Hong Kong's air safety authority said Thursday that a defect in an engine component of a Cathay Pacific Airways Airbus A350 that caused a fire, forcing a Zurich-bound flight to return to Hong Kong, could have caused ''extensive damage'' to the aircraft.

While the initial emergency directive applied only to the Airbus A350-1000 engine, the latest AD was extended to all Airbus A350 engines.

An engine fire on a Cathay Pacific Airbus A350 earlier this month was the result of a fuel leak and could have caused extensive damage to the plane, according to investigators. Hong Kong’s flagship airline grounded planes after being forced to turn a flight around a couple of weeks ago because of an "engine component failure".