INVESTIGATORS have finished extracting data from one of the black boxes from the fated Jeju Air crash on Sunday (December 29), South Korea's transport ministry has said.

The data from the cockpit voice recorder will now be converted into an audio file, while a second black box - a flight data recorder - will be sent to the United States for analysis, according to BBC News.

Investigators hope data on the flight and voice recorders will provide insights into the crucial moments leading up to the tragedy.

Some 179 people died after the plane crashed into a structure and exploded, making it the deadliest plane crash on South Korean soil.

Investigators say it is not feasible to locally decode the flight data recorder, which was damaged in the crash and is missing a crucial connector.

South Korean experts will be involved in the analysis process in the US, they said, adding that they are in discussion with the US National Transportation Safety Board (NTSB) on when to hand over the flight data recorder.

NTSB has deployed officials to the crash site in South Korea's Muan county to help investigate the cause of the plane crash.

The Boeing 737-800 plane was travelling from Bangkok when it crash-landed at Muan International Airport on Sunday and slid into a wall off the end of the runway, bursting into flames and killing everyone on board except two crew members.

Many questions remain unanswered, and investigators are looking at the role a bird strike or weather conditions may have played.

They are also examining the concrete wall at the end of the runway, which some experts say could have exacerbated the impact of the crash.