The world’s fleet of Airbus A380 aircraft will need to replace around 40 Rolls-Royce (RR.L) engines to ensure safety after one such engine broke apart in flight this month, Australia’s Qantas (QAN.AX) said on Thursday.

That would represent about half of all Rolls-Royce engines currently in service on A380 aircraft, the world’s largest passenger plane with a list price of around US$350 million ($456 million) each.

“We’ve been talking to Airbus and Rolls-Royce and we understand that the number (of engines to be replaced) is around 40,” Qantas Chief Executive Alan Joyce told reporters. “We’ve already replaced three and there could be more.”

On Nov 4, a Qantas A380 with 466 people on board made an emergency landing in Singapore after one of its Rolls-Royce  (RR.L) engines disintegrated mid-flight after an oil fire.

Since then, airlines have sought to replace their existing engines with newer versions. The problem with the Rolls-Royce Trent 900 engine is thought to develop over time, so the new engines should not present any safety issues and will give Rolls-Royce time to come up with a permanent solution.

Qantas’s six A380s have been grounded since the incident, while rival Singapore Airlines (SIAL.SI), which has 11 Rolls-Royce-powered A380s, has also been forced to cancel several flights in order to swap out some old engines.

Joyce declined to confirm an Australian newspaper report on Thursday that his airline’s six A380 planes were likely to remain grounded until at least early December.

But he confirmed Qantas wanted Airbus (EAD.PA) to replace some of Qantas’s existing Rolls-Royce engines with new engines from aircraft still in production on the Airbus assembly line.

So far, the world fleet of A380s comprises 37 aircraft, including 21 powered by the Trent 900, with four engines for each plane. Airbus has orders for almost 200 more A380s.