A lack of spare Rolls-Royce Trent 900 engines is preventing Qantas Airways from returning two more Airbus A380 aircraft to service, the carrier says.

Its A380 fleet is at one-third operation following two of its six aircraft resuming flights last month.

Qantas has not been able to replace any further Trent 900 engines since last Friday when the carrier said it had so far managed to change only five of 16 engines that required "modification to the latest standard or full replacement".

"We are still waiting for 11 engines to be modified or changed," a spokesman says.

"It's clear Rolls needs to be able to provide replacement engines."

Immediately after the 4 November uncontained engine failure that grounded Qantas' A380 fleet, the airline had a single spare engine in Sydney. But it had to rely on worldwide spares after utilising it, the carrier says. At the same time, Lufthansa and Singapore Airlines were pressed to obtain spare engines for powerplant changes they conducted.

As a result Qantas pooled its unaffected Trent 900 engines by demounting them from airframes and installing them on two core aircraft, the spokesman says. He declines to specify how many engines Qantas had to move.

"We have moved engines around and are assessing options for our remaining aircraft," the spokesman says.

"We have limitations based on location," he cautions, explaining the carrier's four non-flying A380 aircraft are dispersed on four separate continents, making it difficult to further condense unaffected engines.

The damaged airframe remains in Singapore, one aircraft is undergoing a scheduled C check in Germany, and the two aircraft that could return to service are in Sydney and Los Angeles, the spokesman says.

Airbus says it can demount engines upon request on a customer's production aircraft to provide a spare powerplant for a delivered aircraft in need of an engine swap.

While Qantas has not yet requested Airbus to demount engines on its four aircraft in production, the spokesman says "it's certainly an option we are looking at."

Source: Air Transport Intelligence news