The South Korean Transportation Ministry said on Saturday the black boxes pulled out from the wreckage of the Jeju Air plane that crashed last month, stopped recording about four minutes before the fatal accident that killed 179 people.
After initial analysis of the devices, the US National Transportation Safety Board concluded that both the flight data and cockpit voice recorders stopped working about four minutes before the crash, the ministry said in a statement.
The Jeju Air plane — Boeing 737-800 — heading from Bangkok to Muan International Airport in South Korea was attempting an emergency landing on December 29 when it skidded on the runway and exploded after hitting a concrete wall, killing 179 out of 181 people on board.
The incident occurred a few minutes after the airport control tower had warned the flight pilot of the risk of bird strikes.
The ministry also said that it wasn’t immediately clear why the devices failed to record data in the last four minutes.
A joint investigation team comprising Korean and US officials is seeking to determine what caused the devices to stop working, it added.
The black boxes have been sent to the NTSB for closer examination after discovering that some of the data was missing.
“Data from the CVR (cockpit voice recorder) and FDR (flight data recorder) are crucial in investigating accidents, but such investigations are conducted through the examination and analysis of various sources of information, and we plan to do our utmost to determine the cause of the accident,” the ministry said.
South Korean government have pledged to improve airport safety after experts linked the high death toll to Muan airport’s localiser system, the structure hit by the aircraft as it crashed.
The localiser is a set of antennas designed to guide aircraft during landings.
One of the engines appears to have lost power in flight because of a bird strike, according to video footage, but it hasn’t been confirmed if the other one was also shut down, either by accident or because of bird strike.