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 …”