Lockheed Martin Potentially Mixed Up Structural Fasteners in Most F-35s

Hundreds of F-35s could have the wrong fasteners in “critical areas,” according to the Defense Contract Management Agency. But F-35 builder Lockheed Martin says the problem may not need to be fixed. “All aircraft produced prior to discovery of this [problem] have titanium fasteners incorrectly installed in locations where the design calls for Inconel,” the F-35 Joint Program Office said in an email. Inconel is an alloy of nickel and chromium, and is supposed to be used in places where greater strength and corrosion resistance are required, while the titanium bolts are used in areas where its strength and lightness helps reduce weight. Titanium, however, has a lower shear strength than Inconel. Read more ►