Originally Posted by
YYZjim
There has been a fine debate between two posters about the handover of control from PIC to SIC on the Indonesian LT610 accident flight. One can deduce from the ATC transcript that the PIC handed over control about a minute or so before the crash. Unfortunately, I have not been able to find any statement about the exact time it happened.
The FDR traces in a chart shown to the Indonesian parliament show that a significant mechanical failure happened about 45 seconds before the crash. Post #1149 above includes a link to that chart.
Leeham News has drawn a vertical blue line down the chart at the 45-second mark. The forces on the left-side and right-side columns diverged at this time. Forces on the right-side column increased dramatically over those on the left-side. There may have been a breakout between the two columns, possibly due to the SIC now pulling back harder that the PIC had done. But, as Leeham News points out, that is not the only possible cause of the divergence. (Is it possible, I ask, that the horizontal tail surfaces were starting to do the unusual things they can do when the never-exceed speed is exceeded?)
In any event, the handover of control and the mechanical failure occurred at about the same time. But not necessarily at exactly the same time. In my opinion, not enough is known about the timing of the events to blame the mechanical failure on the transfer of control, or on some shortcoming of the SIC. It matters whether the handover happened a minute before or five seconds before.
YYZjim