TAIPEI (Taiwan News) — A China Airlines (CAL) flight from Taipei to Bali was forced to return halfway through its journey due to a “signal abnormality.”

CAL Flight CI771 en route from Taipei to Bali, Indonesia, made a course adjustment over the Sulu Sea near Palawan Island in the Philippines and is currently returning to Taipei, per FTV News. The airline said the Airbus A330-300 experienced a “system signal abnormality” during the flight, and to ensure safety, the plane is returning for inspection. 

Another aircraft will be dispatched to transport passengers to their destination. CAL apologized for the inconvenience and asked for passengers' understanding.

Flight tracker Flightradar24 showed CI771 turning around just off the east coast of Palawan and heading back north over Manila, Luzon, and western Taiwan on its way back to Taipei.