Looking in BEA's reports for information on the forward speed at impact, the closest thing I was able to locate is based on detail examination of fuselage frame segments attached to the base of the vertical stabilizer, from page 28 of BEA's 2nd Interim Report:
The deformations of the frames were probably the consequence of the water
braking the aircraft’s forward movement.
This led me to question the widely held assumption of 'low' forward speed at impact.
Based on the cL-AoA data posted earlier (ignoring ground effect), the following
entirely hypothetical but mutually consistent numbers might be of interest for the purpose of recent scenario discussions:
Airspeed 300 kt CAS (M=0.453); vertical speed 40 fps (2400 fpm); loadfactor 2.5 g.
FPA (airdata) -4.5 deg., AoA 10.5 deg., pitch attitude 6 degrees.
HN39