AF 447 Search to resume

[Hyperveloce]

All the prior/posterior estimations based on the reverse drift analysis (including the initial aerial/naval searches, no matter the number of days from the accident) are uniformly/subjectively underweighted (versus the flight dynamics priors [*]) throughout the whole estimation process. This is why we get a distribution mainly located 20 NM around the LKP with a circular symetry (like the FD prior distribution), and with "holes" in it (linked to the absence of success of the Phases I if we assume the ULBs ere functional, II and III). The BEA seems on the same stance: too much uncertainties on the backdrifting studies: the searches could start from LKP and systematically probe the whole unsearched 40 NM disk region. The several targets of interest are really up north of LKP meaning far beyond the FD distribution for the targets 18, 19, 20, and if we have to assume that these targets could have been floating/drifting several days, I don't see how they could be major parts of the airframe.
JF
[*] FD distribution: in the Metron report it is a 50%-50% mixture between a uniform 40 NM radius disk and the 9 cases distribution.
- there are also large uncertainties about the AF 447 terminal trajectory & scenario after the loss of AP/ATHR: which pich & thrust mismatch or loss of control ? large roll unbalance ? Mach buffet ? stall ? how deep ? spin ? spiral ? adverse crew reaction ? late recovery ? secondary stall ?... this would militate for a uniform or circular symetric distribution.
- but there are some BEA initial findings about the AF 447 impact conditions that should be taken into account for the FD distribution:
flight duration starting from the AP/ATHR OFF between 3 min 45 sec and 4 min 15 hence outlying the entire 9 cases distribution (the 20 NM radius),
Galley G2 putting a limit on the vertical speed probably not compatible with spiral dives,
A/C attitude en "ligne de vol" and deformations of the rear frames (suggesting a significant horizontal speed) probably not compatible with a spiral dives or spin
- a limited number of compatible past cases to estimate a FD prior 2D-distribution (bad for the statistical significance of the estimated distribution), which is assumed with a circular symetry (meaning that a uniform/equal probability is allowed to any route deviation within [-180°,180°], -180° or 180° = U-turn)