Uncommanded nose up trim by pilots
Well, Doze, this is the big question.
How did the THS get trimmed to near the limit?
What happened to AoA protection? And that looks to be a biggie according to the manuals' description of the "protections'.
How did the crew not see attitude steadily increasing? I thought attitude sensors and displays were independent of the pitot-static system? Same for AoA protection.
I can tell you exactly how my little jet trimmed the stab to full nose DOWN as it entered a stable, fairly smooth deep stall. We ran outta nose down pitch moment. Already posted the link and enclosed snippets from the test pilots. So we were briefed, watched movies, had a new switch installed to help us, etc. Better yet, our designers and military management were not so damned proud of their design that they refused to change a few things. They didn't continue claims that "the system did exactly what it was suppose to do" ( even tho it did EXACTLY what it was supposed to do, it wasn't designed for the condition we clever pilots could get to).
But now we see a similar phenomena in the Airbus, and due to a combination stabilizer and elevator, it is possible that the elevator doesn't have the control authority to get the nose down at full forward stick due to the disconnected/locked THS.