Asiana hired the flying pilot in 1994, after which he reported amassing nearly 10,000 hours of total flight time. That experience included time piloting 737, 747 and A-320 aircraft, and he was a ground school and simulator instructor for the latter model.
The instructor pilot, a South Korean air force veteran with about 13,000 hours of flight experience, recalled Flight 214 being "slightly high when they passed 4,000 feet (and) they set vertical speed mode at about 1,500 feet per minute," explained Hersman.
But they ended up coming in low. The third pilot in the cockpit told investigators that, with "the nose ... pitched up, ... he could not see the runway," said the NTSB chief.
In the last few hundred feet before touchdown, the crew was making both lateral and vertical adjustments -- meaning they were both trying to move sideways to get toward the runway and adjust their height.
When the aircraft hit, it spun 360 degrees. An oil tank ruptured and leaked fuel onto the plane's right engine, starting a fire.
Eventually, evacuation chutes deployed, and at least seven of the aircraft's eight doors were opened. (An eighth was found on the ground, Hersman explained.)
Very soon after the plane stopped, tending to the wounded and the investigation began.
That probe will continue for months, though authorities have released significant details so far. So much information, in fact, the Air Line Pilots Association, for a second straight day on Tuesday, criticized what it called the "NTSB's release of incomplete, out-of-context information" that "has fueled rampant speculation about the cause of the accident."
The union further questioned whether some tools were available to the crew, claiming, for instance, that the "Instrument Landing System, a critical aid to pilots, (was) out of service."
"Without the full body of facts surrounding a catastrophic event, partial or incomplete information can lead to erroneous conclusions and, in turn, skew the perception of individuals' behavior," the pilots union said in its Tuesday statement. "This could then lead to misguided assessments of the crew's intentions and actions."
Hersman disputed the union's claims earlier Tuesday on CNN, saying the agency believes that transparent release of information is crucial.
"We believe that it is always better to put out the correct information and factual information so that bad information is not able to propagate," she said.
Aviation experts say that air crashes often involve several factors, and the San Francisco tragedy appears to be following form. Experience, training, crew actions, airport navigation, and now the possible role of a mechanical system are all in the mix. The NTSB is not expected to render a decision on probable cause for months.
During her news conference later Tuesday, Hersman stressed that "there's still a lot of work to be done."
"We will not determine probable cause while we are here on scene," she said, adding there's a lot of information to collect and analyze. "...I would really encourage all of you to be very cautious about speculating on the cause of the crash."