Rolls-Royce advances toward Trent XWB flight test aboard A380

TOULOUSE — The familiar Rolls-Royce Trent 900 flying in the number two engine position under the wing of the first A380 has been replaced by Trent XWB as the engine-maker and Airbus are approaching the start of the powerplant’s 175h flight test program. 
With 1,200h of testing accumulated across eight engines at test facilities in five countries, Chris Cholerton, R-R director of the Trent XWB programme, said specific fuel consumption tests are tracking ahead of expectation for typical early build engines and that it is the company’s expectation that the A350′s engine will be the “world’s most efficient civil turbofan.” 
The 118in (300cm) fan, designed to produce 84,000lbs of thrust for the A350-900, has been installed on A380 MSN001 with a multi-million dollar bespoke pylon that features on one end an A350 engine interface, and an A380 wing interface on the other. 
  
The heavily instrumented engine has already begun ground runs on the A380, and will relay 1,200 individual parameters, the most for a civil programme by Rolls-Royce, will measure and twice as many as any previous evaluation. The instrumentation alone adds 600kg (1,300lbs) of weight to the test engine.
Once the new majority-composite aircraft is flying, each engine for the A350 flight test program will be less instrumented than the certification engine as the 1,300lbs of instrumentation will be spread across the aircraft’s two engines. Both A350 MSN001 and MSN003 will be fully instrumented test aircraft. 
 
On the A380′s flight deck, test pilots have a mechanical link installed between the A380′s throttle quadrant and the A350′s, positioned at the rear of the pedestal. In the cabin of the A380, flight test engineers have live access to all the data streaming off of the engine, as well as access to the Trent’s electronic engine control (EEC) software, which will be able to be changed in flight. 

While Airbus only says the Trent XWB flying test bed would make its first flight in the “coming weeks”, the Rolls-Royce says a minor design change could slide that target further by “a few weeks”.
During the engine’s required 150h endurance testing, which wrapped up in September, Cholerton said R-R discovered damage on the engine’s “rotating air seal that separates the [intermedia pressure] turbine from the back of the [low pressure] turbine”

“That’s an issue we can easily resolve,” he said, adding an updated design has already been manufactured. 

If Rolls opts to install the modification before beginning its flight trials the engine will have to be removed from the A380′s wing.

“We may elect to change that prior to flight, because we can, it’s simple to do,” he said. “We can do it here in Toulouse. We can still be flying the flying test bed over a year ahead of first flight. We want to test the final production standard of part, that’s a good thing to do for our maturity objectives.”