Mammoth Building Projects Underpin 777X Plan | Commercial Aviation content from Aviation Week
"Any doubts about the scale of changes in Boeing’s 777X derivative or its commitment to the new long-haul flagship are dispelled by a visit to the giant construction site in Everett, Washington, where the aircraft’s composite wing will be built.
Construction of building the sprawling $1 billion composite wing center (CWC) and the nearby advanced fuselage assembly facility extension for the 777/777X marks one of the largest single expansion phases for the site since the mid-1960s, when the first trees were felled for the 747 program. The CWC will cover almost 1.3 million sq. ft. when completed next May, while the expansion of Building 40-27 for fuselage assembly adds a further 325,000 sq. ft. of factory capacity.
Boeing officially selected Everett for 777X final assembly in early 2014, following a decision by the International Association of Machinists & Aerospace Workers District 751 to approve, by a razor-thin margin, an eight-year contract extension. Under the contract, the company agreed to fabricate and assemble parts for the 777X composite wings in the Puget Sound area. Boeing broke ground for the facility last October.
Measuring 1,250 X 950 ft., the CWC building is supported by columns built on concrete caissons up to 8 ft. in diameter that penetrate 100 ft. into the ground. Before construction began the site was filled and leveled to a depth of 20 ft. in some areas by the addition of 550,000 cu. yards of earth. Since the end of last year, 150,000 yards of concrete have been poured, requiring delivery of almost 17,000 truckloads. When complete, the building will have a clear span of 460 ft., more than 100 ft. wider than the largest spans at the 40-25 and 40-26 buildings added to Everett for the 777 and 787, respectively.
At the heart of the new building will be three autoclaves for curing skins, spars and stringers of the 114-ft.-long main wing section. The length of each will be extended for flight by an 11-ft. foldable wingtip section, giving the 777X an overall span of 212 ft. 8 in. retracted, and 235 ft. 5 in. deployed. The first autoclave is being constructed on the north side of the nearby Paine Field site and will be installed in the third quarter. Each autoclave is 120 X 28 ft. and 1.2 million lb., making them the largest in the company by working volume. The size of each means the short journey across the airfield to the CWC will take up to four days and conclude with the unit being positioned on rollers into sunken foundations. Welding on the initial oven will be completed by the end of June, with hydrostatic pressure testing set to follow using 7 million lb. of water.
Boeing is also expanding its tooling center in St. Louis where it is building a 367,000-sq.-ft. composites facility to make parts of the wing and empennage. The site, which will be completed in 2016, will house six autoclaves.
In another part of the Everett site, behind closed doors, Boeing has been perfecting production and assembly techniques on a prototype wingbox. Measuring 80 ft. long, the test wingbox comprises composite upper and lower skins and the internal wingbox structure. “It’s not full size, but that’s the largest composite panel we could make with the autoclaves we have,” says Scott Fancher, Boeing Airplane Development senior vice president and general manager. “The features within the wing itself are full size, the wingbox is just shorter. It is as much about automation as the design features,” he adds.
The wing, a fourth-generation derivative of the 787 design, epitomizes the challenges faced by Boeing in developing the 777X. “They are not so much about the design,” says Fancher. “It’s pulling the production system together, building the plant, building the tooling, getting everything installed. It’s going to be a highly automated wing, so we have the automation system to purchase, integrate and stand up.”
With the performance and structural behavior of the wing well understood thanks to the 787 experience, the focus is on perfecting its production. “The wing is a derivative from a design standpoint. It is stretched and has a wing fold, but we are seeing no major risks. The aerodynamic performance of the wing is exactly where we want it to be,” adds Fancher. “We have refined the design and are taking the part count down so it is a simpler design to fabricate and produce.” Much of this simplification has come out of the wing fold and its actuation mechanism. “Over the past year to 18 months we’ve taken 40% of the parts out of the wing fold, and that’s by just refining the design,” says Fancher. The wing fold has achieved “full market acceptance. We have had no questions about that for more than a year.”
The 777X empennage and fuselage will be produced using advanced robotic processes now being developed and tested for introduction on the current 777. Principal among these is the FAUB (fuselage assembly upright build) automated drilling and riveting system, which is being installed in the 40-27 building extension (AW&ST July 21, 2014, p. 47). Based on KUKA robots, FAUB was secretly developed at a marine storage site in Anacortes, Washington, before being transferred to Everett. Resembling the robotic techniques used by car manufacturers, FAUB robots work cooperatively inside and outside the forward and aft fuselage sections.
To ensure the new process has no negative impact on structural integrity, a fuselage barrel made using FAUB and manual riveting processes will begin fatigue tests in August. Although based on the forward Section 41/43, the barrel includes representative elements of fatigue-sensitive parts from other parts that will be made using FAUB, including slightly different elements for the freighter. “It is a bit of a ‘Franken-barrel,’ but we believe this will cover fatigue for these specific automation portions for the 777X analysis,” says 777/777X Manufacturing Vice President Jason Clark. Traditional complete static and fatigue test airframes will also be built for the program, he adds.
A robotic build and assembly process for the empennage, this time developed by Electroimpact, will also be introduced in the fourth quarter at Boeing’s Fabrication Composite Manufacturing Center of Fredrickson, Washington. Horizontal stabilizers and vertical fins will pass pulse-fashion down a single line, rather than down the separate lines used today. The process will avoid repetitive manual actions, improving safety and reducing drilling operations by more than 80%.
To protect the current 787 assembly line, which is producing 100 aircraft per year, Boeing will create a parallel line “to slowly ramp on that technology,” says Clark. While FAUB becomes established in the 40-27 building, with full implementation on the 777 in 2016, the low-rate initial production line for the 777X will be set up in the 40-24 bay, which was used for the 787 temporary surge line. Boeing plans to close out 787 work on the line by year-end, as production steadies at a higher rate between the adjacent assembly line in Everett’s 40-26 bay and at the facility in Charleston, South Carolina.
“In the beginning we will do final assembly for the 777X down this [40-24] bay,” says Elizabeth Lund, 777 vice president and general manager. “We will do the longer-flow 777Xs, the static and fatigue vehicles, the flight-test vehicles and a few of the others to come up to speed on this line. Ultimately, we will transition back to the main line on 40-25 and build both models down this line.” By 2018-19 the line will be converted to flexible 787-like tooling without the permanent monument tooling that exists today. The same line will handle metal-winged 777-300ERs and 777Fs as well as composite-winged 777-8/9s. “You don’t have to re-tool . . . because the flexibility of the tooling accommodates that,” says Lund.
“The key here is [that] the design of the airplane has been stable; we haven’t been chasing range or weight or specific fuel consumption or aerodynamic performance,” says Fancher. “Since we had a stable design, our engineers have had the opportunity to refine their thinking to make it more produceable and maintainable. Firm configuration will occur later this year, marking the start of detailed design.” "