An EVA Air Airbus A330 sent a Mayday call before making an emergency landing in southern Ukraine on 29 September, following a drop in cabin pressure on board.
The aircraft, registration B-16312, was on a flight from Bangkok to Vienna when "engine air supply systems malfunctioned" while the aircraft was cruising at 40,000ft, says Taiwan's Aviation Safety Council (ASC).
This resulted in "cabin pressure abnormalities", adds the council. The aircraft's pilots declared a Mayday call before making an emergency landing at Simferopol airport in southern Ukraine.
Local reports say there were 12 cabin crew and 67 passengers on board the aircraft. There were no reports of injuries.
The ASC is investigating the incident, with assistance from Taiwan's Civil Aeronautics Administration, EVA Air, Airbus, French investigation agency Bureau d'Enquetes et d'Analyses and Ukraine's civil aviation authority.