GE Aviation revealed on June 17, 2019, that it is redesigning a part for the in-development GE9X engine set to power the Boeing 777X after an issue with the component was detected during recent testing. The upgrades mean certification of the engine is unlikely to take place until Autumn 2019 and will delay the maiden flight of the 777X by “several months” as the necessary fixes are applied.

Boeing’s hopes to have its largest twin-engine jet, the 777X, take to the skies around the time of the Paris Air Show (June 17-23, 2019), are far gone. GE Aviation said on Monday, June 17, that it had discovered “unexpected wear” in a part for the GE9X turbine engine, forcing a delay of “several months”, as the company now has to redesign and test the part again, Reuters writes.

What’s the issue?

According to Flight Global, the problem with the GE9X engine appeared during extended block cycle tests, part of the required certification process of the power plant, during which the engine part in question exhibited premature deterioration. The defect was reportedly detected in late May.

The necessary fix by GE will see improvements made to “the stator vane in the second stage of the high-pressure compressor”, Aviation Week writes. GE will move on to install the re-engineered part (an upgraded stator configuration) in eight test engines involved in the GE9X test program, as well as 10 flight compliance engines. The modifications on the engine parts are expected to be finished later this autumn.

“(The) long pole in the tent right now is the GE engine,” Boeing Chief Financial Officer Greg Smith said in a conference. “There’s some challenges they are working through there on testing. So we are having to do some re-testing, and they’re working their way through that,” Smith was quoted as saying in a previous report by Reuters on June 5, 2019.

Boeing originally hoped to begin the 777X flight test program in spring 2019, but various program delays earlier this year kept pushing the date ever so slightly till the beginning of this summer. It was only on March 13, 2019, that the first flight test plane rolled out of Boeing’s Seattle-area Everett plant. That month as well, GE began flight trials of the GE9X, mounted on a specially-designed pylon on a Boeing 747 flying testbed.

Despite the hiccups, Boeing CEO Dennis Muilenberg assures the 777X program remains on track. Kevin McAllister, chief of Boeing Commercial Airplanes, said it was “premature to predict any delays” to the program, and that the company is still planning the 777X’s maiden flight this year and entry into service in 2020, Reuters quotes the executives as saying.

Nevertheless, the plane maker also seems to be aware that its certification processes will be scrutinized with the fallout of the 737 MAX crisis. Here is what McAllister had to say about the GE9X engine issues: “We're making the most of this time obviously and continuing to work to get it right for first flight with this airplane. There’s plenty of activity that we can pull to the left prior to our flight test program to make sure we address any opportunities to advance the readiness of the airplane before its first flight,” he was quoted as saying by Aviation Week.