A Korean Air plane bound for Taiwan’s central city of Taichung returned to Incheon due to defects, the airline said Saturday.

The plane, which departed from Incheon International Airport, west of Seoul, at 4:45 p.m. with 125 passengers on board, detected a problem with its pressurization system in the skies over South Korea’s southern resort island of Jeju 50 minutes into its flight.

This system is responsible for regulating the internal pressure of an aircraft.

The plane returned to its departing airport at 7:38 p.m.

According to the Ministry of Land, Infrastructure and Transport, 15 passengers suffered from eardrum pain and hyperventilation during the descent. Among them, 13 were taken to a hospital. No serious injuries have been reported.

Korean Air said it plans to use another plane to take off again at 10:30 a.m. Sunday, approximately 19 hours later than the original schedule.

Source: Yonhap News Agency