AF447

[Hyperveloce]

Debris distribution, currents & Final trajectory

Hey there !
Thank you very much mm43 for this nice work.
I visualize the final trajectory in a very similar way than yours, two aspects expected maybe:
- this large route deviation would be unvoluntary, this would be the horizontal trace (large roll perturbation) of the high altitude cruise loss of control, this would occur as a consequence of a large exceedance of the MMO (Mach>0.89-0.90) and this severe overspeed would require ~1mn or over to occur [*]: the tight turn would start around ~02:11:00Z
- this turn would not be a constant load factor turn (a part of a circle) with such a high constant curvature radius but a trajectory where the shortest radius (highest load factor, highest roll) is at the beginning of the initial route departure and where it decreases (roll is being controlled) in less than one minute.
This tight turn would probably go with a rapid loss of lift/altitude ?
Once the roll is back under control, the pilots were in position to try to regain control in the vertical plane ? (AoA/incidence, pich). This would be the final part of the trajectory: rather linear in the horizontal plane and in the vertical plane, a rapid loss of altitude (~10 000 fpm), the AoA/incidence decreasing in a first time to regain the aerodynamical authority (also with the loss of altitude and the increasing air density - stall recovery) and increasing again to generate enought vertical Gs to try to break the catastrophic descent. The plane being "en ligne de vol" (straight horizontal trajectory / wings leveled, small horizontal speed component / speed mostly vertical, possibly a slight nose up)



Indeed the drifting of the bodies or of the debris can be very different if you look where was recovered the left wing spoiler (this latter, recovered north of TASIL, seems like an outlier in the debris distribution, it has not been much deviated westward by the westernly surface winds derived from the satellite scatterometers, see windscat). I will have another look to the surface current values over the first days of June since I have used values slightly lower than yours (and much lower than the SHOM values).

I am studying the slopes distribution of the seabed in the area where the debris should have been colocated the 1st of June at 02:15Z. I wish to validate my computations before I produce any graph results (missing values in the numerical terrain model) but it appear that between 5% and 10% of the seabed slopes are between 25° and 50°, using a 1.25km square bin resolution (narroy faults, slope details finer than this 1.25 km are lost/not observable). This bathymetry must be a real pain: towing up and down the multibeam sounder with the relief, varying scanning speed/resolution as a function of the slope, etc... Would it be a luxury to send another high resolution sounder to probe this area ?
Jeff