Boeing 787 Dreamliner planes in production found with wing cracks

Boeing's much-delayed 787 Dreamliner has hit another production snafu.

Hairline cracks have been discovered in the wings of some 787s that are being built. The Chicago-based manufacturer said none of the 122 jets already flown by airlines around the world are affected.

"We are confident that the condition does not exist in the in-service fleet," Boeing spokesman Doug Alder said in an email. "We understand the issue, what must be done to correct it and are completing inspections of potentially affected airplanes."

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The production problem was first reported by The Wall Street Journal.

Boeing said that roughly 40 airplanes might be affected and that it will take one to two weeks to inspect each plane and fix any cracks found on shear ties on a wing rib. A shear tie is an attachment fitting. It is part of the rib — and connects the rib to the wing skin. The company would not give an overall timeframe to inspect all of the wings.

The wings are produced by Japan's Mitsubishi Heavy Industries and then flown to the U.S. to be assembled with other parts of the plane. Inspections are taking place at Boeing's plants in Everett, Wash., and Charleston, S.C., and at the Mitsubishi's plant.

While there might be short-term delivery delays, Alder said Boeing doesn't expect this problem to impact its total year deliveries: 110 new Dreamliners in 2014.

To save on development and production costs, Boeing outsourced major sections of the 787 to other companies. That ultimately ended up costing the company dearly as delays mounted. With suppliers spread out around the globe, Boeing wasn't able to oversee each part of production and fix problems quickly when they arose.

Shares of The Boeing Co. fell 32 cents to $128.54 in regular trading and declined 54 cents in after-hours trading.