And then there's the matter of cracks in airplane wings. But they don't tell you they are there. Down in that wing, wedged among sheets of carbon fiber as thin as a fingernail, where it would be impossible to spot an opening even with a microscope, a gap appears. Maybe air was trapped during manufacturing. Maybe the resin cured weird. Maybe a couple of pieces that should have been combined … weren't. Not quite. From the outside? Perfect. Smooth. Shiny, even. Inside? A problem that might arise 35,000 feet up. Seeing those hidden weaknesses before they have become all-too-evident disasters? That's what composite testing is. And, I've got to say, the tech is pretty freaky.