AF447 stick & THS question

[HappyPass]

Hi everybody.
I didn't feel like posting in af447 thread no.3 (which I'm following), mainly because I'm not a pilot, and also because the thread is getting pretty hot, and a couple of SLF asked for info but their questions were not answered.

I have a doubt - I don't know the inner workings of THS but as far as I could gather the auto-trim helps the pilot in maintaining its inputs.
At 2h10'51" the pilot was holding nose-up sidestick and the THS went 13° nose up (pilots in thread 3 say it was the auto-trim).
At 2h12'17" the pilot commanded nose-down sidestick but BEA says that trim remained 13° nose up. Everybody is saying that trim was "working against the pilot". Why didn't it "help" the pilot in this case also?
Can someone please explain?

Thanks in advance.
HP

[HappyPass]

It has probably been answered indirectly as follows in the other thread a few minutes ago (again correct me if wrong):


Originally posted by henra

At least before probably entering into Abnormal Law when the AoA exceeded 30°, a normal continuous Nose down command by pushing the stick forward should have also reduced THS angle accordingly.
Therefore it is likely that a manual use of the Trim wheel would only have been required when deep in the stall, long after starting the descent.
That point would have been reached somewhere around 2:11:30.
And even after that point Auto Trim could have been regained if continuous Nose Down combined with reduced thrust would have reduced the AoA below 30°.
In that case auto Trim would have been available again.I was searching for failures that would have justified a change in control law in the BEA report, but apparently the increase in AoA between 2h10'51" and 2h11'40" ("exceeded 40°" states the report) is enough to trigger Abnormal Law.