National Transportation Safety Board Chairwoman Deborah Hersman said Tuesday the two pilots also had never flown together before the crash that left two teenagers dead.
Hersman says the pilot who was making the landing was about half-way through his training to fly Boeing 777s.
Investigators also said the aircraft's landing gear hit a seawall before the tail of the plane during a weekend crash. The disclosure came on Tuesday during a news conference by the National Transportation Safety Board.
Two of the flight attendants onboard were ejected from rear of plane on impact and survived.
Hersman cited data from the flight data recorder, saying Flight 214 was 500 feet up and about a half-minute from San Francisco International Airport when its speed dropped below the threshold for a safe landing speed.
The Boeing 777 continued slowing until just about eight seconds before touchdown, when pilots recognized the need for more speed and throttled up.
But it was already too late. By the time the engines started adding speed, the hulking 777 was barely above the San Francisco Bay and the plane clipped the seawall at the end of the runway, slammed down and spun, then caught fire. Incredibly, only two of the 307 people on board died, and most of the survivors suffered few or no injuries.
The two girls who lost their lives were part of a group of students from China, headed to Southern California for a summer study-abroad program.
The teens had been seated toward the back of the plane, where many of the most seriously injured passengers were seated, Hersman said. Their bodies were found on the tarmac.
Hersman also said investigators reviewed flight data and watched airport surveillance video to determine whether an emergency vehicle ran over one of students. But they have not reached any firm conclusions. A county coroner said he would need at least two weeks to rule in the matter.
The teens' parents and relatives of injured passengers arrived at SFO Tuesday. They were quickly bused to a Burlingame hotel, where security was very tight. The girls' parents were expected to go to the San Mateo County Coroner's Office sometime Tuesday, though their bodies have already been identified as Wang Li Jia and Ye Meng Yuan, both 16.
Asiana President Yoon Young-doo said Lee Jeong-min, a 777 pilot, was the pilot on 33 flights to San Francisco and Lee Kang-kook was a pilot on 29 flights into San Francisco but on other planes.
Lee Jeong-min had been named a training pilot on the flight because he was among the top 25 percent of Asiana pilots, Yoon said. Lee Kang-kook had logged nearly 10,000 hours operating other planes but had only 43 hours in the 777, a plane he still was getting used to flying, said Asiana spokeswoman Lee Hyomin.
The airline said Monday that the pilot at the controls had little experience flying that type of plane and was landing one for the first time at that airport.
A big question still looming over the investigation is why the pilots didn't react sooner. Some of those answers are expected to come Tuesday, after details emerge from U.S. and Korean joint interviews with the pilots that began Monday.
Choi Jeong-ho, a senior official for South Korea's Ministry of Land, Infrastructure and Transport, told reporters in a briefing Tuesday in South Korea that investigators from both countries quizzed Lee kang-kook and Lee Jeong-min on Monday, and they planned to quiz the two other pilots and air controllers Tuesday.
Choi said recorded conversation between the pilots and air controllers at the San Francisco airport would be investigated, too.
NTSB managing director Peter Goelz said the pilots would be asked to tell investigators what happend in their own words. He said the interview is an effort to understand what the pilots remember and what they remember saying and doing - not a cross-examination.
There is a possibility a license could be revoked, or fines or penalties issued, Goelz said.
More than 180 people aboard the plane went to hospitals with injuries, but more than a third didn't even require hospitalization. The passengers included 141 Chinese, 77 South Koreans, 64 Americans, three Canadians, three Indians, one Japanese, one Vietnamese and one person from France.
The flight originated in Shanghai, China, and stopped over in Seoul, South Korea, before making the nearly 11-hour trip to San Francisco.
The Associated Press contributed to this report.