Primary markets are expected to be trunk routes from the Middle East to Europe and Asia, as well as transatlantic services for carriers including British Airways and Singapore Airlines, which are among the early launch contenders. Assuming a firm launch decision in early 2013, entry into service is widely expected around 2018-19.
As the 787-10X forms part of Boeing's stated strategy to bracket the A350 between the double-stretch derivative and the 777X, the launch of one of the new aircraft will ultimately determine the go-ahead for the other. For Boeing, the key question on the 777X remains timing, and although the A350-1000 launch continues to show signs of sliding further into the second half of the decade, the main driver appears to be getting the technology decisions correct on its new, big twin derivative.
Compared to the relatively straightforward double-stretch of the 787-10X, the development of a pair of larger rewinged, reengined successors to its 777-200LR/300ER for possible entry into service in 2019 is a far greater gamble in terms of cost, technology and marketing tactics. As well as major choices concerning the use of composites in the wing and major system innovations, Boeing's arguably biggest single decision is whether to make the engine dual- or sole-source.
General Electric, in the pole position to supply the engines for the new derivative, is sticking to a technology test plan for the GE9X for the 777X, despite continuing uncertainty over Boeing's development timetable. The engine maker is running a raft of technology demonstration efforts to support FAR33 engine certification in 2018, and entry-into-service in 2019.
“Even though Boeing is still figuring out what they want to do, we're doing the technology,” says GE90 general manager William Millhaem. “It's the right thing to do for the industry.”
Although GE is also reluctant to give specific timetable details, it is expected to run the first version of a new core for the GE9X as early as 2014. A final “Toll Gate 6” decision on freezing the design will likely take place around 2015, with the first engine going to test in the 2016 timeframe. Given this timing, the engine would be tested on GE's Boeing 747-400 flying testbed in 2017 with certification the following year.
Key technology maturation tests in the run-up to the design of the new core include the planned evaluation of a 27:1 pressure-ratio high-pressure compressor (HPC). The initial version of an 11-stage unit will be tested at GE's oil and gas facility in Massa, Italy, in mid-2013, and will be the highest pressure-ratio compressor of its type yet developed for a GE commercial engine.
Testing of the advanced compressor rig will check the configuration “to look if anything unexpected happens at 27:1 and see what happens when we bleed air off and if we get the right clearances,” says Millhaem, who adds that the lessons will be used to improve the baseline design before the first core is built. The advanced “E3” (Energy Efficient Engine) 19:1 compressor developed with NASA was key to the success of the original GE90, while the evolved HPC of the GEnx has a pressure ratio of 23:1. Overall pressure ratio for the entire GE9X is similarly targeted at an ambitious 60:1, compared to 50:1 for the GEnx and 40:1 for the GE90.
“With the GE9X, we're continuing that strategy, but we are reaching into the technology cupboard to pull out new things from the 9X technology pool,” says Millhaem. “If we start with a scaled GEnx-1B, we get about halfway to what Boeing is asking us to do for the 777X,” he says. The 777X is targeting fuel burn around 10% lower than the current GE90-115B-powered 777, while maintaining existing maintenance costs.
Other work is focused on a fourth-generation fan that will operate at higher speed that the one in the current engine.