Gordon Werner

Aerospace Notebook: 747s line up for continuously moving production

Monday, August 27, 2001

By JAMES WALLACE
SEATTLE POST-INTELLIGENCER REPORTER

At the Boeing Co.'s widebody airplane plant in Everett last week, a 747 still in production was turned so that its nose faced the huge doors that are opened when a plane is finished and ready to be rolled out to the paint factory.

It was a small move for the 747, but potentially a big move for Boeing.

Since it entered production more than 30 years ago, the 747 has been assembled in the traditional slanted work positions on the factory floor.

The one plane was turned nose forward as part of an evaluation that could lead to the venerable jumbo jet being built on a continuously moving line by 2004.

So far, Boeing has only attempted to incorporate the moving-line concept for its two smallest commercial jets -- the 737, which is assembled in Renton, and the 717, which is assembled in Long Beach, Calif.

Boeing also plans to eventually assemble the single-aisle 757 on a moving line at the Renton factory.

That would leave the twin-aisle 747, 777, 767 as the only Boeing jetliners still being produced the old-fashioned way.

Although the processes have grown much more complex, the same basic station-to-station production method has been used for decades to build commercial jetliners. (During World War II moving lines were used to mass-produce bombers such as Boeing's B-17.)

Commercial jetliners are typically moved from one station to the next and parked each time at a slant.

On a moving line, planes are parked nose to tail and pulled along the line at a constant rate. The line can be stopped at any time if there is a problem.

There are several advantages to a moving line. It can free up valuable factory floor space, dramatically reduce inventory and shave days off the flow time to assemble a jetliner. And that means significant cost savings and more competitive aircraft pricing.

The concept has spread rapidly through much of Boeing in recent years. Modified moving lines are being used by Boeing to build the Apache helicopter and Delta 4 rocket. The idea first jumped to Boeing's commercial operations in Long Beach, where a modified "pulsed" line is being used to simultaneously move six planes in six different work stations. The plan is for that pulsed line to become a continuously moving line in a few months.

By next year, Boeing plans to have two continuously moving lines producing the 737 at the Renton plant.

To accomplish that, the moving 737 line is being implemented in stages, beginning with the final two assembly stations before the jet leaves the factory. The planes move along the line about two inches per minute.

The moving-line evaluation for the 747 began in July, when a plane was first turned nose forward in the last of three 747 assembly positions.

A second plane was turned nose forward in that same final assembly position last week. Among other things, the engines are attached to the 747 in the final workstation.

As it considers the possibility of moving assembly lines at the Everett factory, Boeing decided to experiment with the 747 first because it has the lowest production rate of the three widebody models.

More simulations are planned this year. But it could be some time before Boeing knows whether its biggest jetliner will be assembled on a moving line.

"We think we can do this, but we have to know we can overcome the technical challenges," said Gary Lesser, Boeing's 747 spokesman.

"The 747 is so big that the challenges are magnified."

Aerospace Notebook is a weekly feature by P-I aerospace reporter James Wallace. He can be reached at jameswallace@seattlepi.com or 206-448-8040.