A350-1000 Engine Concerns Hang Over Emirates Order Talks

Credit: Mark Wagner Aviation Images

DUBAI—Emirates Airline President Tim Clark has effectively ruled out an order for Airbus A350-1000s if Rolls-Royce does not come up with major improvements to the Trent XWB-97 engine, including a significant thrust increase.

“The engine is not doing what we want it to do,” Clark said on the sidelines of the Dubai Airshow Nov. 14. “So, we won’t order until it does.”

Clark’s comments come after Emirates placed a large order for 90 additional Boeing 777Xs on the opening day of the show Nov. 13 and was in the midst of negotiating a deal with Airbus for up to 50 A350-1000s. The airline has commitments for 50 A350-900s, the first of which is due to arrive in August 2024.

According to Clark, the airline is requesting guarantees for up to 2,500 cycles on wing for the Trent XWB-97 “at a maintenance cost per hour that is alright.” If Rolls-Royce was to meet that target, Emirates would “reconsider” an order. However, in the harsh environment in which the airline operates and at the utilization levels expected, the engine is reaching “less than a quarter of the cycles on wing,” Clark claims referring to durability levels seen by other airlines operating under similar conditions. In the Gulf region, both Etihad Airways and Qatar Airways are operating the A350-1000.

“Why would you buy a defective engine?” Clark asked. “Four or five hundred hours on wing is not doing the job.” He does not have similar concerns about the baseline Trent XWB-84 engine which powers the A350-900.

Rolls-Royce acknowledges that XWB-97 durability and time-on-wing for operators in the region needs to improve, but rejects the idea that the engine is "defective."

“It's not defective,” Ewen McDonald, chief customer officer of Rolls-Royce Civil Aerospace, tells ShowNews.

“This is durability, and you can look at the meaning of defective or whatever, but this engine is reliable—99.9%. It’s just not staying on wing as long as customers would want and that's our focus,” McDonald says. “It's better for Rolls-Royce because if engines stay on wing for longer, they have less shop visits and less cost. So, I couldn't be more aligned as far as what he wants to do with this engine which is to improve durability and time on wing.”

The issue cannot be settled financially through a much lower cost maintenance agreement, Clark added. He would like to see technical improvements to the engine beyond those which Rolls-Royce has already committed to.

Rolls says just such improvements are underway or in the pipeline, some of which will be derived from its extensive technology demonstrator series—the latest of which is the UltraFan. 

However, McDonald adds: “We understand that in the harsh hot and sandy environment we are not meeting our customers’ expectations at the moment. And I would say there's no one at the moment in a new-generation engine that is meeting expectations in service. We are all suffering with new-generation engines in these conditions.”

In temperate or colder climates, McDonald said the “A350-1000 and -97 is working great in what we call benign operations and achieving a life that customers are really happy with. The engine is the most efficient that we have and it's the most successful program we have. But like all our products we continue to advance."

McDonald continued, "The good thing is that we have all the demonstrator programs—the UltraFan being one of those—that are generating new technologies which we are de-risking through these programs, and it gives us optionality as far as what we may be able to do to improve the engine—we're determined to continue to improve the product.”

“We also have the Sunrise mission,” said McDonald, referring to the ultra-long-haul "Project Sunrise" for which the A350-1000 was selected by Qantas. “You probably can’t have a harsher mission—without the sand—to fly all the way to Sydney from London. We are supporting that, and we've done the deal with Qantas, so this [region] is very particular as far as the harsh environment and we understand what it is. Yes, it takes quite some time to find out what the solution is and to put that into the engine,” he adds.

Perhaps indirectly divulging potential future mission goals for the A350-1000, Clark is also pushing for a 10,000 lb. thrust increase to 107,000 lb. “The engine is under-‘spec’-ed for what the aircraft could do,” he said. “It does not have enough power, the technology is not proven.”

While Rolls-Royce appeared to be unaware of Clark’s concerns over thrust levels, the engine-maker says it has worked with Airbus over time to match the A350-1000’s weight growth—the latest phase of which saw the aircraft’s type certificate amended in October with a higher maximum takeoff weight (MTOW) of 709,890 lb. (322 tons), an increase of more than 6,600 lb.

Beyond relatively modest throttle push increases, it is unlikely that a thrust increase of the magnitude called for by Clark would be feasible with the existing architecture of the XWB-97. The 97,000-lb. version for the A350-1000 retains the same 118-in.-dia. fan as the lower thrust XWB-84, despite significant internal changes such as a 5% larger core.

As part of the deal for 777Xs, Emirates has also come back to the redesigned 777-8, of which it is now taking 35 units. The redesigned layout optimized for the 777-8F caught Emirates’ attention for the passenger variant, which now “hits a sweetspot for us,” Clark said. The aircraft is also close in capacity and range capabilities to the A350-1000, so the role of an aircraft meeting these parameters is covered regardless of whether Emirates will ultimately buy the -1000.

As for the 777-9, Clark does not “see the risk of a program slip to 2026” as Boeing and airworthiness authorities are “getting on top of the regulatory issues, too—so far so good, we are hoping it will be okay for us.” 

Clark expects Boeing to gain U.S. FAA Type Inspection Authorization, the formal start of certification testing, by February 2024. Emirates is to receive its first 777-9 by the end of 2025, five and a half years later than planned.

After having considered to drop the type, Emirates recommitted to the 787, too, but switched to the -8 and -10 versions from the -9. The higher gross MTOW set to be introduced for the -10 in 2024 means that the largest of the 787 variants will now be able to cover 85% of the current Emirates network. “For anything up to eight hours, it is good to go,” Clark added.

Jens Flottau

Based in Frankfurt, Germany, Jens is executive editor and leads Aviation Week Network’s global team of journalists covering commercial aviation.

Guy Norris

Guy is a Senior Editor for Aviation Week, covering technology and propulsion. He is based in Colorado Springs.