On December 29, a plane belonging to South Korean low-cost airline Jeju Air crashed and burst into flames at Muan Airport in South Korea, killing almost all on board (179 dead out of 181 on board).

The black boxes were recovered from the scene of the tragedy. One – the fatal plane’s damaged flight data recorder – had been sent to the US for analysis while the data from the cockpit voice recorder was converted to an audio file to be studied in detail.

Analysis of the cockpit voice recorder was initially done in South Korea and then, when the data loss was discovered, sent to a US National Transportation Safety Board laboratory

Today the country’s transport ministry announced that the “black boxes”, the flight data recorder and the cockpit voice recorder, had stopped recording four minutes before the plane crashed.

“Analysis revealed that the cockpit voice recorder (CVR) and flight data recorder (FDR) did not record the four minutes preceding the plane’s crash,” the ministry said in a statement.

Essentially, they give no information about what happened in those fateful four minutes before the Boeing 737-800 crashed at incredible speed.

So far, “it is unknown why the devices stopped saving recorded files 4 minutes before the crash,” the ministry said.

Investigators are still looking into whether a bird or bird strike caused the crash, a process expected to take several months to piece together the sequence of events.