As a 777 pilot, that’s really interesting. My experience of the fuel quantity system is that it is very accurate 99.9% of the time but every now-and-then gets confused. I remember once the indicated fuel quantity dropping quite rapidly in one wing, to the point that we thought an engine shutdown might be on the cards but as there was no roll tendency with the AP out and no visible leaking, we had a further think about it and while we were doing that, the fuel came back again!
"It was fortuitous that the aircraft had been fuelled with much more fuel than it needed," says the inquiry.
I’m afraid I disagree with that one. Being >40t overweight for your calculated performance is a big deal in these days of multiple derates, improved climb and CofG adjustments. You could hit something AEO, let alone OEI, not to mention being on the wrong side of the drag curve the whole flight.
From my reading of it, the problem was with the centre tank programmed capacity, so once the CT fuel was down to what the aeroplane thought was its nominal capacity (it’s used first) it’s likely that the total fuel indication would have been correct. There would still have been a large discrepancy between that and the totaliser, so definitely still an issue that might have caused a precautionary landing but not a fuel exhaustion scenario.