AF447

[mm43]

Current Data - Crash Location?

Hyperveloce;

Careful examination of the OSCAR/NOAA surface current data provides 065°T x 22.5cm/sec at 3°N 31°W over the 5 day period centered on 2 June 2009. I have therefore examined the positions in which bodies were recovered from on 6/7/8 June and constructed a likely current line based on what we know, i.e. that for the 3 days just mentioned and a calculated rate for the 5 - 6 June of 19cm/sec (9NM/day) back to the time of the accident at about 02:14:30Z on 1 June of 22.5cm/sec (10.5NM/day).

The reason for using the bodies as a check on the current is that they will have initially sunk to a point of equilibruim, and provided the depth was not too great, the water temperature would have commenced the decomposition process. Then over a period of time each of these bodies would have gained enough buoyancy to become visible on or near the surface - which explains the number of days it took to find those that they did. The point is that the bodies will have been subject to little or no leeway effects due to the surface wind. SHOM data shows that large easterly vectors on the surface become small westerly vectors the deeper you go, which helps to explain why some debris items floating with possibly little or no windage have been found to the east of the general drift line in which the bodies were found.

The reduced size graphic below shows 2 significant cumulonimbus cells, the one on the track and another left of the track shortly after passing ORARO. It seems that each of these mesoscale cells has played a part in this incident.



I surmise that for some unknown reason the WX radar has not revealed the presence of the cell the a/c penetrated at around 0209, but when everything turned pear shape at 0210 the PF made a decision to get out of the ITCZ and commenced a lefthand 180 and descent hand flying the a/c with somewhat degraded control systems provided in Alternate/Direct law. Singpilot described his experience a few posts back, but the conditions in the cockpit of AF447 were surely somewhat different.

The lefthand turn was unfortunately taking the a/c toward the Cb cell NNW of ORARO.

What happened during the SATCOM outage between 0213 and 0214 is of course speculative, but at some point in this rapid descent it can be assumed that IAS became available and an effort was made to stabilize the rate of descent. If a nose up attitude was adopted, the updraft associated with the next Cb cell may have resulted in a flameout of both engines.

Well the graphic shows the general idea, but if the current vector at 3°N 31°W was in fact 055°T x 20cm/sec, the impact point would have been about 10NM further east. This would give better GS but with a tighter turn - to be expected if the speedbrakes were deployed.

Here is the link to the full scale graphic.

http://i846.photobucket.com/albums/a...-lkp-lge-3.jpg

mm43