Restatement (Third) of Torts: Products Liability § 3 cmt. b:
Although the rules in this Section, for the reasons just stated, most often apply to manufacturing defects, occasionally a product design causes the product to malfunction in a manner identical to that which would ordinarily be caused by a manufacturing defect. Thus, an aircraft may inadvertently be designed in such a way that, in new condition and while flying within its intended performance parameters, the wings suddenly and unexpectedly fall off, causing harm.
Although the “inadvertently” is good—suggesting as it does that someone in a moment of weakness got careless and accidentally designed an aircraft—the part that cracks me up is the “causing harm.”