Rolls-Royce has stated that the new engine is certified for use with sustainable aviation fuel (SAF) blends up to 50%, with plans for 100% SAF compatibility in the future. This aligns with broader industry efforts toward sustainability.
As airlines look for ways to expand their route networks, especially between distant city pairs such as those connecting Europe or North America with Australia’s major cities like Melbourne or Sydney, the increased range offered by these engine improvements may open new possibilities. The A350-900 currently ranks among commercial airliners with some of the longest ranges worldwide—just behind other A350 variants such as the A350-1000 and A350-900ULR—and could move closer to enabling flights between almost any two airports globally.
Despite these advancements, Rolls-Royce is also developing a next-generation turbofan called UltraFan. With a larger fan diameter and higher bypass ratio than current engines, UltraFan aims to offer a 25% improvement in fuel burn over first-generation models like the Trent 700 and a 10% increase over today’s XWB engines. It is designed from launch to be compatible with 100% SAF. However, UltraFan’s entry into service is not expected until after ground tests planned for 2028 and flight tests before 2030.
In June, Delta Air Lines became the first carrier to receive an A350-900 equipped with the new XWB-84 EP engine. While Singapore Airlines was initially identified as a customer for this model, more airlines are now receiving deliveries. The higher-thrust XWB-97 EP variant remains under testing and could appeal to carriers operating in challenging environments; Emirates President Tim Clark has indicated interest if reliability improvements are delivered.
Pete Young, chief engineer for the Trent XWB-84 EP at Rolls-Royce, commented: “The certification of the Trent XWB-84 EP is the result of a rigorous design and testing programme. It reflects the continuous improvement of the Trent XWB family, ensuring it remains a competitive option for airlines navigating evolving industry challenges. We now look forward to its introduction into service in 2025.”
Even marginal gains can have significant financial impacts; on long-haul flights lasting up to 18 hours, operators could save substantial amounts on fuel due to improved efficiency. In addition to cost savings, extended maintenance intervals add further value by reducing downtime.
These developments highlight ongoing efforts by manufacturers like Airbus and Rolls-Royce to enhance aircraft performance while supporting environmental goals through greater fuel efficiency and future-proofing engines for alternative fuels.
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