If you doubt he would try to prevent this, then why would he go to the SIO to hide the plane? An undisclosed high value cargo would be a reason for taking the plane. If Z was in fact politically motivated and had an opportunity to steal a high value cargo from the MY govt, he might try and put it where they could not recover it without spending it's value to do so.
Umm and how do you know he actually went to the SIO, especially with intention? Official theory is just a theory based on assumptions, it is most likely but it isn't the only one possible, far from that. If there was just one slight change of altitude at any of the ping rings it would render all their calculations useless, BFO is extremely sensitive to RoC.
You assume he would try to sink the plane without debris, but wouldn't make any effort to sink it in an optimal location?
Well roaring forties are everything but optimal location for sinking, you would have to be very very lucky to stumble upon a calm patch of sea there. He had many locations to choose before fuel exhaustion that had much calmer sea and that were even further from Australia. Oh and also very deep.
Yes. Diamantia would be a logical goal for sinking the plane. It is curious that the official flight path is on a direct course for Diamantina. And since the official theory is designed around pilot intent, why not take that intent to a reasonable goal rather than a random ocean target/direction. That doesn't mean he was successful in reaching DD.
Well that's what I'm talking about, the search area is everything but a reasonable goal for any intention including sinking. If he wanted to crash the plane at DD he would do it exactly at that location, just entering coordinates into flight computer, he wouldn't miss it by 200-300 miles.
And the search hasn't found the plane yet with their assumptions. Other assumptions about altitude and speed could perhaps reach it.
well if they searched all southern arc they would sure find it, the only problem is that such search would cost billions...so they have to narrow it for sheer economical reasons