Originally Posted by BOAC
I repeat - there is NOTHING in the BEA report to tell you that the pilots caused the climb. A 'nose up' input of unspecified size or duration does NOT prove that and may well have been of short duration - you do not know.
Well, this is quite authoritatively expressed... but also quite illogical as for addressing the fact that any
pilot nose-up imput (whatever duration and amplitude) could not have caused this aircraft to climb (at whatever rate, as this is likely proportional).
Considering this high speed profile, manual flight and elevators sensibility, what would be the illogical part about me mentioning that?
The BEA is providing this information about a pilot imput in the same direction as the trajectory followed by the aircraft, what would be the logic to affirm : the climb wasn't related to this imput?
Obviously, you are taking the possibility (that I'm also sharing) that this full climb rate
could not have been fully achieved by pilot imput
alone by translating it into
"nothing in the BEA is telling us that the pilot caused the climb".
Hence, you are rhetorically jumping into the breach of us lacking the full detailed picture of this imput as making an illogical point by saying that there is
absolutely no causality between a pilot imput nose up and a following climb.
For my part, I'm saying that whatever else could have been added to the climb rate (turbulences, initial pitch rate at AP off, whatever else you'll like more...), this single imput "nose-up" was certainly part of it because, of course, the system would have taken it as a commanded +x g maneuver order, translated it into pitch attitude increase and, once achieved, would maintain the trajectory in climb (1 g).
What we'll need to know is the value of "x", the resulting maneuver g-load, adding/substracting possible turbulence impact, as to verify if something else was not a factor of the climb rate achieved... which is certainly what the BEA would have to acertain before mentioning, as a fact, that climb was
entirely due to pilot imput.
Saying otherwise (it was unrelated) seems fallacious.
Originally Posted by BOAC
As for your bit about "There is another way to change pitch attitude than pulling up on the sidestick as simply applying thrust could do the job if the amount is large enough." - you don't say? Now show me where the report tells you they increased thrust. You are making this up!
I'm just looking at the joined DFDR tracks of N1 % thrust and read that, when autothrust kicked off, N1 was already auto-throttled back at ~70%, then moved to 100% during the climb sequence.
You should know that thrust would freeze where it was (~70%) when autothrust disconnected; Hence, this increase was manually applied, even if not reported in the narative, which include an incoherence about "alpha-floor" kicking which is not available at such speed (inactive above Mach 0.53). This is based on AIB interpreted pilot confusion about "Alpha-lock" corrected by "Alpha-floor", while it certainly was "Thrust-lock" alarm (when ATHR disconnected).
Look by yourself if I'm making up this stuff:
Originally Posted by BOAC
Now to TC-JDN - have another look at the trace. The a/c began pitching while the engines were throttled back, the side stick did not move but the THS did.
The system will use every surface control and thrust to maintain 1g flight. Changes in THS trim were very limited during the whole sequence (much less than 0.5 deg), including a "zoom climb", "apogee", "descent"... while elevators moved in both sense with a much larger amplitude. Nonetheless, the system trimming THS seems to have not been "pitch up", but the other way as there is no such 5ND in the range of THS.
Originally Posted by BOAC
I note you come 'from Toulouse'
Right, I was there some time ago. I also note that you come from "Per Ardua ad Astraeu", but who cares?