What happened in the final minutes of Asiana Flight 214 before it crashed on runway 28L at San Francisco International Airport?
It's the primary question investigators with the National Transportation Safety Board are asking as they debrief the pilot at the controls of Asiana 214.
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"What we do know is that we have an experienced pilot. He has a lot of hours, but he is new to the 777," said Deborah Hersman, chairwoman of the NTSB. "We need to understand what that transition training looks like and the initial operating experience, which is what he was doing. Getting time in the aircraft with an experienced instructor."
As of Tuesday morning, the NTSB had interviewed two of the four pilots.