A phased array probe system and method for testing a spot-weld on a structure. The phased array probe includes a plurality of transducers and may include a flexible delay line. The phased array probe is positioned at a first position on the structure relative to the spot-weld. First ultrasonic signals are generated to and received from the spot-weld using at least one first transducer of the phased array probe. The first received ultrasonic signals are processed to determine a second optimized position on the structure relative to the spot-weld. Second ultrasonic signals are generated at the second optimized position to and received from the spot-weld using second transducers of the phased array probe. The second received ultrasonic signals are processed to determine a feature dimension of the spot-weld.