The world's most advanced civil aircraft production line is taking shape in Seattle, as the 787 begins the final lap of its journey to first flight
Inside Boeing's cavernous Everett construction plant near Seattle the race is on to assemble the first 787 by the planned 8 July roll-out date. Yet, compared with the bustling 777 production line in the adjacent 40-25 building, the 787 appears to be coming together almost by stealth.
Currently the 787 line in the 40-26 building contains only the first aircraft, ZA001, but it will seem relatively empty even when it is pumping out the twinjets at a rate of one every three days - a record for any widebody. Gone, for example, are the massive traditional "monument" assembly tools, and the complex infrastructure that is the usual feature of a large-aircraft assembly line.
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Boeing's 777 line at Everett "pulses" along, with the aircraft assembled in a nose-to-tail position |
The line and its new processes are unlike anything seen in the Everett building since the first bays were built for the 747 programme over 40 years ago. This is due to lean manufacturing principles used to design the line, and the decision to bring in the 787 parts as large subassemblies.
"This is a very different production model," says 787 manufacturing and quality vice-president Steve Westby. "There are changes in technology covering everything from the way we exchange information to the logistics involved in how we get the parts here."
Westby says Boeing focuses on ease of manufacturing as well as ease of design. "We've taken a lot from the people who are helping us build this around the world. But by far, we've taken the most from what we've learned on our other lines, particularly the 737 and 777," he says.
Both these lines are now flowing through the factories, with the aircraft assembled in a nose-to-tail position. The 737 line at Boeing's Renton plant near Seattle moves continuously and the 777 line at Everett "pulses" along. Both lines were originally organised in Boeing's traditional slant arrangement, in which aircraft were put together and moved from position to position down the line, before being reconfigured along lean production principles. "This is the first time we've designed a line from the start for nose-to-tail positions," says Westby.
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The super efficient 787 line will produce one aircraft every three days - a record for any widebody |
The process begins with the delivery of subassemblies to the site by Boeing's 747LCF Dreamlifter, or by road from local suppliers and partner sites. The cargo loader brings them around the 40-36 building on the north side of the complex. Here, like the large parts of a model aircraft kit, the assemblies are prepared to be fitted together in a process called pre-integration. The 40-36 building also houses the horizontal stabiliser assembly area, as well as outboard wing integration, fin and rudder assembly, installation of floors and tail cone completion.
One of the key mobile tools in 40-36 is the mobile gantry crane, nicknamed the "boat loader" because it resembles the cranes seen at docksides. It transfers the large subassemblies from the cargo loader as they come in from the Everett ramp, and inducts them into the pre-integration process. The crane then takes them to the flexible tools at the major body join area at position 1 in the adjacent 40-26 building.
Here the final assembly takes place in a line that houses four positions. Initially the line will be pulsed but Boeing will be able to move it like the 737 and 777 lines if necessary. Westby says the plan is to initially use the first three positions, with the fourth reserved for future expansion.
Assembly time for the first 787 is expected to be around seven weeks. Boeing plans to reach a six-day flow by line number 100, and a three-day flow by 2010, when it will be assembling 10 aircraft a month.
The 'big bang'
The aircraft comes to life in position 1, where final body join and systems installation begins. Known as the "big bang", the work at position 1 includes wing body and fin join along with the assembly of the finished section 48 empennage unit.
Wings are brought to the position on large mobile cradles, which also function as tools for the fitting of the raked tip and engine pylon. Other cradles are provided to transport section 41 and other fuselage parts into place at the station for body joining.
By far the most impressive piece of equipment in 40-26 is the huge mobile structure dubbed the MOATT, or "mother of all tooling towers". Consisting of twin towers supporting cantilevered booms, the MOATT "acts like a clamshell and surrounds the aft part of the aircraft", says Westby. Supporting the join between the aft sections 47 and 48, the MOATT picks up the horizontal stabiliser, fin and "acts as a stand to build the whole aft end of the aircraft", he adds.
In front of the tower is a pair of circumferential join tools, located on either side of the wing. The front tool is used to join section 41 to the mid-fuselage assembly, while the aft joins sections 47 and 48 to the rest of the fuselage. "There are very few manually drilled holes," says Westby, who adds that determinate assembly techniques minimise the requirement for traditional assembly methods.
