snowfalcon2
I hear what you say and must admit I may have missed a few pages of this thread. Probably been covered before, but so far as I am aware, the fuel pumps on commercial aircraft (not x feed) are gravity-fed pumps as the aircraft is not expected to fly inverted or in any aerobatic attitude, also as a result, the outflow from the wing tanks is at the lower point.
Not knowing the full specs of the pumps on the 777 would they be able to draw such a vacuum as to result in physical distortion to the wing tanks, given the stresses they are designed to cope with in normal flight?
Give the fact that thrust was commanded on both engines at the same time with a slight imbalance of fuel in each wing tank, if vents were iced then the problem would replicate in each engine at more or less the same time.
Will have to wait for the final report by those who know but if fuel is ok and no apparent systems problems then the fault is either narrowed down to almost nothing or exponentially/impossibly widened to the point of never being identified