Regarding the turnback after IGARI. I had a good friend who failed command training twice by acting in this manner, i,e knee-jerk instantaneous reactions to emergency indications during sim rides. Zaharie was a TRE who taught and checked the principles of "ANC" in every flight/simride he undertook.
You are halfway between KL and Ho Chi Mihn, both company main airports; both wide open with little traffic. Two minutes before the turn, everything was normal. Zaharie was talking on the radio and responding to a frequency change request. 109 seconds later MH370 is going in the opposite direction, with absolutely no indication of distress, no ACARS CMC message, all the means of communication either shut down or ignored, and not a peep from the crew. The aircraft flies normally for over 6 hours. The SATCOM comes back on a little over an hour later.
Can someone explain to me what sort of aircraft malfunction would cause a TRE, and with many years in MAS and on the 777, and the 777 systems, to react in this manner? Because I cannot.