Another unsettling factor here, is that a leading marine geologist, Robin Beaman, from James Cook University. has pointed out that the seafloor in the aircraft search area is largely unmapped - and there's a chain of undersea volcanoes in the region, the Southeast Indian Ridge.
He's pointing out that the "complex terrain" of the Ridge will make underwater recovery difficult at best - and the lack of 3D sea floor mapping will only exacerbate the problem.
Australia's only sea-floor mapping vessel, the RV Southern Surveyor, was retired in December, and its replacement is still undergoing sea trials.
To say the timing of the aircraft loss was unfortunate as regards our sea-floor mapping ability is an understatement, to say the least.