Motorer igjen - Boeing har hatt problemer med B777X, mye grunnet motoren - AW&ST

GE9X Engines Nearly Ready for 777X Flight Tests

by Gregory Polek

 - November 15, 2019, 7:59 AM

A GE9X flight test article hangs from GE's Boeing 747 flying testbed. (Photo: GE Aircraft Engines)

GE Aviation has delivered the first three fully compliant GE9X turbofans to Boeing’s Everett, Washington, widebody plant following retrofit of redesigned Stage 2 stator vane assemblies in the engines' compressors, GE9X program head Ted Ingling reported just ahead of the Dubai Air Show. Ingling explained that the process that led to the fix to the titanium part involved revamping the geometry to ensure a proper wear profile. With testing completed, GE has now retrofitted the fix on six engines, the fourth of which it was preparing to send to Everett when Ingling spoke with AIN on November 8.

In all, GE has built 10 compliant engines, eight of which will go on flying test airplanes, along with two spares.

While Boeing CEO Dennis Muilenburg said during the company’s recent third-quarter earnings call that the engine remains a “pacing item” for the new Boeing 777X, Ingling told AIN that the timing of the fix has not deviated from the schedule set for it when GE discovered the problem in late May. With both engines now mounted, the first 777X awaits final installation work and on-wing testing before making its first flight, scheduled now for the first quarter of next year. As a result of the engine delay, Boeing has moved the airplane’s certification target from late this year to early in 2021. “We continue to explore opportunities to improve the timeline such as leveraging our system integration labs and additional airplane ground testing,” said Muilenburg.

GE’s stator vane fix involved what Ingling called some geometrical changes outside of the flow path, meaning engineers did not alter the aerodynamics of the design. “So that, number one, is paramount to hanging on to our performance and our operational characteristics,” said Ingling. “So it didn't need to change. It was the boundary conditions around it that had to change.”

Although GE halted certification testing while it devised the stator vane fix, maturation testing continued unabated. “We had certification vehicles we had to incorporate into our development vehicles as we continued to prepare the engine for entry into service,” explained Ingling. “We're doing the final couple of certification tests to finish that up. We halted those while we were waiting for this fix.