The present invention provides a bypass duct and boss assembly comprising: a bypass duct having an exterior surface, an interior surface, an edge surface, an inner bonding surface, and a side wall surface, wherein the edge surface further defines an aperture; a boss having a lip surface, a side surface, and a face surface, wherein the boss is disposed within the aperture of the bypass duct such that the lip surface of the boss forms matched bonding surfaces with a portion of the exterior surface of the bypass duct, and such that the side surface of the boss forms matched bonding surfaces with the edge surface of the bypass duct; a patch having a patch edge, a patch inner surface, and a patch outer surface, wherein the patch is disposed such that the patch inner surface forms matched bonding surfaces with the inner bonding surface of the bypass duct and the face surface of the boss, and such that the patch edge forms matched bonding surfaces with the side wall surface of the bypass duct, the patch further having a thickness and curvature, and the patch further disposed such that the patch outer surface forms a continuous curvature with the interior surface of the bypass duct; and adhesive disposed between the matched bonding surfaces so as to firmly bond the bypass duct, boss, and patch into the assembly.