How much fuel did they have? How many options did they have?
ANA dispatches their flights very conservatively, I wouldn't doubt (as a matter of fact, I'm pretty sure) that given the circumstances in terms of WX, they had enough fuel to go back to PEK if they needed to, how about we stop assuming that they were cornered into making the approach, that is just silly, the dispatchers are very proactive in sending us turb & windshear reports constantly, there is no hidden company culture here that would have prevented them to divert if they needed to, stop making ridiculous assumptions without all the facts
