Rolls-Royce Homes In on Cause of Trent 900 Failure

 - November 12, 2010, 8:43 AM
An advisory directive issued by the EASA on November 10 calls for repetitive inspections of Rolls-Royce Trent 900s every 20 flight cycles. (Copyright Rolls-Royce)

Rolls-Royce today confirmed that an oil fire led to the November 4 uncontained failure of a Trent 900 on a Qantas A380 on its way from Sydney to Singapore. In a statement issued this morning, the engine company said that the failure involved "a specific component" in the turbine area of the engine and led to the release of the intermediate pressure turbine disc.

A380 watchers continue to await word on the fate of Qantas's grounded fleet of six superjumbos after inspections prompted by the November 4 incident uncovered oil leaks in the turbine area of three engines on three different airplanes. Meanwhile, one of three Singapore Airlines A380s that underwent engine changes this week has returned to service.

SIA ferried the airplanes to its base at Changi International Airport to replace three Trent 900s that also showed evidence of oil leaks. One other Trent 900-powered A380, flown by Lufthansa, returned to service on Wednesday after that airline replaced an engine for an unrelated reason.

Today's confirmation from Rolls-Royce comes less than two days after authorities concluded that an oil fire in the destroyed engine's high pressure/intermediate pressure structure cavity "may have caused" the failure of the intermediate pressure turbine disc. Consequently, the European Aviation Safety Agency on November 10 issued an emergency airworthiness directive that calls for inspections of the engines' low-pressure turbine stage one blades and case drain and the high pressure/intermediate pressure air buffer cavity and oil service tubes. The AD requires the inspections within 10 flight cycles of its November 10 effective date and at least every 20 cycles thereafter.

In an effort to avoid resulting schedule disruptions, Singapore Airlines, for one, said it would back-fill its A380 routes with Boeing 747s and 777s. Qantas continues to fly Boeing 747s on its A380 routes.

For its part, Rolls-Royce moved quickly to refute any link between the Qantas incident with the August failure of a Trent 1000 at Rolls's Derby, UK, test center. "We can be certain that the separate Trent 1000 event which occurred in August 2010 on a test bed in Derby is unconnected," Rolls-Royce said in a November 8 statement. "This incident happened during a development program with an engine operating outside normal parameters. We understand the cause and a solution has been implemented."

Soon after the Qantas incident officials from the Australian Licensed Aircraft Engineers Association (ALAEA) suggested that increased "outsourcing" of maintenance work by the Australian flag carrier has led to a higher frequency of safety incidents over the past few years. Qantas CEO Alan Joyce characterized the ALAEA's claims as "ludicrous," and consistently attributed the November 4 incident to either a design fault or a material defect.