The “Assembly” Product Defect Case

Under New York law, there are three product defect theories:  (a) design defect; (b) manufacturing (or “assembly”) defect; and (c) failure to adequately warn.   In order to survive a Daubert [1]   challenge (when your case is in federal court), your expert must be able to set forth in detail not only that a product failed, but why it failed, and what caused it to fail.

In this newsletter, I’ll discuss the manufacturing defect case.  In a manufacturing defect case, your expert need not prove that the entire line of products was defectively designed.  Rather, your expert must be able to show that “the harm arises from the product’s failure to perform in the intended manner due to some flaw in the fabrication process.” [2]   Your expert must show that “the product was not built to specifications or that the product, as constructed, deviated from any such specifications or design.” [3]   That is,  the particular product involved in the loss “differs from the manufacturer’s own internal quality standards.”[4]   In layman’s terms, you don’t have to show that all  of the products wer “bad”, only that “one bad apple” came through the manufacturing process with a defect in it.  In a summary judgment motion, the burden is on the defendant initially to prove that the product was not defective. [5]  If the defendant comes forward with this proof, the burden shifts to the plaintiff to set forth competent evidence of a defect in the product.

Fortunately, where the product is so badly damaged that a specific design or manufacturing defect cannot be identified, it may be possible to reach a jury if you can show “the product did not perform as intended and exclude all other causes for the product’s failure that are not attributable to defendant.” [6]  This allows you to get to a jury based solely on “circumstantial” evidence – i.e., without being able to present direct proof of the defect.

Bottom Line:    The “manufacturing defect” case is usually easier to prove than the design defect case, because you are not faulting all of the manufacturer’s products – you are just faulting the one bad apple that came off the assembly line containing a defect.


[1] Daubert v. Dow Chemical, 509 US 579 (1993) which sets forth the criteria for Courts to determine if an expert is qualified to give an opinion at trial.
[2] Denny v. Ford Motor, 87 NY2d 248, 257 n.3 (1995)
[3] Searle v. Suburban Propane, 263 AD2d 335, 340
[4] NY PJI Vol IA 2:120 at 707 (2009)
[5] Rachlin v. Volvo Cars, 289 AD2d 981, 982
[6] Speller v. Sears, 100 NY2d at 41

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