Location and identification of faults in multilayer elastic materials by ultrasound is aided by a physically based parametrization of the input, scattered, and detected fields. When the transducer input is beam shaped, the beam‐to‐mode conversion in the unflawed layered environment suggests a ‘‘good’’ parametrization in terms of a self‐consistent hybrid beam‐mode format. The scattered field produced by interaction of this beam‐mode field with a fault zone should then be parametrized in a similar manner. This strategy guides the present investigation of scattering from a weak bonding flaw in a multilayer aluminum plate. The horizontal and vertical displacements excited by a high‐frequency two‐dimensional dilatational (P) Gaussian input beam have previously been tracked through successive cross sections in the perfectly bonded material [Lu et al., J. Acoust. Soc. Am. 87, 42–53 (1990)]. This input is now allowed to interact with a smoothly tapered weak‐bond zone of moderate length. The equivalent forcing ter...