Last week, Boeing released images of the first two Boeing 777X test aircraft on the final assembly line at its plant, in Everett, Wash. Engineers have attached the first fuselage barrels for the first two Boeing 777-9s, the lead variant in the General Electric GE9X-powered family.

The company is expected to complete the static test airframe by the end of the year, and has moved the wings for the larger of the two 777X variants into laydown and systems installation. Meanwhile at the company’s Composite Wing Center (CWC), it has begun fabricating wings for the fifth airplane. So far, Boeing has sent four sets of wings out of the CWC and into spar assembly.

The company has now completed 98 percent of its engineering releases, as well as a static test rig in Everett, and now is loading it with all its test equipment, while the fatigue test rig has reached the halfway point of construction. The airplane’s folding composite wingtips have also arrived from their production site in St. Louis for the static airplane and the first flight-test article. Boeing also has begun construction of the second autoclave, scheduled to move into the CWC later this year.

Boeing’s Composite Wing Center will support the production of the longest wing Boeing has ever produced. The 777X features lightweight wing design based on a composite spar made of over 400 miles of carbon tape cured in a specially built autoclave.

As of now, Boeing is still aiming at 2019 for the 777X’s first flight, with delivery of the first plane on pace for 2020 to launch customer Emirates.