A Rolls-Royce Group Plc engine that exploded last November on an Airbus SAS A380 operated by Qantas Airways Ltd. caught fire because the U.K. company made an oil pipe too thin, safety investigators said today.
The defect caused a fracture that allowed oil to leak and ignite, weakening a turbine disc which fractured and came away from its shaft before accelerating to “critical burst speed,” the Australian Transport Safety Bureau said in a report.
Incomplete measurement records meant Rolls was also unable to establish which other turbines suffered from the same flaw, forcing the grounding of 53 more Trent 900 engines, according to the ATSB, including one from the latest batch produced. Rolls said it supports the probe and is addressing the points raised.
“Clearly there are matters the ATSB is still pursuing, notably in respect of Rolls-Royce’s quality assurance,” said Sandy Morris, an analyst at Royal Bank of Scotland in London with a “buy” rating on the company’s stock. “I don’t doubt that Rolls itself will want to make sure it never happens again.”
Qantas grounded its six A380 superjumbos after the Nov. 4 explosion on a flight from Singapore, during which debris from the engine penetrated the plane’s wing. No-one was hurt and the flight managed to make an emergency landing in the city-state.
The Australian airline has said it’s seeking compensation from London-based Rolls-Royce, which posted its first decline in annual profit for almost a decade in 2010 because of costs from fixing the faulty engines and developing new ones.
Singapore Airlines Ltd. and Germany’s Deutsche Lufthansa AG, the only other carriers with Rolls-powered A380s, also pulled planes out of service.
The ATSB said today that the lack of measurement records caused the removal of 42 engines with oil-feed pipes built to an early design. Ten powerplants with modules made between 2007 and 2009 were also grounded, including seven where the pipe walls were found to be too thin when measured on the wing, plus one from a batch produced between 2009 and January this year.
“We fully support the ATSB’s ongoing investigation and are actively addressing the points raised,” Rolls-Royce said in an e-mailed comment. “As the investigation is still ongoing it would be inappropriate for us to comment further at this stage.”
Airlines were told in March that “intrusive” checks on Trent 900s were no longer necessary after more had been learned about the blowout. Rolls has developed software to shut down an engine before it reaches dangerous speeds at which a disc might burst, the European Aviation Safety Agency said.
Rolls-Royce closed 0.2 percent higher at 636 pence in London. The stock has advanced 3.7 percent so far this year, valuing the company at 11.9 billion pounds ($19 billion).
“The ATSB’s interim report adds substance to what was widely reported at the time,” RBS’s Morris said. “It helps to draw the line more firmly under that unfortunate event.”