Qantas Airways will change two Rolls-Royce Trent 900 engines on its A380 aircraft as a result of ongoing inspections following the fleet's grounding on Thursday.

The number three engine on an A380, registration VH-OQC, will be changed after an inspection in Sydney found abnormalities including an oil leak, say sources familiar with the matter. Another Qantas A380 currently grounded in Los Angeles will have one of its engines changed due to unspecified problems.

The abnormalities in the number three engine of VH-OQC could have potentially led to a repeat of Thursday's incident on QF32, sources say.

Qantas could not be reached for comment. Earlier today Qantas general manager David Epstein said Qantas and Rolls-Royce engineers were inspecting engines one-by-one on three A380s in Los Angeles and one in Sydney. Each engine takes up to eight hours to inspect.

The carrier's fifth A380 is undergoing a scheduled C-check at Lufthansa Technik in Frankfurt while the sixth A380, the aircraft involved in Thursday's incident, is undergoing a separate inspection.

Inspections for the carrier's serviceable A380s may not be complete for a number of days, Epstein says. He warns repair periods "could take some time".

Further delays may occur if the demand for spare engines exceeds worldwide spares, Epstein says. "As far as engines go, there are not a lot of Trent [900] engines around the world." Airlines worldwide have taken delivery of only 20 Trent-powered A380 aircraft, according to Flightglobal's ACAS database.

In Thursday's incident, Qantas' A380 VH-OQA experienced an uncontained failure in its number two engine approximately six minutes after departing Singapore's Changi Airport for Sydney. Debris struck the aircraft's port wing and fell over Indonesia.

The aircraft safely returned to Singapore but with only half of its ailerons working, footage from the incident shows. Additionally, the crew were not able to control the number one engine, leading firefighters to hose down the engine to forcibly shut it down.

Qantas chief executive Alan Joyce says one aircraft could return to service as early as tomorrow. "We are hopeful it is within days [that] the A380 fleet will start flying again. We are happy to proceed if no adverse findings come out of [inspections from] those jets."

Lufthansa and Singapore Airlines also operate A380 aircraft with Rolls-Royce engines. Singapore Airlines says it inspected its 11 A380 aircraft and cleared them to return to service. Lufthansa says it is inspecting its three A380s.

Engine Alliance powers the Air France and Emirates A380s.

As a result of the grounding Qantas has delayed some A380 flights, swapped aircraft, and charted aircraft from fellow OneWorld carrier British Airways.

Source: Air Transport Intelligence news