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Old 15th Aug 2010, 12:20
  #1906 (permalink)  
HazelNuts39
 
Join Date: Jul 2009
Location: France - mostly
Age: 80
Posts: 1,689
mm43;

thanks for pointing out the wider range of possibilities. I was just addressing the 'bottom line' of mr. Squair's analysis. So, based on the ACARS messages alone, the ROD in the final seconds could have been anywhere between 2463 and 16320 fpm, while the average ROD in the preceding descent was of the order of 7850 fpm: 35000 (2:10:10) - 2176 (2:14:21).

I also believe that the airplane probably stalled one or more times in those final minutes. Is it certain that it was stalled in the final seconds?

some juggling of a flight termination time could give a v/s that fits with the BEA reports (high vertical speed, 'en ligne de vol', and 'arm 36 g' etc..).
The 320 ditched in the Hudson at 780 fpm, 125 kt, 9.5 deg pitch. Its fuselage received substantial damage but stayed in one piece.

The Turkish 737 in Amsterdam impacted stalled at 3000 fpm, 100 kt, 22 deg. pitch, its fuselage broke into three sections.

AF447's stall speed (Vs1g; V_alphamax) was 158 kCAS; 162 kTAS; 274 fps. The corresponding alphamax can be estimated as 14.5 degrees. Interpreting "avec une assiette positive, une faible inclinaison et avec une vitesse verticale importante" as 2.5 degrees nose-up, leaves an FPA of 12 deg. down, or 3418 fpm.

So was it stalled?

regards,
HN39

Last edited by HazelNuts39; 16th Aug 2010 at 08:20. Reason: error corrected: Hudson ROD is 780 ft/min
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