Take this broken wing

I wanted to briefly talk the successful destructive testing over the weekend of a 787 Dreamliner composite wing box, and point you to a fascinating video of the milestone.

The test is part of the certification process – but doesn’t literally require us to “destroy” the wing box. However we did take it to the breaking point, as you can see in the photo – and that point was indeed beyond the required 150% of the highest stress the jet could experience in operation.


Click on the image to go to a video of the 787 wing box destructive testing and to see some other images.

Testing to destruction means putting the structure through pressures higher than its intended design, to a point where it breaks in a critical location. It’s a way to evaluate how the structure – in this case the wing box – behaves under high stress. If in fact, as was the case here, the structure goes beyond what’s required for the design, it speaks well for the integrity and safety of that element of the airplane.

The wing box, by the way, is the structure that connects the wing to the fuselage and supports a number of key systems including landing gear and engines. In this test we used a section that is about 50 feet (15.2 meters) long and attached more than 1,700 sensors, or strain gauges on the wing box for the test.

Now, you may recall the dramatic video of the last time Boeing Commercial Airplanes conducted a wing-break test. That was back in 1995 for the 777. As the 787 primary wing structure is the first on a Boeing commercial jetliner to be made out of composites, the test, and the end result was a bit different.

Structural testing continues on two full-scale 787s as part of the ongoing certification. And the next tests for the Dreamliner wing will be done on a full-scale airplane.

As the song says, “take these broken wings and learn to fly …”

Comments (7)

Paulo M (Johannesburg, RSA):

My friend, that is an excellent specimen, and, that is an excellent song. You know, taking all these composites 'well beyond' the 150% threshold is breaking a lot of myths and fairy tales out there. It's music to my ears!

BWJones (SLC, Utah):

So, will it result in the two wings actually touching as alleged? If so, that'll be an interesting test rig...

Patrick McArdle (Seattle, Wash., USA):

Watching that video, and seeing the ultimate test results, gives us additional confidence in our engineering. Our new materials performed exactly as predicted. As we move the prototype Dreamliners into our Flight Test program, we will continue to test them most rigorously, always to our highest standards.

The Boeing Company has a long history of delivering safe, reliable, economical airplanes to the flying public, and test results such as these give us additional pride in our decades-long tradition of excellence. Great work, Everett, and I look forward to my test flights on our magnificent machines.

Freddie M (Storrs, CT):

What a difference over a decade can make! I am relieved to read about this overwhelming success with the 787. The specifications astonished me as well. Good luck with the test on the full-scale Boeing! Your quote could never have been any more appropriate.

Yvonne Fang (Tianjin, China) (Tianjin, China):

Hah, I like the last sentence.

Norman (Long Beach, California, United States):

I just saw the video, the wing test looks very good as it exceeds 150% of it's maximum prescribed strength, the test kind of reminds me of the 777 wing bend test. This should definitely serve as physical proof that composite materials are as reliable and as tough as aluminum. Very good news from the 787 project.

Bob Fitts (Kailua-Kona, Hawaii):

Aloha Boeing,

Really disappointed at the way the 787 and 747-8 have gone. I'm a minor investor, and trying to cheer for you......been pretty difficult the last year. I really would like to see the 747-8 do well, but it appears to be a bit too little too late. I am a very frequent flyer, and absolutely love the 777. My favorite of all, however, I think it's possible the 747-8 could out do it if the company could get this thing off the ground, and get rid of some of the ridiculous mistakes that are really hurting the company. Are the workers taking any responsibility for this fastener fiasco???? Come on Boeing, you're better than this!!!

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