Boeing began construction of a 367,000-square-foot facility in St. Louis, Mo., where it will build parts for the 777X aircraft.

Construction should be complete in 2016 with work on 777X wing and empennage parts starting in 2017. The facility is an expansion of Boeing’s current tooling center at the site and will contain six autoclaves.

Earlier this year, Boeing selected its Everett, Wash. site as the location for a new composite wing center for the 777X program. In this wing center, Boeing will perform fabrication and assembly of the 777X’s composite wing. Additionally, Boeing will perform final assembly of the 777X in Everett.

There will be two 777X models, the 777-8X, with approximately 350 seats and a range capability of more than 9,300 nautical miles, and the 777-9X, with approximately 400 seats and a range of more than 8,200 nautical miles. Boeing says the 777X has 300 orders and commitments from six customers worldwide. First delivery is targeted for 2020.