Originally Posted by
AAKEE
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The SJ182 initial upset is a carbon copy, the parallel displacement is the same, the initial altitude loss is about the same so the trajectory of SJ182 can be used to understand how Mu5735 got from the fine cruise on level to the first datapoint in the upset.
So we more or less know “what” but we do not have the “why”.
Before the upset, MU5735 was flying nearly double the ground speed of SJ182. Ground speed is what counts for the kinetic and subsequent rotational energy of an object, implying nearly 4 (OK, maybe closer to 3.5) times the energy for MU5735. That increase in energy implies the same 3.5 times increase for the mass related forces involved and 2^3 (=8, round down to 6-7 for the effect of not completely the double ground speed) times for the aerodynamic forces involved.
Implying, significant g-forces are required to accomplish a 3D-360 within something like 12 seconds, immediately followed by another 40 seconds with good directional stability. Easy to accomplish, when being completely shaken by a probably completely uncoordinated 3D-360 and stiff controls, due to the high speed, the aircraft obtained.
Also, it does not explain, WHY this diving stage happened again, this time, without the S-curve (or assumed 3D-360).
From earlier experiences, we do know that rudder hard-over is a difficult to control item at low speed, not at high speed. Unpleasant, but manageable at high speed.
From earlier experiences, we do know, that aerodynamic engine damage does not (have to) lead to control issues. Again, unpleasant, but manageable.
We do know, the aircraft got "stable" on course again (and even recovered from the initial dive), so the aerodynamic damage to the aircraft isn't that big (at that moment).