. Perhaps it should latch?...but that can't be determined until a full analysis of all possible/knowable outcomes are tested.
After that things were pear shaped anyway and recovery was getging more and more unlikely. Once they were at 40° AoA things were set firmly for a bad ending. (Anyone trained in doing a 45° Nose dive at 30kFt in a 200t airliner at night in IMC with uncertainty about validity of instrument readings?)
Well, there has been input, (by
Owain Glyndwr) that recovery may have been possible at various altitudes. Owain indicates that a reasonable "unloading" of the wing/reduction in AoA could be done with a steadily-held 10deg ND and in fact lower down, (thicker air), the recovery would be slightly quicker.