Originally Posted by RetiredF4
The conclusion for the southern arc as the most probable track relies heavily on the assumption of near constant track, near constant altitude and near constant speed, simplified on a flight to a preset target in the south flown by autopilot.
No, it doesn't. Although some reconstructions have been based on those assumptions, that statement is not correct. After 18:40 UTC all BFO values indicate a southward component of groundspeed if one assumes level flight. They also show a smooth progression, increasing almost linearly with time. To support a northern route it is necessary to assume that the airplane was climbing at approximately 3500 fpm at the times of all six 'handshakes' and two 'unanswered ground-to-air telephone calls'. During the first unanswered call at around 18:40 86 responses were received from the aircraft during approximately one minute, all with BFO's of 88 +/- 2 Hz.