A police forensic team conducts an on-site investigation at the scene of the Jeju Air crash at Muan International Airport in Muan County, South Jeolla Province, Jan. 2. Yonhap

Investigators have secured audio files from the retrieved voice recorder of a Jeju Air aircraft involved in this week's deadly crash, government officials said Thursday.

The Ministry of Land, Infrastructure and Transport said the investigators have successfully completed the conversion of data from the cockpit voice recorder (CVR) from Jeju Air's fallen B737-800 aircraft into voice files.

"The CVR contains up to two hours of recordings, and we have secured the maximum capacity of data," the ministry said.

Authorities will begin analysis of the audio files and produce a transcript.

The CVR records conversations between cockpit crew members, communications with air traffic control and various warning sounds inside the cockpit. It is known to record two hours of audio during a flight until the engines of the aircraft are shut down.

The device from Jeju Air's crashed B737-800 aircraft was recovered in relatively intact condition on the day of the tragic accident Sunday.

As for the separate flight data recorder, also retrieved from the aircraft, it will be sent to the headquarters of the U.S. National Transportation Safety Board in Washington for analysis, according to officials.

The ministry said it has also begun on-site inspections of air navigation safety facilities, including localizer equipment, which has been identified as a factor that exacerbated the Jeju Air accident, at airports nationwide. (Yonhap)