A joint investigation to identify the exact cause of the crash of a South Korean passenger jet in San Francisco got underway with an analysis of the flight data recorder (FDR) from the crashed jet, the government said Wednesday.

A joint investigation of the FDR began shortly after two South Korean investigators arrived in Washington, D.C. on Tuesday (U.S. time), according to the Ministry of Land, Infrastructure and Transport.

Two pilots from Asiana Airlines Inc., the South Korean operator of the crashed jet, are also taking part in the joint analysis of the FDR as observers.

Asiana Flight 214, a Boeing 777 plane, from Seoul's Incheon International Airport crashed while landing at San Francisco International Airport on Saturday, killing two Chinese passengers while injuring over 180 others.

Most injured passengers have been treated, with 25, including four flight attendants, still remaining in the hospital, according to the ministry.

Both the government and Asiana Airlines, the country's second-largest flag carrier, are doing their utmost to assist injured passengers and their family members, together deploying some 90 officials in the country and in the United States as part of a joint assistance team, it said.

Thirty-one family members of the injured passengers, including those of the two Chinese schoolgirls killed in the crash, have been provided with transportation to visit their loved ones in the United States with 12 others scheduled to head for San Francisco on Wednesday.

Eighteen South Korean passengers have also returned home with nine others set to arrive in Seoul later in the day, according to the ministry.

The ministry said the joint investigation of South Korea and the U.S. will include additional interviews of the four pilots from the crashed jet, as well as air traffic controllers from the San Francisco airport to check for any errors by either side.

Earlier reports have noted a possible error by the pilots, but the captain of the flight has said the plane's automatic throttle control may have failed to maintain the programmed speed.   

In an earlier press conference in the U.S., Deborah Hersman, chief of the U.S. National Transportation Safety Board, quoted the captain as saying that the automatic throttle was not maintaining the speed he had thought it was programmed to.

A failure of the automatic throttle control may explain the reason the plane approached the runway at San Francisco airport at what Seoul has called an "unusually" slow speed.

The ministry earlier confirmed that the Asiana flight was traveling at 103 knots or 191 kilometers per hour when its tale struck a seawall at the end of the runway at San Francisco airport, much slower than the recommended landing speed of 137 knots or 254 kilometers per hour. (Yonhap News)