It was revealed the defect was due to Spirit AeroSystems' improper installation of the fittings, the suit contended. Spirit AeroSystems "belatedly confirmed the tail fin fittings defect" after Boeing revealed it. When those issues came to light, the suit said, they led Spirit AeroSystems' stock to decline, and the plaintiffs suffered "significant losses and damages" due to the company's "false and/or misleading statements and/or material omissions." In the Alaska Airlines case, investigators will look into whether the blown-out door plug was a result of the Spirit AeroSystems manufacturing process or the Boeing assembly line.