Delta Air Lines has become the first carrier to take delivery of an Airbus A350-900 powered by the new “Enhanced Performance” (EP) variant of the Rolls-Royce Trent XWB-84 engine.
Rolls-Royce claims a 1% reduction in specific fuel burn from the powerplant, which was certificated at the aircraft level in April.
Andy Ward, vice-president of programmes at the UK engine maker, says no “novel technologies” have been incorporated in the EP, with the performance gain achieved through “world-class systems engineering”.
“We have optimised the engine knowing how it performs in service; we know exactly how customers use the [Trent XWB-84].”
Rolls-Royce had previously only identified Singapore Airlines as a customer for the EP - an option to the baseline 84,000lb thrust (373kN)-rated XWB-84 – but now says Delta is the first operator to put the engine into service.
It does not say the date Delta acquired the jet. Cirium fleets data shows that Delta received an A350 from Airbus on 30 April and that it is scheduled to received another on 15 June.
Development of the EP variant is part of a £1 billion ($1.35 billion) package of improvements the manufacturer is rolling out across its in-production Trent family.
Next to enter service will be a durability enhancement for the Trent 1000 – an option on the Boeing 787 – which is intended to double the engine’s time-on-wing.
Changes are designed to improve the life of high-pressure turbine blades, which have proved less durable than hoped, posing availability challenges for operators.
Aircraft-level certification from the US regulator is “very, very close”, says Alan Newby, Rolls-Royce director for research and technology.
Testing on a further upgrade package for the Trent 1000 and related Trent 7000, again focussed on the HPT blade, will get under way this year, ahead of an expected roll-out in 2026. Trent 7000s power A330neos.
Newby is “confident” the modifications will deliver another 30% time-on-wing gain.
In addition, ground testing of new components for the A350-1000-powering Trent XWB-97 is also in full swing, says Newby. “We have got an engine on the bed as we speak. We are doing really, really well on that one.”
Forming the largest part of the £1 billion investment, enhancements to the 97,000lb-thrust XWB-97 include redesigned HPT blades, nozzle guide vanes, ceramic matrix composite seal segments and optimisation to the combustor.
Rolls-Royce aims for the XWB-97 improvements to be rolled out in 2028. They are particularly designed to address the engine’s durability in hot and sandy environments.
Meanwhile, the engine maker expects to wrap up flight tests in late June or early July of the latest iteration of its ALECSys lean-burn combustor.
Tests of the system, using a Trent 1000 donor engine installed on the company’s 747-200 flying testbed, have been ongoing since early this year. They included a short cold-weather campaign conducted in Fairbanks, Alaska.
“We have just about finished that piece of work,” says Newby, adding that the tests were “mostly about the maturity of the system” and to validate Rolls-Royce’s modelling.
Originally flown in 2022, Rolls-Royce has since tweaked the technology, improving both the fuel injector and the control system.
“Effectively what we are testing now, we believe, is the final version of the both the fuel nozzle – the injection system – but also the control system as well,” says Newby.
ALECSys improves the pre-mixing of fuel and air prior to ignition – delivering a more-complete combustion of the fuel, lowering NOx and particulate emissions.
Newby says testing carried out in Cologne and on a rig have shown a 40% reduction in NOx emissions.
“We are very happy that it is delivering everything that we wanted it to,” he says.
ALECSys is a key part of the UltraFan engine which Rolls-Royce hopes will enter service next decade.
