NEW YORK/BENGALURU (Aug 27): Boeing Co said on Thursday it has determined the basic design of its 777-9 jetliner, a key milestone in developing the plane that suggests the company is on schedule to deliver the first of its new family of long-range 777X jets by 2020.

Development of the 777X, which includes the 777-9 and smaller 777-8, comes as Boeing speeds up commercial aircraft production to more than 76 a month by 2020 from 62 now, taking output to the highest level in the company's 100-year history.

Boeing said it is due to begin making the first 777-9 in 2017. The company has said it does not expect to slow down output of the current 777 during the transition, although some industry observers and analysts remain skeptical.

The 777X, a successor to the 777 introduced in 1995, will have carbon-fiber composite wings and an aluminum fuselage, and is expected to use 12% less fuel and be 10 percent cheaper to operate than competing jets, Boeing said, adding that the 777X jet will compete with the Airbus A350.

Boeing's announcement on Thursday that the 777-9 had reached "firm configuration" means the plane's basic design and capabilities are determined, setting the stage for the design of specific parts and systems. Boeing also said it had conducted wind tunnel, aerodynamic and structural load tests of the design.

"The program is right where we want it to be," said Bob Feldman, who heads the 777X program. "We have an airplane and a production system that are on track and on schedule."

Boeing is using new automated technology to help assemble the 777X, and installing autoclaves, or industrial ovens, in a massive new building in Everett, Washington, to cure the wings under heat and pressure, next door to the assembly line.

The 777X has garnered 306 firm orders and another 14 commitments.