alf5071h,
I agree with your comments.
Either I, didn't find any reference to longitudinal trim in the report, nor in the FDR data. That's strange.
FDMII,
The THS trim position is a function of elevator movement and position, nothing else -> True, BUT elevator is not a direct function of sidestick position. In the AF447 FDR, PF pushed sidestick forward couple of times, but the elevator didn't rotate more than half nose-up and THS was at max nose-up.
Even without THS graph, I'm quite positive that is the case for QZ8501. maybe worse with apparently abnormal law triggered by AOA>30 deg, then THS was fix at max NU.
As the airplane's flight control system continued to attempt to maintain the commanded the low g-load, as the airplane started to sink, the pitch trim ran to full nose-up. From that point on, recovery may have been impossible unless the crew had the awareness to reduce that manually. Even with full nose-down pitch command, as the airspeed built up in the recovery the nose-up trim had too much influence to overcome and the airplane would pitch up despite any action on the sidestick.
Something fundamental has to change on this matter, for a simple reason: under stall it's imperative to reduce the AOA, if PF demands nose down rotation then A/C should start rotate that direction not opposite. How? engineers to figure out: THS position, moving fuel foward, etc