The structural flaw that has grounded Boeing's 787 Dreamliner originates with Boeing's engineering and will likely add months of delay to the new jet program, an executive with key partner Mitsubishi Heavy Industries said Wednesday.

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The structural flaw that has grounded Boeing’s 787 Dreamliner will likely add months of delay to the new jet program, an executive with one of Boeing’s key Japanese partners said Wednesday.

Kiyotaka Ichimaru, an executive at the aerospace division of Mitsubishi Heavy Industries (MHI), which makes the 787’s carbon-fiber composite plastic wings in Japan, also said the problem announced Tuesday stems from Boeing’s engineering design, not MHI’s — an assessment confirmed by Boeing.

Ichimaru said MHI engineers are drawing upon the experience of similar problems on the Mitsubishi F-2 jet-fighter program in working with Boeing to fix the problem: a need for reinforcement of the structure where the Dreamliner’s wing is joined to the load-bearing box at the center of the fuselage.

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Ichimaru doesn’t believe the structural flaw represents a fundamental safety concern.

“We are not seeing this as a very, very serious issue,” he said in an interview Wednesday.

It’s the business consequences of the new delay that may be more damaging. Boeing shares fell another 5.8 percent Wednesday after losing 6.5 percent Tuesday, when the company unexpectedly said it would postpone the Dreamliner’s scheduled first flight. The company’s stock has lost $5.58 in two days, shrinking its total market value by $4 billion.

Working on schedule

Ichimaru said he couldn’t predict precisely how much time it will take to correct the problem. But given that the Boeing executives in charge of the program said Tuesday that working out the new flight schedule will take several weeks, he said, “It may be a few months, probably, for the time we need to fix it.

“We are eagerly looking for the result of Boeing’s estimate for the changes in the flight schedule,” he said.

The costs of the fix and of any production delays at the supplier partners can only be worked out after the fix is decided upon and a new schedule is set, Ichimaru said.

MHI learned of the concerns at Boeing after a test inside the Everett factory in late May that entails bending the wings of a 787.

Last month’s test

This test produced delamination of the composite material — separation of the carbon-fiber layers — in small areas where the MHI wings join the structural box embedded in the center fuselage made by Fuji Heavy Industries (FHI) of Japan.

The test was done on a plane designated for stress testing on the ground, not for flight tests.

The upper wing-skin panel has 17 composite plastic stringers, or longitudinal stiffeners, that are baked onto the wing panel in the high-pressure oven that hardens the composite plastic material.

The stress points occurred on each wing where these stringers meet the FHI fuselage structure that bears the weight of the wings.

“This trouble is in the Boeing design,” Ichimaru said. “That is admitted by Boeing.”

Boeing spokeswoman Yvonne Leach agreed that MHI had no responsibility for the design problem. And though FHI did contribute to the design, she said, it’s Boeing that is responsible for the interfaces between the sections made by different partners.

“It’s our engineers that designed this interface,” Leach said. “Boeing is responsible for the overall design and the integration of the sections and takes responsibility for both.”

The company offered no new details about the structural problem Wednesday.

Ichimaru said MHI is helping Boeing work on the problem because it has experience with a similar issue on its F-2 fighter program.

The F-2 is a version of the Lockheed Martin F-16 built by Mitsubishi for the Japanese defense forces. It, too, has a composite plastic wing, though it’s a much smaller airplane and of a very different shape than a jetliner.

“We experienced the same type of reinforcement (requirement) during the F-2 development,” Ichimaru said. “We are now trying to contribute to Boeing by utilizing our experience.”

Leach said Boeing will work out the best engineering solution, then fabricate the pieces and confirm that the fix is good enough by testing it on the ground-test airplane in the factory. Once satisfied, Boeing will then come up with a plan for the mechanics to do the modification on all the airplanes, including Dreamliner No. 1.

All that could take some time.

Effect on suppliers

The delay has a ripple effect on 787 suppliers, who cannot send new plane sections to Everett until those already there are cleared out of the way.

Ichimaru said the new delay could mean “some slowdown in the near future” inside the MHI production facilities in Nagoya, Japan.

How much of a slowdown depends on the design changes Boeing comes up with, he said. MHI will then analyze the impact on its work force, its schedule and its production facilities, as well as the associated costs.

“Those business issues will come after,” Ichimaru said.

That’s when Boeing will have to count the cost, including likely payments to suppliers like MHI as well as to customers.

Dominic Gates: 206-464-2963 or

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