The missing data deepens the puzzle of what caused the deadly air disaster in Muan, South Korea, late last month.

The Boeing 737-800 skidded off a runway in the South Korean city of Muan on Dec. 29 after its landing gear failed to deploy, slamming into the concrete structure and bursting into flames, killing all but two of the 181 people on board.

The nation’s transport ministry reviewed structures near airport runways after the deadly crash of a Jeju Air flight late last month.

A former transport ministry accident investigator said the discovery suggests all power, including backup, may have been cut, which is rare.

Jeju Air flies its planes more than any other major airline in South Korea, data show. Read more at straitstimes.com.

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. South Korean investigators previously said the flight data and cockpit voice recorders were key to finding out the cause of last month's crash that killed 179 people.

The black boxes of the crashed Jeju Air plane stopped recording flight data four minutes before the aircraft crashed in the worst accident in South Korean aviation history, the Ministry of Transport reported on Saturday.

South Korea said it planned to improve the structures housing the antennas that guide landings at its airports this year after December's fatal crash of a Jeju Air plane, which skidded off the runway and burst into flames after hitting such a structure.

South Korea will extend runway safety areas and redesign infrastructure after the crash of a Jeju Air Co flight last month that killed almost everyone on board, sparking criticism that the design of the airport might have exacerbated the accident.

Son Chang-wan was in office while works were undertaken at Muan International Airport. Last month, a plane crashed into a concrete barrier there, killing 179 people.

South Korean authorities said on Wednesday they would change the concrete barriers used for navigation at some airports across the East Asian country after the Jeju Air crash that left 179 people dead.