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Originally published Thursday, November 15, 2012 at 9:21 AM

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Boeing confirms third line for 737

Boeing will build a third assembly line in Renton alongside one of two existing lines. It has tweaked the airplane’s design with larger cockpit flight displays and the elimination of a small fuselage bump.

Seattle Times aerospace reporter

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Boeing confirmed Thursday it will build a third assembly line for its 737 MAX jet family alongside one of the two existing lines in Renton.

The company also said it has refined the airplane design, adding better visuals for pilots and a slightly smoother fuselage line.

“The 737 MAX factory-integration plan is now final,” Michael Teal, chief project engineer on the jet program, said in a media teleconference.

Space for the third line will be created mostly by moving and compressing the feeder lines and parts-storage areas now covering the floor alongside one of the current lines, said Beverly Wise, MAX program manager and vice president.

Within the next five years, the company will hire hundreds of new production workers to staff its burgeoning Renton assembly lines and will also add hundreds of engineering jobs for the MAX.

The 737 is being built at a rate of 35 per month. That will rise to 38 per month in the second quarter of next year, and to 42 per month a year later.

Those increases will be accommodated on the two existing lines, which by 2014 will each be rolling out slightly more than one jet per workday.

Wyse said the third line will allow Boeing to smoothly introduce the initial jets of the new MAX model, which will inevitably be built more slowly.

Later, she said, it can be used to increase the rate beyond 42 per month.

“We don’t have specific plans on the next rate increase,” Wyse said, “but we’re pretty sure it’s coming.”

The first four jets built on that third assembly line, starting in 2015, will be 737 MAX 8 flight-test airplanes, with lots of flight-test instrumentation installed on the assembly line.

Later, Boeing will build four more test-flight jets for the two subsequent MAX 7 and MAX 9 models.

Thursday, the jet-maker declared it has achieved “firm concept” on the MAX design, defining all the significant changes needed to deliver the 13 percent improvement in fuel economy promised to airlines.

The latest features add to the previously announced MAX design, which includes new fuel-efficient LEAP-1B engines from CFM International, raked “dual feather” winglets and a redesigned tail cone.

Wyse announced two tweaks to the earlier concept.

First, pilots flying the MAX will have large instrument display panels in the cockpit. Boeing said that will allow the flight deck to be upgraded at lower cost as cockpit avionics advance.

In addition, Boeing engineers have managed to eliminate a small exterior bump in the fuselage where the nose landing gear tucks into the wheel well.

A bump had been thought necessary because the landing gear is 8 inches longer than on the current 737 so the jet can stand higher off the ground and accommodate the much bigger LEAP engines. Those engines have a 69-inch fan compared to the current 61-inch fan.

Engineers therefore expected the nose gear would have to stick out a little. But Teal said Boeing will avoid that by changing the way the landing gear folds, so that it tucks in a little higher into the wheel well.

In addition, Boeing has decided to use only radial tires on the MAX nose gear versus traditional cross-ply bias tires. Radial tires don’t expand as much during service, Teal said.

CFM is to finalize the design of the new LEAP engine in April, Teal said, with firm configuration of the final airplane design by midyear.

That’s when Boeing will begin detailed design work on the MAX and inform suppliers of which parts need to be different from those supplied for the current 737s.

Wyse said the program is on track to deliver the first MAX jets in late 2017.

Dominic Gates: (206) 464-2963 or

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