The following quote reporting on the cause of a BA1-11 prototype test flight crash in 1963 caught may attention - more to do with the wording than anything else.
The aircraft was evaluating stall characteristics at varying center of gravity locations when the flight crew found the flight controls unresponsive after entering a stable stall and the aircraft struck the ground at a wings level attitude with a high rate of descent and little forward speed.
Bearing in mind that that BA1-11 was an aft powered T-Tail, and the circumstances of its crash identified the "deep stall" condition, I couldn't resist being drawn to the "center of gravity" comment and the possible implications of that in the case of AF447 if in fact it entered a stable stall with a +20°nose-up attitude and low IAS. The later part of the quote replicates the BEA's description of the crash.
I believe the original crash report determined that G-ASHG descended from FL180 in 80 seconds - 13,850 fpm. How accurate that figure is or how it was determined, I have no idea.
Some important questions spring to mind in respect of AF447 -
(a) Was it also in a flat spin, i.e. tail rotating to port on impact?
(b) Likely engine flame-outs?
(c) Why no ACARS WNG from the FADEC on engine(s) status?
(d) Relevance of RTLU WNG. Was the rudder booted?
mm43