Under the wing of Boeing's conceptual 777X would be General Electric's GE9X, a 90,000- to 100,000lb-thrust class engine, contributing a 10% improvement in fuel burn for the -8X/-9X family, say those directly familiar with the concept.

"We feel pretty good about the technologies we've delivered." said David Joyce, chief executive of GE Aviation in a February interview. "And we feel even better about the technologies that we currently have in development to deliver for the 9X."

Compared to the 115,000lb-thrust GE90-115B that powers the 777-300ER, the lower thrust 99,500lb and derated-88,000lb GE9X for the 777-9X and -8X, respectively, are enabled by the larger, higher-lift and comparatively lighter composite wing. The eCore-inspired engine would also feature a GEnx-style composite fan casing and third-generation Twin Annular Premixing Swirler (TAPS) Combustor, dubbed TAPS III, say those familiar with the engine maker's planning.

The engines for the 777X family are identical, addressing the lack of commonality between the Rolls-Royce Trent XWB engine on the A350-1000, compared to that on the smaller -900 and -800.

Under development for nearly three years, GE is spending $50 million on technology advancement on the GE9X in 2012, with plans for a late-decade availability, Joyce said. "We'll take our leads from Boeing and Boeing's schedule, just like we always do."

The 325cm (128in) diameter GE9X engine is believed to tout an approximately 10:1 bypass ratio, 60:1 overall pressure ratio and 27:1 high pressure compressor ratio, compared to the 42:1 and 23:1 pressure ratios, respectively, on today's GE90-115B, .

Despite strong suggestions of a request for proposal to Rolls-Royce and Pratt & Whitney for a 90,000-100,000lb engine, Joyce is confident that GE will remain an engine provider to the programme as the 777 moves to its next generation.

"Incumbency or not, our job is to prove that we can demonstrate the value of GE9X on the 777, just like we have on the [GE90], and we have a good track record to prove it. So, game on," he said.

Source: Air Transport Intelligence news