UPDATED: Boeing says wing box fix won't affect first flight

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James Wallace on Aerospace

« Updated! 787 facing another delay - Steve Hazy | Main | WSJ says 787 to be another 6 months late »

UPDATED: Boeing says wing box fix won't affect first flight

Boeing just issued the following statement about the center wing box problem on the 787.

It is a normal part of the development of a new airplane to discover
need for improvements, and that is what we are experiencing on the 787.
The robust test process in place on the 787 program has confirmed the
majority of our designs but we have found the need for some
improvements.

The center wing box issue has been addressed. The fix is being installed
on Airplanes 1-6 in the Everett factory. Installations have begun on the
four airplanes currently in Final Assembly. All airplanes after
Airplane 7 will have the solution incorporated from the beginning.

The fundamental technologies being used on the 787 are proving to be
reliable and effective. The material choices and manufacturing
techniques for the airplane are sound.

Boeing is working its normal processes for developing a new airplane.
The test process is working when issues are discovered and we are
reacting appropriately by implementing normal design validation and
fixes when we find issues.

Also, Jon Ostrower of Flight International, who posts under flightblogger, has a detailed account of the wing box problem, based on information from his sources.

He writes that there is the potential for premature buckling in the structural spars in the massive wing box, in part because of the 787 weight gains.
Stiffeners will be needed to fix the problem, he reports.

During the initial development phase of the center wing box, the structural spars were designed to the appropriate width to support the required structural loads.

The original design for the center wing box was changed when the weight of the Dreamliner began to increase. The structural spars, which are made of composite, were reduced in width as a weight saving measure.

Boeing and Fuji Heavy Industries manufactured composite test pieces to demonstrate the structural capabilities of the spars. Findings indicated that the composite spars were buckling prematurely compared to metal spars of the same width.

This is the story I filed Thursday about ILFC's Steven Udvar-Hazy's comments about problems with the center wing box and Boeing's response.

UPDATE: Boeing tells me the wing box issue WILL NOT affect power on or first flight, contradicting what Hazy said.

But that does not mean those major milestones will not be further delayed for other reasons.

Here is my report, which will be posted on the P-I Web site shortly:

By James Wallace
P-I aerospace reporter

In trying to shave pounds on the overweight 787 Dreamliner, The Boeing Co. ended up with a costly structural issue � but one it says is being fixed.

A day after published reports that a key 787 customer said the program faced more delays of as much as six months because of structural problems in a critical area of the wings, Boeing said the issue is being resolved.

The problem involves the center wing box, which is where the wings are attached to the fuselage. It also holds fuel.

Engineers have figured out a fix and it will be accomplished on six test flight planes by Boeing workers at the Everett plant, the company said.

Starting with the first planes that are delivered to customers, Boeing said, the redesign will be incorporated into the center wing box before that structure leaves the Fuji factory in Japan.

The wing box issue, Boeing said, will not affect two critical 787 milestones � "power on" and first flight.

But Boeing will not say if those two events may be delayed by production and supply chain issues that have slowed work on the first 787 at the Everett plant and resulted in delays that already stretch about nine months.

The wing box issue, sources confirmed, involves the spars that provide strength to the massive structure, which measures some 19 feet wide and 17.5 feet long. The skin and spars are composite.

Boeing's own 787 weight-saving efforts caused a potential problem, sources said.

Boeing has acknowledged before that the 787 is overweight. Parts have been redesigned to save weight, and different and lighter materials have been used in some cases, according to Boeing.

But in trying to shave weight from the huge wing box, the width of the spars was reduced. Subsequent testing showed the thinner spars could possible buckle under severe loads, the sources said, confirming what was first reported Thursday by Jon Ostrower of Flight International magazine, who posts as "Flightblogger.''

The spars must now be "beefed up'' the sources said.

Boeing would not comment on whether the wing box problems involved the spar. But the company did release a statement Thursday that said the center wing box issue is being fixed.

"It is a normal part of the development of a new airplane to discover need for improvements, and that is what we are experiencing on the 787,'' the statement said. "The robust test process in place on the 787 program has confirmed the majority of our designs but we have found the need for some improvements.

"The center wing box issue has been addressed. The fix is being installed on airplanes 1-6 in the Everett factory. Installations have begun on the four airplanes currently in final assembly. All airplanes after airplane 7 will have the solution incorporated from the beginning.''

The first two of six test flight planes are in final assembly at the Everett plant, as well as two planes that will be used for static and fatigue testing on the ground. It's not clear how much work is involved in making the necessary fixes to the center wing box in those planes in final assembly.

But Yvonne Leach, chief 787 spokeswoman, said the wing box issue "is not a pacing item'' for either power on or first flight.

Boeing is expected to update media and industry analysts about the status of the 787 program in early April, after it completes an on-going review with its partners. That overall program assessment includes the flight test and delivery schedules.

Boeing has already announced two delays for the 787 totaling about nine months. In its last program update in January, Boeing said it hoped to have "power on" around the end of the first quarter and first flight by the end of June or early July. Deliveries would begin in early 2009, Boeing said at the time.

First flight was to have originally occurred around the end of August 2007, with the first plane delivered to launch customer All Nippon Airways of Japan in May of this year.

Some industry analysts are expecting Boeing to announce yet another delay when executives give the 787 update next month.

Earlier this week, Steven Udvar-Hazy, chairman of International Lease Finance Corp. told a JPMorgan aviation conference in New York that he believes the 787 will be delayed as much as six more months. He cited the structural issue with the center wing box as driving the delay. Hazy told the conference "power on" and first flight are likely to be further delayed, with first deliveries slipping to the end of the third quarter of 2009.

Boeing has nearly 900 orders for the 787, which will be the first large commercial jetliner with a composite airframe.

In its statement Thursday, Boeing said the "fundamental technologies being used on the 787 are proving to be reliable and effective. The material choices and manufacturing techniques for the airplane are sound.''

ILFC has ordered 74 Dreamliners and Hazy has said he is in talks with Boeing for 26 more.

In an e-mailed statement Thursday to Commercial Aviation Online, Hazy said the 787 "will turn out to be a good aircraft.''

He added that "ILFC plans to keep its 74 orders firm
and we are having a careful review later this year to see if ILFC needs to order more 787s to meet airline customer lease demand.''

Posted by at March 20, 2008 10:56 a.m.
Categories: 787 Dreamliner, Boeing

Comments

#110041

Posted by unregistered user at 3/20/08 11:39 a.m.

Boeings inexperience of using composites has already started to show.

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