The NTSB hopes to shed more light at a briefing later Tuesday morning on the pilots in control of that Asiana flight that crashed at San Francisco's international airport.
Investigators will return to the runway Tuesday morning to continue inspecting the debris for clues about those final moments.
At an airport in South Korea, the president of Asiana airlines bowed in apology to the parents of the two teens killed when flight 2-14 crashed.
He's on his way to San Francisco this morning where he'll be greeted by a team of investigators focusing on the four crew members in charge of handling the plane.
"In our investigations we are often looking for things that might affect human performance
like fatigue, like illnesses or medication, like health issues," said NTSB Chairman, Debbie Hersman.
One of the pilots was still in training to fly the Boeing 777. Asiana's president has said responsibility for the plane lies with his instructor captain. " When we are looking at issues of the crew, we want to understand what they knew and why they were doing it," said Hersman.
Investigators say the pilots allowed their air speed to drop well below the 137-knot target for landing.
Three seconds before the crash, the plane was stalling at just 103- knots. "There was a lack of interaction between the two pilots - the pilot who was manipulating the flight controls and the co-pilot who should be monitoring air speed, altitude and sink rate," said Former NTSB Investigator, Greg Feith.
New video shows the seconds just after the crash, emergency chutes are deployed and passengers are seen running from the burning plane. "By the time we removed the final victim, the conditions were, the fire was banking down on us" Lt. Chrissy Emmons of the San Francisco Fire Department.
Investigators now say it could be three weeks before they complete an investigation to determine whether one of the teens killed in the accident was hit by an arriving fire engine. "Anything we might offer at this point would be conjecture and would further complicate the investigation," said Dale Carnes, Assistant Department Chief, San Francisco Fire Department.
Tuesday morning investigators will continue identifying the wreckage.
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