South Korean authorities seeking answers to the country’s deadliest plane disaster are investigating the role of a hardened barrier at the end of a runway that was hit after the jet crash-landed on Sunday. The structure may only partly explain the sequence of events that led Sunday’s Jeju Air flight to end in such a violent manner. All but two of the 181 people onboard died when the plane slid down the runway at Muan international airport and burst into flames after hitting a dirt-and-concrete embankment built to house navigation equipment. A report by the Chosun Ilbo newspaper on Tuesday