Investigators have completed data extraction from one of the black boxes of the ill-fated Jeju Air plane that crashed on Sunday, according to South Korea’s transport ministry.

The cockpit voice recorder’s data will now be converted into an audio file. However, accessing the data from the second black box, the flight data recorder, will take longer as it is missing a critical component.

Investigators aim to analyze data from both recorders to uncover key details about the moments leading up to the tragedy. The crash, which involved 179 fatalities, is the deadliest aviation disaster in South Korea’s history.

Deputy Minister for Civil Aviation Joo Jong-wan stated that discussions are underway on how to decode the flight data recorder, which currently lacks a crucial connector. Officials from the U.S. National Transportation Safety Board have joined the investigation in Muan.

The Boeing 737-800 was traveling from Bangkok when it crash-landed at Muan International Airport on Sunday. It skidded into a structure at the runway’s end, igniting a fire that claimed the lives of all on board except for two crew members.

Investigators are examining potential causes, including a bird strike or adverse weather conditions. Passengers aboard flight 7C2216 ranged in age from three to 78, with most in their 40s, 50s, and 60s, according to Yonhap News Agency. Two Thai nationals were among the victims, while the rest were believed to be South Korean.

Due to the severity of the crash, it took days to identify the victims through fingerprints and DNA, with family members providing saliva samples to assist the process. Acting President Choi Sang-mok announced on Wednesday that all 179 victims have now been identified.

In response to the tragedy, New Year’s Day celebrations across the country have been canceled or reduced, and a seven-day national mourning period has been declared.