The parents of Wang Linjia, one of the Chinese girls killed in the Asiana accident at San Francisco airport, prepare to board the flight for Seoul Monday afternoon at the Shanghai Pudong International Airport. From Seoul, they will fly eastward to San Francisco. Photo: Yang Hui/GT

The South Korean government and the US National Transportation Safety Board (NTSB) launched a joint investigation Monday into the cause of the crash landing of Asiana Airlines Flight 214, with the public questioning whether the pilot was to blame.

Lee Kang-kook, the pilot, was making his first attempt to land a Boeing 777 at the San Francisco International Airport with captain and co-pilot Lee Jeong-min. The airline said it was not his first time flying the jet although he was still "in training" and had 43 hours controlling a 777 out of his total 9,793 hours of piloting experience.

The four pilots on board have been interviewed by the investigation team, Choi Jeong-ho, head of South Korea's Aviation Policy Bureau, said Monday.

NTSB chairman Deborah Hersman said it is too soon to draw any conclusions. A preliminary data analysis of the plane's cockpit voice recorder and flight data recorder showed that the plane proceeded normally for descending, but the throttles were at idle and the plane was coming much slower than the target speed of 254 kilometers per hour during the approach, said Hersman.

The voice recorder revealed that a crew member was trying to increase speed around seven seconds prior to impact and a stall warning occurred around four seconds prior to that, suggesting low altitude. "A call to initiate a go-around happened 1.5 seconds prior to impact," said Hersman.

Investigators will also check if the shutdown of the instrument landing system in the airport since June could have played a role in the accident.

By 7 pm Beijing time Monday, the Chinese consulate general in San Francisco had confirmed that 120 Chinese citizens out of the 141 aboard were safe and was contacting the rest.

The San Francisco Fire Department said that one of the two Chinese girls killed may have been run over by an emergency vehicle. The Chinese consulate general also said San Mateo County Coroner Robert Foucrault is examining the girls to determine cause of death.

The parents of Ye Mengyuan, 16, and Wang Linjia, 17, the two girls killed in the crash took off Monday afternoon from Shanghai on an Asiana flight to San Francisco, along with the parents of some seriously injured students, China News Service reported.

Ye and Wang from Zhejiang Province were heading to California for a summer camp at the West Valley Christian School, which will hold a prayer vigil for them Thursday.

Yoon Young-doo, president of Asiana, expressed his condolences to the Chinese people in a letter of apology and vowed to conduct a thorough investigation.

South Korean President Park Geun-hye sent a diplomatic cable to Chinese President Xi Jinping Monday expressing her condolences for the accident.

"We don't have a clear compensation plan yet, but we are working on it," Suh Ki-won, from Asiana's public relations department, told the Global Times. 

Agencies contributed to this story