Boeing's new factory will house three large autoclaves, or pressurised ovens, for curing the jet's carbon-composite wings.
New York - Plane-maker plans to start building 777Xs next year, deliver the first in 2020
Boeing opened a $1 billion factory in Washington state that will make carbon-composite wings for its newest jetliner, the 777X, a key step toward delivering the first aircraft by 2020.
The building, adjacent to Boeing's wide-body aircraft plant in Everett, Washington, covers 27 acres (11 hectares) putting under one roof the equivalent of more than 20 football fields, Boeing said.
The facility will play an important role "in keeping the Puget Sound [region] at the forefront of aerospace leadership for decades to come", Ray Conner, chief executive of Boeing Commercial Airplanes, said in a statement.
Boeing's investment in the wing plant and its decision to build the 777X in Washington fulfill a commitment the company made in 2013, when state lawmakers approved a package of industry tax reductions worth $8.7 billion over 16 years.
Lawmakers had feared that Boeing would build the 777X in another state, which could reduce aerospace work in Washington. Boeing has 320 orders from six customers for the 777X, which replaces the highly successful 777, introduced in 1995.
The company plans to start building 777Xs next year and deliver the first one in 2020, after testing and certification.
The new factory will house three large autoclaves, or pressurised ovens, for curing the jet's carbon-composite wings, which replace the conventional aluminum construction process used for the current 777.
The autoclaves are 120 feet (37 metres) long and 28 feet in diametre and weigh more than one million pounds (453,600kg) each, large enough to hold two 737 fuselages, Boeing said.
Boeing broke ground for the plant in August 2014, saying at the time it expected to occupy the plant this year. As many as 1,700 contractors were employed on the project at its peak, Boeing said.
The company did not say how many people will work at the plant.
Boeing plans two versions of the 777X: the -8, with about 350 seats and a range of 9,300 nautical miles; and the -9 with about 400 seats and a range of 8,200 nautical miles.
The smaller 777X competes with the Airbus A350-1000, a composite-fuselage jet that the European planemaker plans to introduce in 2017. The Airbus jet seats about 366 passengers and has a range of 7,900 nautical miles.
Airbus last year introduced the smaller A350-900, which seats 325 passengers and can fly up to 8,100 nautical miles.