No verdict yet on completed tests to 787 wing repairs

Boeing has finished torture-testing the side-of-body repair to the 787 Dreamliner responsible for the most recent delay in its maiden flight. But for now, the company is mum on the results which some sources have reported as successful.
Written by John Dodge, Contributor on

A top Boeing executive said on his blog yesterday that the company has completed a critical test on a "side- of-body" repair to the 787 Dreamliner that has delayed its first flight by six months.

However, Boeing says it needs another 10 days to analyze the results before it clears the 787 for first flight,  which company officials have promised will be before the end of the year and just before Christmas or as early as Dec. 14.  Successful static tests to a stationary 787 airframe that sits in a rack and subjected to extreme forces far in excess of what would be encountered in flight must be run to validate the repair (see photo and video below).

Boeing 787 static airframe. Photo Credit: Boeing/Randy's Journal blog

"The airplane did go to limit load as intended, but we’re not going to characterize the results in any way until the analysis is complete. As you’re aware, a successful result is needed to clear the Dreamliner for first flight before the end of the year," vice of marketing for Boeing Commercial Airplanes Randy Tinseth wrote Monday in his blog, Randy's Journal.

Tinseth's comments means we are unlikely to get a date until Boeing gives the official thumbs up or down on the test results. That won't happen at least until the middle of next week, but Flightglobal blogger Jon Ostrower just reported it could be as soon as Dec. 14 (it seems out of corporate character to make the media, dignitaries and Boeing employees trek to Seattle just before the biggest U.S. holiday of the year).

The "side of body" fix required the addition of 34 stringers  fittings in an area where the wing meets the wingbox, a large structure comprising the 787's belly on the center bottom of the fuselage. So far, two test planes and the static airframe have been repaired.

Boeing executives have been confidently predicting the 787 will fly before year's end, but Tinseth's comment could be interpreted as a potential out should the results be less than satisfactory. On the other hand, why would Tinseth write about the tests if there were any doubt? Taken at face value, Boeing is being cautious with the 787 which has been beset by more than two years of delays and broken first flight dates.

While Boeing exercises caution about the results, Flightglobal blogger Jay Ostrower is reporting the tests flexed the wings 18 feet and no delamination in the composites that occurred in previous tests was found. The so-called load limit test nicknamed 2C placed 100% more force on the wings than the plan is projected to ever encounter in flight.

Watch the year-old video below of Boeing breaking the wing by placing in excess of 150% per cent of the force it would encounter in flight. It was a test like this in June that presumably discovered an overly-stressed area that contradicted Boeing's computer models and necessitated the side-of-body repair.

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This post was originally published on Smartplanet.com

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