HazelNuts39,
Indeed, the graphs at page 41 and 42 with their granularity illustrate better the variations - thanks for pointing that out, and explanation.
Following the cause/effect chains a little further:
a) Pitch command -> Elevator action -> Pitch Attitude
The "integrated" angle of the Elevator NU is roughly 1 degree, perhaps less, in the time interval 2:10:08 - 2:10:16 in which the pitch attitude goes from approx 3 to 10 degree NU, which is a 7 degree delta.
b) Thrust -> Pitch Attitude
The thrust is on a decreased level, on a downward gradient variation rather than upward, if any gradient variation.
c) Elevator -> Normal Acceleration
The Normal Acceleration show 2 consecutive aggressive spikes of roughly 0.6-0.8g excursion upward/downward, corresponding to two spikes of roughly 1 degree in Elevator NU.
d) Turbulence -> Normal Acceleration
We don't have a graph of turbulence alone; it would be interesting to see.
But the variations in Elevator angle later on the time scale on the lesser granularity graphs - not present on page 41/42 - seem to correspond to lesser amplitude Normal Acceleration variation.
If that were indeed the case, would that leave room for the interpretation that the higher amplitude of the Normal Acceleration spikes between 2:10:08 - 2:10:16 indicates a turbulence contribution to that of the Elevators?
Not that it matters much in the larger perspective of the sad things happening during those 2-3 minutes....
Originally Posted by
HazelNuts39
The increase of normal acceleration between 02:10:07 and 02:10:15 is strongly correlated with the increase in pitch attitude in the same period. The increase in pitch was in response to elevator movement (quite sensitive at M=0.8) which in turn corresponded to sidestick command - see BEA#3 top of page 41 (english version). [Sentence DELETED. Reason: The graph on page 42 does show the elevator angle]
In an encounter with an updraft the airplane would also experience an increase of normal acceleration, but it would not pitch up in this manner.