December 2004/January 2005 
Volume 03, Issue 8 
Commercial Airplanes

High-speed performance
Extreme Makeover In Renton

737 line aims to accelerate its record-setting assembly pace


Before Lean methodsThe Next-Generation 737 claimed another record this fall when employees in the Renton, Wash., factory reduced final assembly time to 12 days. In addition to being the fastest-selling and fastest-delivered jet airplane, the 737 is now the fastest-assembled large commercial jet in history, thanks to Lean manufacturing efforts.

The achievement is impressive considering flow time in Final Assembly five years ago was 22 days.

"But we can't afford to rest on our laurels," said Helene Michael, 737 factory superintendent. "Even Airbus has realized the importance of a nimble and reliable production system. They are starting to focus on Lean to reduce final assembly flow time of the competing A320."

Employees are taking the advice to heart—and to task. Major changes are under way on the factory floor that will lead to more reductions in assembly time. The manufacturing plan is to eventually cut final assembly to eight days.

So committed are people to the eight-day goal that current airplane positions are called by their future flow day. For instance, an airplane reaches the last position in the factory on the 12th day, but that position already is called "flow day 8."

"And before we even get to the eight days, we will once again examine our plan and processes and set a lower target," said Larry Loftis, director of Renton Manufacturing.

After Lean methodsIt's this type of single-minded drive that allowed employees to change the production system on the last four airplane positions to a moving assembly line. The moving line keeps the airplanes in constant motion at a steady pace of 2 inches per minute. All the tools, parts, plans and work instructions are delivered to employees where and when they need them, eliminating the need to search for and gather materials. Standard work processes are being implemented, which reduce variability and the chance for defects.


To improve flow time even further, employees now are making dramatic changes in the back of the factory—in the Wing-to-Body Join and Systems Installation positions.

Until this summer, fuselages built in Wichita, Kan., and arriving in Renton were placed into one of eight fixed Systems Installation positions. There, employees installed installed electrical and hydraulic systems and insulation blankets before placing fuselages into the Wing-to-Body Join tool. Today the old System Installation tools are gone, replaced by four new, more flexible tools, and the Wing-to-Body Join tool is in the process of being moved closer to the Systems Installation positions.

These changes are the first steps in eliminating fixed tooling and other "monuments," according to Lean consultant Rich Fiedler. In manufacturing terms, monuments are tools, equipment or structures that prevent the easy movement of products or parts.

Next-Generation 737 accomplishments:

Airlines ordered a total of 737 Next-Generation 737s before the first model was delivered on Dec. 17, 1997. No other commercial jet airplane has matched that predelivery sales mark.

Within five years of entering service, the worldwide fleet of Next-Generation 737s surpassed 10 million flight hours, a feat equal to one airplane flying more than 1,141 years nonstop. The Next-Generation 737 is the first and only commercial jetliner to reach this milestone so quickly.

Boeing made history when it delivered the 1,500th Next-Generation 737 in six years, sooner than any other commercial airplane model. The previous record holder was the family of Classic 737-300s, -400s and -500s, which reached the milestone in 10 years. The competing A320 family reached that mark in 13 years.

Overall, the entire 737 family is the best-selling commercial jet in history, winning orders for more than 5,400 737s. That's more than rival Airbus has sold of all its models.

"We can't have a moving production line if something immovable is in the way," said Fiedler. "Monuments also typically prevent the easy reconfiguration of the production line should we need to quickly respond to customer requirements."

An example of the diminishing role of monuments is the Wing-to-Body Join tool, which was originally installed by digging a huge pit in the factory floor and filling it with tons of concrete.

"The thinking was that it would stabilize the tool. We now know that isn't necessary so we're able to minimize the foundation for the new tool," Fiedler said.

Because the new Wing-Body-Join tool will be bolted to the floor, it could still be considered a monument, but it's an improvement because in the future it can be quickly moved should the need arise. In fact, the tool is being repositioned without needing excavation holes and tons of concrete.

The renovation of the factory floor is intended to accommodate a fifth airplane position on the moving line. Work processes also are being resequenced to provide a balanced amount of work among airplane positions and between work shifts.


The changes in the Systems Installation area are already reaping benefits for some employees.

"With the new tooling, all the processes have been brought closer together. Everything is more organized, and that makes our jobs easier," said Jon Rausch, 737 door installation mechanic.

The changes also are expected to reduce the reliance on overhead cranes and provide an opportunity to shave even more assembly time off the schedule. That opportunity comes just in time, Loftis said.

"The 737 program is already feeling upward pressure in demand for the single-aisle airplane. As orders come back, we'll be ready to ramp up production," he said.

Michael agreed, saying a nimble production system will also help Boeing's airline customers.

"Our Lean production system is making us more responsive and able to act quicker to the market," Michael said. "This makes us better able to meet our customers' demands. The market conditions are constantly changing for our airline customers, so the closer to delivery that they can wait to make critical decisions about interior configuration and systems, the greater benefit it is for them."


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