On one side of Boeing’s “482” building in Renton, Washington, is what Marty Chamberlin, director of 737 factory operations, calls the “freeway” – an assembly line that cranks out an average of one single-aisle aircraft every working day.
Running parallel down the wide hangar, the other side of the 482 building looks today more like a parking lot – but not for much longer. Two-thirds of this space is filled with 737 inventory, forming a vast staging area to feed both 737 “freeways”, including a similarly-sized assembly line in building 481. The final one-third is filled with the scaffolded, monumental systems integration tool, which cradles up to three 737 fuselages, each to be stuffed with wiring, ducts and other systems before entering the assembly lines.
There was a time that this elaborate tool was considered a marvel of modern efficiency. In a sign of today’s feverish demand for single-aisle aircraft, however, a tool that can only accommodate three 737 fuselages at one time is now a production bottleneck. It also happens to be in the way of the next big thing.
“We’re going to clear all this out,” Chamberlin says, “and then implement the  Max line right here. It’s actually in work.”
Over the next few weeks, one-half of building 482 will be converted into a third 737 assembly line. Launched only three years ago, the first 737 Max is due to enter final assembly in less than a year. As Boeing’s marketers continue a 25-year-old duel with the Airbus A320, factory managers like Chamberlin are now preparing to build the 2,038 737 Max orders already in the backlog.
Adding to Chamberlin’s challenge, the 737 Max is scheduled to enter service in 2017 – the same time that Boeing plans to further increase output, raising average monthly production by 12% to 47 aircraft per month.
Pat Shanahan, the senior vice-president and general manager who oversees all Boeing commercial aircraft production, is aware of the difficulty. In a recent interview, he asked rhetorically what the hardest task in the aircraft manufacturing business is, then answered his own question: “Whether it’s development or manufacturing, it’s to increase the production rate. It’s just hard.”
The 737 factory in Renton has managed the challenge better than most. It has steadily ramped up production from 31 aircraft per month to 42 over the last few years, with the last jump coming in April.
“If you get 30 seconds to ask two questions on the way things are going, the two questions you’d ask are: how many part shortages do you have, and what kind of overtime are you running?” Shanahan says. “Across the entire [Renton] site, what did we have, 15 parts shortages? When we tried to do the big ramp up back in the 1990s, it was like 700 parts shortages.”
Opening a third line for the Max will create capacity as Boeing ramps up to 47 aircraft per month
As 737 demand continues to grow, Boeing managers have to look upon the Renton factory with a fresh perspective. The amount of time a single 737 spends in the factory has been cut from 22 to 10 days, and is scheduled to decline to nine days later this year. Boeing managers would like to reduce the flow time even further, but this requires taking a very different approach to aircraft manufacturing, Shanahan says.
“If this were a car plant, you’d be like, there’s a ton of capacity [left in Renton],” Shanahan says. “I think what we’re trying to do more is put our car hats on, even though we think we’re airplane guys.
“When you look through the lens of an automobile company, it’s like, there is a lot of potential.”
One way automobile manufacturers create “free capacity” inside a factory is by going vertical – stacking assembly operations from floor to ceiling. Boeing is keeping both 737 assembly lines firmly on the ground – but not the systems integration tool. As Boeing dismantles the current tool in the 482 building to make way for the Max, it has partially activated a newer, much larger tool on newly-cleared space in the 481 building. When fully activated, this new tool will be able to hold up to nine 737 fuselages, with a monorail system to pass them from position to position within the structure.
This enlarged systems integration area will be implemented gradually. It currently takes three days for a single 737 fuselage to pass through the tool and reach first position in the final assembly line. That flow rate will be maintained after the larger tool is fully activated – but perhaps not for long.
“The going-in position is [that] we will replicate what we have, so it will be the same flow,” Chamberlin says. “But we know based on our applications here that making things move enables us to kind of think differently and create flow reductions.”
As the smaller systems integration tool is dismantled inside the 482 building, Boeing will prepare the newly-vacated space to become a fully-functioning assembly line. That means reinforcing the concrete floor to support the heavy joining tools used on the final assembly line.
Once that project is complete, Boeing can induct the 737 Max test fleet into the company’s newest production line.
The 737 Max fleet is scheduled to enter a year-long flight test programme in 2016. They will be followed on the new assembly line by the first production versions of the 737 Max. By 2016, Boeing will be delivering 21 737s per month down each of the existing assembly lines, plus learning how to ramp up production on the 737 Max line to the same rate.
Although broadly similar to the 737NG, the 737 Max adds a new engine – the CFM International Leap-1B – plus dual-feather winglets, a relofted tail cone, fly-by-wire spoilers and a more reliable, electronic bleed actuator system. In the flightdeck, newer 787-style displays also require a small redesign of the forward electronic equipment bay.
By adding a third, dedicated assembly line for the 737 Max, Boeing’s workers will have time to learn how to accommodate the design changes while not slowing production of the two 737NG lines, says Elizabeth Schreyer, Boeing’s director of 737 operations. As 737 Max production ramps up after 2017, Boeing will continue building the aircraft on the dedicated assembly line, while also sliding aircraft gradually into the two lines now building 737NG, Schreyer adds.
The third line, in theory, also allows Boeing to further increase capacity. Boeing’s wing assembly line in Renton already has the capacity to build more than 60 sets for the 737.
The two final assembly lines are currently at maximum output of 21 aircraft per month. Opening the third line next year for the 737 Max will create extra capacity as Boeing ramps up to 47 aircraft per month. It also gives Boeing an outlet to dramatically increase output even more – as long as the rest of the supply chain can keep up with the pace in final assembly.