Score one for the humans. After four years of trial and error, Boeing Co. is dumping one of its most ambitious forays into automation: the robots that build two main fuselage sections for its 777 jetliners and an upgraded version known as 777X.

Instead, the Chicago-based planemaker will rely on skilled mechanics to manually insert fasteners into holes drilled along the circumference of the airplane by an automated system known as “flex tracks,” which it has honed over years of use on the 787 Dreamliner.

The shift to the new human-plus-machine system began during the second quarter and should be complete by year’s end, Boeing spokesman Paul Bergman said in a statement. Boeing doesn’t plan any change in total staffing for its 777 jetliners, which are manufactured in Everett, Washington, about an hour north of Seattle.

“The flex track solution has proven more reliable, requiring less work by hand and less rework, than what the robots were capable of,” he said.

-BLOOMBERG