Originally Posted by A0283
...last known altitude is about 24,000 ft and the rate of descent is about 7,900 fpm. So roughly, 3 minutes to get down to the point of impact.
The data from which the flight path you are referring to has been constructed from an animated presentation originally prepared by the Indonesian Directorate of Civil Aviation for the Minister of Transport. A distorted grey-scale image later made its way into the media.
As originally constructed, each ADS-B or transponder position recorded was represented as a dot on the track. Some were missing, but overall they were updated every second. In the animation, the aircraft depicted moved along the track at the GS represented by its position, slowing quite dramatically shortly after commencing the left-hand climb.
Some of the data used initially would have been Baro, but it appears that Baro data was lost at some point in the climb and the later data was GEO only. This could indicate the transponder had detected conflict with the Air Data, and as in the case of AF447 had rejected it to prevent causing potential TCAS conflict problems.
The few points on the graphic that were notated with times, should not be used to calculate future or past conditions as they were affected by substantive rates of change. The appearance of a possible spiral turn at the last data point when passing through 24,000' (GEO) with a VS of -11,518 ft/min is unlikely to directly convert into what was happening at impact.