Why Boeing Didn't Stick With One Engine Option For The 787

Despite some significant safety concerns — including those stemming from the deadly Air India Boeing 787 crash in June 2025 — the so-called Dreamliner remains a popular choice for airlines today. Boeing has delivered more than 1,175 Dreamliners through April of this year, and these jets have carried more than a billion passengers. 

There are two engines available for the 787 family: General Electric's GEnx-1B and Rolls-Royce's Trent 1000. Each has its own unique strengths, so giving customers a choice allows them to pick the power plant best suited for specific routes. Airlines also might already have experience repairing or maintaining a given engine, and the choice lets them keep their operations consistent.

Another benefit of Boeing's strategy is that it expands availability; If one engine-maker is having supply chain problems, the other may be able to fill its place. That way, Boeing won't have all of its jet-powered eggs in one basket. Beyond customer appeal and risk management, though, is there any real difference between the GEnx-1B and the Trent 1000? Let's find out!

Let's look at some similarities first. Of these, one of the most important is that the engines are easily interchangeable. The 787 was the first commercial jet to use the same interface with two different engines. Boeing believed this would be an attractive proposition for not just airlines, but also financiers and leasing companies. In some cases, those trying to purchase a plane with one particular engine might not see their preference available. Thanks to their similarities, though, buyers would have a simpler time with just buying the airplane anyway, letting them get the "right" engine later down the line.

As for the engines themselves, both are turbofan jets that deliver thrust two ways. At the core is a standard jet engine that burns a mixture of fuel and air. There's also a bypass system that lets some intake air skip combustion, with a fan channeling it around the core before expelling it out of the rear. The result is an engine that delivers more thrust than the jet alone while using less fuel than a bigger power plant producing the same output. It's that combination of advantages that allowed the aviation industry to abandon tri-jet commercial planes.

Rolls-Royce's engine has a particularly high bypass ratio of 10:1, compared to the 8.8 to 9:1 ratio on the GEnx-1B. Bypass ratios look at the amount of air that's avoiding combustion and shooting straight out the back, comparing it to the air that actually makes it into the engine. For the Trent 1000 specifically, it means the fan — not the more fuel-hungry jet — is producing around 85% of the engine's thrust. 

General Electric also takes an innovative approach to engine design by using lightweight carbon-fiber composites for components like the turbofan blades and casing. Speaking of fan blades, the GEnx-1B managed to reduce its number to 18 — down from 22 in the previous version — to save even more weight. The Trent 1000 features 20 turbofan blades, as well as three compressor shafts compared to the pair used by GEnx-1B. This was done to boost efficiency, lengthen the engine life, and improve the aerodynamics of Rolls-Royce's engine.

Yet, what might be the biggest difference in the engines' real-world abilities has to do with their initial reliability. The Trent 1000 launched with a myriad of issues that led to expensive repairs for customers, forcing them to deal with the cost and downtime required to make those fixes. Rolls-Royce responded with design enhancements from other power plants, but even British Airways decided to drop London-headquartered Rolls-Royce engines for the GEnx-1B. It's also worth pointing out these aren't the only companies that build Boeing's jet engines.