All quotes Clandestino
Originally Posted by Retired F4
Those pages miss one vital information, the outcome of the actions in relation to airframe loadfactor.
Clandestino
There are acceleration graphs for all three axes in the appendix.
Exactly those i was refering, if you noted. But they are not incorporated in the pages 30 + 31, where they would directly show the outcome of the actions. Loadfactor finally is the vital indication what SS inputs and other factors accomplished to the aerodynamical behaviour of the aircraft.
Originally Posted by Retired F4
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.
Clandesstino
Acceleration graphs don't confirm that, especially longitudinal accel, at the bottom of page 111, which comes as no surprise as at high altitude a) thrust is quite lower than low down b) there's not much difference between cruise and TOGA. N1 trace is on page 108. It hovers around 100% untill 2:10:45 when TLs are pulled back. Suddenly, stall warning fires and TOGA is selected at 2:10:52. There's dip in N1 with lowest being 80% at around 2:10:50. - just as stick is pulled.
Think it over again. Some thrust vector is pointed downward and adding to lift factor instead of longitudonal acceleration. Also indicated by the VVi increasing again and altitude gain by further 500`feet. As we had a deceleration due to continuous loss of speed, you might see a slow down of longitudonal acceleration due to thrust, but no acceleration as you seem to expect (and PF did as well!). See BEA below
Quote BEA IR3 Page 91: (bolding by me)
02:10:54 The thrust levers are positioned in the CLB detent
02:10:56 The thrust levers are positioned on the TOGA detent.
The N1 increase progressively and reach
103% at 2 h 11 min 02.
The copilot sidestick is positioned:
- between the
half-travel position nose-down and ū of the stop
position nose-up with a nose-up position on average
- between 4/5 of the stop position to the left and 4/5 of the stop
position to the right.
The
pitch attitude fluctuates between 17.9° and 10.5° (Period
of 5 seconds).
The THS varies from -3.8° to -8.3°.
The roll angle fluctuates between 8.8° to the left and 4.9°
to the right (Period of 5 seconds).
The
angle of attack 1 increases from 7.4° to 18.3° while the
angles of attack 2 and 3 increase from 10.9° to 22.9°.
The
CAS decreases from 207 kt to 161 kt and the Mach
decreases from 0.66 to 0.51.
The
vertical speed changes from +2272 ft/min to
-3904 ft/min.
The normal load factor decreases from 1.13 g to 0.75 g
(at 2 h 11 min 03) then goes up and stabilises at 0.85 g.
Quote:
Originally Posted by Retired F4
Correction followed, again the loadfactor was being kept below 1 g to get the nose slightly down and recover the altitude FL350.
Clandestino
No. Sidestick traces are clear. Very short excursion into nose down were way too short to affect anything. Aeroplane stalled at her apogee and never recovered.
Sidestick traces show a command to change loadfactor, and would be deflected whatever deemed necessary. And as the loadfactor was well below 1 g (although due to increasing sinkrate) and aircrew not aware that they stalled, there was obviously no reason to increase the unloading further. I give them that credit. We know now that they should have pushed further.... though.
Originally Posted by Retired F4
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.
Clandestino
No. Have a look at TLA (thrust lever angles) and N1. Nose drop was due to power reduction. The aerodynamic stall of horizontal stabilizer, trimmable or otherwise, is way more violent than what is seen in pitch trace.
So you are saying, that adding power had no noticable effect, reduction had a big one? Generally you are right, i didīnt take the power change into my equation. Lastly it may have been a combination of both, as the engines with that pitch attitude produce a direct lift vector with part of the thrust.
Originally Posted by Retired F4
The THS unstalled due to the pitchchange and grabbed air again, load factor got positive.
Clandestino
No. TOGA was reselected.
I disagree. TOGA was selected 02:12:33. Recheck BEA IR3 page 113.
Between 02:11:45 and 02:12:30 THS and elevators had been full down, so SS input, whatever it was, had no aerodynamic effect as it didnīt change any flight control deflection. We can take those out of the equation for any pitch /AOA or loadfactor changes.
Power was idle until 02:12:10, when CLB was selected
Power was CLB until 02:12:33, when TOGA was selected.
Power change to CLB could only have an influence after 02:12:15, considering some conservative spoolup time from idle to CLB.
The G-load change however started already at 02:11:52 from 0.7 g to 1 g at 02:12:00 to 1.1 g at 02:12:10. The pitchdown had resulted in an decrease of AOA, thus wing and THS and elevators got more effective again.
Originally Posted by Retired F4
I think it is not fair to say, they pulled all the way from the beginning.
Clandestino
That's what RH sidestick trace shows. Is it non-PC to state in plain words what publicly available report has made clear through graph?
The SS graph does not indicate, what the reason for the overall pulling was. For that we have to look deeper and take the reaction of the airframe into account. Those are the position of the flightcontrols (as those are only indirectly positioned by the SS) and the loadfactor, as that one shows the final reaction to the inputs and is the only feedback (as there is no direct one) the crew had available (by instruments and by feel).
Originally Posted by Retired F4
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.
Clandestino
Maybe it indeed had. For the time being, I can't figure out what was the sense behind it.
We have to open up our mind to grasp the unpossible and the unthinkable and have to put aside for a moment the obvious. Then we are prepared to dig deeper, to put ourselves in the Cockpit of AF447, in the LH or RH seat or in between / behind like the captain. As long as we make up our mind based on own trained behaviour, based on public oppinion and based on some own agenda (not saying that you do), we will not be open enough.
We also have to get rid of this permanent A vs B bashing or old vs new comparing. We have to think about every aspect of possibilities regardless who invented and designed it. It is hindering and distracting and it is without weight. Anytime i get dragged into that A vs B scheme by an answer to one of my posts, i feel uneasy with the response. Sometime iīve got the feeling that by doing so some posters try to categorize the contributions and make them thus more or less trustworthy.
I for myself believe, that in the FDRīs is still a lot of truth hidden. The compilation of the vital stuff (Speed,Thrust, altitude, VS, AOA, G, SS, elevator, THS and cockpit communication into one graph and with better resolution will give us a better grasp on things. Unfortunately iīm too dumb to fiddle with those and make them myself.