Keeping all the pieces precisely lined up is a sophisticated, rail-guided jacking and alignment system comprised of nine major units. Positioning data is derived from the digital toolset and precisely aligned and rechecked using a series of laser alignment transmitters mounted in a specially constructed truss up in the rafters.
From position 1 the airframe moves on the rail-guided jacking pads to position 2, where the inboard trailing and leading edges, fairings, engines, nacelles and main landing gear doors are fitted. The main landing gear itself is also fitted, allowing the aircraft to roll forward to position 3 without the need for external support. The final position is dedicated to interior completion and production test work.
Throughout the assembly process, the one-piece flow is speeded along by third-party logistics firm New Breed, which also supports other parts of Boeing. New Breed interfaces between the suppliers and the final assembly line, providing receiving, sequencing, kitting, inventory and order management, logistics, container management and tooling. The pre-kitted parts are provided for line-side delivery at point-of-use positions. Larger parts, such as engines and nacelles, are supplied separately by the manufacturers.
"The challenge for New Breed at the moment is that there are a lot of 'travelled parts' - which is not a part of their plan," says Boeing vice-president of airplane development and production Scott Strode.
"Travelled parts" is Boeing's way of describing work that is out of sequence as a result of delays to the delivery of components to the appropriate position in the assembly process.
The first section 41, for example, was delivered from Wichita without many of the avionics and flightdeck systems installed. Extra work and additional strain on the logistics system has been caused because these parts are having to be installed at Everett instead. However, follow-on aircraft will come pre-packaged in the nose section as planned.
Another key change initiated by the 787 assembly is a move to a mixed workforce, combining experienced employees from other lines and a group of specially trained new employees. Under Boeing's Lean+ initiative, the employees, called manufacturing technicians, are cross-trained and certified in a variety of disciplines instead of just one. The technicians are trained to verify their own work and follow a "clean-as-you-go" policy to reduce the dangers of foreign object damage.
"We partnered with Edmunds Community College to provide pre-employment training at our new Employment Resource Center in Everett," says Westby.
Training technicians
To get a place on the 787 line, applicants undergo various assessments before completing 87h of pre-employment training in their own time. This includes standard assembly process work as well as specialist composite training.
Training for the first class started in January, with trainees completing 10 weeks of coursework covering 44 different job functions. The training also involves working on actual 787 fuselage sections for added realism.
"We expect over 1,100 people will be going through the Employment Resource Center by the end of 2007," says Westby, who adds that the mixed intake scheme helps relieve the potential for putting stress on the skilled workforce.
"When we started work on the 787 the other programmes were already running at a fairly high rate of production and we didn't want to interrupt those."
The systems tests are also accelerating towards the finishing line, with around 90% of the required parts "on dock" at the company's test laboratory facility close to Boeing Field. The complex - which includes the integrated test vehicle, aircraft energy management, engineering laboratories, landing-gear test labs, lightning laboratory, hydraulics and electrics test rooms - was due to receive the last wire bundle in early June.
"We're coming to the final stretch," says 787 systems director Mike Sinnett.
Functional service-ready tests are set for the end of July and beginning of August before the final run-up to the first flight. Initial avionics facility integration tests started in October 2006, with the first wire bundle arriving at the laboratories the following month. In the avionics integration laboratory, the test team reached the "full functionality" point at the end of May.
Excluding software development for the in-flight entertainment systems, as well as that used in the commercial off-the-shelf processors aboard the aircraft, the 787's systems required 6.5 million lines of code, or more than three times that used in the 777.
Benchmarking the 787 systems development against the same common toolset, Boeing has reached the interface control document (ICD) block point 6.5 release and at 7.0 will be "ready to go", according to Sinnett. "The next block point is reserved for fixes, and in the next few months we'll be putting that through the wringer," he says.
The exact point when this milestone block is released "hasn't been committed yet. It depends on how clear it is, and is really a tactical decision we will make as part of the development."
Work to progress through the block points "has taken longer than anyone has anticipated" says Sinnett.
He adds: "The same could be said for the tool we developed to produce all our wiring. That came online later than we'd hoped, but both use self-audits and I think that what we're getting is more quality than we expected.
"With the ICD we're catching problems that in the past would have shown up in the software and would have had to be corrected later on. For example, there's around a fifth of the engineering errors in the wiring design [compared to previous developments at this stage] so at the end of that we found ourselves pretty far ahead."
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Source: Flight International
