Some low-cost airlines and game companies in South Korea saw problems with booking or experienced interruptions in their servers Friday, industry sources said, in an apparent IT disruption that affected the global airline and financial sectors. The cyber outage affected the airport ticketing of Jeju Air Co., Eastar Jet Co. and Air Premia Inc., prompting employees to conduct check-ins by hand, according to sources. The three airlines use computer systems based on Microsoft's cloud service, the sources said. Online game companies here were also affected by the IT outage. The management of Black Desert of South Korean game developer Pearl Abyss posted a notice on its website and said it experienced "server instability" due to "sudden failure" in its equipment. Other game makers like Gravity Co., the developer of online role-paying game Ragnarok, said they also suffered disruptions. "We are conducting a temporary inspection as it has been confirmed that an error in our system that is provided by another co mpany is preventing users from gaining access to our website and games," the company said in a release. IT authorities said they are closely monitoring the situation for any disruptions in local services using Microsoft's cloud services. Source: Yonhap News Agency