Boeing announced it has determined the basic design of its 777-9 jetliner, the first member of the 777X program to be developed. Production of the 777-9 will begin in 2017, and is on pace for its first delivery by 2020. The 777X program has already received orders and commitments for 320 airplanes from six customers worldwide.

Before announcing the milestone for the 777-9, Boeing put the jet through wind tunnel tests, as well as aerodynamic performance and structural loads evaluations to ensure all requirements were met.

“The program is right where we want it to be,” said Bob Feldmann, Vice President and General Manager of the 777X program at Boeing. “We have an airplane and production system that are on track and on schedule, and we remain laser focused on meeting our commitments to our customers.”

The 777X will have carbon fiber composite wings and an aluminum fuselage. This is notably different from the design of Boeing’s 787, which had a composite fuselage. One of the benefits of a composite fuselage, according to ACMA’s CompositesLab website, is that in highly tension-loaded applications, composites help decrease fatigue and maintenance. Aluminum, on the other hand, is more sensitive to tension loads.

Boeing expects the 777-9 to use 12 percent less fuel and be 10 percent cheaper to operate than competing jets, including the competing Airbus A350, which recently began production of its XWB carbon fiber wings. In a recent article by the Puget Sound Business Journal, Addison Schonland, a partner at aviation consulting company AirInsight, said the two jets are “neck-and-neck” in the aerodynamic efficiency of their respective wings.

While the A350 currently has the largest carbon fiber composite wing (105 feet for each wing), the jets in the 777X program will be 106 feet long and will extend to 117 feet with a unique folding wingtip. The Boeing jets will also be able to carry close to 50 more people than the A350.