Boeing announced on Monday that it has grounded its fleet of 777X test aircraft for inspections after a component failure related to the jet’s engine was discovered over the weekend.
The issue was identified when a 777X test aircraft landed in Hawaii on Friday, and maintenance mechanics found damage in a structural part that connects the engine to the airframe.
Following inspections of the two other active 777X test planes, cracks were found in the same structural part, according to The Air Current, an online aviation news outlet that first reported the incident on Monday.
In a statement, Boeing confirmed the damage on the Hawaiian plane was found “during scheduled maintenance” and that it is conducting inspections on the other test planes.
“Our team is replacing the part and will resume flight testing when ready,” Boeing stated.
The affected part, known as a “thrust link,” is a heavy titanium component that transfers the engine’s thrust to the airframe. It is unique to the 777X and is a Boeing-designed connector to the GE-9X engine, which is not part of the engine itself. The massive GE-9X engine weighs about 11 tons and has a front fan over 11 feet in diameter. Each engine uses two thrust links for redundancy in case of failure.
This development is another setback for Boeing’s 777X program. Originally launched in 2013, the jet first flew in 2020, but its certification by the Federal Aviation Administration (FAA) has faced multiple delays. Just last month, Boeing received FAA clearance to begin test flights for certification credit, but those flights are now on hold.
Boeing has informed the FAA and its 777X customers about the issue. While the company aims to deliver the first 777X in 2025—five years behind schedule—some customers, such as Gulf carrier Emirates, have already adjusted their expectations to mid-2026.
Ken Herbert, a financial analyst with RBC Capital Markets, noted in a memo to investors that the grounding could further erode investor confidence in the 777X program, even if flight testing resumes soon.
In 2022, after producing about 20 777X aircraft in addition to four test jets, Boeing halted production until certification neared. Production resumed late last year, but Herbert warned that if this new issue disrupts production again, it could further delay Boeing’s cash flow recovery.
Of the four 777X test planes, only three are currently active: one in Hawaii, one parked at Boeing Field, and another in Everett.
