Boeing announced Tuesday that 787 program partner Kawasaki Heavy Industries has begun major assembly of the 787-10, the largest of its three-member family of Dreamliners. KHI began installing the circular frames into the mid-forward section of the fuselage on March 14 in Japan, a full two weeks ahead of schedule.

“Beginning major assembly early underscores the commitment, discipline and performance of the entire Boeing and partner team worldwide,” said Ken Sanger, Boeing Commercial Airplanes vice president of 787 Airplane Development. “We are taking all the right steps to ensure we integrate the 787-10 into the production system smoothly.”

Boeing completed detailed design of the 787-10 in early December, allowing it to release information needed to build parts and tools for assembly of the aircraft.

Officially launched at the 2013 Paris Air Show, the 787-10 incorporates a pair of fuselage plugs–one toward the front of the fuselage and one near the rear–that extends the 787-9’s fuselage by 18 feet, allowing for a 15 percent increase in passenger capacity, enough for 40 passengers. According to Boeing, the standard 6,430 nautical mile range of the -10 covers more than 90 percent of the world’s twin-aisle routes while seating between 300 and 330 passengers. The company estimates that 95 percent of the design and build of the 787-10 mirrors that of the 787-9.

Final assembly of the Boeing 787-10 will take place exclusively in North Charleston, South Carolina, where schedules call for the start of final assembly next year and first delivery in 2018.

With 10 of the 18-foot increase in fuselage length residing in the midbody section, the 787-10 midbody would not fit into Boeing’s Dreamliner cargo airplanes, meaning it would prove too long for efficient transport from North Charleston—the site of systems installation–to Boeing’s main plant in Everett, Washington, for final assembly, according to the company. Meanwhile, said Boeing, introducing the 787-10 in North Charleston takes advantage of that facility’s capacity while allowing the Everett facility to continue improving productivity on the 787-8 and 787-9.

Now building ten 787s a month, Boeing plans to increase that rate to 12 this year and 14 by the end of the decade. The plant in Everett will continue to assemble seven airplanes per month, while Boeing South Carolina gradually increases from three to five per month this year and seven per month by the end of the decade, said the company.

The 787-10 has won orders for 153 airplanes from nine customers, accounting for 13 percent of the total 787 order count.