But Saturday marked his first time landing a Boeing 777 at San Francisco International Airport and was the ninth time he had flown the model, with 43 hours at the controls, the airline said. He has about 10,000 hours as a pilot, Asiana said.
Hersman, who has discouraged speculation about whether the crew bore responsibility for the crash, downplayed the significance of the pilot's experience in her New Day interview.
"It's not unusual for crew to change aircraft types," she said. And with air crews flying all around the world, it's not unusual for pilots to fly into unfamiliar airports for the first time either.
She said it's important for the two pilots in charge of the aircraft during the "very risky" landing phase to work closely together, and while she said investigators have no evidence of cockpit communications problems, it's something investigators will be looking at.
Mary Schiavo, a former inspector general for the U.S. Department of Transportation, said video and other data related to the crash suggest the crew "lost situational awareness" while approaching the airport.
"They're low and slow, and that's a problem," Schiavo said.
All four pilots have been interviewed by NTSB and South Korean investigators, said Choi Jeong-ho, the head of South Korea's Aviation Policy Bureau.
"We cannot reveal what's been said as it is an ongoing investigation," Choi said.
The pilots represented two teams -- a crew and a relief crew, said Hersman.
"I think it really is too early to conclude pilot error, because there is so much that we don't know," she told CNN's Wolf Blitzer.
The cockpit voice recorder -- which has been flown to Washington for analysis -- contains conversations between the pilots that were carried out in a combination of English and Korean, she said.
Hersman said that in most airplane crashes, investigators rarely find a single explanation for what went wrong.
"In most of our investigations, we find that it's not just one thing, it really is a combination of factors that lead to an accident," she said.
While weather has been ruled out as a factor, other factors officials are investigating include whether construction at the airport may have played a role, Hersman said Sunday.
Work to extend a runway safety area required the temporary shutdown of a system designed to help pilots land planes safely, she said.
Clues from voice recorder
The pilots apparently tried to speed up seven seconds before the crash, cockpit voice and flight data recorders showed.
A stall warning sounded three seconds later, telling the pilots the plane was about to lose its ability to stay in the air.
Then -- just 1.5 seconds before the plane slammed into the runway -- the crew decided to call off the landing and try to pull up for another try, Hersman said.
It was too late.
The frightening crash
With no warning from the cockpit, survivors said, the plane's rear struck the sea wall at the end of the runway. The impact severed the plane's tail and sent the rest of the body spinning on its belly.
Amateur video obtained exclusively by CNN shows the plane crashing and spinning counterclockwise and coming to a stop.
In addition to the two deaths, 182 people were hospitalized with injuries ranging from severe scrapes to paralysis.
"We're lucky there hasn't been a greater loss of life," San Francisco Fire Chief Joanne Hayes-White said.