From page 41 of Interim report #3:
At the request of the BEA, Airbus conducted a simulation of the operation of the flight control computers, which involved recalculating the movements of the elevators and of the trimmable horizontal stabiliser (PHR) based on pilots’ inputs and compare the results against FDR parameters. This simulation could be continued up until the end of the flight. The recalculated deflection angles for the elevators and the PHR are consistent with the parameters recorded.
At the request of the BEA, Airbus conducted a simulation of the aircraft behaviour based on the theoretical model and on the actions of the PF (sidestick and thrust). The validity of the model is limited to the known flight envelope based on wind tunnel and flight tests data. Consequently, it was possible to conduct the simulation to mirror the period from 2 h 10 min 00 to 2 h 10 min 54. However, in view of the complexity of such a simulation, it was agreed that, initially, the simulation would be confined to the longitudinal axis, without introducing turbulence. The lateral parameters used are those recorded in the FDR.
Shortly after the publication of that report, I queried the presence prior to A/P disconnect of variations in elevator position, angle of attack and normal acceleration. What causes these variations in the absence of turbulence, and why are the AoA variations not accompanied by corresponding Nz variations (1° of AoA corresponds to 0.28 g) ?
In my search for a correlation between side stick angle, pitch rate and normal acceleration, based on the C* control law, I started comparing the elevator positions to the side stick commands, and am surprised to find that the elevator seems to be leading the side stick:
