Walter
SPEED May I direct you to Boeing's report (on the web) - the sums are done for you but you can use them as a guide to do it yourself from the various timings etc - basically, to get where it did when it did, the a/c must have maintained its speed (at the top end of cruise) for most of the passage over the sea - there was insufficient reserve of speed for it to have ever been going slow
Beware the Boeing calculations. I posted some time ago that these may be misleading in that the initial fix (at zone boundary) was only ascertained by interview with the controller, not by review of radar recordings. Furthermore, it appears likely that the zone boundary position has been miscalculated by up to 2 nm and the
estimated winds do not seem entirely realistic. My calculations show that a
more likely average airspeed from zone boundary was in the order of 135/136 kts. Of course, this does not prove anything either, except you can't discount the possibility of the aircraft having slowed down at some stage.
Regards
TAC