Originally Posted by Retired F4
Tuote:he SS NU inputs in this phase could be explained as controling the unloading.
Clandestino
If one take this phase out of context, this explanation is plausible. However, on pages 29-31 are some parameters traced more precisely than in appendix and they don't confirm that theory.
I looked at those too, and i came to a differetn result and i´m not giving up yet. Those pages miss one vital information, the outcome of the actions in relation to airframe loadfactor. As the SS is a "loadfactor commanding device" (non technical expression) and the aircrew is feeling the loadfactor result, this value is important in judging the SS inputs the PF made.
Maybe someone capable poster could superimpose the graphs from P30-31 with the loadfactor and maybe the crew communication.
First part, where load is slightly below 1G is where CM2 somewhat heeds CM1 advice to go down. Sidestick input is nose down, pitch goes from 12 to 6 ANU but aeroplane is still climbing and bleeding speed.
agreed
Second phase, with G slightly above 1 is when stall warning goes of and CM2 reacts by pulling up again to 17.9° ANU - there are brief periods of pitch down command, quickly superseded by pulling again.
There we need to look at the TOGA power input as well, because that would have had a great deal in increasing pitch and increasing g-load. And as it looks like, an unexpected one.
G below 1 in third phase you mention is aeroplane stalling with oceanward acceleration accouting for Nz<1 till terminal velocity is attained. Stick is hovering around slight nose-up, to eventually move to full nose up.
Agreed, but again, the g load was less than 1 g, what would we expect a pilot doing, when the stall is not yet recognized and PF felt unloading ( and maybe even acceleration due to SI) for some time already? It was also the phase, where the altitude came down to the assigned FL350 again. The nose up limit stop could be the input to level off in FL 350.
At that point go back to Page 111, at 02:11:45 the THS and elevators and SS input all reach full nose up, and the pitch drops from 12° nose up to 12° nose down within 10 seconds and stays below the horizon until 02:12:15. I interpret that phase, that the THS was stalled and could not keep the nose up anymore. Look further to the loadfactor. The loadfactor increases despite the fact, that the nose drops (or because of it?) In that phase the THS got effective agin.
Must be a funny feeling, positive pitch unloading, negative pitch loading?
IMHO, CM2 was not controlling the unloading by pulling, he was bent on pulling ever since he lost airspeeds and autopilot, for reasons not picked up by the CVR.
My analysis is different.
After the initial unfortunate pullup and the following unloading hey did not recognize the stalled state, as it was against any training. They sure did not expect to be stalled with a loadfactor below 1 g. Their concern was the roll and not to unload too much, leading to the SS inputs. The application of TOGA - after the stall warning sounded- complicated their situation and led to an increase of pitch, loadfactor and altitude. Correction followed, again the loadfactor was being kept below 1 g to get the nose slightly down and recover the altitude FL350. But vertical descent rate picked up (unseen) and the pitch remained high. When approaching FL350 the level off attempt with full NU SS and THS and elevators also full NU the THS stallled and the nose dropped violently. The THS unstalled due to the pitchchange and grabbed air again, load factor got positive.
At that point i dont want to go any further at the moment.
I think it is not fair to say, they pulled all the way from the beginning. There where mistakes, big mistakes like the initial pull and like not recognizing the stalled situation, but the handling of the SS had different motivations than sensless pulling.