Factoid: one black-box's battery was out-of-date via maintenance error. (Other was fresh, so ...)

Latest theory discussed at The Week, U.K.

[. . .]

"It has been the largest ever underwater search carried out to date and so far only covered 40 per cent of the designated search area," it says.
But analysis by a British pilot, who believes the plane performed a final "fly-past" of Penang island before intentionally landing in the sea, suggests the search team might be looking in the wrong place.

Captain Simon Hardy, a senior Boeing 777 captain with a major commercial airline, spent six months analysing Inmarsat's satellite communication "handshake" arcs and using mathematical "reverse engineering" to arrive at his conclusion.
He believes that the missing Malaysia Airlines plane was intentionally landed on the water and sank intact about 100 nautical miles away from where ATSB is currently conducting its search, and outside the core target area being trawled.
His theory was first published on the aviation website Flight Global last year, but ATSB has since been in contact with Hardy to discuss his findings and has described his theory as "credible".

Hardy suggests that MH370's captain, Zaharie Ahmad Shah, who comes from Penang, performed a U-turn after turning off the flight's transponder.
After flying along the border between Malaysia and Thailand, the aircraft reached Penang and made three turns in quick succession.
"It took me months to work out what this was," Hardy tells The Sunday Times. "The clue was Ayers Rock [in Australia]. I have done the same manoeuvre there, to look down and get a great view. Somebody was taking a last emotional look at Penang."

A corollary of this tack (maybe via same pilot, elsewhere?) was the ease of accessing via a hatch: the electronics bay; that hatch located in a view-obstructed spot between lavatories. That thesis, not about a nostalgic loony-Captain, suggested that someone could have accomplished the same effects of transponder shut-off etc. if they understood the e- System.)

("Course this mystery is dwarfed by [Why is there anything at all ?!} but our collective DNA seems really hooked on this pedestrian one,) or maybe it's just about ...Hating the fact that: One Asshole human Can fuck-up any machine ever built?