Service entry for an upgraded variant of the Rolls-Royce Trent XWB-84 engine for the Airbus A350-900 is now not expected until 2025 at the earliest – over five years later than originally planned.

Rolls-Royce unveiled the Enhanced Performance – or EP – variant of the XWB-84 at the Singapore air show in 2016 with a launch order from Singapore Airlines (SIA).

A350-900 Ultra Long Range -c-Airbus

Source: Airbus

SIA says it will deploy the XWB-84 EP engines chiefly on A350-900ULR fleet

Using technologies from the higher-thrust XWB-97, which powers the A350-1000, and the Advance demonstrator programme, the EP model will improve fuel consumption by an expected 1%.

Rolls-Royce had planned to deliver the initial powerplants to SIA by late 2019, but that date has quietly slipped.

SIA now says it expects to “take delivery of the Trent XWB-84 EP engines from the first quarter of 2025”.

They will “be used mainly” on its fleet of A350-900 Ultra Long-Range (ULR) aircraft, the carrier adds.

Equipped with just 161 seats – compared with 359 on SIA’s baseline -900s – the ULRs can fly up to 9,700nm (18,000km), against 8,300nm for the standard A350. On such long sectors, a 1% fuel saving could offer significant operational and cost benefits.

Rolls-Royce declines to comment on the reasons for the delay to the EP variant, but says: “The Trent XWB is the most efficient large-fan aero-engine in service today and is recognised as an industry benchmark for reliability.

“We are proud to power Singapore Airlines and are working with them closely to support their A350 operation.”

However, the late service entry is likely the result of the combined effects of the durability problems experienced on the Trent 1000 – delivering a solution for which consumed vital engineering resources – and the Covid-19 pandemic which followed shortly after and decimated long-haul air travel.

One engine industry source indicates that testing will run until at least 2024, with a firm service entry date to be set after that point once the fuel-burn performance is validated and an improvement can be guaranteed.

Rolls-Royce declines to comment on the status of the development and testing programme.

Launching the upgrade, Rolls-Royce said the EP would be offerable to other “existing customers” for delivery after the first units to SIA. The engine manufacturer declines to say if it has received additional orders for the enhanced model.

But it will be suitable for all A350-900s, not just the ULR variant, and can be used in combination with the existing XWB-84 “to enable simplicity in service”.

Upgrades over the baseline model included improvements to turbine cooling and aerodynamics, and to the secondary air system and inter-stage sealing, plus further optimisation of the turbine tip clearance control system.

Additional reporting by Greg Waldron.