Asiana chief defends 'very experienced' crash pilots

South Korea's Asiana Airlines on Tuesday defended the pilots of the San Francisco crash jet as "very competent" as attention focussed on whether human error caused the Boeing 777 to slam into the runway.

The pilot at the controls was a novice at flying the 777, and his supervising colleague had only just qualified as a trainer, according to Asiana. US investigators say the plane was flying far too slowly when it clipped a seawall short of the runway on Saturday.

Asiana chief executive Yoon Young-Doo said he would travel to California to meet transport safety officials and victims, after US investigators said they had begun questioning the cockpit crew.

Two teenage Chinese girls were killed and more than 180 people injured when the flight from Shanghai via Seoul went skidding out of control on its belly, shredding the tail end of the plane and starting a fire.

Yoon said the trainer who was acting as co-pilot at the time of the crash, Lee Jung-Min, had led 33 flights on 777s to San Francisco and had more than 3,000 flight hours under his belt -- far more than the 500 required to become a trainer.

The pilot who was at the controls, Lee Kang-Kuk, who was still undergoing training on the 777, had also led 29 flights to San Francisco on 747s in the past, he said.

"They are very experienced and competent pilots," he told reporters in Seoul, while adding that South Korea's number two airline would improve its landing simulation training.

"I feel tremendous responsibility for those affected by the crash," Yoon added.

"I am going to San Francisco today to meet with relevant US officials, make a courtesy visit to the NTSB (National Transportation Safety Board) to express regret and to meet with those in hospital."

Passenger Kim Ji-Eun was seated a few rows ahead of dozens of Chinese passengers at the rear of the cabin, including the two girls, and described seeing passengers "being thrown out everywhere".

"It was so scary. The (second) thud was so loud that people started screaming. I blinked once and looked back, only to see no one there," Kim, 22, told the Chosun Ilbo daily.

"I was so shocked to realise that none of the people who were sitting behind me were there," she told the newspaper.

Yoon was speaking after NTSB chief Deborah Hersman said the aircraft's four-man flying crew were being quizzed. Flight data showed the plane had been travelling at approximately 106 knots on impact -- sharply lower than the target speed for landing.

"137 knots is the speed that they want to have when they cross the threshold of the runway," Hersman said. "The crew is responsible to make a safe approach to the airport."

On Monday, Yoon lashed out at reports that pilot inexperience may have been to blame for the fatal crash, saying the speculation was "intolerable". Hersman also said it was too soon to blame the accident on human error.

"We have to understand what these pilots knew, we also need to look at how they were flying the aircraft -- were they hand-flying the airplane? Were they relying on auto-pilot or some combination of the two?" she said.

But attention on the crew's experience has intensified after Asiana said the trainer pilot was on his first day on the job, having received his teaching licence for the Boeing 777 just a month before the crash.

The airline also said the trainee pilot had just 43 hours of experience in piloting the popular 777, although he had accumulated more than 9,000 hours of experience on other planes.

Family and friends in eastern China's Zhejiang province are mourning the two dead passengers -- identified by state media as high-school classmates Ye Mengyuan, 16, and Wang Linjia, 17.

One of the girls may have been run over by an airport fire engine rushing to the scene, San Francisco Fire chief Joanne Hayes-White told reporters on Monday.

According to aviation safety databases, the two dead teens are the Boeing 777's first fatalities in 18 years of service.

It was the first deadly Asiana passenger plane crash since June 1993. Shares in the company tumbled nearly six percent on Monday but clawed back some of their losses on Tuesday to close up 1.14 percent.