atakacs, the heading, altitude, and speed changes after 15:28.31 were a radar trace, and almost certainly occurred after power was lost on the FDR. The FDR, prior to the "thud" noise, seems to have recorded heading, altitude, and speed consistent with the radar trace. Many posts back, the point was made that the abrupt changes in heading, altitude, and speed recorded after 28.31 (and there were several, distinct sequences of such changes) may have resulted from the radar picking up that portion of a disintegrating plance that showed the biggest cross section to it.