SEOUL - 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.

The country's transport ministry, which has been inspecting safety conditions at airlines and airports since the Boeing 737-800 jet crashed at the southwestern Muan airport, announced the move to change the so-called "localizer" structures on Monday.

Seven domestic airports, including Muan, were found to have embankments or foundations made of concrete or steel that needed to be changed, the ministry said in a statement.

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It added that it would prepare measures to improve the structures by this month and it aimed to complete the improvements by the end of 2025. It did not provide details of the planned improvements.

Aviation safety experts have criticized the placement of the embankment at Muan airport and said it likely raised the death toll of the crash, which killed 179 of the 181 people on board.

The government has also finished its inspection of six domestic airlines flying Boeing 737-800s, and found violations at some operators including exceeding the period of inspection pre- and post-flight, and non-compliance with procedures to resolve plane defects or passenger boarding.

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The transport ministry declined to comment on whether Jeju Air was among the airlines where violations were found. A Jeju Air spokesperson could not be immediately reached for comment.

A special safety inspection of the country's major airport facilities will also take place between Jan 13-21, the ministry statement said.

The government also extended the shutdown of Muan airport to Jan 19, the ministry said in a separate statement.