After analyzing the devices, the U.S. National Transportation Safety Board concluded​ that both the flight data and cockpit voice recorders stopped working about four minutes before the crash.

The two black boxes on the Boeing jet involved in the worst aviation disaster on South Korean soil stopped recording about four minutes before the accident, the transport ministry said on Saturday. So

South Korea's transport ministry announced that the black boxes retrieved from the wreckage of the doomed Jeju Air jet are missing crucial data.