Qantas has launched preliminary legal action against Rolls-Royce, the manufacturer of the engine that exploded on one of its A380 superjumbos in mid-air last month.
The airline said today it has filed a statement of claim in a federal court that will allow it to launch legal action against Rolls-Royce at some point.
Qantas chief executive officer Alan Joyce has said the airline will seek compensation from Rolls-Royce over the November 4 incident in which an engine disintegrated shortly after takeoff.
Qantas said today's legal action would ensure it could sue Rolls-Royce if it was not satisfied with a compensation offer from the UK-based company.
The legal move was announced after Australian investigators said they had identified the source of an oil leak that caused the engine to blow apart in mid air last month, and said a suspected manufacturing defect in the Rolls-Royce engine was to blame.
They warned airlines the potential flaw could cause engine failure.
The Australian Transport Safety Bureau recommended the three airlines that use Rolls-Royce's Trent 900 engines on their A380s go back and conduct more checks now it has pinpointed the problem area. Three airlines fly a total of 20 such planes.
Earlier warnings blamed an oil leak for a fire and subsequent chain of failures that sent heavy parts flying off an engine on a Qantas A380 shortly after it took off from Singapore on November 4, the most serious safety problem for the world's largest and newest jetliner.
The ATSB, which is leading the international investigation into the Qantas break-up, added some specifics today, saying a section of an oil tube that connects the high-pressure and intermediate-pressure bearing structures of the engine was the danger area.
"The problem relates to the potential for misaligned oil pipe counter-boring, which could lead to fatigue cracking, oil leakage and potential engine failure from an oil fire within the HP/IP bearing buffer space," the ATSB said in a brief statement.
It called the problem "a potential manufacturing defect".
Counterboring is when you place a larger hole over a smaller hole to make room for a seal. The ATSB said a misalignment of those holes had produced a thinning of the oil pipe wall and fatigue cracks. That could have led to oil leaking into a section of the engine that contains extremely hot gas - a mixture of burned fuel and air. If oil comes into contact with the hot gas, it will burn.
"It is a design error and obviously a major one," said Peter Marosszeky, a jetliner maintenance expert at the University of New South Wales.
The ATSB recommended close inspections of all Trent 900 engines to look specifically for signs of the counterboring problem. Any engines that display such signs should be removed from service, it said.
In response to that recommendation, Rolls-Royce, affected airlines and other safety regulators were taking action to ensure the A380s involved were safe, the bureau statement said.
The three airlines, Qantas, Singapore Airlines and Germany's Lufthansa, conducted extensive checks of their Trent 900 engines and modified some parts in compliance with a November 11 directive from the European Aviation Safety Authority. That order was to look for oil leaks in the same section of the engine, but did not mention a potential source.