Hong Kong aviation investigators say an engine problem that caused Cathay Pacific to ground its entire fleet of Airbus A350 jets for inspection earlier this month could have escalated into “extensive damage.

A midair engine fire on a Cathay Pacific Airways Ltd. flight earlier this month could have spread and caused widespread damage to the plane, a preliminary report said, as investigations continue into the incident and the failed components.

The European Union Aviation Safety Agency (EASA) on Thursday gave an update on the inspections it ordered on Rolls-Royce-made engines used in Airbus A-350 aircrafts following a security incident, pointing to issues possibly stemming from a cleaning process.

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".

European regulators have pinpointed a potentially flawed cleaning process during maintenance as investigators probe an engine fire that caused a Cathay Pacific Airbus jet carrying 348 people to turn back to base.