Mechanical issues were ruled out by the NTSB, not exactly surprising in my opinion, because no emergency was declared prior to the approach. As for for why the throttles were at idle, and stayed there, could have been A/T off, or (from what i've read, could be a few different combinations of autopilot settings): "...level of automation: A/p on a/t on here you have chose a vertical flight mode-vs or flch or fpa or vnav (path or speed) flch will close thrust lever and try to descent to selected altitude eg 500' above runway or even circling mda, which ever is selected. when close by the minimum usually the g/a altitude is selected if you are still in flch the airplane will try to strt climb back to the set altitude incl adding power unless you hold the throttles and the throttle indication is HOLD, vs.fpa or vnav will maintain the decent a/p off a/t on -normal we don't tun ofF at on the 777 unless in the sim all off and use flch,,,maybe not smart unless you have your hand on the thr lever or maybe ap on an at off not likely turning a/p or a/t or both will complicate things with flch especially when you are tired, being trained, etc depending on your focus like coming in high with high descent rate A bit of an incoherent story..." Odds are pretty good that the regular captain, acting as F/O, would just sit there and watch, he's used to being the captain, and used to being in charge, so he essentially is indifferent to what happens to the "new guy" in the left seat. KAL801 comes to mind, where Asiatic pilots were allowed to do stupid things by their crews. But, there is one case that also comes to mind, where a Japanese Captain actually owned up to the fact that he made a mistake (JAL2 - crashed just off San Francisco as well)... The Eastern/Asian culture is one deeply rooted in respect and honour, strange things happen when a culture like that gets Westernized practices like CRM introduced, because it goes against the grain of their society.