LONDON -- An Airbus executive said Friday that Rolls-Royce has identified a faulty bearing box as the cause of the oil leak problem implicated in the midair disintegration of an engine on one of the world's largest airliners, an Australian newspaper reported.
Airbus Chief Operating Officer John Leahy told reporters in Sydney that Rolls-Royce had at some point fixed the bearing box on newer versions of the massive Trent 900 engine, a model designed for the massive A380 superjumbo. He said Rolls was now fixing it on older versions. The Herald Sun reported his comments on its website.
His comments did not address why Rolls-Royce had not fixed the bearing box in older versions of the engine.
Airbus did not elaborate and Rolls-Royce declined to comment on his remarks.
The box in question contains the metal ball bearings that allow movement of the drive shaft that powers jet engines. Investigators have said they suspect that leaking oil caused a fire in the engine of a Qantas A380 that led it to disintegrate over Indonesia last week, sending pieces of metal into the wing and cutting vital safety systems before the jetliner landed safely in Singapore.
They have focused on broken pieces of the engine's heavy turbine disc, a plate that holds the blades moving air through the motor.
"In the future the computer will have software that can identify a problem at the outset and it will shut down an engine before a turbine disc can go out of control and come apart," Leahy told the Herald Sun.
Rolls-Royce Group PLC said in an update to investors Friday that the disintegration of the engine resulted from a problem in a specific component in the Trent 900, but it did not provide details.
Leahy said the new models of the Trent 900 had been redesigned to eliminate the problem of excess oil causing turbine fires. He said that Rolls-Royce was retrofitting the older versions with new parts to stop the oil leaks and computer software that would shut down an engine with leaking oil before it became at risk of disintegration.
Leaks or oil stains have been discovered on six of the total of twenty A380s operated by Qantas, Lufthansa and Singapore Airlines that use the Trent 900 engines, a technologically advanced model designed to be lighter, quieter and more efficient than older engines. Qantas and Singapore Airlines have grounded nine of the world's largest airliner between them while Germany's Lufthansa has already replaced an engine on one of its A380s.
Engines on the A380 malfunctioned four times before one of them disintegrated during a flight from Singapore to Sydney last week, and aviation experts have said that the earlier mishaps may hold clues to design or construction flaws.
Airbus will take Rolls-Royce engines off the final assembly line in Toulouse, France, and send them to Qantas "so we can get Qantas back up and flying," the Airbus press office said.
In a trading update Friday, London-based Rolls-Royce said the incident will cause full year profit growth "to be slightly lower than previously guided," but it also said that the company's other operations will help to offset any losses. Back in July, the company said that its underlying profits would grow by 4-5 percent compared to 2009.
Shares in the company rose after the update -- a signal that investors are happy to see a definitive statement after days of silence from the world's second-biggest engine maker behind General Electric and one of the last globally important industrial manufacturing companies in Britain.
Rolls-Royce shares were up 4 percent at 607.5 pence ($9.74) in midmorning trade on the London Stock Exchange.
Rolls-Royce said the series of checks made on the Trent 900s after last week's incident had led it to draw two key conclusions.
"First ... the issue is specific to the Trent 900," Rolls-Royce said in a statement to the London bourse. "Second, the failure was confined to a specific component in the turbine area of the engine. This caused an oil fire, which led to the release of the intermediate pressure turbine disc."
The statement supports a report from the European Aviation Safety Agency, which issued an emergency order Thursday requiring airlines to re-examine their Trent 900s and ground any planes with suspicious leaks. EASA said the explosion on the engine of the Qantas jet was caused by an oil fire inside the engine.
Rolls-Royce's chief executive said the company will be replacing the relevant part "according to an agreed program" as inspections on the engine continue in association with aviation regulators.
"This program will enable our customers progressively to bring the whole fleet back into service," Rose said.
Four problems dating to 2008 led to two warnings for airlines to check parts of the Trent 900.
Three of the four previous problems centered on the turbines or oil system.
Joerg Handwerg, a spokesman for the pilots' union for German airline Lufthansa, said that minor problems are routine for any jet engine, but it is possible that the issues were an indication that regulators did not adequately check the engine before approving it for commercial use.
"When you see we have a problem with not just one of these engines but several then it points towards that we have a problem in the certification process," Handwerg said.