100mph horizontal does surprise me. I would be interested in seeing your math, pm it to me if you don't mind.
So would I. My quick calculations were 50-70mph horizontal motion for the tail in a flat spin.
Math: The A330 is almost 200ft long, rounded to 200 ft (1 significant digit for quick calculations. This creates a rotational radius of 100ft.
Multiply by pi and we get 314 ft for the spin circumference. This gives us about 55 to 69 miles per hour. Rounding back to one significant digit gives us 50-70 mph.
EDIT: Calculations are wrong. Should be double: 100 through 140mph. Forgot the 2 in 2(pi)(r)