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Ground testing is underway on the first full GE9X development engine, which is the world’s largest commercial aircraft engine, at GE Aviation’s Peebles Testing Operation.

“The entire GE9X team—from engineering to sourcing to value streams to development assembly—devoted countless hours to enable this achievement to occur,” said Bill Millhaem, general manager of the GE90/GE9X engine programs at GE Aviation.

“The ground testing will generate data on the full engine system and aerodynamic performance, mechanical verification, and aero thermal system validation.”

“We would like to convey our congratulations to the GE team for its achievement of this milestone,” said Bob Feldmann, Boeing 777X vice president and general manager.

“GE’s commitment to technology maturation throughout the GE9X development program continues to deliver results for the 777X program. We look forward to working together with GE to deliver this great airplane to our customers.”

Maturation testing of the GE9X engine began about five years ago and has progressed from component-level all the way to the first full engine to test (FETT). FETT brings all the GE9X technologies together to demonstrate their operability as a complete propulsion system.

Compared to other engine programs, the GE9X FETT happened earlier in the development process, just a mere six months after the engine design was finalized. This timing assures all learnings from FETT will be captured in the certification engines.

Next year will be a busy year for the GE9X program with the start of certification testing and flight testing on GE Aviation’s flying test bed. Engine certification is anticipated in 2018.

With almost 700 GE9X engines on order, the GE9X engine will be in the 100,000 pound thrust class and will have the largest front fan at 134 inches in diameter with a composite fan case and 16 fourth generation carbon fiber composite fan blades. Other key features include; a next-generation 27:1 pressure-ratio 11-stage high-pressure compressor; a third-generation TAPS III combustor for high efficiency and low emissions; and CMC material in the combustor and turbine.

Along with GE Aviation technology and advanced material, the GE9X engine also contains the low-pressure turbine module and accessory drive train (ADT) kit composed of the inlet gearbox, transfer gearbox and accessory gearbox, connecting shafts and related attachments) from Avio Aero, a GE Aviation business.

The ADT, manufactured at the Rivalta plant, allows the engine and the aircraft to function properly and supplies energy drawn from the engine itself for a variety of functions.

The inlet gearbox or IGB draws motor energy from the high pressure compressor of the engine, and the transfer gearbox or TGB transmits it to the accessory gearbox (AGB) on which the engine and aircraft accessories are installed. The AGB provides the power for these accessories, such as the fuel pump, oil pump, hydraulic pumps for flight controls, air turbine to start the engine, as well as various onboard tools and commodities for the pilots and passengers.

For the GE9X, the AGB is the largest yet most compact AGB ever made by Avio Aero, with only 10 axles to drive nine accessories compared with the 11 axles driving eight accessories on the GE90. Additionally, the fuel accessories are connected to each other via full conduits in an additional small fuel adapter installed directly on the AGB, which reduces the external pipe system to improve the engine profile.

“The reduction in the number of axles,” said Rocco Pellettieri, project engineer for the GE9X at Avio Aero, “not only benefits weight, but also reduces the part count and simplifies the supply chain. The design with fewer axles but more accessories compared to the GE90 was made possible thanks to complex optimization studies that allowed us to achieve more with less.”

IHI Corporation, Snecma and Techspace Aero (Safran), and MTU Aero Engines AG are participants in the GE9X engine program.