Engine Problems Are Holding Back Boeing’s 777X
Matthew Greenwood posted on August 29, 2019 |



Boeing’s troubles extend beyond its grounded 737 MAX fleet—with its newest jet, the 777X widebody, delayed due to recurring engine problems.


The 777X is powered by the massive GE9X engine, the biggest aircraft turbine ever built. But the engine has had nagging problems throughout its development and testing. GE claims that the engine’s problems have been solved—but the extensive testing needed to have it certified won’t be completed until later this year.


Earlier this summer GE recalled four of its eight GE9X “compliance engines”—intended to power the 777X during its flight tests.


Engineers at GE Aviation have been redesigning stator vanes in the second stage of the engine’s high-pressure compressor to make it more robust. The vanes slow airflow and increase pressure, but testing revealed that the exhaust temperatures exceeded intended limits and the component deteriorated faster than expected.


GE is also making other design tweaks to boost the engine’s durability. While GE didn’t release details, the company said the changes weren’t related to the troublesome compressor.


Those updates will be deployed in the compliance engines and returned to Boeing for 777X testing.


The GE9X breaks a Guinness world record for thrust.


Despite the GE9X’s setbacks, Boeing stuck fast to its late 2019 target date for the 777X’s first flight—even though the plane manufacturer was well aware of the technical difficulties. Boeing has since given up that time line.


“We are addressing engine issues, and GE has had some challenges on the first engine that we discovered in some of the reliability testing,” said Boeing CEO Dennis Muilenburg. “They’re making some component changes. We believe we have our arms around the change that’s required, but some additional testing has to be done yet, and as a result we don’t expect first flight to occur until early next year.”




Boeing needs the GE9X to be certified before it can fly the 777X—after all, GE’s engine was developed specifically for the aircraft. But delays in its certification mean the aircraft manufacturer will have to fly, test and deliver the widebody all in 2020, requiring an aggressive test schedule.


It seems that the faulty compressor is the only thing holding the engine—and the plane—back. No other problems have arisen, and the engine has completed 85 percent of its certification testing.


The 777X has also passed its share of tests. The aircraft is structurally sound—it just needs the engines to work!


Read more about the 777X’s record-breaking engine at GE’s Massive GE9X Engine Is Ready To Fly—At Last.


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