Qantas Airways may not finish inspecting the Rolls-Royce Trent 900 engines on its grounded A380 fleet until Wednesday, casting further doubt on when the fleet will resume operations.
Inspections are ongoing after last Thursday's uncontained engine failure on the number two engine of VH-OQA during a flight to Sydney from Singapore, says a spokeswoman. The aircraft safely returned to Singapore.
The Australian Transportation Safety Board is focusing its investigation on the engine's geared disk in the intermediate pressure chamber. The ATSB says the disk "could be crucial to a full understanding of the nature of the engine failure, and may have implications for the prevention of future similar occurrences".
Qantas general manager David Epstein confirms that two Trent 900 engines were changed over the weekend. In Sydney, VH-OQC had its number three engine changed. In Los Angeles, VH-OQE had an undisclosed engine changed. Epstein says that engine changes do not "necessarily imply" that the engine is faulty.
"If we found a condition in the engine which suggests we need to examine it further, we're pulling the engines off and swapping in 100% cleared engines in the interest of trying to return the fleet to service as soon as possible," he adds.
Epstein declines to specify the reasons for the changes, but sources familiar with the matter say the number three engine on VH-OQC had oil leaks and other abnormalities. The engine on VH-OQE had different abnormalities, they add.
The spokeswoman says a second engine on VH-OQE has been taken off for further inspection. Qantas had a spare Trent 900 engine in Sydney and has access to the limited worldwide spares, Epstein says.
Only 20 of the 37 delivered A380s are powered by Trent 900 engines, according to Flightglobal's ACAS database.
Epstein says Qantas may "swap clear engines out of a number of aircraft in the fleet and consolidate them on a core group of aircraft". The aircraft that was involved in the Singapore incident, for example, does not need its three other engines as it is unlikely to return to service for weeks.
He also denied reports that Qantas CEO Alan Joyce is blaming Rolls-Royce for the failure.
"He was perhaps misquoted or taken out of context. We are not pointing fingers at anyone," Epstein says. "If you're looking at the range of the possibilities that might have caused [the failure], it appears to be inherent of the physical nature of the engine rather than how it is maintained."
Qantas has, in the past, been criticised domestically for outsourcing some maintenance to other countries. Joyce's alleged comments came as reports re-surfaced of earlier Rolls-Royce uncontained failures.
On 2 August, a Trent 1000 engine experienced an uncontained failure in the intermediate pressure chamber, the same area as the failure on the Trent 900 in last week's incident.
The Trent 1000 failure occurred on a test bed at Rolls-Royce's facility in Derby. The Trent 1000 engine is a derivative of the Trent 900 engine, and is one of two engine options for the the Boeing 787.
Industry sources, however, say the Trent 1000 failure occurred due to "non-adherence to test procedures". That permitted oil and fuel to accumulate throughout the engine.
On 30 August, a RB211 engine on a Qantas Boeing 747-400 experienced an uncontained failure en-route to Sydney from San Francisco, where the aircraft safely returned. A preliminary report from the ATSB suggests the cause was turbine failure that caused damage to the intermediate pressure and low pressure turbine rotors.