After a part failed on one of its Rolls-Royce engines minutes after takeoff from Hong Kong on September 2, Cathay Pacific has said it identified 15 Airbus A350 aircraft that need component replacements.

According to the Guardian, the airline said it expected to cancel 34 return flights through September 4, and would then announce any further service cuts for the rest of the week.

After inspecting its fleet of 48 Rolls-Royce-powered A350s, Cathay identified 15 aircraft with engine components that needed to be replaced. Three had been repaired, and it expected all affected aircraft to resume flying by September 7.

Rolls-Royce confirmed the affected aircraft was powered by its Trent XWB-97 engines, and said it was keeping other carriers informed. Authorities in Hong Kong have launched an investigation, and Rolls-Royce said it was also working closely with them and the aircraft manufacturer Airbus.

According to Reuters, it is thought the problem involves a fuel nozzle inside the XWB-97 engine, the Rolls-Royce model used on the A350-1000.

There are about 88 A350-1000 jets in operation worldwide, according to the Swiss intelligence provider ch-aviation.

The top six operators are Qatar Airways with 24 planes, British Airways with 18, Cathay Pacific with 18, Virgin Atlantic with 12, and Etihad Airways and Japan Airlines with five each.